ITU-R Working Party 8B activities
AMCP-WG F WP/2
Aeronautical Mobile Communications Panel
Working Group F
(Lima, 27 March – 4 April 2001)
Agenda Item 2: Review of outcome of ITU Working Parties and Task Groups (8B, 8D, 8F & 1/5)
ITU-R Working Party 8B activities
(Presented by the Secretary)
The present paper contains information on ITU-R Working party 8B activities that may be of interest to AMCP WGF, in particular with regard to WRC-2003 preparation.
Sources of the information are indicated in the body of the paper as applicable. They include:
- WP8B meeting report Geneva (10-18 October 2000);
- SG8 working papers produced by WP8B;
- liaison statements from WP8B to other groups; and
- WP8B document.
The document is in ten parts. ICAO Secretariat comments and proposed action by AMCP WGF are provided for each part.
Part 1 (p.3): Reply from WP8B to liaison statements of Task Group 1/5 on out-of-band emissions of primary radars and protection of safety services from unwanted emissions (ITU-R Document 1-5/64-E)
Part 2 (p.45) Draft revision of Recommendation ITU-R M.589.2 on the "Technical characteristics of methods of data transmission and interference protection for radionavigation services in the frequency bands between 70 and 130 kHz" (ITU-R Document 8/14).
Part 3 (p.64) Preparations for WRC-03 (Attachment 11 to ITU-R Document 8B/49-E - Report of the eighth meeting of Working Party 8B)
Part 4 (p.78) Liaison statement to WP 1A on a "Study of interference from short-range radio devices using ultra wideband (UWB) technology operating in the 1 - 6 GHz bands (ITU-R Document 1A/28-E).
Part 5 (p.82) Draft revision to question ITU-R 216-1/8 on the "Compatibility of radionavigation, Earth exploration-satellite (active), Space research (active) and radiolocation services operating in the 5350 - 5650 MHz and 2900 - 3100 MHz band." (ITU-R Document SG8/16)
Part 6 (p.85) Preliminary draft new recommendation ITU-R M. – Characteristics of and protection criteria for radiolocation aeronautical radionaviafation and meteorological radars operating in the frequency bands between 5 250 and 5 850 MHz (ITU-R Document 7C/42-E)
Part 7 (p.98) Revised work plan for working party 8B for completing urgent studies under question ITU-R 216/8 (Attachment 5 to ITU-R Document 8B/49-E - Report of the eighth meeting of Working Party 8B)
Part 8 (p.112) Liaison statements to working party 8F on interference from IMT-2000 and other services (including the radiodetermination service) (ITU-R Document 8F/169-E)
Part 9 (p.121) Response to liaison statement from working party 7C on the "sharing between the Earth exploration-satellite service (passive) and the ARNS in the band 4200 - 4400 MHz (ITU-R Document 7C/53E).
Part 10 (p.125) Liaison statement to working party 8D concerning the protection of radar in the band 1215 - 1300 MHz (ITU-R Document 8D/49-E).
Part 1
Reply from WP8B to liaison statements of Task Group 1/5 on out-of-band emissions of primary radars and protection of safety services from unwanted emissions (ITU-R Document 1-5/64-E)
ICAO Secretariat comments:
This ITU-R TG1/5 document is based on Documents 8B/TEMP/1, 10, 11 and 12, produced by the October 2000 meeting of WP8B. It contains various comments from WP8B on liaison statements from Task Group 1/5 on the out-of-band emissions and protection of radar.
1. Attachment 1 to Doc 1-5/64-E provides two techniques for the measurement of unwanted emissions of radar systems that should be used to assess compliance with Appendix S3 (Section II) of the radio regulations.
AMCP WGF ACTION: Review these proposals
2. Attachment 2 to Doc 1-5/64-E contains comments from WP8B to TG 1/5 concerning a preliminary draft new recommendation on the "Protection of safety services from unwanted emissions" . This important draft new recommendation proposes various guidelines to be observed when protecting (aeronautical) safety services from interference from unwanted emissions. The output from TG 1/5 is awaited with a view to secure adequate treatment of the aviation's requirements for the protection of aeronautical services.
AMCP WGF ACTION: Review the PDNR
3. Attachment 3 to Doc 1-5/64-E contains a draft revision of Question ITU-R 202-1/8 ("Unwanted emissions of primary radar systems"). This revision intends to include in the studies of unwanted emissions of primary radar systems references to Recommendation ITU-R F.1097 and ITU-R F.1190 on mitigation option to enhance compatibility between radar and digital radio relay systems and protection criteria for digital radio relay systems to ensure compatibility with radar. Also references to the revised (at WRC 2000) appendix S3 of the Radio Regulations (Table of maximum spurious emission power levels) and Recommendation ITU-R SM.329 are included as well as references to Recommendations ITU-R M.1177 and M.1314 on the techniques for measurement of unwanted emissions from radar systems and the reduction of spurious emission of radar systems are incorporated. The goal is to determine the unwanted emission levels from existing state-of-the-art radar systems and the levels of unwanted emission that can be achieved using various mitigation options. As a result of the widening of the scope of the study question, it is necessary to ensure that mitigation options that might be considered for implementation are realistic and safe and do not cause an unrealistic burden on radar system operators.
AMCP WGF ACTION: Review the revised question
|[pic] |INTERNATIONAL TELECOMMUNICATION UNION | |
| |RADIOCOMMUNICATION |Document 1-5/64-E |
| |STUDY GROUPS |24 October 2000 |
| | |English only |
Source: Document 8B/TEMP/12
Working Party 8B
REPLY TO LIAISON STATEMENTS OF TASK GROUP 1/5
1 INTRODUCTION
Working Party 8B has received several liaison statements from Task Group 1/5 since our last meeting in February 1999*. At the February 1999 meeting of Working Party 8B, the Chairman of Working Party 8B established a Radar Correspondence Group recognizing the accelerated meeting schedule of Task Group 1/5, and urged their participation in Task Group 1/5 meetings.
At the request of the Chairman of Task Group 1/5, members of the Radar Correspondence Group attending the Task Group 1/5 were asked to form a Joint Radar Correspondence Group (JRCG) involving participation of Working Party 8B and Task Group 1/5 members. Recognizing the importance of reaching agreement on matters associated with emission masks and measurements procedures for primary radar systems, the JRCG was formally established. Pursuant to the goals of the JRCG, a formal meeting of the JRCG was held in June 2000 at the Maritime and Coastguard Agency, Southampton, United Kingdom, resulting in agreement on out-of-band emission masks (Annex AD) and the boundary between the out-of-band and spurious emissions.
The following are responses of Working Party 8B to the above source documents.
2 Out-of-Band Emissions and Measurement Techniques for Primary Radars
(Document 8B/109)
Working Party 8B has noted Attachment 1, preliminary draft revision of Recommendation ITU-R SM.329-7; Attachment 2, Out-of-Band Emissions Falling into Adjacent Bands; and Attachment 3, Annex [AD], Primary Radars. These attachments have been overtaken by subsequent liaison statements from Task Group 1/5, and will be discussed later.
With respect to comments on Recommendation ITU-R M.1177, Techniques for Measurement of Unwanted Emissions of Radars, Working Party 8B agrees with the views of Task Group 1/5 that additional information is needed to develop measurement capabilities and to apply the measurement techniques. Pursuant to providing the requested information, Working Party 8B, is developing a preliminary draft revision to Recommendation ITU-R M.1177 which is contained in Attachment 1. Also, Working Party 8B, was informed that a demonstration of the Direct Measurement technique contained in Recommendation ITU-R M.1177 was provided by the United States at the JRCG meeting in June 2000.
3 Boundary Between Spurious and Out-of-Band Emissions (Document 8B/110)
Working Party 8B has reviewed the Attachments to the liaison statement. With respect to Attachment 2, Variation of the Boundary Between Out-of-Band and Spurious Emissions, the text in Section 3.3 of Annex 8 of Recommendation ITU-R SM.329-8; should be modified to reflect the agreement reached in the JRCG. Working Party 8B have discussed this matter and propose the following text for Section 3.3:
“3.3 Primary radars in the radiodetermination service
According to further recommends 2.3 of this Recommendation and RR Appendix S3, the spurious emission region generally begins at a frequency separation equal to 250% of the necessary bandwidth, with exceptions for certain kinds of systems, including those with digital or pulsed modulation. However, it is difficult to apply the general boundary concept of 250% of the necessary bandwidth to primary radar stations in the radiodetermination service.
For the case of primary radar systems, the out-of-band emission mask rolls off at 20 dB per decade from the 40 dB bandwidth to the spurious limit specified in Table II of Appendix S3. The detailed definition of the out-of-band/spurious boundary is contained in Annex AD of Recommendation ITU-R SM {OOB}.
In Annex AD (Paragraph 5) the above definition of the boundary is the subject of ongoing ITU studies with a design objective of 40 dB per decade roll-off. These studies should be completed by the Radiocommunication Assembly 2006.”
Working Party 8B is requesting Task Group 1/5 or Study Group 1 to incorporate the proposed changes to Recommendation ITU-R SM.329-8 at the earliest practical date.
On a related subject Working Party 8B has discussed the revision of Appendix S3 with regard to agenda item 1.8.1 of WRC-03, and in particular with regard to the boundary between out-of-band and spurious emissions for primary radars. A proposal for this revision is as follows:
“Revision of Appendix S3
Add at the conclusion of Paragraph 11 as a new sub-paragraph.
For primary radar stations in the radiodetermination service, the boundary between out-of-band and spurious emissions is defined as at the frequency where the out-of-band emission limits defined in Recommendation {PDNR [OOB Annex AD} are equal to the spurious emission limit defined in Table II”.
4 Protection of Safety Services from Unwanted Emissions (Document 8B/114)
Working Party 8B has reviewed the above liaison statement containing a draft new Recommendation (DNR) on the Protection of Safety Services from unwanted emissions. Working Party 8B comments on the DNR are contained in Attachment 2.
5 Liaison Statement to Working Party 8B (Document 8B/118)
Working Party 8B agrees with Task Group 1/5 on the need to further study Out-of-Band emission limits of primary radars in exclusive radiodetermination bands. This subject will be discussed later in this reply in response to a subsequent liaison statement from Task Group 1/5.
With respect to comments of Recommendation ITU-R M.1177, Working Party has responded to the information requested in Document 8B/109. See above discussion. Also, comments from Task Group 1/5 on the correct measurement bandwidth to determine the –20 dB bandwidth, necessary bandwidth, were taken into consideration and appropriate changes were made to Recommendation ITU-R M.1177. See Attachment 1.
Working Party 8B reviewed Attachment 1, Out-of-Band Emissions Falling into Adjacent Allocated Bands, and can support the draft new Recommendation as provided. Attachment 2, Annex [AD], Primary Radars, has been overtaken by a subsequent liaison statements from the JRCG (Document 8B/2(Rev.1) and Document TG 1-5/5), and will be discussed later. Attachment 3, Working Document on the Determination of OOB Emission Masks for Primary Radars, was taken into consideration by the JRCG. Working Party 8B has no comments on Attachment 4, Out-of-Band Emission Measurements. Reference to Recommendation ITU-R M.1177 in Section 3.3 is sufficient.
Attachment 5, Joint TG 1-5/WP-8B Radar Correspondence Group, Work Plan, was taken into consideration by the JRCG.
6 Joint Radar Correspondence Group, Liaison Statement to Working Party 8B
(Document 8B/2(Rev.1))
Working Party 8B has reviewed the liaison statement from the JRCG. Working Party 8B supports Annex [AD], Out-of-Band Emission Limits for Primary Radars, as contained in Document 8B/2(Rev.1) and Document 1-5/5; and urges Task Group 1/5 to approve the Annex without further change. As mentioned earlier, Working Party 8B recognizes the need to further study Out-of-Band emission limits of primary radars in exclusive radiodetermination bands, and understands that further reduction of OOB emissions will enhance compatibility with other services. Pursuant to this study and the stated design objective in Annex [AD], Working Party 8B has approved a revision to Question ITU-R 202-1/8 to include out-of-band emissions, and calls for the completion of the study by the 2006 Radiocommunication Assembly.
The proposed revision is contained in Attachment 3. The findings of the study will be incorporated into a Study Group 8 Recommendation.
Working Party 8B noted that there was a need to complete the definitions of dBpep and dBpp. After some discussion it was concluded that this work should be finalized in TG 1-5.
Attachments: 3
ATTACHMENT 1
(Source : Document 8B/TEMP/10 + Add. 1)
preliminary Draft REVISION of RECOMMENDATION ITU-R M.1177-1*
TECHNIQUES FOR MEASUREMENT OF UNWANTED EMISSIONS
OF RADAR SYSTEMS
(Question ITU-R 202/8)
(1995-1997)
Summary
This Recommendation provides two techniques for the measurement of radiated radar unwanted emissions. It should be used to assess compliance with the spurious emission limits in Appendix S3 (Section II) of the Radio Regulations (RR).The ITU Radiocommunication Assembly,
considering
a) that both fixed and mobile radar stations in the radiodetermination service are widely implemented in bands adjacent to and in harmonic relationship with other services;
b) that stations in other services are vulnerable to interference from radar stations with unwanted emissions with high peak power levels;
c) that many services have adopted or are planning to adopt digital modulation systems which are more susceptible to interference from radar unwanted emissions;
d) that under the conditions stated in a) through c), interference to stations in other services may be caused by a radar station with unwanted emissions with high peak power levels;
e) that RR Appendix S3 specifies the maximum values of spurious emissions from radio transmitters;
f) that techniques to measure radar unwanted emissions to ensure compatibility with other services require the capability to measure levels of the order of 130 dB below the radar fundamental emission,
recommends
1 that measurement techniques as described in Annex 1 be used to provide guidance in quantifying radiated unwanted emission levels from radar stations, over the required frequency ranges set out in Appendix S3 (Section II) of the Radio Regulations;
2 that results of such usage of this Recommendation be reported to ITU-R, in order to determine any limitations in the techniques, e.g. tolerances of measurements and repeatability over the required frequency ranges, so that confidence can be established in the measurement methods.
ANNEX 1
1 Introduction
Techniques have been developed in response to § 1 of Question ITU-R 202/8. Two techniques known as the direct and indirect methods are recommended.
The direct measurement method accurately measures unwanted emissions from radars that are designed in such a way as to preclude measurements at intermediate points within the radar transmitters. Examples include those which use distributed-transmitter arrays built into (or comprising) the antenna structure.
The indirect method separately measures the components of the radar and then combines the results. The recommended split of the radar is to separate the system after the “rotating joint” (Ro-Jo) and thus to measure the transmitter output spectrum at the output port of the Ro-Jo and to combine it with the measured antenna gain characteristics.
Experience with these techniques has yielded repeatability of (2 dB at any given frequency and under the condition of agreed fixed measurement parameters when the spectrum of any particular radar unit is repeatedly measured.
2 Measurement system bandwidth and detector parameters
|IF bandwidth |≤ |( 0.5/T ) for fixed-frequency, non-pulse-coded radars, where T : pulse length. |
| | |(E.g. if radar pulse length is 1 μs, then the measurement IF bandwidth should be ≤ 0.5/(1 μs) ’ 500 kHz.) |
| |≤ |( 0.5/t ) for fixed-frequency, phase-coded pulsed radars, where t : phase-chip length. (E.g. if radar transmits |
| | |26-μs pulses, each pulse consisting of 13 phase coded chips that are 2-μs in length, then the measurement IF |
| | |bandwidth should be ≤ 0.5/(2 μs) ’ 250 kHz.) |
| |≤ |(0.5 B/T )½, for swept-frequency (FM, or chirp) radars, where B : range of frequency sweep during each pulse and |
| | |T : pulse length. (E.g. if radar sweeps (chirps) across frequency range of 1 250 - 1 280 MHz (’ 30 MHz of |
| | |spectrum) during each pulse, and if the pulse length is 10 μs, then the measurement IF bandwidth should be: |
| | |≤ 0.5((30 MHz)/(10 μs))½ ’ 0.5 ≈ 0.87 MHz.) |
| | |< (1/T) for multi-pulsemode (multi-mode) radars. For multi-mode radars, the effective value of T is determined |
| | |empirically from observations of the multi-mode radar emission. The empirical observation is performed as |
| | |follows: The measurement system receiver is tuned to one of the fundamental frequencies of the multi-mode radar |
| | |(if the radar frequency-hops), or is tuned to a frequency within the chirp range of the radar, if the radar uses |
| | |pulse compression techniques in its transmission. The measurement system IF bandwidth is set to the widest |
| | |available value, and the received power level from the radar in this bandwidth is noted. The measurement |
| | |bandwidth is then progressively narrowed, and the received power level is recorded as a function of the |
| | |increasingly narrow bandwidths. The end result is a graph or table showing measured power as a function of |
| | |measurement system IF bandwidth. The multi-mode radar's effective emission bandwidth will be the narrowest |
| | |bandwidth that allows the full power level (or within 5 dB of the full power level) into the measurement system |
| | |receiver. The measurement system IF bandwidth should be less than this bandwidth. |
|Video bandwidth | |( Measurement IF bandwidth |
|Detector: | |positive peak |
3 Direct method
The direct method described below can be used to measure unwanted emissions (out-of-band and spurious) from radar systems, and has been used to measure the emission characteristics of radar systems operating at frequencies up to 24 GHz, transmitter output powers of several megawatts, and effective isotropically radiated power (e.i.r.p.) levels in the gigawatt range. This direct method may also be carried out in an anechoic chamber.
3.1 Measurement hardware and software
A block diagram of the type of measurement system required for this method is shown in Fig. 1. The first element to be considered in the system is the receive antenna.
The receive antenna should have a broadband frequency response, at least as wide as the frequency range to be measured. A high-gain response (as achieved with a parabolic reflector) is usually also desirable. The high gain value permits greater dynamic range in the measurement; the narrow antenna beamwidth provides discrimination against other signals in the area; the narrow beamwidth minimizes problems with multipath propagation from the radar under measurement; and spectrum data collected with a parabolic antenna require a minimum of post-measurement correction, as discussed in the next paragraph. The antenna feed polarization is selected to maximize response to the radar signal. Circular polarization of the feed is a good choice for cases in which the radar polarization is not known a priori. The antenna polarization may be tested by rotating the feed (if linear polarization is used) or by exchanging left and right-hand polarized feeds, if circular polarization is being used.
Corrections for variable antenna gain as a function of frequency should be considered. Antenna gain levels are usually specified relative to that of a theoretically perfect isotropic antenna, in units of dBi. The effective aperture of an isotropic antenna decreases as -20log(f), where f is the frequency being measured. This means that, if the measurement antenna has a constant effective aperture (that is, has an isotropic gain that increases as 20log(f)), no corrections for variable antenna gain need be performed. This requirement is met by a theoretically perfect parabolic reflector antenna, and is one of the reasons that such an antenna is preferred for a broadband radar spectrum measurement. Conversely, to the extent to which the gain of the measurement antenna deviates from a 20log(f) curve (including a less-than-ideal parabolic antenna), the resulting measurements must be corrected for such deviation.
The cable connecting the measurement antenna to the measurement system should also be considered. A length of low-loss radio frequency (RF) cable (which will vary depending upon the circumstances of measurement system geometry at each radar site) connects the antenna to the RF front-end of the measurement system. As losses in this piece of line attenuate the received radar signal, it is desirable to make this line length as short, and as low-loss, as possible.
[pic]
The RF front-end is one of the most critical parts of the entire measurement system. It performs three vital functions. The first is control and extension of measurement system dynamic range through the use of variable RF attenuation. The second is bandpass filtering (preselection) to prevent overload of amplifiers by high-amplitude signals that are not at the tuned frequency of the measurement system. The third is low-noise preamplification to provide the maximum sensitivity to emissions that may be as much as 130 dB below the peak measured level at the radar fundamental. Each of these sections in the RF front end is considered below.
The RF attenuator is the first element in the front-end. It provides variable attenuation (e.g. 0-70 dB) in fixed increments (e.g. 10 dB/attenuator step). Use of this attenuator during the measurement extends the instantaneous dynamic range of the measurement system by the maximum amount of attenuation available (e.g. 70 dB for a 0-70 dB attenuator). The key to using this attenuator effectively in a radar measurement is to tune the measurement system in fixed-frequency increments (e.g. 1 MHz), called steps, rather than to sweep across the spectrum, as is more conventionally done with manually controlled spectrum analysers. At each fixed-frequency step, the attenuator is adjusted to keep the radar peak power within the dynamic range of the other elements in the measurement system (often the front-end amplifier and the spectrum analyser log amplifier are the limiting elements). With the front-end RF attenuator properly adjusted at each step, a measurement of the radar power at that frequency is performed. In this way, a nominal 60 dB dynamic range for the measurement system is extended by as much as 70 dB, to a total resulting dynamic range of 130 dB. In principle, this attenuator and the stepped-frequency measurement algorithm that it necessitates could be manually controlled, but in practice, control of the frequency-stepping and the attenuator settings via computer is more efficient and more practical.
The next element in the front end, the tunable bandpass filter preselector is necessary because of the need to measure low-power spurious emission levels at frequencies that are adjacent to much higher-level fundamental emissions. For example, it may be necessary to measure spurious emissions from an air traffic control radar at 2 900 MHz that are at a level of –120 dBm in the measurement circuitry, while the fundamental emission level is at +10 dBm and is only 150 MHz away in frequency (at 2 750 MHz). The measurement system requires an unattenuated low-noise amplifier (LNA) to measure the spurious emission at 2 900 MHz, but the amplifier will be overloaded (and thus gain-compressed) if it is exposed to the unattenuated fundamental emission at 2 750 MHz. For this reason, attenuation that has frequency-dependence is required in the front-end at a position before the LNA input. In practice, this tunable bandpass filtering is effectively provided by varactor technology (below 500 MHz) and by yttrium-iron-garnet (YIG) technology (above 500 MHz). The applicable filters may be procured commercially, and should be designed to automatically track the tuned frequency of the measurement system.The final element in the RF front-end is an LNA. An LNA installed as the next element in the signal path after the preselector. The low-noise input characteristic of the LNA provides high sensitivity to low-amplitude spurious radar emissions, and its gain overdrives the noise figure of the rest of the measurement system (e.g. a length of transmission line and a spectrum analyser).
The sensitivity and dynamic range of the measurement system are optimized by proper selection of LNA gain and noise figure characteristics. It is desirable to minimize noise figure while providing enough gain to accommodate all measurement circuitry after the LNA (essentially the RF line loss after the front end, plus the noise figure of the spectrum analyser circuitry). Ideally, the sum of the LNA gain and noise figure (which is the excess noise produced by the LNA with a 50-ohm termination on its input) should be approximately equal to the noise figure of the remaining measurement system. For example, assume that the spectrum analyser noise figure is 25 dB and the RF line loss between the RF front end and the analyser is 5 dB. Thus the front-end LNA must accommodate a total noise figure of 30 dB. The sum of the LNA gain and noise figure should
therefore be approximately 30 dB in this example. A combination for such an LNA would be 3 dB noise figure and 27 dB gain.
Typical spectrum analyser noise figures are 25-45 dB (varying as a function of frequency), and transmission line losses may typically be 5-10 dB, depending upon the quality and the length of the line. As a result of variation in measurement system noise figure as a function of frequency, a variety of LNAs used in frequency octaves (e.g. 1-2 GHz, 2-4 GHz, 4-8 GHz, 8-18 GHz, 18-26 GHz, and 26-40 GHz) may be required. Each LNA can be optimized for gain and noise figure within each frequency octave. This also helps match LNAs to octave breaks between various YIGs (e.g. 0.5-2 GHz, 2-18 GHz, etc.). Use of an LNA after the preselector (and, if required, a cascaded LNA at the spectrum analyser input) may reduce the overall measurement system noise figure to about 10-15 dB. This noise figure range has been found to be adequate for the measurement of broadband radar emission spectra with dynamic range as high as 130 dB.
Another option for LNA configuration is one in which LNAs are cascaded. The first LNA is placed between two stages within the YIG or varactor bandpass preselector filter. It has low noise figure, but only enough gain to accommodate the insertion loss of the second YIG stage. A second (possibly lower-performance) LNA is placed immediately after the YIG. This option will provide somewhat lower overall system noise figure because the second stage of the YIG is accommodated by the first LNA. However, this option may require more advanced design and engineering modifications to the preselector filter than an administration may deem practical.
A third option for the measurement system LNA configuration, and one not requiring any redesign or retrofitting of the front end preselector filter, is to place a lower-gain LNA in the front end and a second LNA at the spectrum analyser signal input. The first LNA is selected to have very low noise figure and just enough gain to accommodate the RF line loss and the noise figure of the spectrum analyser LNA. The spectrum analyser LNA, in turn, is selected for a gain characteristic that is just adequate to accommodate the spectrum analyser's noise figure in the appropriate frequency range of the radar measurement. This set of two cascaded LNAs may be more easily acquired than a single, extremely high-performance LNA, and will typically be less susceptible to overload because the 1 dB compression points can be expected to be higher than those for individual high-performance LNAs.
The remainder of the RF measurement system is expected to be essentially a commercially available spectrum analyser. Any spectrum analyser which can receive signals over the frequency range of interest, and which can be computer-controlled to perform the stepped-frequency algorithm, can be used. As noted above, the high noise figure of currently available spectrum analysers must be accommodated by low-noise preamplification if the measurement is to achieve the necessary sensitivity to observe most spurious emissions.
The measurement system can be controlled via any computer which has a bus interface (GPIB or equivalent) that is compatible with the computer controller and interface card(s) being used. In terms of memory and speed, modern PC-type computers are quite adequate. The measurement algorithm (providing for frequency stepping of the spectrum analyser and the preselector, and control of the front-end variable attenuator) must be implemented through software. Some commercially available software may approach fulfilment of this need, but it is likely that the measurement organization will need to write at least a portion of their own measurement software. While the development of software requires a significant resource expenditure, practical experience with such systems has shown such an investment to be worthwhile if radar emission measurements are to be performed on a frequent and repeatable basis.
Data may be recorded on the computer's hard drive or on a removable disk. Ideally, a data record is made for every 100-200 measurement steps, so as to keep the size of data files manageable, and to prevent the loss of an excessive amount of data if the measurement system computer or other components should fail during the measurement.
3.2 Measurement system calibration
The measurement system is calibrated by disconnecting the antenna from the rest of the system, and attaching a noise diode to the RF line at that point. A 25 dB excess noise ratio (ENR, where ENR = (effective temperature, oK, of noise diode/ambient temperature, oK)) diode should be more than adequate to perform a satisfactory calibration, assuming that the overall system noise figure is less than 20 dB. The technique is standard Y-factor, with comparative power measurements made across the spectrum, once with the noise diode on and once with the noise diode off.
The noise diode calibration results in a table of noise figure values and gain corrections for the entire spectral range to be measured. The gain corrections may be stored in a look-up table, and are applied to measured data as those data are collected. Appendix II to Annex 1 describes the calibration procedure in more detail.
The measurement antenna is not normally calibrated in the field. Correction factors for the antenna (if any) are applied in post-measurement analysis.
3.3 Measurement procedure
Appendix III to Annex 1 describes the Direct Method in detail; this section provides a summary of the method. In addition to the parameters listed in § 2, the spectrum analyser should be set up as follows:
|Spectrum analyser centre | |lowest frequency to be measured. (E.g. if radar centre frequency is 3 050 MHz, but the spectrum is to be |
|frequency: | |measured across 2 - 6 GHz, then initial spectrum analyser centre frequency would be 2 GHz.) |
|Spectrum analyser frequency span |’ |0 Hz. (Analyser is operated as a time-domain instrument.) |
|Spectrum analyser sweep time |> |radar beam rotation interval. (E.g. if radar rotates at 40 r.p.m., or 1.5 s per rotation, then sweep time |
| | |should be > 1.5 s; 2 s would be a reasonable selection.) |
With the radar antenna beam scanning normally, and with the measurement system set up as described above, the first data point is collected. A data point consists of a pair of numbers: measured power level and the frequency at which the power level was measured. For example, the first data point for the above measurement might be -93 dBm at 2 000 MHz. The data point is collected by monitoring the radar emission at the desired frequency, in a frequency span of 0 Hz, for an interval slightly longer than that of the radar rotation. This time-display of the radar antenna beam rotation will be displayed on the spectrum analyser screen. The highest point on the trace will normally represent the received power when the radar beam was aimed in the direction of the measurement system. That maximum received power value is retrieved (usually by the control computer, although it could be written down manually), corrected for measurement system gain at that frequency, and recorded (usually in a data file on magnetic disk).
The second measurement point is taken by tuning the measurement system to the next frequency to be measured. This frequency is optimally equal to the first measured frequency plus the measurement bandwidth (e.g. if the first measurement was at 2 000 MHz and the measurement
bandwidth were 1 MHz, then the second measured frequency would be 2 001 MHz). At this second frequency, the procedure is repeated: measure the maximum power received during the radar beam rotation interval, correct the value for gain factor(s), and record the resulting data point.
This procedure, which consists of stepping (rather than sweeping) across the spectrum, continues until all of the desired emission spectrum has been measured. The stepping process consists of a series of individual amplitude measurements made at predetermined (fixed-tuned) frequencies across a spectrum band of interest. The measurement system remains tuned to each frequency for a specified measurement interval. The interval is called step-time, or dwell. The dwell time for each step is specified by the measurement system operator, and is normally equal to the IF bandwidth of the measurement system. For example, measurements across 200 MHz of spectrum might use 200 steps at a 1 MHz step interval and a 1 MHz IF bandwidth (ideally paired with a 1 μsec pulse width transmitted by the radar). Computer control of the measurement system is desirable if this process (step, tune, measure, correct for gain, and repeat) is to be performed with efficiency and accuracy.
The stepped technique is required for the insertion of RF attenuation at the front-end of the measurement system as the frequencies approach the centre frequency (and any other peaks) of the radar spectrum. This ability to add attenuation on a frequency-selective basis makes it possible to extend the dynamic range available for the measurement to as much as about 130 dB, if a 0-70 dB RF attenuator is used with a measurement system having 60 dB of instantaneous dynamic range. This is of great benefit in identifying relatively low-power spurious emissions. To achieve the same effect with a swept-frequency measurement, a notch filter could be inserted at the centre frequency of the radar, but there would be no practical way to insert a notch filter for all the other high-amplitude peaks that might occur in the spectrum.
It is important to provide adequate bandpass filtering at the front-end of the measurement system, so that strong off-frequency signal components do not affect the measurement of low-power spurious components.
These measurements may be performed without the radar antenna being rotated, provided that the directions of both maximum fundamental emission and any unwanted emission are known.
4 Indirect method
Figure 2 illustrates a recommended component separation for the Indirect method. In this Indirect method, where unwanted emissions are measured at the Rotating-Joint and then, combined with the antenna characteristics measured separately at distances of 5 m and 30 m with appropriate far-field correction, the procedure is:
a) make measurements of a radar transmitter emissions at the Rotating-Joint (Ro-Jo) with a feeder (as shown in Figure 3);
b) then make separate measurements of a radar antenna maximum gain at the emission frequencies found in step a). Here, measurements are made at the distances of 5 m for frequencies below 5 GHz and 30 m for frequencies above 5 GHz (as shown in Figure 4);
c) correct the measured gains with an appropriate correction factor (using a software program, given in Appendix I, for the frequencies, at which the emissions were observed in step a));
d) finally, steps a) and c) are combined to obtain the Indirect e.i.r.p. radiation at the observed unwanted emission frequencies.
[pic]
[pic]
4.1 Methods of measurement and problems associated with a waveguide
There are two main problems in measuring the transmitter output power spectrum. The one is accessing the higher frequency components of the transmitted spectrum without distortion and; the other is measuring very low level emissions in the presence of the fundamental transmitting pulse of perhaps 60 kW peak power.
In any waveguide, the propagation mode, TE10, can be measured using a calibrated measuring system. The characteristic of such a system is such that it attenuates the powerful fundamental signal sufficiently to protect the measuring equipment, at other frequencies offers a negligible attenuation and energy is being measured in the TE10 mode.
However, it is recognized that with radars employing magnetrons, the spurious frequency emissions of the transmitter output could be in higher order modes at any time and the energy levels may be greater than that in the fundamental mode. Determination of modal content at the transmitter output is, potentially, expensive and technically may not be of significance anyway, because it is most probable that higher order modes may get trapped in a waveguide to coaxial adaptor, or in antenna feeder and the Ro-Jo connecting to the radar antenna. (i.e. waveguide to coaxial adaptors are only designed to couple energy in TE10 mode).
4.2 The measurement system for the measurement of unwanted emissions in a waveguide
This measuring system allows the measurement of low levels of emissions accurately in the presence of high power radar pulses.
The main components of the system are a notch filter and a set of waveguide tapers, from WG 10 to smaller waveguide sizes, to cover the whole frequency range of interest. The notch filter comprises of a straight WG 10 waveguide with absorbent elements inside, which attenuates the fundamental signal while at other frequencies it offers negligible attenuation. To achieve the required attenuation to protect the measuring equipment, and to measure emissions at higher frequencies, linear tapers are used at the output of the notch filter.
The waveguide taper is a high pass filter and thus rejects, by reflecting back, signals below the cut off frequency. If a taper had been used directly at an output port of a radar transmitter, the fundamental would have been reflected back into the transmitter causing an undesirable mismatch. But with the taper after the notch filter the reflected signals are absorbed a second time. Thus the return loss at the fundamental frequency is typically 34 dB, which is low enough to avoid frequency pulling of the magnetron.
Frequencies above the cut off are transmitted through the transitions and into the measuring equipment. If possible, a short waveguide section, should be included to prevent coupling of evanescent modes between a taper and a waveguide to coaxial transition.
4.3 Results of measurement at the Ro-Jo port
The measurement technique comprises an exploratory search of a frequency band of interest to locate and tag significant spurious emissions by frequency, followed by a revisit to each noted emission for detailed and accurate measurement of maximum amplitude of that emission.
4.4 Measurement uncertainty in a waveguide
The system has a measurement accuracy of (1.3 dB across the frequency band 2 to 18.4 GHz for the waveguide port. Total uncertainties with a confidence level of not less than 95% can be calculated to be (3.4 dB for the waveguide port including the spectrum analyser.
4.5 Measurement of antenna gain characteristic at measured emission frequencies
This indirect method recommends that near-field measurements be made on the antenna on an Open Area Test Site (OATS) at distance of 5 m for frequency below 5 GHz and 30 m for frequencies above 5 GHz. Correction factors are then applied to correct the measurement to an equivalent far field gain, which provide an acceptable correlation with the far field gain. A typical measurement arrangement is shown in Figure 4.
[pic]
4.6 Near field gain measurement procedure for 5 m and 30 m distances
The measurement of maximum gain of the Antenna Under Test (AUT) shall be carried out at spurious and out-of-band frequencies measured or identified, using the method specified in subclause 4.3. At each measured, or identified, emission frequency, the gain of AUT shall be maximized by first rotating through 360% and then further maximized by moving the test horn up, or down. The gain of the AUT is obtained by measuring e.i.r.p. at each distance with a known level of power into the AUT at each frequency of interest. Equations (1) and (2) show details of calculations to arrive at the equivalent far field gain (Ga) of the AUT from the measured spectrum analyser level (S).
Ga of the AUT (dBi) = Measured e.i.r.p. (dBm) - Pinput (dBm) + Gc (dB) (1)
Measured e.i.r.p. (dBm) = S (dBm) + [pic]- Gr (dBi) (2)
where:
Ga = Equivalent far field gain of the AUT (dBi)
Pinput = Power input into the AUT (dB)
Gc = Gain correction factors for 5 m and 30 m distances, which can be calculated for the AUT using a software program specified in Appendix I
S = Measured spectrum analyser level (dBm)
Gr = Gain of the receiving test horn antenna (dBi)
d = measuring distance (m)
l = wavelength of a frequency of interest (m)
4.7 Gain correction and reduction factors
The software program gives the far field correction factors from a near field measurement. The program derives the correction factor for each distance at the frequency of interest by considering the phase changes of the received wave across the linear antenna. (At near distances the wave front is spherical and not linear.) Therefore, it can be used to infer the maximum antenna gain at infinity from a near field measurement.
An important point to bear in mind is that the antenna gain pattern is not addressed. It must be noted that at spurious frequencies the electrical length of the antenna is different from the mechanical length; it may well be much shorter. This is due to the different illumination pattern of the antenna length at frequencies other than the designed frequency. A copy of the program is given in Appendix I.
4.8 Near field gain measurement uncertainty with the applied correction factors
The worst-case measurement uncertainty can be calculated to be (6 dB, which includes, uncertainties due to a spectrum analyser, test horn gain, cable loss and source and site imperfection. Total uncertainties with a confidence level of not less than 95% can be calculated to be (4.2 dB.
The derivation of the correction factors for these distances assumes the AUT radiating aperture to be constant at all frequencies.
4.9 Producing a radar transmitter emission spectrum as an e.i.r.p. by combining measured emissions and antenna gain characteristic
The technique used to obtain a maximum value for omnidirectional e.i.r.p. is to add, for each emission frequency, the maximum power generated by radar transmitter (dBm), to the maximum directional gain (dBi) from the AUT. This means one only has to characterize the AUT at frequencies at which the radar transmitter emissions were observed.
The effects of the AUT mismatch are considered to be taken into account automatically in the measurements of gain, because the test equipment is matched to 50 ohms, the nominal impedance of the coaxial connectors and the emissions are measured in the 50 ohms measuring receiver.
4.10 Summary
The indirect method, which is cost effective in time and facilities, is sensitive enough to allow measurement of low level emission values with a reasonable accuracy and repeatability. Furthermore, it can be used in all weather conditions. With this indirect method, the measurement frequency range can easily be extended to 40 GHz or higher.
appendix I
TO ANNEX 1
Calculation of gain correction factors for a planar antenna array using
a software program written in BASIC
'**************************************************************************
This program is written, in BASIC, to determine the far field from a near field measurement. Uses only the considerations of the phase changes of the received wave due to the difference between the spherical RF wavefront and the planar antenna array. Thus the program should only be used to determine the boresight or maximum antenna gain at infinity from a near field measurement. Antenna gain pattern is not addressed here.
'***************************************************************************
'Test data for error -.025 pi radians ; error ~.3 dB
'freq = 3000
'l = 10
'd = 1
'
CLS
'
INPUT "Enter the antenna frequency in MHz "; freq
INPUT "Now enter the measuring distance in metres from the antenna "; l
INPUT "Enter the maximum dimension of the antenna in metres "; d
'
'
'
CONST c = 300
CONST pi = 3.141592654#
'
'
lamda = c / freq
num = 100
'
'
IF d < (5 * lamda) THEN
PRINT "Antenna dimensions should be much greater (* 5) than";
PRINT " the wavelength for accurate use of this prog"
STOP
END IF
'sum of inphase and quadrature field elements
sumi = 0
sumj = 0
'
' system is symmetrical so integrate from 0 to d/2
FOR i = 0 TO num - 1
dprime = i * d / (2 * (num - 1))
phasediff = (l - ((l ^ 2) + (dprime ^ 2)) ^ .5) * 2 * pi / lamda
' PRINT " phase diff is ";
' PRINT USING "##.##"; phasediff;
icomp = COS(phasediff)
sumi = sumi + icomp
jcomp = SIN(phasediff)
sumj = sumj + jcomp
NEXT i
PRINT " Max phase error is ";
PRINT USING "##.##"; phasediff / pi;
PRINT " * pi rads"
'form final received planar power received from spherical RF wave
res = ((sumj) ^ 2 + (sumi) ^ 2) ^ .5
'PRINT "Result is "; res; "i is "; i; " num is "; num
'Calc gain reduction
gprime = num / res
'
glog = 20 * (LOG(gprime) / LOG(10#))
PRINT "Gain reduction from infinite far field is ";
PRINT USING "##.### "; glog;
PRINT " dB"
END
appendix II
TO ANNEX 1
Gain and noise figure calibration using a noise diode
Measurement system calibration should be performed prior to every radar emission spectrum measurement. As measurements are performed, gain corrections may be added automatically to every data point. For measurement system noise figures of 20 dB or less, noise diode Y-factor calibration (as described below) may be used. This Appendix describes the theory and procedure for such calibration.
Theory
The noise diode calibration of a receiver tuned to a particular frequency may be represented in lumped-component terms as shown in Figure 1. In this diagram, the symbol ( represents a power-summing function that linearly adds any power at the measurement system input to the inherent noise power of the system. The symbol g represents the total gain of the measurement system. The measurement system noise factor is denoted by nf, and the noise diode has an excess noise ratio denoted as enr. (In this Appendix, all algebraic quantities denoted by lower-case letters, such as "g," represent liner units. All algebraic quantities denoted by upper case letters, such as "G," represent decibel units).
[pic]
figure 1
Lumped component diagram of noise diode calibration
Noise factor is the ratio of noise power from a device, ndevice(W), and thermal noise,
[pic]
where k is Boltzmann's constant (1.38·10-23W·s/k, Watt-seconds per degree kelvin), T is system temperature in kelvin, and B is bandwidth in hertz. The excess noise ratio is equal to the noise factor minus one, making it the fraction of power in excess of kTB. The noise figure of a system is defined as 10 log (noise factor). As many noise sources are specified in terms of excess noise ratio, that quantity may be used.
In noise diode calibration, the primary concern is the difference in output signal when the noise diode is switched on and off. For the noise diode = on condition, the power, Pon(W), is given by:
[pic]
where nfs is system noise factor and enrd is the noise diode enr.
When the noise diode is off, the power, Poff(W), is given by:
[pic]
The quantity k, Boltzmann's constant, is 1.38×10-20 mW × s/K (milliwatt seconds per kelvin). T is the system noise temperature in kelvin, and B is the bandwidth in hertz. The ratio between Pon and Poff is the Y factor:
[pic]
[pic]
Hence the measurement system noise factor can be solved as:
[pic]
The measurement system noise figure is:
[pic]
Hence:
[pic]
[pic]
or
[pic]
In noise diode calibrations, the preceding equation is used to calculate measurement system gain from measured noise diode values.
Although the equation for NFs may be used to calculate the measurement system noise figure, software may implement an equivalent equation:
[pic]
[pic]
And substituting the expression for gain into the preceding equation yields:
[pic]
The gain and noise figure values determined with these equations may be stored in look-up tables. The gain values are used to correct the measured data points on a frequency-by-frequency basis.
Excluding the receive antenna, the entire signal path is calibrated with a noise diode source prior to a radar spectrum measurement. A noise diode is connected to the input of the first RF line in place of the receiving antenna. The connection may be accomplished manually or via an automated relay, depending upon the measurement scenario. The noise level in the system is measured at a series of points across the frequency range of the system with the noise diode turned on. The noise measurement is accomplished with the IF bandwidth set to 1 MHz and the video bandwidth set to 10 Hz. The noise diode is then turned off and the system noise is measured as before, at the same frequencies. The measurement system computer thus collects a set of Pon and Poff values at a series of frequencies across the band to be measured. The values of Pon and Poff are used to solve for the gain and noise figure of the measurement system in the equations above.
appendix III
TO ANNEX 1
Direct method detailed description of procedures and software
The direct method assumes that the following conditions can be met:
1) The far field radiation zone of a radar can be accessed by a measurement system as described in the body of this Annex;
2) Unwanted feed-through of radar signals directly into the measurement system hardware (i.e. bypassing the measurement system antenna) can be minimized to a sufficiently low level to ensure that measurement results are accurate.
The direct method does not require that the radar operation be coordinated with the measurement system, although in some cases cooperative operation may be beneficial in expediting the measurement.
The direct method process is as follows:
Step 1: Determine a measurement location. The measurement location should be within or as nearly as possible to the radar main radiation beam. For surface search radars and some other radar types, this may be relatively easy, as the radar beam will sweep across the surface, and the measurement system need only be placed within this area. For many air search radars, however, the main beam does not directly illuminate the ground. For these radars, the measurement system should be located within the maximum coupling zone on the surface. This zone may be determined by tuning the measurement system to the radar fundamental frequency and then driving the measurement system in a vehicle from a position close to the radar to a position far (on the order of a few kilometres) from the radar. The measurement system is used to monitor received signal level as a function of position. This can be done by running a spectrum analyser in a zero frequency span with a sweep time of 500 seconds, and watching the peak level every few seconds when the radar sweeps past the vehicle. The result is a time display that shows the maximum coupling location(s).
Any place within the maximum coupling zone should be adequate. In practice, this zone has been found to begin no closer than about 0.75 km from air search radars, and to extend to no further than about 2 km from the same radars. There is usually no sharply defined point where maximum coupling occurs, but rather a broad zone within these limits.
The question of multipath should be considered. Multipath effects have been observed very rarely. When they have been observed, it has been in cases in which the radar and the measurement system were separated by calm, smooth water surfaces. In other cases, irregular intervening terrain and the use of parabolic reflector antennas by the measurement system minimize multipath effects to an extent that makes them negligible. Multipath effects can be checked by repeating the radar measurement at a second location and comparing the results from the two measurement locations. Multipath is also believed to be minimized by raising the measurement antenna on a telescoping mast to a height of about 10 meters above the ground. This also provides a better line-of-sight between the radar and the measurement system.
Step 2. Set up the measurement system and check for unwanted feed-through signals. The measurement system is configured with a parabolic reflector antenna at the top of a 10 metre mast (optional), or at a height of at least a few metres above the ground, to avoid multipath effects and provide reasonably good line-of-sight propagation. The measurement system should be tuned to the radar fundamental frequency or maximum emission frequency, if it is chirped or frequency-hopping.
When this is accomplished, it is necessary to check for unwanted feed-through (i.e. the unwanted reception of radar energy within the measurement equipment, bypassing the measurement antenna). Feed-through is checked by disconnecting the measurement antenna and terminating the input line with a 50-ohm load. If feed-through is present, the following options may be exercised:
1) check to ensure measurement equipment racks (if any) are sealed;
2) check connectors for firm fittings;
3) move the radar measurement system to an alternative location, in which the measurement equipment is shielded from the radar by buildings or foliage, and in which the antenna is raised above these obstacles on the telescoping mast;
4) move the radar measurement system to a larger distance from the radar.
A well-designed measurement system should minimize the possibility of unwanted feed-through.
Step 3. Determine radar emissions parameters. The parameters that are most critical to determine before the measurement begins are beam scanning interval and effective emission bandwidth. Beam scanning interval and other characteristics are acquired by tuning the spectrum analyser in a zero span mode and a sweep time interval of several seconds, and then observing the beam scanning of the radar.
Determination of the emission bandwidth is accomplished as described in the main body of this Annex, with the spectrum analyser tuned to the radar fundamental frequency in a zero span mode, and the IF and video bandwidths initially set to their widest available values. The IF bandwidth is then reduced each time the radar beam swings past the measurement system, and the bandwidth at which the received power level drops is noted. This is the widest available measurement bandwidth that is less than the radar emission bandwidth. This will be the measurement bandwidth used, unless circumstances such as a need to observe the radar in a particular receiver bandwidth dictate otherwise.
Additional radar emission parameters that should be noted are: pulse repetition rate, pulse jitter (if any), pulse stagger (if any), and pulse width (as measured on an oscilloscope connected to the spectrum analyser video output).
Step 4. Calibrate the measurement system. See Appendix II of this Annex. Noise diode calibration is recommended, although alternative methods using signal generators can be used.
Step 5. Configure measurement system software. The measurement software must be configured to the desired start frequency (MHz), stop frequency (MHz), step size (MHz), step interval (MHz), IF bandwidth (MHz), video bandwidth (( IF bandwidth), detector (positive peak), spectrum analyser reference level (usually –10 dBm), initial attenuation at the start frequency (usually zero dB), and additional data as location, radar name, project name for the measurement, etc.
Step 6. Check for linearity during the measurement. It is critical to maintain the integrity of the measurement by checking for linearity as the measurement progresses. When measuring both at the fundamental frequency and in the spurious emissions, system linearity should be checked by periodically inserting 10 dB of RF attenuation at the rf front end, ahead of the LNA. The result should always be a 10 dB drop in measured signal level. If more than a 10 dB drop is observed, overload of the LNA may be occurring. If less than a 10 dB drop is observed, then unwanted feed-through may be occurring. Good system design will minimize these potential problems. If they do occur, it may alternatively be necessary to either take additional steps to shield the measurement system, or else to move to another location, as described in Step 2, above.
Step 7. Measure the radar in more than one IF bandwidth (recommended but not required). It may be useful to measure radar emissions in several bandwidths. Such measurements provide an unequivocal indication of the variation in measured radar power as a function of receiver bandwidth at any given frequency in the spectrum.
ATTACHMENT 2
(Source: Document 8B/TEMP/11)
Comments on liaison statement from TG 1/5 concerning preliminary draft new Recommendation on protection of
safety services from unwanted emissions
WORKING PARTY 8B WISHES TO SUGGEST POSSIBLE ADDITIONS AND MODIFICATIONS TO THE ABOVE PRELIMINARY DRAFT NEW RECOMMENDATION (DOCUMENT 8B/114), AS SHOWN IN THE ATTACHMENT TO THIS DOCUMENT.
New text is shown underlined whilst text for removal is shown in strikethrough.
Attachment: 1
Attachment (to attachment 2)
(Source: Document 1-5/TEMP/140(Rev.2))
PRELIMINARY DRAFT NEW RECOMMENDATION ITU-R SM.[SAF]
THE PROTECTION OF SAFETY SERVICES FROM UNWANTED EMISSIONS
The ITU Radiocommunication Assembly,
considering
a) that, in some cases, safety services and services employing high power transmitters have been allocated to adjacent or nearby frequency bands;
b) that, in making these allocations, practical transmitter and receiver compatibility may not have been considered;
c) that No. S1.59 defines a safety service as any Radiocommunication service used permanently or temporarily for the safeguarding of human life and property;
d) that some services, such as those safety services concerned with safety of life or property, are based on the reception of emissions with a higher probability of integrity and availability than is generally required for other radio services;
e) that No. S1.169 defines harmful interference as interference which endangers the functioning of a radionavigation service or of other safety services or seriously degrades, obstructs, or repeatedly interrupts a radiocommunication service operating in accordance with the Radio Regulations;
f) that No. S4.10 of the Radio Regulations recognizes the requirement of radionavigation and other safety services for special measures to ensure their freedom from harmful interference;
g) that it is important to avoid harmful interference to safety services because of the potential for loss of life and property;
h) that several footnotes of the Radio Regulations draw attention to the need for greater availability and priority for safety services in certain bands (e.g., Nos. S5.353A, S5.357A, S5.362A). High-power emissions and emissions from spaceborne or airborne stations can be particularly harmful;
j) that there are various operational practices and mitigation techniques that can be used by safety services to minimize the impact of interference from other services;
k) that there are various operational practices and mitigation techniques that can be used to avoid causing harmful interference to the safety services;
l) that general limits for spurious emissions, such as those in Appendix S3, may not protect to the desired extent the safety services from interference;
m) that WRC-97 called for ITU-R to "study those frequency bands and instances where, for technical or operational reasons, more stringent spurious emission limits than the general limits in Appendix S3 may be required to protect safety services ... and the impact on all concerned services of implementing or not implementing such limits";
n) that WRC-97 called for ITU-R to "study those frequency bands and instances where, for technical or operational reasons, out-of-band limits may be required to protect safety services ... and the impact on all concerned services of implementing or not implementing such limits";
o) that suitable measures can be taken to avoid the potential of harmful interference to safety services,
noting
a) that explanations of why safety services may need special attention with respect to interference from out-of-band or spurious emissions are presented in Annex 1;
b) that ITU Radio Regulations contain definitions and terminology related to safety services (e.g., Nos. S1.28-S1.31, S1.32, S1.33, S1.36, S1.43, S1.44 S1.46, S1.47 - services, S4.10, S1.59 - general, S1.166, S1.167, S1.168, S1.669 - interference);
c) that safety services can only be defined in terms of safety requirements which seek to show that the system reaches a specified integrity level under all conditions of use. In the case of protection requirements it is necessary to demonstrate that a safety system's integrity is not compromised;
d) that information on past history of compatibility between safety services and other services may be useful,
recommends
1 that the following measures may be taken to avoid the potential of harmful interference to safety services:
a) consultation;
b) agreement among safety services and other transmitting organizations; and
c) appropriate spectrum management techniques including unwanted emission limits;
2 that the mitigation techniques and measures described in Annex 2 be used by transmitting systems to avoid harmful interference generated by unwanted emissions, bearing in mind the constraints placed on system design;
3 that the mitigation techniques and measures described in Annex 3 may be used by safety services to reduce or avoid the impact of interference from other services where they do not degrade the performance of safety service equipment;
4 that where it is determined to be necessary, more stringent spurious emission limits than the general limits in Appendix S3 be used in the frequency bands in Annex 4; special cases may be resolved by using applicable ITU-R Recommendations;
5 that the frequency bands listed in Annex 4 are those safety service bands where, for technical or operational reasons, out-of-band limits may be used by active services to protect safety services;
6 that the level of harmful interference for safety of life systems shall be determined on a case by case basis in the form of a safety analysis. This analysis will assess the use to which the safety system is being put and demonstrate that the specified integrity level is still maintained under all conditions of use.
Annex 1
(to Document 1-5/TEMP/140(Rev.2))
Protection of safety services
Safety services are radiocommunications services used for safeguarding human life and property. For example, all aeronautical operational and air traffic control communications channels and many maritime communications channels are fundamentally safety of life channels. The systems, including radionavigation systems and radionavigation satellite systems, used for safety-of-life often depend on the ability to detect a weak or distant signal where interference can critically affect reception. This means special protection may be required for safety services as stated in RR S4.10, because of the criticality of protecting life and property. The necessity for safety systems to detect weak signals makes it important that these systems operate in an environment free from harmful interference. The international radio regulatory authorities recognize that special protection is required for the safety services. In addition to the general spurious emission limits specified in the ITU Radio Regulations, specific standards or applicable ITU-R Recommendations are required to protect some safety services. Some examples are Recommendations:
ITU-R M.218-2, M.441-1, M.589-2, M.690-1, M.1088, M.1233, M.1234, M.1313, M.1317, M.1318, M.1460, M.1461, M.1463 and M.1464.
1 Aeronautical systems
For international civil aviation, specific safety standards are specified in International Civil Aviation Organization's (ICAO) Standards and Recommended Practices, Annex 10 to the Convention on International Civil Aviation. ICAO states "The Radio Regulations also have a major concern with the prevention of interference of all kinds, whether between services or regions, between assignments, or from other sources of radiation such as industrial or medical equipment. Particular attention is accorded to services where there is a predominant safety-of-life function, as in aeronautical services."
In the design of aeronautical communications, navigation, and surveillance (CNS) systems, the attributes of spectrum efficiency and robustness of system operation (e.g., adequate link margin, resistance to interference, minimal failure modes) often will be in conflict. When this is the case, it should be recognized that robustness of system design must be given priority due to the safety-critical nature of aeronautical CNS systems.
2 Space based distress alerting and location systems
Distress and safety systems operating in space stations with sensitive receivers are particularly vulnerable to interference from terrestrial emitters. Systems such as Cospas-Sarsat have fields of view that extend over thousands of square kilometres to receive and locate signals from low power satellite EPIRBs. Interference to Cospas-Sarsat in the band 406-406.1 MHz has been shown to originate from equipment in adjacent and near-adjacent bands as well as from transmitters with broadband modulation characteristics operating at frequencies as much as 20 MHz away from 406 MHz. The out-of-band and spurious emissions from high power systems that use pulse and digital modulation techniques can be at levels that completely mask reception of EPIRB transmissions.
Recommendation ITU-R M.[Doc. 8/84], Protection Criteria For Cospas-Sarsat Search and Rescue Processors in the Band 406-406.1 MHz, establishes the broadband signal spectral power flux-density threshold level at the input to the satellite antenna as -198.6 dB(W/m2/Hz). This document also establishes that narrow band spurious emissions should not exceed -185.8 dB(W/m2) at the input to the Sarsat antenna. Recommendation ITU-R SM.1051 also provides information on principles of EPIRB detection and location, processing of 406 MHz interfering signals, and harmful interference levels.
ANNEX 2
(to Document 1-5/TEMP/140(Rev.2))
Mitigation techniques and measures that may be used at the transmitter
Several possible mitigation techniques have been described in ITU R Recommendations, such as Recommendation ITU R SM.328-10, which may have direct relevance to the categories listed below:
Practical hardware and system measures to be considered at an early stage in the design of systems in order to reduce interference from unwanted emissions
• Transmitter architecture.
• Design of the output power amplifier to avoid spectral regrowth of the signal into adjacent channels, or intermodulation.
• Use of components that operate with linear characteristics to the extent possible.
• Design of the modulation process to avoid unwanted emissions.
• Antenna patterns.
• Power control.
Traffic loading management
See Trunking
Band utilization
• One way to avoid co-channel harmful interference is to make optimum use of frequency reuse.
• Geographic and frequency separations are standard methods of precluding harmful interference.
• Safety services are more easily protected from harmful interference due to unwanted emissions when they are allocated frequency bands for their exclusive use.
• Space-based distress alerting and location systems have sensitive receivers and the following considerations should be addressed when planning new systems or upgrading old systems:
• Proposed protection bandwidths must account for Doppler shifts due to relative motion between the transmitter and space station. This is especially important when the transmitter is also located in space.
• Special consideration must be given to the impact of out-of-band and spurious emissions from systems employing pulse, spread spectrum, and other broadband modulation techniques. These types of systems can cause interference when the transmitter frequency is relatively near in frequency to the safety system carrier frequency.
• Desensitization of low noise amplifiers can occur when both the safety and non-safety systems are located in space. A potential for burnout of low noise amplifiers also exists for cases, where orbital geometries are such that the safety and non-safety systems are in close proximity.
• Applicable ITU-R recommendations identifying harmful interference levels to safety systems should be used as aids to establish proper frequency separation between safety and non-safety systems.
Guard channels
Channel 16 in the marine band has been protected in the past by providing vacant channels either side of the distress and safety calling and working channels. For example, in the past channels 15 and 17 were not used in order to avoid interference to channel 16. The present Appendix S18 includes protection for channel 16 by footnotes encouraging the use of low power operation and on-board communications on channels 15, 75, 76, and 17. The use of guardbands in allocations adjacent to safety services can help to mitigate interference.
Monitoring
Reports of interference can be used to determine the type of interference or service being dealt with to determine whether the problem is to be dealt with by local or international monitoring stations.
Facilities for monitoring from VLF through to "L" band and above and mobile monitoring teams and mobile EMC Laboratories can be used to supplement the fixed facilities.
Sector blanking
Operating procedures may be established whereby the transmitter is inhibited when the radiated main beam is in the field of view of a safety service system (particularly applicable to VTS radar systems).
Annex 3
(to Document 1-5/TEMP/140(Rev.2))
Mitigation techniques and measures that may be used by safety services
to minimize harmful interference from other services
Mitigation techniques vary for different services and systems. Not all of the techniques listed below are suitable in all cases. For example, some communications and surveillance systems used by civil aviation have frequency diversity and signal processing. However, other techniques such as tailoring the antenna pattern or beam-tilting may limit the performance of some aeronautical safety systems and would not be appropriate.
Receiver architecture
Improved RF selectivity will reduce unwanted signals outside of the tuned bandwidth.
Double Superheterodyne design will give both good image and adjacent channel rejection performance.
Site-shielding
Mesh fences and suitable use of local topography can provide attenuation to interfering signals.
Operational measures
The use of correct operational procedures (e.g. use of call-sign prior to passing traffic) reduces the risk of misinterpretation of unwanted signals.
Error correction and interleaving
The use of error correction coding and interleaving techniques may improve the performance of digital systems in the presence of unwanted signals.
Frequency Diversity
Where a number of channels are available for use at any time or a signal is transmitted on two or more frequencies simultaneously. If harmful interference is detected on any of the available channels, a clear channel can be selected.Signals can be either combined at the receiver or the strongest signal is selected. It should be noted that this technique is, however, spectrally inefficient.
Space Diversity
Weak signals are enhanced by the use of antennas separated in space with their outputs correlated combined at the receiver.
Beam down-tilt
Not only can the interfering signal be reduced by as much as 3dB (even co-channel) but also penetration can be increased. Antenna techniques such as "null fill" have been used to provide a better quality service.
Antenna pattern
Corner reflectors and other directional antennas can be used to tailor the service area of interest and minimize interference from outside the service area.
Signal Processing (Radar)
Recommendation ITU-R M.1372 (Efficient use of the radio spectrum by radar stations in the Radiodetermination service) provides some of the methods that can be used to enhance spectrum efficiency of radar systems operating in radiodetermination bands. Several receiver post-detection interference suppression techniques currently used in radionavigation, radiolocation and meteorological radars are addressed along with system performance trade-offs (limitations) associated with the interference suppression techniques.
RF Filtering
Notch filtering has successfully been used in the past to protect hyperbolic navigation systems such as Loran from harmful interference. This type of filtering can easily be used to attenuate large power signals nearby the wanted signal. Other types of filtering, such as band pass filtering etc., could also be usefully employed, where only a few channels or bands are of interest. These techniques can be applied to both transmitters and receivers.
TDMA/FDMA systems
Time and Frequency multiplexing systems can offer greater immunity to some types of interference than asynchronous and large bandwidth systems.
Digitally Coded Squelch (DCS)/Continuous Tone Control Signalling System (CTCSS)
A receiver using this technique is only activated when traffic is intended for that particular unit.
Monitoring
The Cospas-Sarsat system has the ability to locate many types of interfering signals. This capability has been implemented at numerous ground stations and the information is routinely reported to administrations and ITU. An example of spectrum monitoring procedures is given in Recommendation ITU-R SM.1051-2.
Trunking
The radio system comprises a number of channels that are available for traffic at a given time. A control signal allocates the next available working channel when a user tries to access the system. In the case where safety services are provided by the trunking systems, priority features should also be built into this system to provide instant access for priority traffic. Other systems will be able to detect interference on a working channel and automatically take the relevant channel out of service.
Path Diversity
This system is particularly applicable to CDMA systems in urban environments. A number of de-spreading circuits are employed at the receiver which decode the wanted signal contributions after successively longer finite periods of time (this is known as "rake" reception). The received signal contributions are correlated and are processed using either "switched", "equal gain" or "maximal-ratio" combining to obtain a better estimate of the message signal.
Adaptive Power Control
A mobile transmitters power can be automatically adjusted.
ANNEX 4
(to Document 1-5/TEMP/140(Rev.2))
Relevant frequency bands for safety services
This Annex lists frequency bands that have been identified as being used for safety services. Some other bands under the control of national administrations may be in use for safety services, but these may not be included in the list.
|Frequency band |Brief description of use |
|70-130 kHz |Hyperbolic phase comparison |
|90-110 kHz |Hyperbolic time difference LORAN-C |
|190-435 kHz |Non-directional beacons |
|275-335 kHz |DGNSS hyperbolic RANA |
| | |
|1 625-1 635 kHz |Hyperbolic phase comparison TORAN |
|1 800-1 810 kHz |Hyperbolic phase comparison TORAN |
|2 160-2 170 kHz |Hyperbolic phase comparison TORAN |
|2.1-28 MHz |Aeronautical Mobile (In-Route and Off-Route) Service and GMDSS |
|(various bands) |communications in accordance with Article S5 |
|74.8-75.2 MHz |Instrument Landing System marker beacons |
|108-118 MHz |Radionavigation aids – VHF Omni-directional Range, Instrument Landing |
| |System Localizer, terrestrial augmentation for radionavigation-satellite |
| |systems |
|118-137 MHz |Air-to-Ground and Ground-to-Air Safety Communications |
|121.45-121.55 MHz |Distress Beacons: COSPAS SARSAT and Aeronautical Emergency location |
|156-162 MHz |GMDSS Maritime Communications, Automatic Identification System |
|242.95-243.05 MHz |Distress Beacons: COSPAS-SARSAT |
| |and Aeronautical Emergency Location |
|225-328.6 MHz |Air-to-Ground and Ground-to-Air Safety Communications |
|328.6-335.4 MHz |Instrument Landing System Glide Slope |
|335.4-400 MHz |Air-to-Ground and Ground-to-Air Safety Communications |
|406.00-406.10 MHz |Distress Beacon COSPAS-SARSAT (E-s), GMDSS |
| | |
|960-1 215 MHz |Aeronautical radionavigation aids – Distance Measuring Equipment, |
| |Tactical Air Navigation, Radar Beacons, Secondary surveillance radar, |
| |Airborne Collision Avoidance System Radionavigation-satellite systems |
|1 215-1 400 MHz |Aeronautical Radar |
|1 215-1 260 MHz |Radionavigation satellite systems |
|1 525-1 559 MHz (s-E) |Mobile satellite distress and safety communications, GMDSS and AMS(R)S) |
|1544-1545 MHz (s-E) |COSPAS-SARSAT Distress Beacon |
| |L-band EPIRB GMDSS |
|1 559-1 610 MHz |Radionavigation satellite systems |
| | |
| |Terrestrial and satellite based augmentations for satellite navigation |
| |systems |
|1 626.5-1 660.5MHz (E-s) |Mobile satellite distress and safety communications, GMDSS and AMS(R)S) |
|1 645.5-1 646.5 MHz |L-band EPIRB (E-s) GMDSS |
|2 700-3 300 MHz |Radar (shipborne, land-based , racons and Aeronautical), weather radar |
|4 200-4 400 MHz |Airborne Radio Altimeter |
|5 000-5 150 MHz |Microwave Landing System |
| |Radionavigation-satellite systems |
|5 350-5 650 MHz |Radar beacons, radar on-board, Terminal Doppler Weather Radar |
|8 750-8 850 MHz |Airborne Doppler navigation aids (radar) |
|8 900-9 280 MHz |Land-based radar, Aeronautical radar |
|9 200-9 500 MHz |Radar (shipborne), radar beacons and target enhancers, airborne and |
| |land-based weather radar, aeronautical ground-based radar and SARTs. |
|13.25-13.4 GHz |Airborne Doppler navigation aids (radar) |
|15.4-16.4 GHz |Airport Surface Detection Equipment |
| |Weather radar |
| |Aircraft landing systems, radar sensing and measurement system |
Attachment 3
(Source: Document 8B/TEMP/1)
draft revision of question itu-r 202-1/8*
UNWANTED EMISSIONS OF PRIMARY RADAR SYSTEMS
(1993-1997)
The ITU Radiocommunication Assembly,
considering
a) that the radio spectrum available for use by the radiodetermination service is limited;
b) that the radionavigation service is a safety service as specified by No. S4.10 of the Radio Regulations, and in addition that some other types of radar systems such as weather radars may perform safety-of-life functions;
c) that the necessary bandwidth of emissions from radar stations in the radiodetermination service is large in order to effectively perform their function;
d) that new emerging technology systems may use digital or other technologies that are more susceptible to interference from unwanted emissions from radar systems due to their high peak envelope power;
e) that Radiocommunication Study Group 8 has been studying the question of efficient use of the radio spectrum by radar systems including the study of inherent unwanted emission characteristics of various types of output devices;
f) that Radiocommunication Study Group 9 completed studies on the effects of unwanted emissions from radar systems on systems in the fixed service and developed Recommendations ITU-R F.1097 Interference Mitigation Options to Enhance Compatibility between Radar Systems and Digital Radio-Relay Systems and F.1190 Protection Criteria for Digital Radio-Relay Systems to Ensure Compatibility with Radar Systems in the Radiodetermination Service;
g) that unwanted emissions from radar systems may in some cases cause unacceptable interference to systems in other radio services operating in the adjacent and harmonically related bands, especially when the technical and operational characteristics of the other radio service systems are changed in ways that make them more susceptible to interference;
h) that performance (bandwidth, coherency, etc.), expected lifetime, cost, weight, size and mechanical ruggedness are important factors that must be considered in the design-to-performance specifications of radiodetermination systems;
j) that Radiocommunication Study Group 1 revised Recommendation ITU-R SM.329 which includes spurious emission limits for the radiodetermination service;
k) that WRC-2000 revised Appendix S3 Table of Maximum Permitted Spurious Emission Power Levels based on Recommendation ITU-R SM.329, and decided that radiodetermination service transmitters installed after 1 January 2003 and all transmitters after 1 January 2012 must comply with these power levels;
l) that Study Group 8 developed Recommendation ITU-R M.1177 on Techniques for Measurement of Unwanted Emissions of Radar Systems;
m) that Study Group 8 developed Recommendation ITU-R M.1314 on Reduction of Spurious Emissions of Radar Systems Operating in the 3 GHz and 5 GHz bands,
noting
that the out-of-band limits in bands allocated to the radiodetermination service on an exclusive basis are under the purview of Study Group 8,
decides that the following Question should be studied
1 What are the unwanted emission levels from existing and state-of-the-art radar systems below 26 GHz taking into account:
a) radar missions such as safety of life, radionavigation, surveillance, tracking, etc.;
b) type and size of the platform (e.g. fixed, mobile, shipborne, airborne, etc.);
c) available technologies; and
d) economic considerations?
2 What mitigation options, such as the choice of output device, could be taken into consideration in the design and implementation of radar systems to reduce radar spurious emissions, and what are their associated impacts on operational performance (bandwidth, coherency, etc.) expected lifetime, relative cost, weight, size and mechanical ruggedness?
3 What unwanted emission levels can be achieved using these mitigation options, and what compatibility can then be achieved with other radio services?
further decides
1 that the results of the above studies should be included in (a) Recommendation(s);
2 that the above studies should be completed by the 2006 Radiocommunication Assembly.
__________
Part 2
Draft revision of Recommendation ITU-R M.589.2 on the "Technical characteristics of methods of data transmission and interference protection for radionavigation services in the frequency bands between 70 and 130 kHz" (ITU-R Document 8/14).
ICAO Secretariat comments:
This ITU-R SG8 document is based on Document 8B/TEMP/5 produced by the October 2000 meeting of WP8B. This Recommendation is proposed to be expanded with material regarding data transmission from LORAN and Chavka stations to augment GNSS. This material includes protection criteria and signal level determination guidelines. Furthermore, material is proposed to be included on the technical characteristics of tri state pulse position modulation and message types and message formats. The GNSSP should provide the necessary information on the proposed amendments
AMCP WGF ACTION: Review GNSSP comments
|[pic] |INTERNATIONAL TELECOMMUNICATION UNION | |
| |RADIOCOMMUNICATION |Document 8/14(Rev.1)-E |
| |STUDY GROUPS |6 November 2000 |
| | |Original: English |
Source: Document 8/14
Working Party 8B
DRAFT REVISION OF RECOMMENDATION ITU-R M.589-2*
TECHNICAL CHARACTERISTICS OF METHODS OF DATA TRANSMISSION AND INTERFERENCE PROTECTION FOR RADIONAVIGATION SERVICES IN THE FREQUENCY BANDS BETWEEN 70 AND 130 KHZ
(1982-1986-1992)
Summary
A number of administrations are providing radionavigation services in the frequency band between 70 and 130 kHz. This Recommendation defines protection criteria to these radionavigation services and provides signal level determination guidelines.
Furthermore, a number of administrations are implementing or considering implementing data transmissions from Loran-C and Chayka stations to augment Global Navigation Satellite Systems (GNSS). This Recommendation contains the technical characteristics to which tri-state pulse position modulation data transmissions should conform. The Recommendation also describes the message types and the message format associated with this method of data transmission.
The ITU Radiocommunication Assembly,
considering
a) that radionavigation systems exist or are being implemented in the three Regions of the ITU;
b) that various services, including radionavigation systems, operate in frequency bands between 70 and 130 kHz;
c) that the operating characteristics of these radionavigation systems are well established and sufficiently documented by the appropriate service providers;d) that radionavigation being a safety service, all practical means consistent with the Radio Regulations (RR) should be taken to prevent harmful interference to any radionavigation system;
e) that users of phased pulsed radionavigation systems in the band 90-110 kHz receive no protection outside that band, yet may receive benefit from their signals outside the occupied bandwidth;
f) that in the band 90-110 kHz, different phased pulsed radionavigation systems may operate in adjacent areas, on the same assigned frequency and within the same occupied bandwidth;
g) that Loran-C and Chayka systems are characterized by ground waves that follow the Earth's contours with ranges that exceed comparably powered medium frequency systems, and by sky waves that may be received at considerably greater distances;
h) that Loran-C or Chayka provides an independent radionavigation system to complement GNSS;
j) that GNSS components exist or are being implemented and the accuracy may not be enough for some specialized navigation, or for the position sensor in electronic chart systems;
k) that safety applications require integrity information for position fixes derived from GNSS;
l) that the accuracy and integrity of GNSS can be improved considerably by the transmission of differential corrections or other data;
m) that appropriate modulation of Loran-C and Chayka transmissions enables these systems to transmit differential GNSS corrections, integrity messages and other data without interfering with the Loran-C or Chayka navigation function;
n) that the transmission of differential GNSS corrections, integrity messages and other data may benefit from the long-range transmission characteristics of Loran-C or Chayka;
o) that appropriate modulation of Loran-C and Chayka transmissions increases the efficiency of the use of the available bandwidth;
p) that a number of administrations currently provide Loran-C or Chayka coverage of coastal waters and land areas enabling a worldwide standard for the transmission of differential GNSS corrections, integrity messages and other data to be introduced efficiently and economically;
q) that other methods of data transmission using Loran-C or Chayka signals may be introduced,
recommends
1 that information be exchanged between the authorities operating radionavigation systems in the band 90-110 kHz with those operating other systems in the band 70-130 kHz employing stable transmissions;
2 that administrations operating radionavigation systems in the band 90-110 kHz in adjacent areas coordinate the technical characteristics of their individual systems in accordance with the RR;
3 that within the allocated band 90-110 kHz, the protection criteria for pulsed radionavigation systems (e.g. Loran-C and Chayka) should be in terms of unwanted to wanted emissions and in accordance with Annex 1;
4 that determination of Loran-C signal levels should be in accordance with the guidelines given in Annex 1;5 that any method of data transmission using Loran-C and Chayka signals should preserve the utility of the existing radionavigation services;
6 that a data service using tri-state pulse position modulation of Loran-C or Chayka signals should be designed in accordance with the technical characteristics given in Annex 2.
ANNEX 1
Loran-C/Chayka protection criteria and signal level
determination guidelines
1 Protection criteria
1.1 The protection criteria for Loran-C/CW interference as a function of frequency offset are given in Fig 1.
1.2 Near-synchronous interference at frequency, f, should satisfy the following relationship:
where:
GRI : group reception intervals
n : any integer, and
ƒb : response bandwidth of the receiver (related to response time).
In the track-mode, typical Loran-C receivers have a –3 dB tracking response of 0.01 Hz for marine receivers and 0.1 Hz for aeronautical receivers. However, in the signal acquisition, or search mode, the response may be of considerably higher frequency. The value of ƒb = 1.0 Hz is therefore recommended to be used.
[pic]
1.3 The protection criteria for Loran-C/FSK interference as a function of frequency offset are given in Fig. 2.
2 Signal level determination guidelines
The application of Figs. 1 and 2 to determine a maximum acceptable field strength of a specific unwanted signal to a known frequency requires knowledge of the expected Loran-C signal strength. This expected signal strength varies widely within the coverage area of a specific Loran-C chain. However, a minimum level may be determined at the coverage boundary.
The area of Loran-C coverage is specified by the administration operating the stations within a chain. This chain coverage area is determined on the basis of the Loran-C signal strength with respect to expected ambient noise levels. The signal-to-noise ratio at the boundary of the coverage area is typically –10 dB. Therefore, the signal-to-noise ratio within the defined coverage area is greater than that value. The ambient noise levels used to calculate the boundaries are derived from Recommendation 372, characteristics and applications of atmospheric radio noise data. The Loran-C field strength, measured at the boundary of that coverage area, then represents the minimum expected. For example, if the expected noise level is 55 dB(µV/m), a Loran-C signal level of 45 dB(µV/m) or higher would likely be found throughout the coverage area. 45 dB(µV/m) could then be used as the value of the wanted signal in conjunction with Figs. 1 and 2.
A study relative to chains operated within the United States of America reported that Loran-C signal levels within defined coverage areas may be as low as 43 dB(µV/m). Using this value, and considering a near-synchronous CWI signal between 90 and 110 kHz, the maximum unwanted to wanted signal level, determined from Fig. 1 is –20 dB. In this case, the unwanted field strength at the Loran-C receiver may have to be below 23 dB(µV/m) to prevent interference.
[pic]
ANNEX 2
Technical characteristics of a tri-state pulse position modulation (3s-PPM) data service
using Loran-C and Chayka transmissions in the frequency band 90-110 kHz
1 Structure
The following structure is used for signal specification:
|1 |Physical layer |Loran-C and Chayka signal specification|As documented by the appropriate service providers |
|2 |Modulation/demodulation layer |Description of the 3s-PPM |Chapter 2 of this Annex |
|3 |FEC layer |Description of the Forward Error |Chapter 3 of this Annex |
| | |Correction algorithm | |
|4 |Message coding layer |Description of the message coding |Chapter 4 of this Annex |
| | |algorithm | |
2 Modulation/demodulation layer
These definitions give the modulation of the Loran-C or the Chayka signal to enable data transmissions. The definitions include the low level modulation type, the modulation strategy to minimize devaluation of Loran-C or Chayka use for positioning and the relation between modulation patterns and other data representations.
2.1 Pulse modulation
2.1.1 Timing
A 3s-PPM should be applied to pulse three (3) to eight (8) of each pulse group. The modulation should consist of a time-shift of one (1) (s of the pulse transmission, with respect to an unmodulated pulse. The three possible states of the modulation are given in Table 2-1.
Table 2-1
States of the modulation
|Pulse state |Transmission time minus time of |Indication |
| |reference pulse ((s) | |
|Advanced pulse |(1 |( |
|Prompt pulse |0 |0 |
|Delayed pulse |+1 |+ |
2.1.2 Modulation balance
The number of advanced and delayed pulses of one channel in one pulse group should be equal. The modulation of six (6) pulses in one pulse group resolves in 141 possible balanced patterns, refer to Table 2-2, of which 128 should represent valid data, one (1) should indicate no data transmission and 12 should be not used.
Table 2-2
Modulation pattern combination
|Modulation pattern combination |Example |Number of combinations |
|6 x zero (0) |0 x plus (+) |0 x minus (() |0 0 0 0 0 0 |1 |
|4 x zero |1 x plus |1 x minus |0 0 + 0 - 0 |30 |
|2 x zero |2 x plus |2 x minus |0 + - + 0 - |90 |
|0 x zero |3 x plus |3 x minus |+ + - - - + |20 |
|Total = |141 |
2.1.3 Timing accuracy
The timing accuracy of the modulated signal should conform to the same timing accuracy requirements as for the unmodulated signal.
2.2 Modulation patterns
2.2.1 Pattern/data translation
Each of the 128 valid modulation patterns should uniquely represent a 7 bit binary block of data as shown below.
|Decimal Hexa- Pattern | |Decimal Hexa- Pattern | |Decimal Hexa- Pattern |
|decimal | |decimal | |decimal |
|0 |0 |--00++ | |43 |2B |00-+-+ | |86 |56 |++-00- |
|1 |1 |--0+0+ | |44 |2C |00-++- | |87 |57 |++0--0 |
|2 |2 |--0++0 | |45 |2D |00+--+ | |88 |58 |++0-0- |
|3 |3 |--+00+ | |46 |2E |00+-+- | |89 |59 |++00-- |
|4 |4 |--+0+0 | |47 |2F |00++-- | |90 |5A |-0000+ |
|5 |5 |--++00 | |48 |30 |0+--0+ | |91 |5B |-000+0 |
|6 |6 |-0-0++ | |49 |31 |0+--+0 | |92 |5C |-00+00 |
|7 |7 |-0-+0+ | |50 |32 |0+-0-+ | |93 |5D |-0+000 |
|8 |8 |-0-++0 | |51 |33 |0+-0+- | |94 |5E |-+0000 |
|9 |9 |-00-++ | |52 |34 |0+-+-0 | |95 |5F |0-000+ |
|10 |A |-00+-+ | |53 |35 |0+-+0- | |96 |60 |0-00+0 |
|11 |B |-00++- | |54 |36 |0+0--+ | |97 |61 |0-0+00 |
|12 |C |-0+-0+ | |55 |37 |0+0-+- | |98 |62 |0-+000 |
|13 |D |-0+-+0 | |56 |38 |0+0+-- | |99 |63 |00-00+ |
|14 |E |-0+0-+ | |57 |39 |0++--0 | |100 |64 |00-0+0 |
|15 |F |-0+0+- | |58 |3A |0++-0- | |101 |65 |00-+00 |
|16 |10 |-0++-0 | |59 |3B |0++0-- | |102 |66 |000-0+ |
|17 |11 |-0++0- | |60 |3C |+--00+ | |103 |67 |000-+0 |
|18 |12 |-+-00+ | |61 |3D |+--0+0 | |104 |68 |0000-+ |
|19 |13 |-+-0+0 | |62 |3E |+--+00 | |105 |69 |0000+- |
|20 |14 |-+-+00 | |63 |3F |+-0-0+ | |106 |6A |000+-0 |
|21 |15 |-+0-0+ | |64 |40 |+-0-+0 | |107 |6B |000+0- |
|22 |16 |-+0-+0 | |65 |41 |+-00-+ | |108 |6C |00+-00 |
|23 |17 |-+00-+ | |66 |42 |+-00+- | |109 |6D |00+0-0 |
|24 |18 |-+00+- | |67 |43 |+-0+-0 | |110 |6E |00+00- |
|25 |19 |-+0+-0 | |68 |44 |+-0+0- | |111 |6F |0+-000 |
|26 |1A |-+0+0- | |69 |45 |+-+-00 | |112 |70 |0+0-00 |
|27 |1B |-++-00 | |70 |46 |+-+0-0 | |113 |71 |0+00-0 |
|28 |1C |-++0-0 | |71 |47 |+-+00- | |114 |72 |0+000- |
|29 |1D |-++00- | |72 |48 |+0--0+ | |115 |73 |+-0000 |
|30 |1E |0--0++ | |73 |49 |+0--+0 | |116 |74 |+0-000 |
|31 |1F |0--+0+ | |74 |4A |+0-0-+ | |117 |75 |+00-00 |
|32 |20 |0--++0 | |75 |4B |+0-0+- | |118 |76 |+000-0 |
|33 |21 |0-0-++ | |76 |4C |+0-+-0 | |119 |77 |+-+-+- |
|34 |22 |0-0+-+ | |77 |4D |+0-+0- | |120 |78 |-+-+-+ |
|35 |23 |0-0++- | |78 |4E |+00--+ | |121 |79 |+-+--+ |
|36 |24 |0-+-0+ | |79 |4F |+00-+- | |122 |7A |-+-++- |
|37 |25 |0-+-+0 | |80 |50 |+00+-- | |123 |7B |+--+-+ |
|38 |26 |0-+0-+ | |81 |51 |+0+--0 | |124 |7C |-++-+- |
|39 |27 |0-+0+- | |82 |52 |+0+-0- | |125 |7D |+--++- |
|40 |28 |0-++-0 | |83 |53 |+0+0-- | |126 |7E |-++--+ |
|41 |29 |0-++0- | |84 |54 |++--00 | |127 |7F |+0000- |
|42 |2A |00--++ | |85 |55 |++-0-0 | | | | |
2.2.2 "No data transmission" pattern
The pattern "000000" should be used to indicate that no data is being transmitted.
2.2 Message structure
One (1) 3s-PPM message should consist of thirty (30) consecutive pulse groups.
2.3 Blanking
A blanked pulse group should be considered to have been transmitted for modulation purposes.
3 Forward Error Correction layer
A systematic Reed-Solomon (30,10) 27-ary code should be applied to all messages. All messages should consist of 30 symbols, each symbol representing a 7 bit element. Of these symbols, 10 should be data and 20 should be Reed-Solomon parity.
3.1 Primitive polynomial
The symbols should be elements of the Galois field GF(128), constructed using the primitive polynomial:
[pic].
The relationship between GF(128) elements and binary data should be to consider the value of the power of alpha as a 7 bit binary value converted to decimal. The symbol "0" should correspond to a 7 bit value of 127.
3.2 Generator polynomial
The FEC parity should be defined by the following generator polynomial:
[pic].
The relation between a symbol representation and a polynomial is given in Table 3-1.
Table 3-1
Relation between symbol representation and
polynomial representation
|Position |Symbol number |Multiply with |
|Least significant symbol |S1 |x0 |
| |S2 |x1 |
| |… |… |
| |… |… |
|Most significant symbol |Sn |xn-1 |
The following steps should be used in the message encoding process:
1) translation of the binary data to a symbol representation, using the primitive polynomial;
2) translation of the symbol representation obtained in step 1 to a polynomial;
3) multiplication of the polynomial obtained in step 2 with x20;
4) division of the polynomial obtained in step 3 by the generator polynomial;
5) summation of the polynomial obtained in step 3 with the remainder of the division in step 4;
6) translation of the polynomial obtained in step 5 to a symbol or binary representation.
3.3 Order of transmission
The first transmitted pattern of an FEC-encoded message should correspond to the least significant symbol of that message.
3.4 Continuity of modulation
Messages should be transmitted consecutively without interleaving. The pattern transmitted in the first pulse group after the last pattern of a message shall be the first pattern of the next message.
4 Message coding layer
4.1 Generic structure
All message types should be defined with the same structure, consisting of a Message Type, a Message body, and a Cyclic Redundancy Check (CRC). The Message Type should identify the type of data contained in the Message body. The generic structure is given in Table 4-1.
Table 4-1
Generic structure of data section
|Field |Bits used |Bit numbers |
|Message Type |4 |I1 – I4 |
|Message body |52 |I5 – I56 |
|CRC |14 |I57 – I70 |
|Total |70 | |
4.2 Message Type Identification
The Message Type should be in accordance with the information presented in Table 4-2.
Table 4-2
Interpretation of Message Type
|Indication |Message Type |Decimal |
| | |I4 |I3 |I2 |I1 | |
|Type 1 |DGPS Corrections |0 |0 |0 |1 |1 |
|Type 2 |DGLONASS Corrections |0 |0 |1 |0 |2 |
|Type 3 |Reserved |0 |0 |1 |1 |3 |
|Type 4 |Reserved |0 |1 |0 |0 |4 |
|Type 5 |Text Message |0 |1 |0 |1 |5 |
|Type 6 |Reserved |0 |1 |1 |0 |6 |
|Type 7 |Reserved |0 |1 |1 |1 |7 |
|Type 8 |Reserved |1 |0 |0 |0 |8 |
|Type 9 |Reserved |1 |0 |0 |1 |9 |
|Type 10 |Reserved |1 |0 |1 |0 |10 |
|Type 11 |Reserved |1 |0 |1 |1 |11 |
|Type 12 |Reserved |1 |1 |0 |0 |12 |
|Type 13 |Reserved |1 |1 |0 |1 |13 |
|Type 14 |Reserved |1 |1 |1 |0 |14 |
|Type 15 |Reserved |1 |1 |1 |1 |15 |
|Type 16 |Reserved |0 |0 |0 |0 |0 |
4.3 Message bodies
Table 4-3a
Message bit assignment table
| |Message Type |
|Bit Num. |1 |2 |3 |4 |5 |6 |7 |8 |
|1 |0001 |0010 |0011 |0100 |0101 |0110 |0111 |1000 |
|2 | | | | | | | | |
|3 | | | | | | | | |
|4 | | | | | | | | |
|5 |Modified |Modified | | |Sequence Number | | | |
| | | | | | | | | |
| |Z-Count |Z-Count | | | | | | |
| | | | | | | | | |
| |13 bits |13 bits | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | |R |R | |R |R |R |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | |e |e | |e |e |e |
| | | | | | | | | |
| | | | | | | | | |
| | | |s |s | |s |s |s |
| | | | | | | | | |
| | | | | | | | | |
| | | |e |e | |e |e |e |
| | | | | | | | | |
| | | | | | | | | |
| | | |r |r | |r |r |r |
| | | | | | | | | |
| | | | | | | | | |
| | | |v |v | |v |v |v |
| | | | | | | | | |
| | | | | | | | | |
| | | |e |e | |e |e |e |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | |d |d | |d |d |d |
|6 | | | | | | | | |
|7 | | | | | | | | |
|8 | | | | |End | | | |
|9 | | | | |Text | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | |ASCII with | | | |
| | | | | |Cyrillic | | | |
| | | | | |extensions | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | |6 words | | | |
| | | | | |by | | | |
| | | | | |8 bits | | | |
| | | | | |per | | | |
| | | | | |word | | | |
|10 | | | | | | | | |
|11 | | | | | | | | |
|12 | | | | | | | | |
|13 | | | | | | | | |
|14 | | | | | | | | |
|15 | | | | | | | | |
|16 | | | | | | | | |
|17 | | | | | | | | |
|18 |Scale |Scale | | | | | | |
|19 |UDRE |UDRE | | | | | | |
|20 | | | | | | | | |
|21 |Satellite |Satellite | | | | | | |
| |PRN |PRN | | | | | | |
|22 | | | | | | | | |
|23 | | | | | | | | |
|24 | | | | | | | | |
|25 | | | | | | | | |
|26 |P |P | | | | | | |
| | | | | | | | | |
| |R |R | | | | | | |
| | | | | | | | | |
| |C |C | | | | | | |
| | | | | | | | | |
| |15 bits |15 bits | | | | | | |
|27 | | | | | | | | |
|28 | | | | | | | | |
|29 | | | | | | | | |
|30 | | | | | | | | |
|31 | | | | | | | | |
|32 | | | | | | | | |
|33 | | | | | | | | |
|34 | | | | | | | | |
|35 | | | | | | | | |
|36 | | | | | | | | |
|37 | | | | | | | | |
|38 | | | | | | | | |
|39 | | | | | | | | |
|40 | | | | | | | | |
|41 |R |R | | | | | | |
| | | | | | | | | |
| |R |R | | | | | | |
| | | | | | | | | |
| |C |C | | | | | | |
| | | | | | | | | |
| |8 bits |8 bits | | | | | | |
|42 | | | | | | | | |
|43 | | | | | | | | |
|44 | | | | | | | | |
|45 | | | | | | | | |
|46 | | | | | | | | |
|47 | | | | | | | | |
|48 | | | | | | | | |
|49 |I |Change | | | | | | |
| | | | | | | | | |
| |O | | | | | | | |
| | | | | | | | | |
| |D | | | | | | | |
| | | | | | | | | |
| |8 bits | | | | | | | |
|50 | |T | | | | | | |
| | | | | | | | | |
| | |O | | | | | | |
| | | | | | | | | |
| | |D | | | | | | |
| | |7 bits | | | | | | |
|51 | | | | | | | | |
|52 | | | | | | | | |
|53 | | | | | | | | |
|54 | | | | | | | | |
|55 | | | | | | | | |
|56 | | | | | | | | |
|57-70 |CRC |CRC |CRC |CRC |CRC |CRC |CRC |CRC |
Table 4-3b
Message bit assignment table
| |Message Type |
|Bit Num. |9 |10 |11 |12 |13 |14 |15 |16 |
|1 |1001 |1010 |1011 |1100 |1101 |1110 |1111 |0000 |
|2 | | | | | | | | |
|3 | | | | | | | | |
|4 | | | | | | | | |
|5 | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | | | | |
| |R |R |R |R |R |R |R |R |
| | | | | | | | | |
| | | | | | | | | |
| |e |e |e |e |e |e |e |e |
| | | | | | | | | |
| | | | | | | | | |
| |s |s |s |s |s |s |s |s |
| | | | | | | | | |
| | | | | | | | | |
| |e |e |e |e |e |e |e |e |
| | | | | | | | | |
| | | | | | | | | |
| |r |r |r |r |r |r |r |r |
| | | | | | | | | |
| | | | | | | | | |
| |v |v |v |v |v |v |v |v |
| | | | | | | | | |
| | | | | | | | | |
| |e |e |e |e |e |e |e |e |
| | | | | | | | | |
| | | | | | | | | |
| |d |d |d |d |d |d |d |d |
|6 | | | | | | | | |
|7 | | | | | | | | |
|8 | | | | | | | | |
|9 | | | | | | | | |
|10 | | | | | | | | |
|11 | | | | | | | | |
|12 | | | | | | | | |
|13 | | | | | | | | |
|14 | | | | | | | | |
|15 | | | | | | | | |
|16 | | | | | | | | |
|17 | | | | | | | | |
|18 | | | | | | | | |
|19 | | | | | | | | |
|20 | | | | | | | | |
|21 | | | | | | | | |
|22 | | | | | | | | |
|23 | | | | | | | | |
|24 | | | | | | | | |
|25 | | | | | | | | |
|26 | | | | | | | | |
|27 | | | | | | | | |
|28 | | | | | | | | |
|29 | | | | | | | | |
|30 | | | | | | | | |
|31 | | | | | | | | |
|32 | | | | | | | | |
|33 | | | | | | | | |
|34 | | | | | | | | |
|35 | | | | | | | | |
|36 | | | | | | | | |
|37 | | | | | | | | |
|38 | | | | | | | | |
|39 | | | | | | | | |
|40 | | | | | | | | |
|41 | | | | | | | | |
|42 | | | | | | | | |
|43 | | | | | | | | |
|44 | | | | | | | | |
|45 | | | | | | | | |
|46 | | | | | | | | |
|47 | | | | | | | | |
|48 | | | | | | | | |
|49 | | | | | | | | |
|50 | | | | | | | | |
|51 | | | | | | | | |
|52 | | | | | | | | |
|53 | | | | | | | | |
|54 | | | | | | | | |
|55 | | | | | | | | |
|56 | | | | | | | | |
|57-70 |CRC |CRC |CRC |CRC |CRC |CRC |CRC |CRC |
4.4 Definitions
1 "Modified" Z-count
The Z-count represents the reference time for the differential data messages. The Z-count begins at 0, at the beginning of each hour in GPS or GLONASS time and ranges to a maximum value of 3 599.4 s, with a resolution of 0.6 s. It is used to compute the GPS time or GLONASS time of the corrections, in the same manner as other time calculations are made in the user's receivers.
2 Scale factor
Two states of the scale factor for pseudorange corrections may be used and these are defined in Table 4-4. The rationale for the two-level scale factor is to maintain a high degree of precision most of the time, and the ability to increase the range of the corrections on those rare occasions when it is needed.
TABLE 4-4
Scale factor
|Code |No. |Indication |
|0 |(0) |Scale factor for pseudorange correction is 0.02 m and for range rate correction is 0.002 m/s|
|1 |(1) |Scale factor for pseudorange correction is 0.32 m and for range rate correction is 0.032 m/s|
4.4.3 User differential range error (UDRE)
An estimate of the root-mean-square error in the differential pseudorange correction. It is influenced by such factors as satellite signal-to-noise ratio, multipath effects and data smoothing. Table 4-5 defines the format for the UDRE field.
TABLE 4-5
User differential range error (UDRE)
|Code |No. |1 σ differential error |
| | |(m) |
|00 |(0) |≤ 1 |
|01 |(1) |> 1 and ≤ 4 |
|10 |(2) |> 4 and ≤ 8 |
|11 |(3) |Reference station not useable |
4.4.4 Satellite ID
Standard format (1-32, 32 is indicated with all zeros).
4.4.5 Pseudorange Correction (PRC)
The pseudorange correction describes the estimated correction at the time of measurement in the reference receiver. The relationship between pseudorange correction, range rate correction and reference time is defined by the following equation:
[pic].
The pseudorange correction is given as a 2's complement value. The resolution depends on the scale factor.
4.4.6 Range-rate Correction (RRC)
The range rate correction describes the estimate of the rate of change of the pseudorange correction at the time of measurement in the reference receiver. The use of the range rate correction is described by the previous equation. The resolution depends on the scale factor.
4.4.7 Issue of data (IOD)
The issue of data (IOD) as broadcast by the reference station is the value in the GPS navigational messages which corresponds to the GPS ephemeris data used to compute corrections. This is a key to ensure that the user equipment calculations and reference station corrections are based on the same set of broadcast orbital and clock parameters.
4.4.8 Tb of navigation data (TOD)
The time within the current 24 h period by UTC(SU), which includes the operational information transmitted in the frame.
4.4.9 Sequence Number
The Message Number should be equal for all portions of one text message. The Message Number should increase with unit step for subsequent text messages, restarting at "000" after "111".
4.4.10 End of Message (End)
The End-of-Message indicates the last portion of a text message. A value of "0" should indicate that more portions are required to complete the text message. A value of "1" should indicate completion of the text message.
4.4.11 Text characters
Up to six (6) characters of eight (8) bits each are accommodated in each portion of a text message. Codes from 0-127 should correspond to standard ASCII codes. Cyrillic characters should be represented by codes greater than 127.
4.5 Cyclic Redundancy Check (CRC)
The cyclic redundancy check should be generated using the following polynomial:
[pic].
The following steps should be used in the calculation of the cyclic redundancy check:
1) translation of the data, including the Message Type field to a polynomial following the convention defined in Table 6. The resulting polynomial will not contain higher orders of x than x55;
2) multiplication of the polynomial obtained in step 1 with x14;
3) division of the polynomial obtained in step 2 by the generator polynomial;
4) translation of the remainder of the division in step 3 to a binary representation is the CRC.
Table 4-6
Relation between binary representation and
polynomial representation
|Position |Bit number |Multiply with |
|LSB |I1 |x0 |
| |I 2 |x1 |
| |… |… |
| |… |… |
|MSB |In |xn-1 |
_______________
Part 3
Preparations for WRC-03 (Attachment 11 to ITU-R Document 8B/49-E - Report of the eighth meeting of Working Party 8B)
ICAO Secretariat comments:
This paper is based on on Document 8B/TEMP/6, produced by the October 2000 meeting of WP8B. It provides a work plan for WP 8B on ITU-R preparatory work in which Working Party 8B is responsible.
This work plan includes:
1 Items for which WP 8B is primary responsible.
a. WRC-2003 agenda item 1.4 "to consider the results of studies related to Resolution 114 (WRC-95), dealing with the use of the band 5091 - 5150 MHz by the fixed satellite service (Earth-to-space) (limited to non-GSO MSS feeder links), and to review the allocation to the aeronautical radionavigation service and the fixed satellite service in the band 5091 - 5150 MHz."
In ICAO, work on this agenda item has been initiated by AMCP WG F, in collaboration with the European Frequency Management Group (FIG). A preliminary ICAO position on this agenda item has been developed and further work is ongoing. Results have to be presented to ITU-R in a timely manner.
b. WRC-2003 agenda item 1.14 "to consider measures to address harmful interference in the band allocated to the maritime mobile and aeronautical mobile (R) services, taking into account Resolutions 207 and 350, and to review the frequency and channel arrangements in the maritime MF and HF bands concerning the use of new digital technology, also taking into account Resolution 347."
In ICAO, work on this agenda item has been initiated by AMCP WG F. Only Resolution 207 is relevant to the AM(R)S. An initial ICAO position on this agenda item has been developed and further work is ongoing.
c. WRC-2003 agenda item 4 "in accordance with Resolution 95, to review the resolutions and recommendations of previous conferences with a view to their possible revision, replacement or abrogation."
This agenda item of the WRC requires primarily further consideration by AMCP WG F. Work on this subject will be initiated at the WG F meeting planned for March/April 2001.
AMCP WG ACTION: initiated review of resolutions/recommendations
2. Items for which WP 8B is contributing (to other WP's) or interested.
a. WRC-2003 agenda item 1.24 "to review the usage of the band 13.75 - 14 GHz, in accordance with resolution 733, with a view to addressing the sharing conditions"
On this agenda item an ICAO position has been drafted and further review of it is unlikely.
b. WRC-2003 agenda item 1.5 "to consider, in accordance with resolution 736, regulatory provisions and spectrum requirements for new and additional allocations to the mobile, fixed, Earth exploration satellite and space research services, and to review the status of the radiolocation service in the frequency range 5150 - 5725 MHz, with a view to upgrading it, taking into account the results of ITU studies."
On this agenda item an ICAO position has been drafted and further review of it is unlikely. Developments on the work on this agenda item needs to be followed carefully in order to preserve the future use of the band 5360 - 5470 MHz by the aeronautical radionavigation service.
c. WRC-2003 agenda item 1.8 "to consider issues related to unwanted emissions"
On this agenda item an ICAO position has been drafted. However, in the light of further developments in ITU-R, further refinement of this position may be required in order to avoid unduly constraints to the aeronautical mobile and radionavigation services.
d. WRC-2003 agenda item 1.15 "to review the results of studies concerning the radionavigation satellite service in accordance with resolutions 604, 605 and 606."
This agenda item refers to the introduction of allocations to the radionavigation satellite service in various frequency bands. The involvement of 8B mainly relates to the need to protect existing use of the bands around 1 GHz for TACAN/DME and radar systems.
e. WRC-2003 agenda item 1.31 "to consider additional allocations to the mobile satellite service in the 1-3 GHz band, in accordance with resolutions 226 and 227."
On this agenda item an ICAO position has been drafted and further review of it is unlikely.
AMCP WGF ACTION: Note
ATTACHMENT 11
(Source: Document 8B/TEMP/6)
preparations for wrc-03
WP 8B CREATED AN ELECTRONIC CORRESPONDENCE GROUP TO PROGRESS THE WORK OF CPM AND WRC-03 PREPARATIONS IN THE INTERIM BETWEEN MEETINGS. MS DARLENE DRAZENOVICH WAS NOMINATED AS THE RAPPORTEUR FOR THIS GROUP.
The WRC-03 agenda items assigned to WP 8B as the responsible group and contributing/interested group are detailed in Annexes 1 and 2 respectively. WP 8B will contribute to the work of the Special Committee on Regulatory/Procedural matters, as appropriate, and as it pertains to WRC-03 agenda item 1.4 specifically and any other agenda item that WP 8B deems to have regulatory and procedural implications per Annex 3. A work plan to prepare for WRC-03 to include deliverables and a timeline for WP 8B completion of the deliverables is contained in Annex 4. Administrations and members are requested to submit contributions to next meeting of WP 8B to advance the studies required for WRC-03.
Annexes: 4
Annex 1
(to Attachment 11)
Allocations of ITU-R preparatory work for the 2003 World Radiocommunication Conference
WP 8B as Responsible Group
|Topic |Responsible |Action to be taken by the ITU-R Study Group |Contributing/ |
| |Group* | |interested Group |
|1.4 to consider the results of studies related to Resolution 114 (WRC-95), dealing with the use of the band 5 091-5 150 MHz by the fixed-satellite service (Earth-to-space) (limited to non-GSO MSS feeder links), and |
|review the allocations to the aeronautical radionavigation service and the fixed-satellite service in the band 5 091-5 150 MHz; |
|Resolution 114 (WRC-95) |SG 8 |1 to study the technical and operational issues relating to sharing of this band between the aeronautical |WP 8D, |
|Use of the band 5 091-5 150 MHz by the fixed-satellite service |(WP 8B) |radionavigation service and the fixed-satellite service providing feeder links of the non-GSO |WP 4A, WP 7E |
|(Earth-to-space) (limited to feeder links of the | |mobile-satellite service (Earth-to-space); | |
|non-geostationary mobile-satellite service) | |2 to bring the results of these studies to the attention of WRC-01, | |
|1.9 to consider Appendix S13 and Resolution 331 (Rev.WRC-97) with a view to their deletion and, if appropriate, to consider related changes to Chapter SVII and other provisions of the Radio Regulations, as |
|necessary, taking into account the continued transition to and introduction of the Global Maritime Distress and Safety System (GMDSS); |
|Resolution 331 (Rev.WRC-97) |SG 8 |invites the Radiocommunication Study Group 8 | |
|Transition to the Global Maritime Distress and Safety System |(WP 8B) |to review the operational and procedural incompatibilities between the old and new systems with a view to | |
|(GMDSS) and continuation of the distress and safety provisions | |presenting the information to WRC-01. | |
|in Appendix S13 | | | |
|1.10 to consider the results of studies, and take necessary actions, relating to: |
|1.10.1 exhaustion of the maritime mobile service identity numbering resource (Resolution 344 (WRC-97)); |
|Resolution 344 (WRC-97) |SG 8 |1 to keep under review the Recommendations for assigning MMSIs, with a view to identifying alternative | |
|Exhaustion of the maritime mobile service identity numbering |(WP 8B) |resources before the resources are exhausted; | |
|resource | |2 to consult each other when addressing changes to any of the Recommendations affecting the MMSI numbering | |
| | |resources; | |
| | |3 to complete studies on an urgent basis when a future world radiocommunication conference identifies the | |
| | |impending exhaustion of the MMSI resource, | |
|1.10.2 shore-to-ship distress communication priorities (Resolution 348 (WRC-97)); |
|Resolution 348 (WRC-97) |SG 8 |recognizing | |
|Studies required to provide priority to distress communications |(WP 8B) |a) that life and property may be lost if rapid access is not provided for distress related communications | |
|originated by shore-based search and rescue authorities | |originated by the rescue authority; | |
| | |b) that the International Maritime Organization (IMO) has considered this problem and decided that | |
| | |provisions are necessary for giving priority to shore-originated distress communications; | |
| | |c) that Inmarsat is currently studying how to provide such priority communications, | |
| | |resolves to invite | |
| | |1 ITU-R to monitor the status of these studies and to develop suitable Recommendations; | |
|1.14 to consider measures to address harmful interference in the bands allocated to the maritime mobile and aeronautical mobile (R) services, taking into account Resolutions 207 (Rev.WRC-2000) and 350 [COM5/12] |
|(WRC-2000), and to review the frequency and channel arrangements in the maritime MF and HF bands concerning the use of new digital technology, also taking into account Resolution 347 (WRC-97); |
|Resolution 207 (Rev.WRC-2000) |SG 8 |1 to study possible technical and regulatory solutions to assist in the mitigation of interference to |WP 3L, WP 9C |
|Measures to address unauthorized use of and interference to |(WP 8B) |operational distress and safety communications in the maritime mobile service and aeronautical mobile (R) | |
|frequencies in the bands allocated to the maritime mobile service| |service; | |
|and to the aeronautical mobile (R) service | |2 to increase regional awareness of appropriate practices in order to help mitigate interference in the HF | |
| | |bands, especially on distress and safety channels; | |
| | |3 to report the results of the above studies to the next competent conference, | |
|Resolution 350 [COM5/12] (WRC-2000) |SG 8 |1 to invite ITU-R to study the interference to the distress and safety frequencies 12 290 kHz and 16 420 kHz |WP 9C |
|Study on interference caused to the distress and safety |(WP 8B) |caused by routine calling on channels 1221 and 1621; | |
|frequencies 12 290 kHz and 16 420 kHz by routine calling | |2 to instruct the Radiocommunication Bureau, in consultation with administrations, to organize monitoring | |
| | |programmes for the support of these studies; | |
| | |3 to urge administrations to participate actively in these studies; | |
| | |4 to invite ITU-R to complete these studies in time for consideration by WRC-03; | |
| | |5 to invite WRC-03 to consider this issue, | |
|Resolution 347 (WRC-97) | |To be noted. | |
|Use of digital telecommunication technologies in the MF and HF | | | |
|bands by the maritime mobile service | | | |
|1.17 to consider upgrading the allocation to the radiolocation service in the frequency range 2 900-3 100 MHz to primary; |
| |SG 8 |to complete the studies on technical and operational issues related to the upgrading of the radiolocation | |
| |(WP 8B) |service allocation taking into account Nos. S5.425, S5.426 and S5.427 | |
|1.28 to permit the use of the band 108-117.975 MHz for the transmission of radionavigation satellite differential correction signals by ICAO standard ground-based systems; |
| |SG 8 |to undertake studies for consideration by WRC-03, relating to technical and operational issues relating to | |
| |(WP 8B) |the use of 108-177.975 MHz for the transmission of radionavigation-satellite differential corrections by | |
| | |ICAO standard ground-based systems | |
|4 in accordance with Resolution 95 (Rev.WRC-2000), to review the resolutions and recommendations of previous conferences with a view to their possible revision, replacement or abrogation; |
|Resolution 95 (Rev.WRC-2000) | | instructs the Director of the Radiocommunication Bureau | |
|General review of the resolutions and recommendations of world | |1 to conduct a general review of the resolutions and recommendations of previous conferences and, after | |
|administrative radio conferences and world radiocommunication | |consultation with the Radiocommunication Advisory Group and the chairpersons and vice-chairpersons of the | |
|conferences | |radiocommunication study groups, submit a report to the second session of the Conference Preparatory Meeting| |
| | |in respect of resolves 1 and resolves 2; | |
| | |2 if practicable, to include in the above report an indication of the agenda item, if appropriate, and | |
| | |possible responsible committees within the conference for each text, based on the available information as | |
| | |to the possible structure of the conference, | |
| | |invites the Conference Preparatory Meeting | |
| | |to include, in its report, the results of a general review of the resolutions and recommendations of | |
| | |previous conferences. | |
Contributing Group (bolded) shall submit the contribution.
Interested Group (not bolded) may submit the contribution.
Annex 2
(to Attachment 11)
Allocations of ITU-R preparatory work for the 2003 World Radiocommunication Conference WP 8B as Contributing/Interested Group
|Topic |Responsible |Action to be taken by the ITU-R Study Group |Contributing/ interested |
| |Group* | |Group |
|1.24 to review the usage of the band 13.75-14 GHz, in accordance with Resolution 733 [COM5/10] (WRC-2000), with a view to addressing sharing conditions; |
|Resolution 733 [COM 5/10] (WRC-2000) |JTG 4-7-8 |1 to conduct studies, as a matter of urgency and in time for consideration by WRC-03, on the sharing | |
|Review of sharing conditions between services in the band 13.75-14| |conditions indicated in Nos. S5.502 and S5.503, with a view to reviewing the constraints in No. S5.502 | |
|GHz | |regarding the minimum antenna diameter of GSO FSS earth stations and the constraints on the e.i.r.p. of| |
| | |the radiolocation service; | |
| | |2 to identify and study, in time for consideration by WRC-03, possible alternative sharing conditions | |
| | |to those indicated in Nos. S5.502 and S5.503. | |
|1.5 to consider, in accordance with Resolution 736 [GT PLEN-2/1] (WRC-2000), regulatory provisions and spectrum requirements for new and additional allocations to the mobile, fixed, Earth exploration-satellite and |
|space research services, and to review the status of the radiolocation service in the frequency range 5 150-5 725 MHz, with a view to upgrading it, taking into account the results of ITU-R studies; |
|Resolution 736 [GT PLEN-2/1] (WRC-2000) |JTG |resolves | |
|Consideration by a future competent world radiocommunication |4-7-8-9 |that, on proposals from administrations and taking into account the results of studies in ITU-R and the| |
|conference of issues dealing with allocations to the mobile, | |Conference Preparatory Meeting, [WRC-03] should consider: |WP 4A, WP 7C WP 8A, 8D, |
|fixed, radiolocation, Earth exploration-satellite (active), and | |1 allocation of frequencies to the mobile service in the bands 5 150-5 350 MHz and 5 470-5 725 MHz for |WP 9B, |
|space research (active) services in the frequency range 5 150-5 | |the implementation of wireless access systems including RLANs; |WP 9D, WP 7C |
|725 MHz | |2 a possible allocation in Region 3 to the fixed service in the band 5 250- | |
| | |5 350 MHz, while fully protecting the worldwide Earth exploration-satellite (active) and space research|WP 8A, 8B, WP 7C, WP 9B |
| | |(active) services; |WP 8B, WP 7C |
| | |3 additional primary allocations for the Earth exploration-satellite service (active) and space | |
| | |research service (active) in the frequency range 5 460-5 570 MHz; | |
| | |4 review, with a view to upgrading, of the status of frequency allocations to the radiolocation service| |
| | |in the frequency range 5 350-5 650 MHz, | |
| | |invites ITU-R | |
| | |to conduct, and complete in time for [WRC-03], the appropriate studies leading to technical and | |
| | |operational recommendations to facilitate sharing between the services referred to in the resolves and | |
| | |existing services. | |
|1.8 to consider issues related to unwanted emissions: |
|1.8.1 consideration of the results of studies regarding the boundary between spurious and out-of-band emissions, with a view to including the boundary in Appendix S3; |
|Recommendation 66 (Rev.WRC-2000) |SG 1 |4 study the reasonable boundary of spurious emissions and out-of-band emissions with a view to defining|SG 7, 8 |
|Studies of the maximum permitted levels of unwanted emissions |(TG 1/5) |such a boundary in Article S1; |WP 6E, WP 6S, WP 4A, WP |
| | | |9B, WP 9C |
|1.8.2 consideration of the results of studies, and proposal of any regulatory measures regarding the protection of passive services from unwanted emissions, in particular from space service transmissions, in response |
|to recommends 5 and 6 of Recommendation 66 (Rev.WRC-2000); |
|Recommendation 66 (Rev.WRC-2000) |SG 1 |5 study those frequency bands and instances where, for technical or operational reasons, more stringent|SG 3, 4, 8 |
|Studies of the maximum permitted levels of unwanted emissions |(TG 1/5) |spurious emission limits than the general limits in Appendix S3 may be required to protect safety |WP 6E, 6S, WP 7D, WP 9B, |
| | |services and passive services such as radio astronomy, and the impact on all concerned services of |9C |
| | |implementing or not implementing such limits; | |
| | |6 study those frequency bands and instances where, for technical or operational reasons, out-of-band | |
| | |limits may be required to protect safety services and passive services such as radio astronomy, and the| |
| | |impact on all concerned services of implementing or not implementing such limits; | |
| | |8 report the results of these studies to a competent world radiocommunication conference(s). | |
|1.12 to consider allocations and regulatory issues related to the space science services in accordance with Resolution 723 (Rev.WRC-2000) and to review all Earth exploration-satellite service and space research |
|service allocations between 35 and 38 GHz, taking into account Resolution 730 [COM5/1] (WRC-2000); |
|Resolution 723 (Rev.WRC-2000) |SG 7 |resolves |WP 7B, |
|Consideration by a future competent world radiocommunication |(WP 7E) |to recommend that WRC-03 consider the following matters: |SG 8, WP 6E, WP 9D |
|conference of issues dealing with allocations to science services | |1 provision of up to 3 MHz of frequency spectrum for the implementation of telecommand links in the |WP 7B |
| | |space research and space operations services in the frequency range 100 MHz to 1 GHz; |WP 9 D |
| | |2 to consider incorporating in the Table of Frequency Allocations the existing primary allocation to |WP 7B, WP 9D WP 4A, WP 3M |
| | |the space research service in the band 7 145-7 235 MHz under No. S5.460; | |
| | |3 to review the allocations to the space research service (deep space) (space-to-Earth) and the |WP 7B, WP 9D SG 8, WP 3M, |
| | |inter-satellite service, taking into account the coexistence of these two services in the frequency |WP 4A, |
| | |range 32-32.3 GHz, with a view to facilitating satisfactory operation of these services; | |
| | |4 to review existing allocations to space science services near 15 GHz and 26 GHz, with a view to | |
| | |accommodating wideband space-to-Earth space research applications, | |
| | |invites ITU-R | |
| | |to complete the necessary studies, as a matter of urgency, taking into account the present use of | |
| | |allocated bands, with a view to presenting, at the appropriate time, the technical information likely | |
| | |to be required as a basis for the work of the conference, | |
|Resolution 730 [COM5/1] (WRC-2000) |SG 7 |1 to invite ITU-R to study sharing between spaceborne precipitation radars and other services in the |WP 7C, WP 8B |
|Use of the frequency band 35.5-35.6 GHz by spaceborne |(WP 7E) |band 35.5-35.6 GHz; |SG 3, 9, WP 4A |
|precipitation radars | |2 to recommend that WRC-03 review the results of those studies and consider the removal of the | |
| | |restriction currently contained in No. S5.551A on spaceborne precipitation radars operating in the | |
| | |Earth exploration-satellite service in the band 35.5-35.6 GHz. | |
|1.13 to consider regulatory provisions and possible identification of existing frequency allocations for services which may be used by high altitude platform stations, taking into account No. S5.5RRR and the results |
|of the ITU-R studies conducted in accordance with Resolutions 122 (Rev.WRC-2000) and 734 [COM5/14] (WRC-2000); |
|Resolution 734 [COM5/14] (WRC-2000) |SG 9 |to carry out, as a matter of urgency, regulatory and technical studies to determine the feasibility of |SG 8, WP 9D |
|Feasibility of use by high altitude platform stations in the fixed|(WP 9B) |facilitating systems using HAPS in the fixed and mobile services in bands above 3 GHz allocated | |
|and mobile services in the frequency bands above 3 GHz allocated | |exclusively by the Table of Frequency Allocations or by footnotes for terrestrial radiocommunication, | |
|exclusively for terrestrial radiocommunication | |taking account of existing use and future requirements in these bands, and any impact on allocations in | |
| | |adjacent bands, | |
|1.15 to review the results of studies concerning the radionavigation-satellite service in accordance with Resolutions 604 [COM5/16] (WRC-2000), 605 [COM5/19] (WRC-2000) and 606 [COM5/20] (WRC-2000); |
|Resolution 604 [COM5/16] (WRC-2000) |SG 8 |1 to conduct, or continue to conduct, as a matter of urgency and in time for consideration by WRC-03, the|WP 7D |
|Studies on compatibility between the radionavigation-satellite |(WP 8D) |appropriate technical, operational and regulatory studies to review the provisional pfd limit concerning | |
|service (space-to-Earth) operating in the frequency band | |the operation of space stations, including the development of a methodology for calculating the aggregate| |
|5 010-5 030 MHz and the radio astronomy service operating in the | |power levels in order to ensure that the RNSS (space-to-Earth) in the band 5 010-5 030 MHz will not cause| |
|band 4 990-5 000 MHz | |interference detrimental to the RAS in the band 4 990-5 000 MHz; | |
| | |2 to report to CPM-02 on the conclusions of these studies, | |
|Resolution 605 [COM5/19] (WRC-2000) |SG 8 |to conduct, as a matter of urgency and in time for WRC-03, the appropriate technical, operational and |WP 8B |
|Use of the frequency band 1 164-1 215 MHz by systems of the |(WP 8D) |regulatory studies on the overall compatibility between the radionavigation-satellite service and the | |
|radionavigation-satellite service (space-to-Earth) | |aeronautical radionavigation service in the band 960-1 215 MHz, including an assessment of the need for | |
| | |an aggregate power flux-density limit, and revision, if necessary, of the provisional pfd limit given in | |
| | |No. S5.328A concerning the operation of radionavigation-satellite service (space-to-Earth) systems in the| |
| | |frequency band 1 164-1 215 MHz, | |
|Resolution 606 [COM5/20] (WRC-2000) |SG 8 |to conduct, as a matter of urgency and in time for WRC-03, the appropriate technical, operational and |WP 7C, |
|Use of the frequency band 1 215-1 300 MHz by systems of the |(WP 8D) |regulatory studies, including an assessment of the need for a power flux-density limit concerning the |WP 8B |
|radionavigation-satellite service (space-to-Earth) | |operation of radionavigation-satellite service (space-to-Earth) systems in the frequency band 1 | |
| | |215-1 300 MHz in order to ensure that the radionavigation-satellite service (space-to-Earth) will not | |
| | |cause harmful interference to the radionavigation and the radiolocation services, | |
|1.31 to consider the additional allocations to the mobile-satellite service in the 1-3 GHz band, in accordance with Resolutions 226 [COM5/29] (WRC-2000) and 227 [COM5/30] (WRC-2000); |
|Resolution 226 [COM5/29] |SG 8 |1 to study, as a matter of urgency, sharing between the MSS and aeronautical mobile telemetry in all the |WP 9B, 9D, |
|Sharing studies for, and possible additional allocations to, the |(WP 8D) |Regions in the band 1 518-1 525 MHz, taking into account, inter alia, Recommendation ITU-R M.1459; |WP 8B |
|mobile-satellite service (space-to-Earth) in the 1-3 GHz range, | |2 to review, as a matter of urgency, the pfd levels used as coordination thresholds for MSS |WP 4A, WP 6E, WP 6S, WP 7E|
|including consideration of the band | |(space-to-Earth) with respect to the protection of point-to-multipoint fixed-service systems in the band | |
|1 518-1 525 MHz | |1 518-1 525 MHz in Regions 1 and 3, taking into account the work already done in Recommendations ITU-R | |
| | |M.1141 and ITU-R M.1142 and the characteristics of fixed-service systems contained in Recommendations | |
| | |ITU-R F.755-2 and ITU-R F.758-1, and the sharing methodologies contained in Recommendations ITU-R | |
| | |F.758-1, ITU-R F.1107 and ITU-R F.1108; | |
| | |3 in the event that the studies of the specific frequency bands referred to in this resolution lead to an| |
| | |unsatisfactory conclusion, to carry out sharing studies in order to recommend alternative MSS | |
| | |(space-to-Earth) frequency bands in the 1-3 GHz range, but excluding the band 1 559-1 610 MHz, for | |
| | |consideration at WRC-03; | |
| | |4 to bring the results of these studies to the attention of WRC-03, | |
|Resolution 227 [COM5/30] |SG 8 |1 to complete, as a matter of urgency and in time for WRC-03, the technical and operational studies on |WP 7C, WP 9D, |
|Sharing studies for, and possible additional allocations to, the |(WP 8D) |the feasibility of sharing between MSS and MetSat, by determining appropriate separation distances |WP 8B |
|mobile-satellite service (Earth-to-space) in the 1-3 GHz range, | |between mobile earth stations and MetSat stations, including GVAR/S-VISSR stations, in the band 1 683-1 |WP 4A, WP 6E, WP 6S, WP 9B|
|including consideration of the band | |690 MHz, as stated in Recommendation ITU-R SA.1158-2; | |
|1 683-1 690 MHz | |2 to assess, with the participation of WMO, the current and future spectrum requirements of the MetAids | |
| | |service, taking into account improved characteristics, and of the MetSat service in the band 1 683-1 690 | |
| | |MHz, taking into account future developments; | |
| | |3 in the event that the studies of the specific frequency band referred to in this resolution lead to an | |
| | |unsatisfactory conclusion, to carry out sharing studies in order to recommend alternative MSS | |
| | |(Earth-to-space) frequency bands in the 1-3 GHz range, but excluding the band 1 559-1 610 MHz, for | |
| | |consideration at WRC-03; | |
| | |4 to bring the results of these studies to the attention of WRC-03, | |
|8 to recommend to the Council that additional budgetary and conference resources be provided so that the following items can be included in this agenda for WRC-03: |
|8.1 to examine the adequacy of the frequency allocations for HF broadcasting from about 4 MHz to 10 MHz, taking into account the seasonal planning procedures adopted by WRC-97; |
| |SG 6 | |WP 8A, 8B, WP 9C |
| |(WP 6E) | | |
ANNEX 3
(to Attachment 11)
Organization of the work of the Special Committee
on Regulatory/Procedural matters
Pursuant to Resolution ITU-R 38-2 the CPM invites the Special Committee on Regulatory/Procedural Matters (SC) to focus its work, in particular, on the following topics, for which the CPM has noted that four Rapporteur Groups will be created. This does not preclude that the SC may establish other Rapporteur Groups or to address other issues of a regulatory/procedural nature as necessary.
|SC-1 |Regulatory/procedural aspects relating to Appendices S30, S30A and unplanned BSS in the |
|Mr Jean CHARTIER |framework of WRC-03 agenda items 1.27 and 1.34 |
|chartier@anfr.fr | |
|SC-2 |Regulatory/procedural aspects relating to the fixed-satellite service in the framework of |
|Mr Edward DAVISON |WRC-03 agenda items 1.19, 1.25, 1.26, 1.29. 1.30, 1.32 and 7.1 |
|edavison@ntia. | |
|SC-3 |Regulatory/procedural aspects relating to space science services and to sharing issues in |
|Mr Srinivasan SAYEENATHAN |the 5 GHz band in the framework of WRC-03 agenda items 1.4, 1.5, 1.6 and 1.12 |
|srinivasan.sayeenathan@ties.itu.int | |
|SC-4 |Regulatory/procedural aspects relating to high altitude platform stations in the framework |
|Mr Katsuhiko KOSAKA |of WRC-03 agenda items 1.13 and 1.33 |
|katsuhiko.kosaka@ties.itu.int | |
ANNEX 4
(to Attachment 11)
Work programme
|Agenda item |Deliverables |Timeline |
|1.4 |DNR technical and operational characteristics of systems in the aeronautical |October 2001 |
| |radionavigation service in the band 5 091-5 150 MHz | |
|1.4 |DNR on sharing between systems in the aeronautical radionavigation service |October 2001 |
| |and non-GSO feeder links in the mobile satellite service in the band 5 091-5 | |
| |150 MHz | |
|1.9 |Report on the operational and procedural incompatibilities between the old |October 2001 |
| |and new systems | |
|1.9 |Modification to Chapter SVII as a result of consequential suppression of |October 2001 |
| |Appendix S13 | |
|1.10.1 |Revision to Recommendation ITU-R M.585-2 Assignment and use of MMSIs, with a |October 2001 |
| |view to identifying alternative resources before the resources are exhausted | |
|1.10.2 |PDNR or report on priority for shore-originated distress communications |October 2001 |
|1.14 |PDNR or report on technical and regulatory solutions to assist in the |October 2001 |
| |mitigation of interference to operational distress and safety communications | |
| |in the maritime mobile service and aeronautical mobile (R) service | |
|1.14 |Report on increasing regional awareness of appropriate practices in order to |October 2001 |
| |help mitigate interference in the HF bands, especially on distress and safety| |
| |channels | |
|1.14 |Develop a monitoring programme in consultation with the BR for the support of|Completed* |
| |studies on the interference to the distress and safety frequencies 12 290 kHz| |
| |and 16 420 kHz caused by routine calling on channels 1221 and 1621 | |
|1.14 |Report on the interference to the distress and safety frequencies 12 290 kHz |October 2001 |
| |and 16 420 kHz caused by routine calling on channels 1221 and 1621 | |
|1.17 |PDNR on sharing, technical and operational issues between radars in the |October 2001 |
| |radiolocation and radionavigation services (taking into account Nos. S5.425, | |
| |S5.426 and S5.427) | |
|1.241 |Report on usage in the band 13.75-14 GHz |October 2001 |
|1.24 |Liaison statement to JTG 4-7-8 |October 2000 |
|1.241 |DNR on technical and operational characteristics of radars in the 13.75-14 |May 2001** |
| |GHz band | |
|1.28 |Report on technical and operational issues relating to the use of 108-117.975|October 2001 |
| |MHz for the transmission of radionavigation-satellite differential | |
| |corrections by ICAO standard ground-based systems | |
|1.5 |Liaison statement to JTG 4-7-8-9 |October 2000 |
|1.52 |PDNR for operational and technical characteristics of radars in the |May 2001 |
| |radiolocation service in the frequency range 5 350-5 650 MHz | |
|1.83 |study the reasonable boundary of spurious emissions and out-of-band emissions|October 2001 |
| |with a view to defining such a boundary in Article S1 | |
|1.83 |study those frequency bands and instances where, for technical or operational|October 2001 |
| |reasons, more stringent spurious emission limits than the general limits in | |
| |Appendix S3 may be required to protect safety services, and the impact on all| |
| |concerned services of implementing or not implementing such limits; | |
| |study those frequency bands and instances where, for technical or operational| |
| |reasons, out-of-band limits may be required to protect safety services, and | |
| |the impact on all concerned services of implementing or not implementing such| |
| |limits | |
|1 WP 8B contributes to Responsible Group JTG 4-7-8. |
|2 WP 8B contributes to Responsible Group JTG 4-7-8-9. |
|3 WP 8B contributes to Responsible Groups SG 1 and TG 1/5. |
|( BR issued Circular Letter CR147 (see . Administrations are requested to take |
|note of and participate in this monitoring programme as it will support WRC-03 activities. |
|(( WP 8B requests contributions regarding this PDNR be submitted to the ITU-R no later than April 2001 in order for administrations|
|to review prior to the May 2001 WP 8B meeting. |
Part 4
Liaison statement to WP 1A on a "Study of interference from short-range radio devices using ultra wideband (UWB) technology operating in the 1 - 6 GHz bands (ITU-R Document 1A/28-E).
ICAO Secretariat comments
This paper is based on on Document 8B/TEMP/9, produced by the October 2000 meeting of WP8B. It contains a draft new question on the compatibility between short range communications and radar devices using ultra wide band modulations and aeronautical safety-of-life services has been forwarded to WP 1A for consideration since the use of these devices may have consequences on other radio services as well. The outcome of the discussion in WP 1A is awaited
AMCP WGF ACTION: Review in the light of outcome of the discussion in WP1A
|[pic] |INTERNATIONAL TELECOMMUNICATION UNION | |
| |RADIOCOMMUNICATION |Document 1A/28-E |
| |STUDY GROUPS |1 November 2000 |
| | |English only |
Source: Document 8B/TEMP/9
Working Party 8B
LIAISON STATEMENT TO WORKING PARTY 1A
STUDY OF INTERFERENCE FROM SHORT-RANGE RADIO DEVICES
USING ULTRA-WIDEBAND (UWB) TECHNOLOGY OPERATING
IN THE 1-6 GHZ BAND
Various administrations and international organizations are studying, for potential regulatory action, devices that use ultrashort, monocycle pulses, which may occupy up to several giga-hertz of bandwidth. The frequencies used by these devices may overlap all or a portion of the 1-6 GHz band. Such overlap could create harmful interference to a wide range of radio services, including safety-of-life services such as the aeronautical radionavigation service. The Radio Regulations do not contain provisions to accommodate these devices. Some proposed UWB devices might operate at low average power and distribute their power over a wide region of spectrum, which normally yields a low spectral power density for one single device. Nonetheless, the full interference characteristics resulting from complex sequences of UWB pulses, singly and in aggregate, are unknown.
WP 8D noted that the Short-Range Devices Maintenance Group in the CEPT has developed draft material identifying subjects to be studied on UWB devices, including: technical definition of UWB devices, frequency bands to be used or avoided, possible limitations to the operation of UWB devices to protect particular existing services, and regulatory treatment and legal aspects. WP 8B noted concerns expressed to date on the protection of existing services such as the mobile service, mobile-satellite service, radio astronomy service and space services. In particular, the effects of the operation of UWB devices on safety services such as the aeronautical mobile service, radionavigation service, and radiolocation service requires special attention. WP 8D was informed that CEPT is planning a workshop on UWB technology to be held in 2001.
ICAO has considered the necessity for an analysis of the possible interference potential from UWB devices to the aeronautical safety-of-life services operating within the frequency range of 1-6 GHz. These studies need to take into consideration the aggregate effect of interference caused by the potential widespread operation of UWB devices, should they be approved for use within one or more administrations. Working Party 8B is particularly concerned with potential harmful interference from transmission systems using technologies for which there is no information available in ITU-R. However, UWB technology has the ability to affect multiple services, not just those used for safety-of-life.
WP 8B, in reviewing aspects related to the introduction of UWB devices, noted that is may be necessary to study the conditions for a safe introduction and implementation of UWB devices. These studies might identify the need for one or more ITU-R Recommendations, providing the technical and operating conditions for UWB devices, to be developed. These conditions could in particular address measures to secure the avoidance of harmful interference to the services operating in the frequency bands in which the UWB devices may operate. Special attention to protection of the safety-of-life services should be given in these studies.
WP 8B is of the opinion that a broader attention to the introduction of UWB devices might be required than WP 8B, or even Study Group 8, can offer within its terms of reference, since the introduction of UWB devices might affect all radio services operating in the bands between 1-6 GHz. ICAO has proposed a new Study Question concentrating only on the protection of aeronautical safety-of-life services from interference that can be caused by UWB devices, which is attached to this liaison statement for information purposes. WP 8B has not taken any action on this proposal.
WP 1A is invited to review this matter with a view to identifying the need for ITU-R to initiate, through a new Study Question, studies on UWB devices. Administrations are further invited to monitor UWB-related developments to determine if and when action within ITU-R is warranted.
ANNEX
DRAFT NEW QUESTION
COMPATIBILITY BETWEEN SHORT RANGE COMMUNICATIONS AND
RADAR DEVICES USING ULTRA-WIDEBAND (UWB) MODULATIONS
AND AERONAUTICAL SAFETY-OF-LIFE SERVICES
The ITU Radiocommunication Assembly,
considering
a) that UWB devices are planned to operate across numerous frequency bands in the range of 1 to 6 GHz;
b) that UWB imaging devices may offer new capabilities to public safety, construction, engineering, science and law enforcement;
c) that typical emissions from UWB devices are at a low average power;
d) that the potential for interference from UWB to aeronautical safety-of-life services services, has not yet been adequately addressed;
e) that the aggregate effects of interference from a large numbers of UWB devices on the existing electromagnetic environment has not been studied;
f) that the spectrum requirements for UWB devices vary according to operational usage;
g) that UWB devices might be considered for unlicensed operations without protection from other telecommunication services,
decides that the following Question should be studied
1 What power levels and other technical criteria (for example, peak-to-average power, pulse repetition frequency, dithering of the signal, pulse width) could be allowed for UWB devices to ensure that harmful interference is not caused to telecommunication services, particularly safety services, such as aeronautical radionavigation?
2 What are the spectrum requirements that could be used to support UWB devices that may allow global access and application?
3 What operating parameters are proposed and what is the mechanism for interference to other services?
4 What measures are required to secure a reliable operation of UWB considering the electromagnetic environment for which they are proposed? What UWB receiver characteristics are necessary to ensure operations in the existing environment?
5 What categories of applications can be identified for these devices and what should their allocation be?
further decides
1 that the results of the above studies should be included in (a) Recommendation(s);
2 that the above studies should be completed by December 2001.
________________
Part 5
Draft revision to question ITU-R 216-1/8 on the "Compatibility of radionavigation, Earth exploration-satellite (active), Space research (active) and radiolocation services operating in the 5350 - 5650 MHz and 2900 - 3100 MHz band." (ITU-R Document SG8/16)
ICAO Secretariat comments
This paper is based on on Document 8B/TEMP/13, produced by the October 2000 meeting of WP8B. The proposed amendments mainly serve the purpose of better defining the scope of the studies.
AMCP WGF ACTION: Review
|[pic] |INTERNATIONAL TELECOMMUNICATION UNION | |
| |RADIOCOMMUNICATION |Document 8/16-E |
| |STUDY GROUPS |26 October 2000 |
| | |English only |
Source: Document 8B/TEMP/13
Chairman, Working Party 8B
DRAFT REVISION TO QUESTION ITU-R 216-1/8*
COMPATIBILITY OF RADIONAVIGATION, EARTH EXPLORATION-SATELLITE (ACTIVE), SPACE RESEARCH (ACTIVE), AND RADIOLOCATION SERVICES OPERATING IN THE BAND5 350-5 650 MHZ AND COMPATIBILITY BETWEEN THE RADIONAVIGATION AND RADIOLOCATION SERVICES IN THE BAND 2900-3100 MHZ
(1997-1998)
The ITU Radiocommunication Assembly,
considering
a) that the radionavigation service provides a safety of life function (RR S4.10) and harmful interference to it cannot be accepted;
b) that radars in the radiolocation service operate on a primary basis worldwide in bands including the 3 100-3 300 MHz band and operate on a secondary basis to the radionavigation service in several bands around 3 and 5 GHz;
;
c) that considerable radiolocation spectrum (approximately 1 GHz) has been removed or downgraded since WARC-79, particularly affecting the band 3 400-3 700 MHz, and that a need is emerging for increased primary spectrum allocation for the radiolocation service;
d) that the International Maritime Organization (IMO) has recently increased their safety requirements for shipborne radars that lead to the need for use of shorter pulse widths;
e) that Recommendation ITU-R M.1372 identifies interference reduction techniques which enhance compatibility among pulsed radars;
f) that radiolocation services, while recognizing radionavigation as a safety service as delineated in RR S4.10, have demonstrated compatible operations with radionavigation services in the bands 2 900-3 100 MHz and 5 350-5 650 MHz over many years because of using similar system characteristics of low duty cycle emissions, scanning beams, and interference reduction techniques;
g) that the active spaceborne earth sensors in the Earth exploration-satellite and space research services have demonstrated compatible operations with the radiolocation service in several bands over many years,
h) that Resolution 800 agenda item 1.17 calls for WRC-03 to consider upgrading the status of radiolocation allocations in the 2900-3100 MHz band;
j) that Resolution 800 agenda item 1.5 and Resolution 736 call for WRC-03 to consider allocating the 5460-5570 MHz band to the earth exploration satellite (active) and space research (active) service and to consider allocating the 5470-5570 MHz band to the mobile service for wireless access systems including RLAN, and to review the status of the radiolocation service with a view to upgrading it in the frequency range 5150-5725 MHz.
decides that the following Questions should be studied
1. What are the technical characteristics, protection criteria, and other factors of radiolocation and radionavigation services needed to conduct studies of compatibility between these services in the bands 2 900-3 100 MHz and 5 350-5 650 MHz?
2. What is the feasibility of sharing between the radiolocation and radionavigation services in the 2900-3100 MHz band?
3. What is the feasibility of sharing between the aeronautical radionavigation and radiolocation services in the 5350-5470 MHz band?
4. What is the feasibility of sharing between the radionavigation and radiolocation services in the 5460-5470 MHz band?
5. What is the feasibility of sharing between the maritime radionavigation and radiolocation services in the 5470-5650 MHz band?
6. What is the feasibility of sharing between the mobile (RLAN) and radiolocation services in the 5470-5650 MHz band?
further decides
1 that the results of the above studies should be included in one or more Recommendations;
2 that the above studies should be completed by 2003.
NOTE 1 –These studies need to respect the safety-of-life considerations of the radionavigation service expressed in RR S4.10 to ensure that future safety systems can operate without harmful interference.
______________
PART 6
Preliminary draft new recommendation ITU-R M. – Characteristics of and protection criteria for radiolocation aeronautical radionaviafation and meteorological radars operating in the frequency bands between 5 250 and 5 850 MHz (ITU-R Document 7C/42-E)
ICAO Secretariat comments
This paper is based on on Document 8B/TEMP/25, produced by the October 2000 meeting of WP8B. It contains a liaison statement to working party 7C and JTG 4-7-8-9 containing information for conducting sharing studies in frequency bands between 5250 and 5850 MHz. It makes reference to ITU-R Document 8B/37-E (also attached). Information of aeronautical airborne weather radar is relevant.
AMCP WGF ACTION: Review
|[pic] |INTERNATIONAL TELECOMMUNICATION UNION | |
| |RADIOCOMMUNICATION |Document 4-7-8-9/8-E |
| |STUDY GROUPS |Document 7C/42-E |
| | |31 October 2000 |
| | |English only |
Source: Doc. 8B/TEMP/25
Working Party 8B
LIAISON STATEMENT TO WORKING PARTY 7C AND JOINT TASK GROUP 4-7-8-9
INFORMATION FOR CONDUCTING SHARING STUDIES IN FREQUENCY
BANDS BETWEEN 5 250 AND 5 850 MHZ
At its meeting in Geneva, 18-27 October, 2000, Working Party 8B reviewed several input documents related to sharing in the bands near 5 GHz. One of the documents submitted (Doc. 8B/37) was a Preliminary Draft New Recommendation- “Characteristics of and Protection Criteria for Radiolocation, Aeronautical Radionavigation, and Meteorological Radars Operating in the Frequency Bands Between 5 250 and 5 850 MHz”. This information should assist in completing sharing studies in the bands between 5 250 and 5 850 MHz.
Working Party 8B will further review the sharing study contained in Doc. 8B/7 (source: Doc. 7C/TEMP/15) through a correspondence group. However, Working Party 8B noted that results presented on the sharing between EESS and the radiodetermination service (RR S5.448A and S5.448B apply) and observed that the conclusion on the feasibility of sharing is limited to the assumptions on the characteristics of the EESS that were used in the study. It was noted by Working Party 8B that this should be reflected in any regulatory provision that might need to accompany a primary allocation to EESS in the frequency range 5 460-5 570 MHz.
_______________
|[pic] |INTERNATIONAL TELECOMMUNICATION UNION | |
| |RADIOCOMMUNICATION |Delayed Contribution |
| |STUDY GROUPS |Document 8B/37-E |
| | |13 October 2000 |
| | |English only |
Received: 12 October 2000
Subject: Question ITU-R 226/8
United States of America
PRELIMINARY DRAFT NEW RECOMMENDATION ITU-R M.
CHARACTERISTICS OF AND PROTECTION CRITERIA FOR RADIOLOCATION, AERONAUTICAL RADIONAVIGATION, AND METEOROLOGICAL RADARS OPERATING IN THE FREQUENCY BANDS BETWEEN 5 250 AND 5 850 MHZ
The attached preliminary draft new recommendation (pdnr) presents the technical characteristics and protection criteria of meteorological , radiolocation and aeronautical radionavigation radars operating in the bands between 5 250–5 850 MHz This information can be used for conduction sharing studies between incumbent systems operating between 5 250 and 5 850 MHz and new services.
Attachment: 1
Attachement
PRELIMINARY DRAFT NEW RECOMMENDATION ITU-R M.
CHARACTERISTICS OF AND PROTECTION CRITERIA FOR RADIOLOCATION, AERONAUTICAL RADIONAVIGATION, AND METEOROLOGICAL RADARS OPERATING INTHE FREQUENCY BANDS BETWEEN 5 250 AND 5 850 MHZ
Rec. ITU-R M.1464
Summary
This Recommendation describes the technical and operational characteristics of, and protection criteria for radars operating in the frequency band 5 250–5 850 MHz. These characteristics are intended for use when assessing the compatibility of these systems with other services.
The ITU Radiocommunication Assembly,
considering
a) that antenna, signal propagation, target detection, and large necessary bandwidth characteristics of radar to achieve their functions are optimum in certain frequency bands;
b) that the technical characteristics of radiolocation, radionavigation and meteorological radars are determined by the mission of the system and vary widely even within a band;
c) that the radionavigation service is a safety service as specified by RR No. S4.10 and harmful interference to it cannot be accepted;
d) that considerable radiolocation and radionavigation spectrum allocations (amounting to about 1 GHz) have been removed or downgraded since WARC-79;
e) that some ITU-R technical groups are considering the potential for the introduction of new types of systems (e.g. fixed wireless access and high density fixed and mobile systems) or services in bands between 420 MHz and 34 GHz used by radionavigation, radiolocation, and meteorological radars;
f) that representative technical and operational characteristics of radiolocation, radionavigation and meteorological radars are required to determine the feasibility of introducing new types of systems into frequency bands in which the latter are operated;
g) that procedures and methodologies to analyse compatibility between radars and systems in other services are provided in ITU-R M.1461;
h) that radiolocation, radionavigation, and meteorological radars operate in the bands between 5 250- 5 850 MHz;
j) that ground-based radars used for meteorological purposes are authorized to operate in the band 5600 - 5650 MHz on a basis of equality with stations in the aeronautical radionavigation service (see RR No. S5.452),
recommends
1 that the technical and operational characteristics of the radiolocation, radionavigation, and meteorological radars described in Annex 1 be considered representative of those operating in the frequency bands between 5 250 and 5 850 MHz (see Note);
2 that Recommendation ITU-R M.1461 be used as a guideline in analysing compatibility between radiolocation, radionavigation and meteorological radars with systems in other services; that the criterion of interfering signal power to radar receiver noise power level (I/N) of –6 dB be used as the required protection level for the radiolocation and meteorological radars, and that the criterion (I/N) of –10 dB be used as the required protection level for safety-of-life (per S4.10) radionavigation radars. These protection criteria represent the net protection level if multiple interferers are present;
Note: Recommendation ITU-R M.1313 should be used with regard to the characteristics of maritime radionavigation radars in the frequency band 5 470-5 650 MHz.
ANNEX 1
Characteristics of radiolocation, aeronautical radionavigation
and meteorological radars
1 Introduction
The bands between 5 250 and 5 850 MHz are allocated to the aeronautical radionavigation service and radiolocation service on a primary basis as shown in Table 1. Ground-based radars used for meteorological purposes are authorized to operate in 5600-5650 MHz on a basis of equality with stations in the maritime radionavigation service (see RR No. S5.452).
|Band (MHz) |Allocation |
|5 250 – 5 255 |Radiolocation |
|5 255 – 5 350 |Radiolocation |
|5 350 – 5 460 |Aeronautical Radionavigation |
|5 460 – 5 470 |Radionavigation |
|5 470 – 5 650 |Maritime Radionavigation (Note 1) |
|5 650 – 5 725 |Radiolocation |
|5 725 – 5 850 |Radiolocation |
NOTE 1- In accordance with S5.452, between 5 600 and 5 650 MHz, ground based radars for meteorological purposes are authorized to operate on a basis of equality with stations in the maritime radionavigation service.
The radiolocation radars perform a variety of functions, such as
• tracking space launch vehicles and aeronautical vehicles undergoing developmental and operational testing,
• sea and air surveillance,
• environmental measurements (e.g., study of ocean water cycles and weather phenomena such as hurricanes),
• Earth imaging, and
• national defense and multinational peacekeeping.
The aeronautical radionavigation radars are used primarily for airborne weather avoidance and windshear detection, and perform a safety service (see RR No. S4.10).
The meteorological radars are used for detection of severe weather elements such as tornadoes, hurricanes and violent thunderstorms. These weather radars also provide quantitative area precipitation measurements so important in hydrologic forecasting of potential flooding. This information is used to provide warnings to the public and it therefore provides a safety-of-life service.
Recommendation ITU-R M.1313 should be used with regard to the characteristics of maritime radionavigation radars in the frequency band 5 470–5 650 MHz.
2 Technical characteristics
The bands between 5 250 and 5 850 MHz are used by many different types of radars on land-based fixed, shipborne, airborne, and transportable platforms. Tables 1 and 2 contain technical characteristics of representative systems deployed in these bands. This information is sufficient for general calculation to assess the compatibility between these radars and other systems.
TABLE 1: Characteristics of Aeronautical Radionavigation and Meteorological Radar Systems
|Characteristics |Radar A |Radar B |Radar C |Radar D |Radar E |Radar F |Radar G |
|Function | | |Meteorological |Aeronautical |Meteorological |Meteorological |Meteorological |
| |Meteorological |Meteorological | |Radionavigation | | | |
|Platform type (airborne, |Ground/Ship |Airborne |Ground |Airborne |Ground |Ground |Ground |
|shipborne, ground) | | | | | | | |
|Tuning range (MHz) |5300-5700 |5370 |5600-5650 |5440 |5600-5650 |5300-5700 |5600-5650 |
|Modulation |N/A |N/A |N/A |N/A |N/A |N/A |N/A |
|Tx power into antenna |250 kW Peak |70 kW Peak |250 kW Peak | 200 W Peak |250 kW Peak |250 kW Peak |250 kW Peak |
| |125 kW Avg. | |1500 W Avg. | | | | |
|Pulse width (μs) |2.0 |6.0 |0.05 - 18 |1 – 20 |1.1 |0.8-2.0 |3.0 |
|Pulse rise/fall time (μs) |TBD |TBD |TBD |TBD |TBD |TBD |TBD |
|Pulse repetition rate (pps) |50, 250 and |200 |0-4000 |180 - 1440 |2000 |250-1180 |259 |
| |1200 | | | | | | |
|Output device |TBD |TBD |Klystron |TBD |TBD |TBD |Coaxial Magnetron |
|Antenna pattern type (pencil, fan,|Conical |TBD |Pencil |Pencil |TBD |TBD |Pencil |
|cosecant-squared, etc.) | | | | | | | |
|Antenna type (reflector, phased |Solid metal parabolic |TBD |Parabolic |Slotted array |TBD |TBD |Solid Parabolic |
|array, slotted array, etc.) | | | | | | | |
|Antenna polarization |TBD |Horizontal |TBD |TBD |Horizontal |Horizontal |Horizontal |
|Antenna mainbeam gain (dBi) |46 dBi |37.5 |44 |34 |50 |40 |40 |
Table 1 (Continued)
|Characteristics |Radar A |radar B |Radar C |Radar D |Radar E |Radar F |Radar G |
|Antenna elevation beamwidth |4.8 |4.1 |0.95 |3.5 | ................
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