1、 Report ITU-R SA.2190(10/2010)Study on compatibility between the mobile service (aeronautical) and the space research service (space-to-Earth)in the frequency band 37-38 GHzSA SeriesSpace applications and meteorologyii Rep. ITU-R SA.2190 Foreword The role of the Radiocommunication Sector is to ensur
2、e the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of t
3、he Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in
4、Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R pate
5、nt information database can also be found. Series of ITU-R Reports (Also available online at http:/www.itu.int/publ/R-REP/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television
6、) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service
7、systems SM Spectrum management Note: This ITU-R Report was approved in English by the Study Group under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2010 ITU 2010 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without writ
8、ten permission of ITU. Rep. ITU-R SA.2190 1 REPORT ITU-R SA.2190 Study on compatibility between the mobile service (aeronautical) and the space research service (space-to-Earth) in the frequency band 37-38 GHz (2010) TABLE OF CONTENTS Page 1 Introduction 2 2 Single-entry analyses 2 2.1 Single-entry
9、narrow-band transmitter mode . 5 2.2 Single-entry wideband transmitter mode 5 2.3 Maximum AMS e.i.r.p. densities for single-entry case 5 2.4 Interference time duration . 6 2.4.1 Static link considerations . 6 2.4.2 Dynamic simulation . 6 2.5 Interference to the planned SRS mission ASTRO-G . 8 3 Mult
10、iple-entry analysis . 11 3.1 Methodology summary . 11 3.2 SRS station parameters . 11 3.3 Air-traffic model parameters 11 3.4 Simulation description and results 13 4 Compatibility of low power AMS systems with the PFD spectral density mask 15 5 Conclusions 18 2 Rep. ITU-R SA.2190 1 Introduction Eart
11、h stations for the space research service (SRS) have very sensitive receivers. To protect these (deep-space and near-Earth) SRS earth stations from interference, the ITU has published protection criteria in Recommendation ITU-R SA.1157 for the 2 GHz, 8 GHz, 13 GHz and 32 GHz bands. For the 37-38 GHz
12、 band, Recommendation ITU-R SA.1396 gives the SRS earth station protection criterion as 217 dBW/Hz not to be exceeded more than 0.1% of the time for unmanned missions and 0.001% of the time for manned missions. This limit is applicable for both the deep-space and near-Earth SRS missions. The analyse
13、s in 2 show that since the range of an aircraft transmitter is much less than the range of SRS missions (see Table 1), interference from a transmitter in the aeronautical mobile service (AMS) to an SRS earth station receiver can significantly exceed the SRS earth station protection criteria. TABLE 1
14、 Typical slant ranges from an earth station Slant range(km) Relative inverse square loss (dB) Aircraft at 12 km altitude, 60 elevation 14 0 LEO at 300 km altitude, 15 elevation 1 400 40 GEO 33 000 67Deep space mission at minimum distance 2 000 000 102 Recommendation ITU-R SA.1016 provided an example
15、 of a narrow-band aeronautical mobile transmitter interfering with a space research earth station (space-to-Earth) (deep space) at frequencies up to 32 GHz. Given an aircraft transmitter with maximum e.i.r.p. density of 10 W/4 kHz (equivalent to 26 dBW/Hz), antenna gain of 0 dBi, and altitude of 12
16、km, the results in Annex 1 (see Table 3) of this Recommendation showed that the minimum interference received by the SRS earth station would exceed the protection criteria. Therefore, the Tables of Frequency Allocations in the ITU Radio Regulations have excluded aeronautical mobile in the frequency
17、bands 2.29-2.3 GHz, 8.4-8.5 GHz, 22.21-22.5 GHz and 31.5-31.8 GHz, where the mobile service is co-allocated with the space research service. This Recommendation did not, however, consider very low power AMS systems. The following sections will present the results of compatibility studies for a singl
18、e AMS transmitter or multiple AMS transmitters for sharing the 37-38 GHz band by SRS and AMS. 2 Single-entry analyses The interference from a single aeronautical mobile transmitter to the space research earth stations is analyzed for a narrow-band (NB) mode and a wideband (WB) mode. Rep. ITU-R SA.21
19、90 3 For the narrow-band mode, the aircraft e.i.r.p. density is assumed to be 10 W/4 kHz, which is equivalent to 26 dBW/Hz. For the wideband mode, the aircraft e.i.r.p. density is assumed to be 70 W/10 MHz, which is equivalent to 51.5 dBW/Hz. For both narrow and wideband modes, two cases are analyze
20、d: Case 1 The aircraft altitude is 12 km and it is at 0-degree elevation relative to the SRS earth station, with a transmit antenna gain of 0 dBi towards the SRS earth station. Furthermore, the SRS earth station antenna is assumed to have a 10 dB gain in the direction of the aircraft, corresponding
21、to a boresight separation angle greater than 48 (using the antenna gain pattern given in Recommendation ITU-R SA.509). This case represents the minimum interference from AMS transmitter to the SRS earth station. Case 2 The aircraft altitude is 12 km and it is at 60-degree elevation relative to the S
22、RS earth station, with a transmit antenna gain of 0 dBi towards the SRS earth station. Furthermore, the SRS earth station antenna is assumed to have a 0 dB gain in the direction of the aircraft, corresponding to a boresight separation angle of 19 (using the antenna gain pattern given in Recommendati
23、on ITU-R SA.509). This case represents a more typical interference. Note that in Recommendation ITU-R SA.1016, the interference analyses were done using Case 1 for the narrow-band mode only. Here we have extended the link analyses in Recommendation ITU-R SA.1016 given for the frequency bands below 3
24、2 GHz to the 37-38 GHz band. Table 2 gives the results for Cases 1 and 2 using the narrow- and wideband modes. TABLE 2 Aeronautical mobile interference to space research service for narrow-band and wideband modes at 38 GHz Narrow-band (NB) mode Wideband (WB) mode Case 1 Case 2 Case 1 Case 2 Aeronaut
25、ical mobile space station Transmitter power (W) 10 70 Reference bandwidth (kHz) 4 10 000 Aircraft antenna gain toward victim (dBi) 0 0 Aircraft e.i.r.p. (dBW) 10 18.5 e.i.r.p. density (dBW/Hz) 26 51.5 Altitude (km) 12 12 Elevation (degrees) 0 60 0 60 Slant range (km) 391 14 391 14 Space loss (dB) 17
26、6 147 176 147 4 Rep. ITU-R SA.2190 TABLE 2 (end) Narrow-band (NB) mode Wideband (WB) mode Case 1 Case 2 Case 1 Case 2 SRS earth station Victim antenna off-boresight angle (degrees) 48 19 48 19 Victim antenna gain toward interferer (Recommendation ITU-R SA.509) (dBi) 10 0 10 0 Maximum received PSD (d
27、BW/Hz) 212 173 237.5 198.5 Protection criterion (deep-space and near-Earth) (Recommendation ITU-R SA.1396) (dBW/Hz) 217 Max received PSD exceedance above SRS protection criterion (deep-space and near-Earth) (dB)5 44 20.5 18.5 In Fig. 1, the received interference power spectral densities are plotted
28、with respect to the aircraft elevation angle for narrow- and wideband modes. The figure also shows the Cases 1 and 2 points, which are analyzed in detail in Table 2. FIGURE 1 Received power spectral density vs. aircraft elevation angle for the narrow-band and wideband modes 0 102030405060708090Aircr
29、aft elevation angle (degrees)217 dBW/Hz (SRS Earth station protection)WB (SRS G = 0 dBi)NB (SRS G = 10 dBi)NB (SRS G = 0 dBi)Case 2Case 1Case 1Case 2WB (SRS G = 10 dBi)160170180190200210220230240250ReceivedPSD (dBW/Hz)Rep. ITU-R SA.2190 5 In deriving the results shown in Fig. 1, we have used the par
30、ameters for the narrow- and wideband AMS transmitter modes with the receive antenna gains of 10 dBi and 0 dBi. The assumed aircraft altitude is 12 km. The figure also shows the deep-space earth station protection criterion for comparison. 2.1 Single-entry narrow-band transmitter mode For the narrow-
31、band mode, Table 2 above shows that in Case 1, the interferences will exceed the SRS protection criterion by 5 dB, whereas in Case 2, the interferences will exceed the SRS protection criterion by 44 dB. These interferences far exceed the protection criterion of space research earth stations for deep
32、-space and near-Earth missions. Note that, for the narrow-band mode, the minimum expected interference is above the SRS earth station protection for all aircraft elevation angles (see Fig. 1). 2.2 Single-entry wideband transmitter mode As shown in Table 2, for the wideband mode, we considered a poss
33、ible aircraft transmission with 10 MHz bandwidth, at a carrier frequency less than 40 GHz, and with transmitter power of 70 W. The e.i.r.p. density for this wideband mode is calculated to be 51.5 dBW/Hz. This is 25.5 dB lower than the e.i.r.p. density of the narrow-band mode. As shown in Table 2, in
34、 Case 1, the interference levels will be below the protection criterion by 20.5 dB, but in Case 2, they will exceed the protection criterion by 18.5 dB. Note that, for the wideband mode, the minimum expected interference is above the SRS earth station protection when the aircraft elevation angle is
35、greater than 19 (see Fig. 1) 2.3 Maximum AMS e.i.r.p. densities for single-entry case To bound the extent of the sharing situation, it is necessary to calculate the best and worst-case sharing scenarios. The interference power received at an SRS earth station is calculated by using the free space lo
36、ss and the minimum gain of the SRS earth-station antenna, which results in a best case sharing scenario. By calculating this interference power received at different aircraft e.i.r.p. density levels as a function of slant range, it is possible to determine the maximum e.i.r.p. density allowed from t
37、he aircraft to satisfy the interference criteria. These results are in Fig. 2. The maximum altitude of a typical aircraft is 12 km. If an aircraft is flying at an altitude of 12 km, the minimum slant range would be 12 km. From Fig. 2 we see that for this range, the maximum allowed aircraft e.i.r.p.
38、density would be 60 dBW/Hz emanating from the aircraft. However, this best-case sharing scenario does not take into account the aircraft interfering with the earth stations main beam. In practice, SRS earth stations may track satellites in near-Earth orbit, lunar orbit, or deep-space missions, resul
39、ting in a wide variety of antenna pointing angles, and aircraft may fly in any number of directions, altitudes and speeds. Under these circumstances, it is reasonable to assume that the aircraft may be within the main beam of the SRS earth station antenna. Assuming a boresight antenna gain of 80 dB,
40、 the previous static link analysis is repeated. Results of this analysis are also shown in Fig. 2. While an e.i.r.p. density of 60 dBW/Hz emanating from an aircraft is acceptable for the back lobe, the power level received in the main lobe will exceed the interference criteria by 90 dB. Purely on a
41、static basis, in order to completely satisfy the interference power requirement for the SRS earth stations main lobe, an aircraft e.i.r.p. density of 150 dBW/Hz must not be exceeded, at an aircrafts maximum altitude of 12 km. Aircraft operating lower than a 12 km altitude will need lower e.i.r.p. em
42、issions to meet the interference criteria in both the SRS earth stations main and back lobes. Since aircraft position and SRS earth station antenna pointing direction are both changing dynamically, the limit of aircrafts e.i.r.p. should be determined statistically, using a dynamic simulation. 6 Rep.
43、 ITU-R SA.2190 FIGURE 2 Max AMS e.i.r.p. densities for mininimum (10 dBi) and maximum (80 dBi) SRS antenna gains to meet the SRS earth station protection 0 50 100 150 200 250 300 350 400Slant range (km)020406080100120140160180AMStransmittere.i.r.p. density(dBW/Hz)Min SRS Earth station gain = 10 dBiW
44、B-AMS transmittere.i.r.p. density = 51.5 dBW/Hz 200NB-AMS transmittere.i.r.p. density = 26 dBW/Hz Max SRS Earth station gain = 80 dBi2.4 Interference time duration 2.4.1 Static link considerations In the narrow-band mode, as discussed in 2.1, interference from a single aeronautical mobile station is
45、 above the space research earth station protection criteria for all elevation angles of the aircraft and for all pointing directions of the earth station antenna (see Figs 1 and 2). Therefore, the interference is expected to exceed the SRS earth station protection criteria 100% of the time. In the w
46、ideband mode, as discussed in 2.2, the interference under the same geometry will be 25.5 dB weaker than the corresponding narrow-band mode. Therefore, for low elevation angles (less than 19) when the slant range is large the received interference PSD would be less than the SRS earth station protecti
47、on (see Figs 1 and 2). However, if the aircraft elevation is greater than 19 the interference PSD would exceed the protection for all pointing direction of the SRS earth station antenna. Using these facts, it is estimated that the interference levels would exceed the protection criterion for about 7
48、0% of the time. 2.4.2 Dynamic simulation The SRS earth station can track different types of missions, such as polar orbiting spacecraft, manned spaceflight in Earth orbit, lunar missions, and deep-space missions. Each of these applications requires different earth station requirements, and will invo
49、lve different antenna elevation, azimuth, and speed characteristics. Rep. ITU-R SA.2190 7 Two simulation scenarios investigating the interaction between an aircraft and either a polar orbiting lunar satellite or a polar orbiting satellite were used in order to calculate the interference power received at the SRS earth station. The simulations consist of an earth station, the particular SRS mission, and a single aircraft transmitter. Simulation configuration details are summarized in Table 3. TABLE 3 Dynamic simula
