1、 Rec. ITU-R SA.1629 1 RECOMMENDATION ITU-R SA.1629*Sharing between command links in the space research and space operation services with the fixed, mobile and mobile-satellite services in the frequency band 257-262 MHz (2003) The ITU Radiocommunication Assembly, considering a) that in the range betw
2、een 0.1 and 1 GHz, the space research service (SRS) and space operation service have a combined primary allocation of 3.9 MHz and a combined secondary allocation of 10.35 MHz in the space-to-Earth direction, but only a combined 2.4 MHz in the Earth-to-space direction (telecommand links), the latter
3、allocation being subject to agreement under No. 9.21 of the Radio Regulations; b) that Recommendation ITU-R SA.363 contains recommendations on the necessary bandwidth and protection criteria for space operation systems in the frequency range from 0.1 GHz to 30 GHz; c) that Recommendations ITU-R SA.3
4、64 and ITU-R SA.609 contain recommendations on the necessary bandwidth and protection criteria for manned and unmanned near-Earth satellites in the SRS; d) that Recommendation ITU-R SA.514 contains interference criteria for command links in the Earth-to-space direction in bands below 1 GHz; e) that
5、Recommendation ITU-R SA.1017 provides a method for calculating link performance in the SRS; f) that criteria are given in Recommendation ITU-R F.758 for sharing between the terrestrial fixed service and other services which may be used in bands below 1 GHz; g) that the method of determining the coor
6、dination area around an earth station operating with non-GSO satellites in frequency bands shared with terrestrial services is set out in Recommendations ITU-R SM.1448 and ITU-R M.1185, noting a) that a small number of earth stations (less than ten) operating in the space research and space operatio
7、n services (Earth-to-space) may be expected to be deployed in the frequency band 257-262 MHz by a very limited number of administrations (one or two), noting further a) that necessary sharing, compatibility and protection criteria need to be established in the frequency band 257-262 MHz, *This Recom
8、mendation should be brought to the attention of Radiocommunication Study Groups 8 and 9. 2 Rec. ITU-R SA.1629 recommends 1 that analysis of compatibility with other services in the frequency band 257-262 MHz be based on the characteristics of space research and space operations (Earth-to-space) syst
9、ems given in Annex 1; 2 that in those countries operating SRS and space operation service systems in the band 257-262 MHz, the coordination distance for earth stations of these services be 400 km. Annex 1 Link performance analysis and technical equipment characteristics for command links of space re
10、search and space operation systems This Annex sets out the parameters used under the method in Recommendation ITU-R SA.1017 for analysing the performance characteristics of command links in the SRS and space operation service in the band 257-262 MHz. A generalized link performance analysis is given
11、in Table 1. The technical characteristics of command systems that may be used for analysing compatibility with other radio systems in the band 257-262 MHz are given in Table 2. TABLE 1 No. Characteristic Value 1 Frequency (MHz) 257-262 2 Satellite circular orbit height (km) 400.0 2 000.0 3 Maximum l
12、ink distance (km) (for 5 elevation angle) 1 800.0 5 000.0 4 Earth station e.i.r.p. (dBW) 12.0 20.0 5 Earth station antenna gain (dB) 12.0 6 Free-space propagation loss (dB) 145.85 154.73 7 Atmospheric attenuation (dB) 0.2 8 Space station antenna gain (dB) 0 9 Polarization loss (dB) 0.3 10 Modulation
13、/demodulation loss (dB) 1.0 11 Implementation loss (dB) 2.0 12 Necessary bandwidth (kHz) 20.0 13 Space station receiver noise temperature (K) 1 000 14 Link function/modulation Data/PSK Rec. ITU-R SA.1629 3 TABLE 1 (end) TABLE 2 Technical characteristics of command systems in the SRS and space operat
14、ion service which may be used for compatibility analysis No. Characteristic Value 15 Data transmission rate (dB/Hz) 40.0 16 Applicable energy per bit Eb(dB(W/Hz) 177 178.23 17 Spectral noise power density N0(dB(W/Hz) 198.6 18 Ratio Eb/N0(dB) 21.58 20.37 19 Threshold ratio Eb/N0, (dB) (for an error p
15、robability 106) 10.5 20 Link margin (dB) 11.08 9.87 No. Characteristic Minimum value Maximum value 1 Height of orbit (km) 400.0 2 000 2 Power at input to earth station antenna (dBW) 0 10.0 3 Gain of earth station transmitting antenna (dB) 12.0 20.0 4 Necessary emission bandwidth (kHz) 2.4 26.0 5 Width of main lobe of transmitting antenna pattern (degrees) 10.0 20.0 6 Level of side lobes of transmitting antenna (dB) (from main lobe) 20 (far side lobes) 15 (first side lobe) 7 Space station antenna gain (dB) 0 0 8 Noise temperature of space station receiver (K) 1 000 1 000
