1、 Rec. ITU-R SA.1026-4 1 RECOMMENDATION ITU-R SA.1026-4 Aggregate interference criteria*for space-to-Earth data transmission systems operating in the Earth exploration-satellite and meteorological-satellite services using satellites in low-Earth orbit (Questions ITU-R 139/7 and ITU-R 141/7) (1994-199
2、5-1997-1999-2009) Scope The purpose of this Recommendation is to provide interference criteria for space-to-Earth transmissions from low-Earth orbiting satellites, applying to both the Earth exploration-satellite and the meteorological-satellite services. The ITU Radiocommunication Assembly, conside
3、ring a) that the hypothetical reference system specified in Recommendation ITU-R SA.1020 defines space-to-Earth links for a number of functions, including the direct readout of data and playback of recorded data; b) that interference criteria are needed to ensure that systems can be designed to achi
4、eve adequate performance in the presence of interference and to assist in developing criteria for sharing bands among systems, including those operating in other services; c) that spacecraft operating in the Earth exploration-satellite and meteorological-satellite services may utilize low-Earth orbi
5、ts; d) that performance objectives for the relevant space-to-Earth data transmission systems operating in the Earth exploration-satellite and meteorological-satellite services are specified in Recommendation ITU-R SA.1025 for several frequency bands; e) that, although specific data transmission syst
6、ems may have performance objectives that differ from those recommended for the Earth exploration-satellite and meteorological-satellite services, all systems operating in those services should accommodate interference thresholds greater than or equal to the permissible levels of interference that ar
7、e recommended for the services; f) that interference criteria for data transmission systems in the Earth exploration-satellite and meteorological-satellite services may be derived by using the methods in Recommendation ITU-R SA.1022; g) that Annex 1 presents the parameters of representative systems
8、that provide the basis for permissible levels of interference for space-to-Earth transmissions in the Earth exploration-satellite and meteorological-satellite services in some frequency bands, *Interference criteria do not imply automatically sharing criteria. 2 Rec. ITU-R SA.1026-4 recommends 1 tha
9、t the interference levels for the frequency bands specified in Table 1 be used as the permissible total levels of interfering signal power at the antenna output of earth stations operating in the Earth exploration-satellite and meteorological-satellite services with satellites in low-Earth orbit; 2
10、that, in shared frequency bands, the interference thresholds of specific systems must be greater than or equal to the values recommended in Table 1. TABLE 1 Interference criteria for Earth exploration-satellite and meteorological-satellite earth stations using spacecraft in low-Earth-orbit (see Note
11、s 1, 2, 3, 4) Frequency band Type of earth station Interfering signal power (dBW) in the reference bandwidth to be exceededno more than 20% of the time Interfering signal power (dBW) in the reference bandwidth to be exceededno more than 0.0125% of the time. (This value is based on the 99.9% performa
12、nce requirementin Recommendation ITU-R SA.1025-3) Analogue receiver 2 dBic antenna gain Direct data readout 151 dBW per 50 kHz(1)145 dBW per 50 kHz(1)Digital receiver 10 dBic antenna gain Direct data readout 141 dBW per 150 kHz 133 dBW per 150 kHz 137-138 MHz Digital receiver 2 dBic antenna gain Dir
13、ect data readout 142 dBW per 150 kHz(1)136 dBW per 150 kHz(1)400.15-401.00 MHz 0 dBic antenna gain Direct data readout 157 dBW per 177.5 kHz 147 dBW per 177.5 kHz 46.8 dBic antenna gain Recorded data playback 128 dBW per 5 334 kHz 121 dBW per 5 334 kHz 29.8 dBic antenna gain Direct data readout 147
14、dBW per 2 668 kHz 138 dBW per 2 668 kHz 1 698-1 710 MHz 22.5 dBic antenna gain Low rate data 1-metre antenna 144 dBW per 6.0 MHz 134 dBW per 6.0 MHz 55.2 dBic antenna gain Recorded data playback 144 dBW per 10 MHz 129 dBW per 10 MHz 7 750-7 850 MHz 41.7 dBic antenna gain High rate data 2-metre anten
15、na 137 dBW per 10 MHz126 dBW per 10 MHzRec. ITU-R SA.1026-4 3 TABLE 1 (end) Frequency band Type of earth station Interfering signal power (dBW) in the reference bandwidth to be exceededno more than 20% of the time Interfering signal power (dBW) in the reference bandwidth to be exceededno more than 0
16、.0125% of the time. (This value is based on the 99.9% performance requirementin Recommendation ITU-R SA.1025-3) 54.8 dBic antenna gain Recorded data playback System A 145 dBW per 10 MHz 133 dBW per 10 MHz 41.7 dBic antenna gain Recorded data playback (System B) 135 dBW per 10 MHz 127 dBW per 10 MHz
17、8 025-8 400 MHz 42.5 dBic antenna gain Direct data readout (System C) 139 dBW per 10 MHz 129 dBW per 10 MHz 55.2 dBic antenna gain Recorded data playback 135 dBW per 10 MHz 119 dBW per 10 MHz 42.5 dBic antenna gain Direct data readout 139 dBW per 10 MHz 121 dBW per 10 MHz 42.5 dBic antenna gain High
18、-speed direct data readout 136 dBW per 10 MHz 122 dBW per 10 MHz 25.5-27.0 GHz 58.2 dBic antenna gain Stored mission data 126 dBW per 10 MHz 107 dBW per 10 MHz (1)The interfering signal powers (dBW) in the reference bandwidths are specified for reception at elevation angles 25; in all other cases th
19、e minimum elevation angle is 5. NOTE 1 The total interfering signal power level that may be exceeded for no more than x% of the time, where x is less than 20% but greater than the specified short-term time percentage (0.0125% of the time), may be determined byinterpolation between the specified valu
20、es using a logarithmic scale (base 10) for percentage of time and a linear scalefor interfering signal power density (dB). NOTE 2 The interference criteria are specified with respect to the percentage of time of reception by the earth station. Thus, receiver performance statistics associated with re
21、ception from one particular satellite (i.e. cumulative distribution of bit error rate (BER) are the same as the statistics for reception from several similar satellites. The total time of reception includes time periods associated with initial signal acquisition (i.e. before and during local ascensi
22、on of thesatellite), receiver synchronization of the data, and synchronized reception of data. Consequently, because the timerequired for initial signal acquisition and synchronization may constitute up to several tens of seconds out of totalsatellite visibility periods averaging on the order of nin
23、e minutes, the analyses of short-term performance that are presented in Annex 1 (i.e. performance exceeded for all but a small percentage of time p, p 1%) assume that the satellite is located at the minimum elevation angle associated with the applicable performance objective. This yields theBER perf
24、ormance exceeded for all but p% of the time because Eb/N0and BER are monotonically related to elevation angle. NOTE 3 The elevation angle exceeded for all but 20% of the time during reception is approximated well by the angleexceeded for all but 20% of the time that the satellite is visible above th
25、e minimum elevation angle specified in theperformance objective. This approximation is made in the performance analyses presented in Annex 1 because the underlying cumulative time error cannot exceed 1% (i.e. p% of the time) and the associated total error in satellite antenna gain, free space loss,
26、excess path loss, and earth station parameter values are negligible. The resulting elevationangle that is exceeded for all but 20% of the time of reception yields the BER performance exceeded for all but 20% ofthe time because Eb/N0and BER are monotonically related to elevation angle. NOTE 4 For fre
27、quency bands other than those of Table 1, the interference criterion of Recommendation ITU-R SA.514 is applicable. 4 Rec. ITU-R SA.1026-4 Annex 1 Basis for interference criteria 1 Introduction This annex presents the parameters used with the methodology of Recommendation ITU-R SA.1022 in the derivat
28、ion of interference criteria for the Earth exploration-satellite and meteorological-satellite services using the performance objectives specified in Recommendation ITU-R SA.1025 for some frequency bands. The requisite performance analyses are summarized in Table 2. The prominent considerations for e
29、ach band are discussed below. In all cases, the representative systems utilize satellites in highly-inclined circular orbits. Rec. ITU-R SA.1026-4 5 TABLE 2 Performance analyses used as a basis for interference criteria Frequency band (MHz) 137-138 137-138 137-138 Type of earth station Low gain eart
30、h station (APT) Tracking earth station (LRPT) Low gain earth station (LRPT) Percentage of time for link margin not met, p 0.05 20 0.05 20 0.05 20 Elevation angle (exceeded for p) 25 30 5 13 25 30 Satellite antenna input power (dBW) 4.9 6.8 6.8 Satellite antenna gain (dBic) 0.7 1.1 1.2 0.5 0.7 1.1 Sa
31、tellite e.i.r.p. (dBW) 5.6 6.0 5.6 6.3 7.5 7.9Free space loss (dB) 139.4 138.5 144.3 142.2 139.4 138.5 Excess path loss (dB) 0.2 0.1 0.1 0.1 Earth station antenna gain (dBic) 2.0 10.0 10.0 2.0 Antenna mispointing loss (dB) 0.0 0.0 0.0 0.0 Polarization mismatch loss (dB) 1.5 1.5 1.5 1.5 Modulator and
32、 demodulator losses (dB) 0.0 2.0 2.0 2.0 Receiver reference bandwidth (kHz) 50 150 150 Data rate (dB-Hz) 45.7 occupied bandwidth 48.6 48.6 Received energy per bit, Eb(dB(W/Hz) 179.2 (C0) 177.9 (C0) 180.9 178.1 182.1 180.8 Receiver system noise temperature (K) 2 520 1 750 1 750 Thermal noise power de
33、nsity (dB(W/Hz) 194.6 196.2 196.2 Non-thermal receiver noise power density (dB(W/Hz) Total internal noise power density, N0(dB(W/Hz) 194.6 196.2 196.2 Eb/N0(dB) 15.4(C0/N0) 16.7(C0/N0) 15.3 18.1 14.1 15.4 Link bit-error ratio 1010 1010Overall received bit-error ratio 1010 1010Threshold Eb/N0(or C/N)
34、 (dB) 12.0 6.5 6.5 Power margin (dB) 3.4 4.7 8.8 11.6 7.6 8.9 q factor (lt: long-term, st: short-term) 0.5 (lt) 1 (st) 0.6 (lt) 1 (st) 0.6 (lt) 1 (st) Mmin(dB) 0.8 1.2 1.2 Percentage of time for interference criteria 20 0.0125 20 0.0125 20 0.0125 Interference criteria dBW in reference bandwidth 151
35、145 141 133 142 136 6 Rec. ITU-R SA.1026-4 TABLE 2 (continued) Frequency band (MHz) 400.15-401.00 1 698-1 710 Type of earth station Non-tracking antenna (omnidirectional) Recorded data playback (HRPT) Direct data readout Percentage of time for link margin not met, p 0.05 20 0.05 20 0.05 20 Elevation
36、 angle (exceeded for p) 5 13 5 13 5 13 Satellite antenna input power (dBW) 11.1 6.1 6.1 Satellite antenna gain (dBic) 0.0 0.0 2.1 2.0 2.1 2.0 Satellite e.i.r.p. (dBWi) 11.1 11.1 8.2 8.1 8.2 8.1 Free space loss (dB) 153.6 151.4 166.3 164.0 166.3 164.0 Excess path loss (dB) 0.2 0.2 0.0 0.2 Earth stati
37、on antenna gain (dBic) 0.0 46.8 29.8 Antenna mispointing loss (dB) 0.0 0.5 0.5 Polarization mismatch loss (dB) 0.3 0.2 0.5 Modulator and demodulator losses (dB) 2.0 2.7 2.7 Receiver reference bandwidth (kHz) 177.5 5 334 2 668 Data rate (dB-Hz) 49.5 64.2 58.2 Received energy per bit, Eb(dB(W/Hz) 194.
38、5 192.3 179.1 176.7 190.4 188.2 Receiver system noise temperature (K) 400 320 210 370 240 Thermal noise power density (dB(W/Hz) 202.6 203.5 205.4 202.9 204.8 Non-thermal receiver noise power density (dB(W/Hz) 211.7 202.4 204.2 Total internal noise power density N0(dB(W/Hz) 202.1 199.9 200.6 200.5 20
39、1.5 Eb/N0(dB) 7.6 9.8 20.8 23.9 10.1 13.3 Link bit-error ratio 108 1010 10126 105 109Satellite data handling error ratio 5 107 Overall received bit-error ratio 108 10105 1076 105 109Threshold Eb/N0(dB) 5.5 5.5 11.2 10.5 10.5 Power margin (dB) 4.3 9.6 12.7 0.4 2.8 q factor (lt: long-term, st: short-t
40、erm) 0.33 (lt) 1 (st) 0.6 (lt) 1 (st) 0.33 (lt) 1 (st) Mmin(dB) 1.2 1.2 1.2 Percentage of time for interference criteria 20 0.0125 20 0.0125 20 0.0125 Interference criteria dBW in reference bandwidth 157 147 128 121 147 138 Rec. ITU-R SA.1026-4 7 TABLE 2 (continued) Frequency band (MHz) 1 698-1 710
41、7 750-7 850 Type of earth station Low rate data 1-metre antenna Recorded data playback (10-m antenna) High rate data 2-metre antenna Percentage of time for link margin not met, p 0.05 20 0.05 20 0.05 20 Elevation angle (exceeded for p) 5 8 5 13 5 8 Satellite antenna input power (dBW) 9.9 6.5 16.3 Sa
42、tellite antenna gain (dBic) 3.2 3.2 6.0 5.8 4.0 4.1 Satellite e.i.r.p. (dBWi) 13.1 13.0 12.5 12.3 20.3 20.4Free space loss (dB) 166.1 164.0 179.5 177.3 179.4 177.2 Excess path loss (dB) 0.2 0.2 3.5 0.5 0.5 0.5 Earth station antenna gain (dBic) 22.5 55.2 41.7 Antenna mispointing loss (dB) 0.5 0.5 0.5
43、 Polarization mismatch loss (dB) 0.5 0.2 0.5 Modulator and demodulator losses (dB) 2.5 2.0 2.5 Receiver reference bandwidth (MHz) 6.0 10 10 Data rate (dB-Hz) 65.3 78.5 72.4 Received energy per bit Eb(dB(W/Hz) 199.6 197.5 196.4 191.5 193.8 191.5 Receiver system noise temperature (K) 80 70 180 150 115
44、 95 Thermal noise power density (dB(W/Hz) 209.6 210.1 206.0 206.8 208.0 208.8 Eb/N0(dB) 10.0 12.7 9.6 15.4 14.2 17.3 Link bit-error ratio 108107108Threshold Eb/N0(dB) 3.6 7.20 4.1 Power margin (dB) 6.4 9.1 2.40 8.2 10.1 13.2 q factor (lt: long-term. st: short-term) 0.33 (lt) 1 (st) 0.33 (lt) 1 (st)
45、0.33 (lt) 1 (st) Mmin(dB) 1.2 1.2 1.2 Percentage of time for interference criteria 20 0.0125 20 0.0125 20 0.0125 Interference criteria dBW in reference bandwidth 144 134 144 129 137 126 8 Rec. ITU-R SA.1026-4 TABLE 2 (continued) Frequency band (MHz) 8 025-8 400 8 025-8 400 8 025-8 400 Type of earth
46、station Recorded data playback (System A) Recorded data playback (System B) Direct data readout (System C) Percentage of time for link margin not met, p 0.05 20 0.05 20 0.05 20.0 Elevation angle (exceeded for p) 5 13 5 13 5 13 Satellite antenna input power (dBW) 12 3 16.9 Satellite antenna gain (dBi
47、c) 2.4 3.7 28 6.1 Satellite e.i.r.p. (dBWi) 14.4 15.7 31 23 Free space loss (dB) 179.3 177 180 177.8 179.3 177.0 Excess path loss (dB) 1.2 0.8 1.2 0.8 0.7 0.6 Earth station antenna gain (dBic) 54.8 41.7 42.5 Antenna mispointing loss (dB) 0.5 0.1 0.5 Polarization mismatch loss (dB) 0.4 0.2 0.5 Modula
48、tor and demodulator losses (dB) 2.0 1.5 2.0 Receiver reference bandwidth (MHz) 10 10 10 Data rate (dB-Hz) 85.1 83 73 Received energy per bit, Eb(dB(W/Hz) 199.3 195.3 193.3 190.8 190.5 188.1 Receiver system noise temperature (K) 50 50 100 100 292 275 Thermal noise power density (dB(W/Hz) 211.6 211.6
49、208.6 208.6 203.9 204.2 Total internal noise power density N0(dB(W/Hz) 211.6 211.6 208.6 208.6 203.9 204.2 Eb/N0(dB) 12.3 16.3 15.3 17.8 13.5 16.1 Link bit-error ratio 1010 1010 107 1010 107 1010Overall received bit-error ratio 1010 107 1010 105 105Threshold Eb/N0(dB) 7.2 6.3 9.6 Power margin (dB) 5.1 9.1 9.0 11.5 3.8 6.5 q factor (lt: long-term. st: short-term) 0.33 (lt) 1 (st) 0.33
