1、 Rec. ITU-R SA.1159-3 1 RECOMMENDATION ITU-R SA.1159-3 Performance criteria for data dissemination, data collection and direct data readout systems in the Earth exploration-satellite service and meteorological-satellite service (Question ITU-R 141/7) (1995-1997-1999-2006) Scope This Recommendation s
2、pecifies the performance objectives for data dissemination, data collection and direct data readout systems of the Earth exploration-satellite service (EESS) and meteorological-satellite service (MetSat) operating either in low-Earth orbit (LEO) or in geostationary orbit. The ITU Radiocommunication
3、Assembly, considering a) that the hypothetical reference system specified in Recommendation ITU-R SA.1020 defines space-to-Earth links for direct readout of data acquisition of recorded data, as well as links for data dissemination, and direct data readout, data collection and data collection platfo
4、rm (DCP) interrogation by satellite; b) that performance objectives for these transmissions must be consistent with the attendant functional requirements and with the performance limitations associated with the systems and frequency bands in which the requirements will be fulfilled; c) that performa
5、nce objectives for representative systems operating in the Earth exploration-satellite service (EESS) and meteorological-satellite service (MetSat) are intended to provide guidelines for the development of actual systems; d) that performance objectives may be determined using the methodology describ
6、ed in Recommendation ITU-R SA.1021; e) that the performance objectives are a prerequisite for the determination of interference criteria; f) that Recommendation ITU-R SA.1627 contains the telecommunication requirements and characteristics of EESS and MetSat systems for data collection and their plat
7、form locations, recommends 1 that links associated with data dissemination, data collection and direct data readout systems in the EESS and MetSat using satellites in low-Earth orbit (LEO) should have the performance objectives specified for the frequency bands in Table 1; 2 that links associated wi
8、th data dissemination, data collection and direct data readout systems in the EESS and MetSat service using satellites in geostationary orbit should have the performance objectives specified for the frequency bands in Table 2; 2 Rec. ITU-R SA.1159-3 TABLE 1 Performance objectives for links in the EE
9、SS and MetSat service using LEO satellites Frequency band Satellite service ModulationApplicable elevation angle (degrees) Minimum C/N or maximum BER Percentage of time (%) Function and type of earth station MetSat Analogue 25 10 dB 99.9 Direct data readout, low-gain antenna MetSat Digital 5 10699.9
10、 Direct data readout, tracking antenna 137-138 MHz (space-to-Earth) MetSat Digital 5 10599.6 CDA station, tracking antenna 400.15-401.00 MHz (space-to-Earth) MetSat Digital 5 10699.9 Direct data readout, low-gain antenna 401-403 MHz (Earth-to-space) MetSat and EESS Digital 5 10599.6 Data collection,
11、 low-gain antenna 460-470 MHz (space-to-Earth) MetSat and EESS Digital 5 10599.6 DCP interrogation, low-gain antennaDCP data, tracking antenna Digital 5 10399.99 1 670-1 710 MHz (space-to-Earth) MetSat and EESS Digital 5 10699.9 Direct data readout and recorded data acquisition, tracking antenna 2 2
12、00-2 290 MHz (space-to-Earth) EESS Digital 5 10699.6 DCP data, Tracking antenna MetSat Digital 5 10399.99 7 750-7 850 MHz (space-to-Earth) MetSat Digital 5 10699.9 Recorded data acquisition, tracking antenna Rec. ITU-R SA.1159-3 3 TABLE 1 (end) Frequency band Satellite service ModulationApplicable e
13、levation angle (degrees) Minimum C/N or maximum BER Percentage of time (%) Function and type of earth station 8 025-8 400 MHz (space-to-Earth) EESS Digital 5 10399.99 Direct data readout and recorded data acquisition, tracking antenna Digital 5 10699.9 Recorded data acquisition, tracking antenna Dig
14、ital 5 10599.0 Direct data readout, tracking antenna 25.5-27.0 GHz (space-to-Earth) EESS Digital 5 10599.9 Direct data readout and recorded data acquisition, tracking antenna NOTE 1 In Table 1, for the band 137-138 MHz, the elevation angle of 25 and other parameters for analogue receivers correspond
15、 with a level of performance that is guaranteed by designers of some systems. The parameters for the digital receivers correspond with user requirements. NOTE 2 The EESS is only allocated in the 1 690-1 710 MHz portion of the band. NOTE 3 Additional performance objectives could be specified for an a
16、vailability of 99.99% of the time in relation to the need to synchronize the receiver to the data transmission frames and to avoid bit slips within a frame. However, for the purpose of deriving interference criteria, these objectives can be assumed to be met if the objectives associated with the abo
17、ve specified lower availability levels (Table 1) are met. NOTE 4 In all cases in Table 1, it is assumed that earth station sites are selected to yield average levels of environmental radio-frequency noise within the band. For direct data readout stations, which may be deployed in large numbers by va
18、rious operating entities, there is a risk that randomly selected sites will exhibit higher than average levels of environmental noise (especially man-made noise) that may hamper the ability to achieve the stated performance objectives. However, the variance of this noise over all locations is not la
19、rge in relation to receiver thermal noise, even at frequencies as low as 137-138 MHz, such that the performance objectives can generally be met at over 95% of the possible locations given link power margins of a few decibels. In the case of recorded data acquisition stations, sites are carefully sel
20、ected to avoid ambient noise levels that exceed the average level. 4 Rec. ITU-R SA.1159-3 TABLE 2 Performance objectives for links in the EESS and MetSat using geostationary orbits Frequency band Satellite service ModulationApplicable elevation angle (degrees) Minimum C/N or maximum BER Required tim
21、e availability (%) Function and type of earth station 401-403 MHz (Earth-to-space) MetSat and EESS Digital 3 10599.6 Data collection, Low-gain antenna 460-470 MHz (space-to-Earth) MetSat and EESS Digital 3 10599.6 DCP interrogation, low-gain antenna Digital 3 10699.9 Direct data readout and data dis
22、semination, high-gain antenna Analogue 3 10 dB 99.9 Data dissemination, high-gain antenna 1 670-1 710 MHz (space-to-Earth) MetSat and EESS Digital 3 10699.6 CDA station, high-gain antenna 2 025-2 110 MHz (Earth-to-space) EESS Digital 3 10599.6 CDA station, high-gain antenna 7 450-7 550 MHz (space-to
23、-Earth) MetSat Digital 5 10699.9 Direct data readout, high-gain antenna 18.1-18.3 GHz (space-to-Earth) MetSat Digital 5 10799.9 Direct data readout, high-gain antenna 25.5-27.0 GHz (space-to-Earth) EESS Digital 5 10799.9 Direct data readout, high-gain antenna Rec. ITU-R SA.1159-3 5 Notes to Table 2:
24、 NOTE 1 Performance objectives for specific systems may differ from the objectives presented in this Recommendation; however, the objectives defined herein are used as a basis for deriving permissible levels of interference that are the minimum interference thresholds to be accepted by specific syst
25、ems. NOTE 2 Additional performance objectives could be specified for an availability of 99.99% of the time in relation to the need to synchronize the receiver to the data transmission frames and to avoid bit slips within a frame. However, for the purpose of deriving interference criteria, these obje
26、ctives can be assumed to be met if the objectives associated with the above availability levels are met. NOTE 3 The EESS is only allocated in the 1 690-1 710 MHz portion of the band. NOTE 4 In all cases in Table 2, it is assumed that earth station sites are selected to yield average levels of enviro
27、nmental radio-frequency noise within the band. For direct data readout stations, which may be deployed in large numbers by various operating entities, there is a risk that randomly selected sites will exhibit higher than average levels of environmental noise (especially man-made noise) that may hamp
28、er the ability to achieve the stated performance objectives. However, the variance of this noise over all locations is not large in relation to receiver thermal noise, such that the performance objectives can generally be met at over 95% of the possible locations given link power margins of a few decibels.
