1、ITU-R RECMNxSA. LO19 94 4855212 0523374 bbb Rec. ITU-R SA.1019 77 RECOMMENDATION ITU-R SA. 1 O 19 PREFERRED FREQUENCY BANDS AND TRANSMISSION DIRECTIONS FOR DATA RELAY SATELLITE SYSTEMS (Question ITU-R 1 1817) (1994) The ITU Radiocommunication Assembly, considering a) System for Data Relay Satellite
2、(DRS) Systems of Recommendation ITU-R SA.1018; that data relay satellite systems are in operation or are planned corresponding to the Hypothetical Reference b) that these DRS systems support links with widely different characteristics; c) that some DRS user spacecraft require links of low data rate
3、(up to about 6 Mbit/s) which require modest bandwidths which can be most economically implemented, using low-power transmitters, simple wide-beam antennas without complex pointing mechanisms and robust receivers, in frequency bands for DRS inter-orbit links below 3 GHz; d) that some DRS user spacecr
4、aft require links from wide-beam or omnidirectional antennas (in particular to support contingency links) in cases where the attitude of the user spacecraft and the direction of the DRS is not accurately known, thus requiring the use of frequency bands for DRS inter-orbit links below 3 GHz; e) than
5、600 Mbit/s) thus requiring the use of frequency bands for DRS inter-orbit links above 10 GHz; that some DRS user spacecraft require links of medium to high data rates (from about 10 Mbit/s up to more f) that the frequency bands available and suitable for DRS inter-orbit links are limited; s) service
6、; that the forward and return feeder links of data relay satellites could use bands allocated to the fixed-satellite h) frequency bands; that the normal-mode operations of data relay satellites should use their own forward and return feeder-link j) omnidirectional antennas, which require the use of
7、frequency bands below 3 GHz; that launch, early-orbit-phase and emergency operations of data relay satellites require the use of wide-beam or k) that the choice of common frequency bands for different data relay satellite systems permits the consideration of interoperability between user spacecraft
8、designed to use one DRS system and data relay satellites of another DRS system, recommends 1. antennas use assignments within the allocated bands: that the inter-orbit links for DRS user spacecraft requiring low data rates using wide-beam or omnidirectional 1.1 2 025-2 110 MHz band for the forward i
9、nter-orbit link; 1.2 2 200-2 290 MHz band for the return inter-orbit link; 2. allocated bands, subject to the limitations of a secondary allocation: that the inter-orbit links for DRS user spacecraft requiring medium data rates consider assignments within the 2.1 13.4-14.3 GHz band for the forward i
10、nter-orbit link; 2.2 14.5- 15.35 GHz band for the return inter-orbit link; COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesITU-R RECMN*SA* LO17 74 m 4855212 0523175 5T2 m 78 Rec. ITU-R SA.1019 3. the allocated bands: that the inter-orb
11、it links for DRS user spacecraft requiring medium to high data rates use assignments within 3.1 22.55-23.55 GHz band for the forward inter-orbit link; 3.2 25.25-27.50 GHz band for the return inter-orbit link: 4. 2 200-2 290 MHz bands. that the launch, early-orbit-phase and emergency operations of a DRS use the 2025-2 110 MHz and COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling Services
