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GJB 1198 consists of the following eight parts under the general title Telemetry tracking command and data handling for spacecraft:
——Part 1: PCM telecommand;
——Part 2: PCM telemetry;
——Part 3: Telemetry channel coding;
——Part 4: Ranging;
——Part 5: Radio frequency and modulation;
——Part 6: Packet telemetry;
——Part 7: Packet telecommand;
——Part 8: Onboard data handling interface.
This part is Part 5 of GJB 1198.
This part replaces GJB 1198.5-1991 Telemetry tracking command and data handling for satellite - Radio frequency and modulation.
The following main changes have been made in this part with respect to the previous edition:
a) In order to make this revised part compatible with the current standards and recommendations of ESA and CCSDS, only the radio frequency and modulation contents required for S-band telemetry tracking command and space research are compiled, and at the same time, the standard contents required for the suppressed carrier modulation are compiled;
b) According to provisions of ITU and CCSDS, spacecrafts are classified into Category A and Category B spacecrafts, which are beneficial to the assignment and use of radio frequency.
This part was proposed by China Aerospace Science and Technology Corporation.
This part is under the jurisdiction of China Astronautics Standards Institute.
This part was firstly issued in October 1991, and firstly revised this time.
Telemetry tracking command and data handling for spacecraft
Part 5: Radio frequency and modulation
1 Scope
This part specifies the requirements for the use and assignment of the spacecraft radio frequency and the transmitted signals and carrier modulation.
This part is applicable to radio frequency selection and signal modulation for spacecraft S-band telemetry tracking command and space research.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part. For dated reference, subsequent amendments to (excluding any corrigendum), or revisions of, any of these publications do not apply. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For undated references, the latest editions apply to this part.
GJB 727A-1998 Terms and acronyms of space tracking telemetry and command system
GJB 1198.4A-2004 Telemetry tracking command and data handling for spacecraft
Part 4: Ranging
3 Terms and definitions
For the purposes of this part, the terms and definitions established in GJB 727A-1998 and GJB 1198.4A-2004 apply.
3.1
category A spacecraft
spacecraft with an operating height less than 2×106km from the Earth's surface
3.2
category B spacecraft
spacecraft with an operating height greater than 2×106km from the Earth's surface
3.3
occupied bandwidth
frequency width in which the average power transmitted below the lower frequency limit and above the upper frequency limit is equal to the percentage β/2 of the total average power of a given transmission. Generally, β/2 is equal to 0.5%.
3.4
radio frequency spectral mask
restriction on the distribution shape of modulated carrier radio frequency spectrum
4 General
4.1 Use and assignment of radio frequency
The use of radio frequency for spacecraft S-band telemetry tracking command and space research shall meet the relevant requirements on radio frequency division. The radio frequency assignment for spacecraft S-band telemetry tracking command and space research shall follow the relevant radio rules.
4.2 Use for spacecraft S-band telemetry tracking command and space research and frequency supported by earth station
4.2.1 Telemetry tracking command
S-band
2025MHz~2110MHz (uplink)
2200HMz~2290HMz (downlink)
4.2.2 Space research
2025MHz~2110MHz (uplink, Category A spacecraft)
2200MHz~2290HMz (downlink, Category A spacecraft)
2110MHz~2120MHz (uplink, Category B spacecraft)
2290MHz~2300HMz (downlink, Category B spacecraft)
4.3 Procedure and application content of frequency assignment
4.3.1 Procedure
The appropriate channel center frequency assignment for flight mission shall be carried out according to the following steps:
Step 1: in the stage of feasibility study, select the frequency range of the channel center frequency used for the spacecraft flight mission;
Step 2: in the stage of scheme design, select the channel center frequency used for the spacecraft flight mission;
Step 3: coordinate and determine the channel center frequency used for the spacecraft flight mission.
4.3.2 Application content
The application for channel center frequency assignment shall comply with relevant radio rules.
5 Transmitted signal
5.1 Coherence frequency forwarding ratio of spacecraft S-band transponder
The coherence frequency forwarding ratio of spacecraft S-band transponder is 221/240.
5.2 Carrier frequency stability
5.2.1 Spacecraft S-band transmitter
Requirements for the frequency stability of its transmitted carrier are given in Table 1.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 General
5 Transmitted signal
6 Carrier modulation
7 Suppressed carrier modulation