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Methods for matching test of satellite and TT&C station
1 Scope
1.1 Subject content
This standard specifies the matching test contents and methods of satellite TT&C system and ground TT&C station (airship).
1.2 Application scope
This standard is applicable to the matching test of satellite and TT&C system before satellite flight test. Each model may be tailored according to the actual situation.
2 Normative references
There is no provision in this clause.
3 Definitions
3.1 static matching test of satellite and TT&C station
joint test on system performance and working programs of satellite TT&C system and related equipment and TT&C system of TT&C station (airship)
3.2 dynamic matching test of satellite and TT&C station
joint test on system performance and working programs of satellite TT&C system and related equipment on revised flight and ground TT&C station
3.3 satellite TT&C simulator
equipment simulating satellite TT&C function in matching test of satellite and TT&C station
3.4 satellite attitude & orbital motion simulator
equipment that receives attitude and orbit data and converts the attitude and orbit control parameters into remote control command information and control data according to dynamics and kinematics laws
3.5 satellite simulator
generic terms of satellite TT&C simulator and satellite attitude & orbital motion simulator
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4 General requirements
4.1 Test purpose
a. Verify the coordination of joint work of satellite and TT&C system and related equipment;
b. Verify the technical state and main TT&C technical performance of satellite and TT&C equipment;
c. Rehearse the working program of satellite and TT&C system;
d. Simulate satellite failures and rehearse emergency treatment methods;
e. Commanders and operators performing tasks perform field drills according to working programs.
4.2 Test conditions
a. The newly developed satellite system shall be subjected to matching test of satellite and TT&C station;
b. Before each satellite is launched, the matching test of satellite and TT&C station shall be arranged as needed;
c. Due to the needs of satellite TT&C system, when the TT&C equipment has been greatly modified, the matching test of satellite and TT&C station shall be arranged.
4.3 Test site and equipment
4.3.1 Test site
The matching test is generally carried out at satellite TT&C station (airship). Personnel activities and object movements are prohibited near the antenna in test site.
4.3.2 Test equipment
Satellite-borne equipment or simulation equipment and TT&C station (airship) equipment with the same electrical performance as satellite-borne equipment is adopted for matching joint test.
4.4 Test environmental conditions
4.4.1 The test environmental conditions for TT&C station (airship) equipment shall be specified according to the special technical specifications for equipment.
4.4.2 Atmospheric conditions for satellite-borne equipment, simulation equipment and test and detection equipment:
a. temperature: 0~45℃;
b. relative humidity: ≤80%;
c. air pressure: local air pressure.
5 Detailed requirements
5.1 Static matching test of monopulse radar
Place the director radar beacon, radar transponder and their antennas on the radar calibration tower, and set the uplink and downlink levels of RF signals according to the test contents.
5.1.1 Ranging accuracy test of radar
Switch on director radar beacon and radar transponder. The director radar tracks the director beacon antenna, and test the performance of director radar and the stability of signals received by beacon. The director monopulse radar points to the transponder antenna. The radar sends pulse signals to trigger the radar transponder, and the monopulse radar antenna tracks the transponder antenna. At the same time, measure the fixed delay and delay stability of the transponder so as to obtain the ranging accuracy and calculate the statistical angle measurement accuracy.
5.1.2 Frequency measurement accuracy test of radar
When the radar triggers the transponder, measure the RF frequency and frequency stability of the answer signal so as to obtain the frequency measurement accuracy.
5.1.3 Switch-on capture characteristic test of radar transponder
Measure the time from switch-on to normal signal response of radar transponder, and measure the value of frequency and pulse delay varying with time at different time after switch-on.
5.1.4 Working frequency band test of radar transponder
Change the transmitting frequency of radar, and measure the frequency band of transponder transmitting radar signal.
5.2 Static matching test of dual-frequency velocimeter
Place the satellite-borne dual-frequency transmitter and antenna in the test room or calibration tower at TT&C station, and measure the frequency stability of dual-frequency transmitter through the equipment of TT&C station.
Preheat the satellite-borne transmitter, and test the frequency stability after the frequency is stable. The data of continuous measurement for 20min is regarded as a group, and the data are generally processed by Allan variance. During the measurement of multiple groups of data, the time for continuous measurement of each group of data may be shortened appropriately. The high-end and low-end frequency stability, comprehensive frequency stability and dual-frequency frequency accuracy shall be measured.
5.3 Static matching test of ultrashort wave remote control
Place the satellite-borne remote control equipment and antenna on the test room or calibration tower at TT&C station. Generally, the transmitting power of remote transmitter at TT&C station is limited to less than 10mW, and the modulation index is 2.5, 3.0 and 3.5 respectively.
5.3.1 In the test command channel, the remote control command is sent by hand, and the satellite-borne test equipment monitors and records the receiving result of command.
5.3.2 The computer controls the sending of remote control commands, and the satellite-borne test equipment monitors and records the receiving result of command. The computer controls the remote control command chain, and the satellite-borne test equipment monitors and records the receiving result of command.
5.4 Static matching test of ultrashort wave telemetry
Place the satellite-borne telemetry equipment on the test room or calibration tower at TT&C station. Switch on the satellite-borne telemetry equipment and the TT&C station receives the data.
5.4.1 Verify the correctness of telemetry frequency, demodulation, bit error rate and data format.
5.4.2 The TT&C station processes the received telemetry data.
5.5 Static matching test of ultrashort wave ranging
Place the satellite-borne ranging receiver, dual-frequency transmitter and antenna on the calibration tower at TT&C station for test, or use the simulator of satellite-borne equipment to replace satellite-borne ranging equipment for test.
5.5.1 Test with satellite-borne ranging equipment
Use phase modulation/phase modulation mode for the uplink and downlink of ranging system, and carry out the test after the satellite and TT&C station equipment is stabilized after switch-on.
5.5.1.1 Measurement of distance zero value and phase matching value of each sidetone
Adjust the levels of uplink and downlink signals to the receiving sensitivity level through attenuator, the modulation degree is the rated value, the carrier frequency is the used center frequency, and measure the distance zero value and the phase matching value of each sidetone in two states of "measurement" and "self-calibration” by distance measuring equipment at TT&C station. Measure ten groups of data for statistical processing so as to obtain the distance zero value and phase matching value of satellite-borne system.
5.5.1.2 Ranging accuracy of measurement system
Adjust the levels of uplink and downlink signals to the receiving sensitivity level through attenuator, the modulation degree is the rated value, the carrier frequency is the used center frequency, and the distance measuring equipment of TT&C station measures the distance zero value in two states of "measurement" and "self-calibration” and carry out statistical processing for multiple groups of measured data so as to calculate the ranging accuracy value of ranging system.
5.5.1.3 Measurement of retransmitting sidetone modulation degree and frequency spectrum
When the telemetry signal is modulated by the satellite-borne transmitter, measure the sidetone spectrum of the retransmitted signal by a spectrum analyzer, so as to obtain the modulation degree, sidetone spectrum structure and clutter spectrum.
5.5.1.4 Measurement of influence of various factors on ranging accuracy
According to the requirements of satellite orbit measurement, change the uplink and downlink levels, carrier frequency (Doppler frequency offset) and modulation degree by 10%, and measure the change value of distance zero value caused by various changes through distance measuring equipment, so as to obtain the influence on ranging accuracy.
5.5.1.5 Measurement of stability of distance zero value
Take a group of distance zero value data every 10min by the distance measuring equipment at TT&C station, with 10 groups taken in total, and the change of distance zero value shall not be out of the use range.
5.5.2 Test with simulator
Test contents are the same as those in 5.5.1. Compare the measurement result with that of satellite-borne equipment, which may be used as a reference for the equipment detection of TT&C station.
5.5.3 Error propagation test of ultrashort wave ranging distance zero value
Before satellite launch, the test shall be carried out at the final assembly plant, special test site or TT&C station.
Use phase modulation/phase modulation mode for the uplink and downlink of test system. Carry out the test after the satellite and TT&C station equipment is stabilized after switch-on. Adjust the levels of uplink and downlink signals to the receiving sensitivity level through attenuator, the modulation degree is the rated value, and the carrier frequency is the used center frequency.
5.5.3.1 Measure the distance zero value of satellite ranging system and the phase value of each sidetone by distance measuring equipment for satellite comprehensive test.
5.5.3.2 Measure the distance zero value of simulator and the phase value of each sidetone bydistance measuring equipment for satellite comprehensive test .
5.5.3.3 Compare the distance zero value between the satellite-borne ranging system and the simulator and the difference of phase value of each sidetone, which serves as the calibration basis for the equipment of TT&C station to measure the distance zero value.
5.5.3.4 Measure the distance zero value of simulator and the phase value of each sidetone by distance measuring equipment at each ground TT&C station, compare and analyze the measured zero value and phase value with those measured by distance measuring equipment for satellite comprehensive test, complete the error propagation, and obtain the ranging value that shall be deducted when performing the flight mission.
