Method and system for testing and calibrating time difference between a geostationary orbit satellite and the ground

Abstract

The present invention provides a method and system for testing and calibrating the time difference between a geostationary orbit satellite and the ground, including: obtaining the satellite-ground two-way transmission delay based on the remote control command sending time of the ground transmission delay test command, the satellite's forwarding delay, and the telemetry data receiving time of the ground test equipment; setting the first satellite-ground time difference between the ground equipment and the satellite according to the satellite-ground two-way transmission delay, the time when the ground test equipment sends the time synchronization command, and the time when the satellite receives the time synchronization command; obtaining the second satellite-ground time difference according to the first sending time and the first receiving time of the second telemetry data; and calibrating the satellite according to the first satellite-ground time difference, the second satellite-ground time difference, and the satellite-ground two-way transmission delay. Compared with the prior art, the present invention can be used as a routine operation for satellite service operation, has the characteristics of being simple and fast to use, and does not require special satellite-ground ranging operations, and is completely applicable to satellite ground testing and satellite on-orbit testing.

Description

Technical Field

[0001] The present invention relates to the technical field of geostationary satellites, and in particular, to a method and system for testing and calibrating the time difference between a geostationary satellite and the ground. Background Art

[0002] The geostationary meteorological satellite requires the accuracy of the time difference between the satellite and the ground to be controlled within 5 ms, and the test of the satellite-ground transmission delay is the most important link for testing the time difference between the satellite and the ground. The traditional satellite-ground delay test method includes two stages: ground test and on-orbit test; in the ground test stage, the ground test software calculates the satellite-ground transmission delay by estimating the satellite-ground distance and adding the fixed delay of the satellite-ground equipment, and then calculates the time difference between the satellite and the ground for satellite time calibration; after the satellite is fixed in position, the ground test software calculates the satellite-ground distance by satellite-ground ranging, adds the fixed delay of the satellite-ground equipment to calculate the satellite-ground transmission delay, and then calculates the time difference between the satellite and the ground for satellite time calibration.

[0003] Patent document CN107688290A discloses an application method of GNSS time calibration on a high-orbit satellite, including a calculation method of GNSS time calibration data. The GNSS receiver obtains the real-time GNSS time through an autonomous navigation algorithm, calculates the difference between the on-board time and the GNSS time as the GNSS time calibration data; and a usage strategy of the time calibration data by the on-board software. The GNSS time calibration data is sent to the on-board software, and the on-board software uses the time calibration data to complete the time calibration task while ensuring the safety of the overall satellite timekeeping system. However, this method is not applicable to all satellites and does not solve the problem of simplicity and high efficiency in satellite ground testing and satellite on-orbit testing. Summary of the Invention

[0004] Aiming at the deficiencies in the prior art, the purpose of the present invention is to provide a method and system for testing and calibrating the time difference between a geostationary satellite and the ground.

[0005] According to a method for testing and calibrating the time difference between a geostationary satellite and the ground provided by the present invention, it includes:

[0006] Step 1: Obtain the satellite-ground two-way transmission delay according to the remote control instruction sending time when the ground test equipment sends a delay test instruction to the satellite, the forwarding delay of the satellite, and the telemetry data receiving time of the first telemetry data sent by the satellite received by the ground test equipment. The forwarding delay represents the difference between the delay test instruction receiving time when the satellite receives the delay test instruction and the telemetry data sending time when the satellite sends the first telemetry data.

[0007] Step 2: Set the time difference between the ground equipment and the satellite as the first satellite-ground time difference according to the satellite-ground two-way transmission delay, the time when the ground test equipment sends a timing instruction to the satellite, and the time when the satellite receives the timing instruction.

[0008] Step 3: Obtain the second satellite-ground time difference between the ground equipment and the satellite according to the first transmission time when the satellite sends the second telemetry data to the ground test equipment and the first reception time when the ground test equipment receives the second telemetry data;

[0009] Step 4: Calibrate the time of the satellite according to the first satellite-ground time difference, the second satellite-ground time difference, and the satellite-ground two-way transmission delay.

[0010] Preferably, step 4 includes:

[0011] Step 401: Obtain the satellite uplink transmission delay and the satellite downlink transmission delay according to the first satellite-ground time difference, the second satellite-ground time difference, and the satellite-ground two-way transmission delay;

[0012] Step 402: Obtain the third satellite-ground time difference according to the satellite uplink transmission delay and the satellite downlink transmission delay;

[0013] Step 403: Send the third satellite-ground time difference to the satellite for time calibration.

[0014] Preferably, the first telemetry data is used to record the forwarding delay from when the satellite receives the delay test instruction to when it sends the first telemetry data.

[0015] Preferably, step 2 includes:

[0016] Step 201: Obtain a fixed delay according to the satellite-ground two-way transmission delay, and the timing instruction includes the fixed delay;

[0017] Step 202: The ground test equipment sends a timing instruction to the satellite at the timing instruction sending time;

[0018] Step 203: The satellite's data management computer receives the timing instruction at the timing instruction reception time and sets the satellite's time to the timing instruction time;

[0019] Step 204: The data management computer calculates the time difference between the timing instruction reception time and the timing instruction time;

[0020] Step 205: Obtain the first satellite-ground time difference according to the timing instruction sending time, the timing instruction reception time, and the time difference.

[0021] Preferably, the first satellite-ground time difference is equal to the second satellite-ground time difference.

[0022] According to a geostationary satellite satellite-ground time difference test and calibration system provided by the present invention, it includes:

[0023] Module M1: Obtain the space-ground bidirectional transmission delay based on the remote control instruction sending time when the ground test equipment sends a time delay test instruction to the satellite, the forwarding delay of the satellite, and the telemetry data reception time of the first telemetry data sent by the satellite received by the ground test equipment. The forwarding delay represents the difference between the time delay test instruction reception time when the satellite receives the time delay test instruction and the telemetry data sending time when the satellite sends the first telemetry data.

[0024] Module M2: Set the time difference between the ground equipment and the satellite as the first space-ground time difference according to the space-ground bidirectional transmission delay, the time when the ground test equipment sends a time synchronization instruction to the satellite, and the time when the satellite receives the time synchronization instruction.

[0025] Module M3: Obtain the second space-ground time difference between the ground equipment and the satellite according to the first sending time when the satellite sends the second telemetry data to the ground test equipment and the first reception time when the ground test equipment receives the second telemetry data.

[0026] Module M4: Calibrate the time of the satellite according to the first space-ground time difference, the second space-ground time difference, and the space-ground bidirectional transmission delay.

[0027] Preferably, Module M4 includes:

[0028] Sub-module M401: Obtain the space-ground uplink transmission delay and the space-ground downlink transmission delay according to the first space-ground time difference, the second space-ground time difference, and the space-ground bidirectional transmission delay.

[0029] Sub-module M402: Obtain the third space-ground time difference according to the space-ground uplink transmission delay and the space-ground downlink transmission delay.

[0030] Sub-module M403: Send the third space-ground time difference to the satellite for time calibration.

[0031] Preferably, the first telemetry data is used to record the forwarding delay from when the satellite receives the time delay test instruction to when it sends the first telemetry data.

[0032] Preferably, Module M2 includes:

[0033] Sub-module M201: Obtain a fixed delay according to the space-ground bidirectional transmission delay. The time synchronization instruction includes the fixed delay.

[0034] Sub-module M202: The ground test equipment sends a time synchronization instruction to the satellite at the time when the time synchronization instruction is sent.

[0035] Sub-module M203: The satellite's data management computer receives the time synchronization instruction at the time when the time synchronization instruction is received, and sets the satellite's time to the time of the time synchronization instruction.

[0036] Sub-module M204: Calculate the time difference between the time when the time synchronization instruction is received by the digital management computer and the time of the time synchronization instruction.

[0037] Sub-module M205: Obtain the first satellite-ground time difference based on the time when the time synchronization instruction is sent, the time when the time synchronization instruction is received, and the time difference.

[0038] Preferably, the first satellite-ground time difference is equal to the second satellite-ground time difference.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The present invention can be used as a routine operation for satellite service operation, has the characteristics of being simple and fast to use, and there is no need to specifically perform satellite-ground ranging operations, and it is fully applicable to satellite ground testing and satellite on-orbit testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects, and advantages of the present invention will become more apparent:

[0042] Figure 1 It is a schematic flowchart of the present invention;

[0043] Figure 2 It is a schematic diagram of the remote control instruction of the present invention;

[0044] Figure 3 It is a schematic diagram of the telemetry data of the present invention;

[0045] Figure 4a It is a data schematic diagram of the first remote control instruction of the present invention;

[0046] Figure 4b It is a data schematic diagram of the first telemetry data to be of the present invention;

[0047] Figure 4c It is a data schematic diagram of the second remote control instruction of the present invention;

[0048] Figure 4d It is a data schematic diagram of the second telemetry data of the present invention;

[0049] Figure 4e It is a data schematic diagram of the third remote control data of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0050] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill in the art can make several changes and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0051] Figure 1 This is a schematic diagram of the process of the present invention. As Figure 1 shown, the present invention provides a method for testing and calibrating the time difference between a geostationary orbit satellite and the ground, including:

[0052] Step 1: According to the remote control command sending time (T 地1 ) of the delay test command sent by the ground test equipment to the satellite, the forward delay (τ 星 ) of the satellite, and the telemetry data reception time (T 地2 ) of the first telemetry data sent by the satellite received by the ground test equipment, obtain the satellite-ground two-way transmission delay (ΔT 1 ). The forward delay represents the difference between the delay test command reception time (T 星1 ) when the satellite receives the delay test command and the telemetry data sending time (T 星2 ) when the satellite sends the first telemetry data.

[0053] Preferably, the first telemetry data is used to record the forward delay from when the satellite receives the delay test command to when it sends the first telemetry data.

[0054] Specifically, the ground test equipment sends a delay test command to the satellite. The delay test command data is included in the remote control command, and the ground test equipment records the remote control command sending time (T 地1 ); then, the satellite receives the delay test command in the remote control command, and the digital management computer on the satellite records the delay test command reception time (T 星1 ) when it receives the delay test command, and places the delay amount of the satellite sending the first telemetry data in the telemetry fixed channel and sends it to the ground test equipment; the ground test equipment identifies the delay test flag bit and records the reception time of the telemetry frame of the first telemetry data, that is, the telemetry data reception time (T 地2 ); the ground test equipment calculates the satellite-ground two-way transmission delay (ΔT 1 ).

[0055] Figure 2 This is a schematic diagram of the remote control command of the present invention. As Figure 2As shown, it includes: a remote control frame synchronization header, a TC main header, a secondary header, remote control data, and a checksum. Among them, the remote control frame synchronization header is 4 bytes, 32 bits; the TC main header is 6 bytes, 48 bits; the secondary header is 2 bytes, 16 bits; the remote control data is 8 bytes, 64 bits; the checksum is 2 bytes, 16 bits; when the remote control instruction is a delay test instruction, the secondary header is defined as "0xFF00", and the application data is filled with 8 bytes of "0xAA"; when the remote control instruction is a satellite time synchronization instruction, the secondary header is defined as "0x00FF", and the application data is "the count value of 1 us starting from UTC time January 1, 2000"; when the remote control instruction is a satellite time calibration instruction, the secondary header is defined as "0x00F0", and the application data is "the count value of 1 us of the satellite-ground time difference increment".

[0056] It can be understood that after the satellite receives the delay test instruction, the digital management computer on the satellite sets the delay flag bit to binary "11"; when sending the first telemetry data, the digital management computer on the satellite takes the time difference between the time (T 星1 ) when the delay test instruction is received and the time (T 星2 ) when the first telemetry data is sent as the forwarding delay (τ 星 ), and transmits the forwarding delay (τ 星 ) to the ground test equipment; after the ground test equipment receives the first telemetry data, the ground test equipment judges the delay flag bit, records the moment when the first telemetry data is received, that is, the telemetry data reception time (T 地2 ), and calculates the satellite-ground two-way transmission delay (ΔT 1 ).

[0057] Exemplarily, the satellite-ground two-way transmission delay (ΔT 1 ) is equal to the telemetry data reception time (T 地2 ) minus the remote control instruction transmission time (T 地1 ) minus the forwarding delay (τ 星 ).

[0058] Figure 3 This is a schematic diagram of the telemetry data of the present invention, as shown in Figure 3As shown in the figure, it includes: a telemetry frame synchronization header, a TM main header, satellite time, a time delay flag, a forwarding time delay, telemetry data, and a checksum. Among them, the telemetry frame synchronization header is 4 bytes, 32 bits; the TM main header is 6 bytes, 48 bits; the satellite time is 8 bytes, 64 bits; the time delay flag is 4 bytes, 2 bits; the forwarding time delay is 4 bytes, 30 bits; the telemetry data is 1000 bytes; the checksum is 2 bytes, 16 bits. Among them, the satellite time corresponds to the time at the start position of the telemetry frame synchronization header, and the satellite time is "the count value in 1 us starting from UTC time January 1, 2000"; after the data management computer receives the time delay test instruction, the time delay flag is set to binary "11"; the forwarding time delay is the difference between the time when the satellite receives the time delay test instruction and the current satellite time, and it is a cumulative count value in 1 us; after the data management computer receives the time synchronization instruction, the time delay flag is set to binary "00".

[0059] An optional embodiment is to send a time delay test instruction from the ground to the satellite, and the ground test equipment records the time (T 地1 ) when the telecommand is sent; the time delay test instruction is transmitted to the data management computer through the space-ground uplink channel, where the space-ground uplink transmission time delay is τ up ; the first telemetry data sent by the satellite is transmitted to the ground test equipment through the space-ground downlink channel, where the space-ground downlink transmission time delay is τ down ; the data management computer records the time (T 星1 ) when it receives the time delay test instruction, sets the time delay flag bit to binary "11", and fills the forwarding time delay (τ 星 ) into the fixed channel of the telemetry frame when the first telemetry data is downlinked to the ground test equipment, where τ 星 = T 星2 - T 星1 ; the ground test equipment receives and identifies the telemetry frame containing the time delay flag bit, and records the time when the telemetry frame synchronization word is received, that is, the telemetry data reception time (T 地2 ); calculate the space-ground two-way transmission time delay (ΔT 1 ), specifically, ΔT 1 = τ up + τ down = (T 地2 - T 地1 ) - τ 星 .

[0060] In the present invention, a time delay test instruction for space-ground transmission is defined to complete the measurement of the space-ground two-way transmission time delay. Further, the present invention also defines a telemetry data used for the space-ground transmission time delay test to record the time delay information from when the satellite receives the time delay test instruction to when it sends telemetry.

[0061] Step 2: According to the space-ground two-way transmission time delay (ΔT 1) The time (T 地3 ) when the ground test equipment sends the time synchronization instruction to the satellite and the time (T 星3 ) when the satellite receives the time synchronization instruction are set, and the time difference between the ground equipment and the satellite is set as the first ground-satellite time difference (ΔT 3 ).

[0062] Specifically, the ground test equipment sends a time synchronization instruction to the satellite. The time synchronization instruction includes ΔT 1 / 2 of the ground-satellite transmission delay, and the first ground-satellite time difference is set as a fixed value ΔT 3 , where ΔT 3 = (τ up - τ down ) / 2).

[0063] The ground test equipment sends a time synchronization instruction to the satellite's data management computer at time T 地3 . The ground time corresponding to the time synchronization instruction is T 地3 + ΔT 1 / 2; the satellite's data management computer receives the time synchronization instruction and performs time synchronization operations, and sets the first ground-satellite time difference as a fixed value ΔT 3 .

[0064] Preferably, step 2 includes: step 201: obtaining a fixed delay (ΔT 1 / 2) according to the ground-satellite two-way transmission delay (ΔT 1 ), and the time synchronization instruction includes the fixed delay (ΔT 1 / 2); step 202: the ground test equipment sends a time synchronization instruction to the satellite at the time (T 地3 ) when the time synchronization instruction is sent; step 203: the satellite's data management computer receives the time synchronization instruction at the time (T 星3 ) when the time synchronization instruction is received, and sets the satellite's time as the time of the time synchronization instruction (T 地3 + ΔT 1 / 2); step 204: the data management computer calculates the time difference (ΔT 星3 ) between the time (T 地3 ) when the time synchronization instruction is received and the time of the time synchronization instruction (T 1 + ΔT 2 ); step 205: obtaining the first ground-satellite time difference (ΔT 地3 ) according to the time (T 星3 ) when the time synchronization instruction is sent, the time (T 2 ) when the time synchronization instruction is received, and the time difference (ΔT 3 ).

[0065] In the present invention, the fixed delay can be set as half of the ground-satellite two-way transmission delay (ΔT 1 ), that is, ΔT 1 / 2。

[0066] Specifically, the ground test equipment sends a time synchronization instruction containing a fixed time delay at the time of sending the time synchronization instruction (T 地3 ), and the time of the time synchronization instruction is T 地3 +ΔT 1 / 2; when the digital management computer receives the time synchronization instruction, it records the time of receiving the time synchronization instruction (T 星3 ), and calculates the time difference (ΔT 2 ) between the time of the time synchronization instruction and the time of receiving the time synchronization instruction, that is, ΔT 2 =(T 地3 +ΔT 1 / 2)-T 星3 ; after receiving the time synchronization instruction, the digital management computer sets the satellite time to the time of the time synchronization instruction and sets the time delay flag bit to binary "00"; it can be seen that the first satellite-ground time difference (ΔT 3 ) after time synchronization is: ΔT 3 =(T 地3 +τ up )-(T 星3 +ΔT 2 )=(τ up -τ down ) / 2。

[0067] Step 3: Obtain the second satellite-ground time difference (ΔT 星4 ) between the ground equipment and the satellite according to the first transmission time (T 地4 ) when the satellite sends the second telemetry data to the ground test equipment and the first reception time (T 4 ) when the ground test equipment receives the second telemetry data.

[0068] In the present invention, the satellite digital management computer sends the second telemetry data containing the satellite time to the ground for calculating the satellite-ground one-way transmission delay.

[0069] Specifically, after receiving the time synchronization instruction, the digital management computer on the satellite changes the time delay flag bit and sends it to the ground test equipment; the ground test equipment recognizes the change of the time delay flag bit, records the first reception time of the telemetry frame, and calculates the second satellite-ground time difference (ΔT 4 ) including the one-way transmission delay, where ΔT 4 =ΔT 3 .

[0070] In one embodiment, after receiving the time synchronization instruction, the digital management computer on the satellite sets the time delay flag bit to binary "10", and at the satellite time T 星4Send the second telemetry data at a specific moment; after receiving the second telemetry data, the ground test equipment judges the change of the time delay flag bit, records the synchronization moment of the telemetry data frame of the second telemetry data, and obtains the satellite-ground one-way transmission time delay, that is, the second satellite-ground time difference ΔT 4 .

[0071] The specific steps are as follows: The data management computer transmits the second telemetry data with the time code of this moment at satellite time T 星4 ; after receiving the second telemetry data, the ground test equipment marks the time of the header position of the telemetry frame of the second telemetry data as T 地4 . At this time, the second satellite-ground time difference ΔT 4 =ΔT 3 =T 地4 -(T 星4 +τ down )=(τ up -τ down ) / 2; calculate the satellite-ground uplink transmission time delay τ up =(ΔT 1 +ΔT 4 ×2) / 2; calculate the satellite-ground downlink transmission time delay τ down =ΔT 1 -τ up .

[0072] Step 4: Calibrate the satellite according to the first satellite-ground time difference (ΔT 3 ), the second satellite-ground time difference (ΔT 4 ) and the satellite-ground two-way transmission time delay (ΔT1).

[0073] Specifically, the ground test equipment calculates the satellite-ground uplink transmission time delay τ up and the satellite-ground downlink transmission time delay τ down . (τ up -τ down ) / 2 is the third satellite-ground time difference, and this difference is corrected by means of issuing commands.

[0074] Preferably, step 4 includes: step 401: Obtain the satellite-ground uplink transmission time delay (τ 3 ) and the satellite-ground downlink transmission time delay (τ 4 ) according to the first satellite-ground time difference (ΔT 1 ), the second satellite-ground time difference (ΔT up ) and the satellite-ground two-way transmission time delay (ΔT down ); step 402: Obtain the third satellite-ground time difference (τ up ) and the satellite-ground downlink transmission time delay (τ down ) according to the satellite-ground uplink transmission time delay (τ up -τ down ) / 2; step 403: Use the third satellite-ground time difference (τup -τ down ) / 2 is sent to the satellite for time calibration.

[0075] Preferably, the first satellite-ground time difference (ΔT 3 ) is equal to the second satellite-ground time difference (ΔT 4 ).

[0076] A specific embodiment is provided below to illustrate the present invention.

[0077] Figure 4a It is a data schematic diagram of the first remote control command of the present invention. As Figure 4a shown, it includes: a remote control frame synchronization header, a TC main header, delay test instruction data, and verification; Figure 4b It is a data schematic diagram of the first telemetry data of the present invention. As Figure 4b shown, it includes: a telemetry frame synchronization header, a TM main header, satellite time, a delay flag, a forwarding delay, and a telemetry data field, where the satellite time is T 星2 , the delay flag bit is binary "11", and the forwarding delay is τ 星 . First, the satellite-ground two-way transmission delay is tested. In the ground test equipment, after the delay test instruction is output by the command software, it is modulated and frequency-converted and sent to the satellite. The modulation signal output time control accuracy is better than 10 μs. When the delay test instruction is sent, the modulation moment T 地1 of the remote control instruction frame synchronization header in the remote control instruction is recorded by the modulation device, that is, the remote control instruction sending time. The delay test instruction is sent to the satellite through the satellite uplink transmission channel, generating a satellite uplink transmission delay τ up . The digital management computer FPGA software on the satellite recognizes the remote control frame synchronization header and generates a remote control interrupt output to the satellite service management software, and the time accuracy of the interrupt generation is better than 10 us. The satellite service management software records the moment T 星1 when the remote control interrupt is generated, that is, the delay test instruction reception time; when the telemetry frame is ready, the satellite service management software generates a telemetry interrupt, sets the telemetry frame delay flag bit to binary "11", and at the same time, the FPGA software performs serial data modulation and replaces the satellite time with T 星2 , that is, the telemetry data sending time; the difference τ 星 between the remote control interrupt and the telemetry interrupt, that is, the forwarding delay, is filled into the fixed channel of the telemetry frame. The telemetry frame data is modulated and frequency-converted and sent to the ground test equipment through the downlink transmission channel, generating a satellite downlink transmission delay τ down ; the ground test equipment receives the second telemetry data containing the forwarding delay and records the reception moment T 地2, that is, the telemetry data reception time, with a time accuracy better than 0.1 ms. In summary, the time delay test instruction is sent by the ground test equipment, received by the digital management computer on the satellite, recorded and forwarded with time delay to the telemetry frame, sent to the ground test equipment through satellite telemetry downlink, and the two-way satellite-ground transmission time delay ΔT is calculated by the ground test software. 1 .

[0078] Figure 4c is the data schematic diagram of the second remote control instruction of the present invention. As Figure 4c shown, it includes: a telecontrol frame synchronization header, a TC main header, time synchronization instruction data and verification. Among them, the time synchronization instruction data is the time synchronization instruction time T 地3 +ΔT 1 / 2. The command software of the ground test equipment generates a time synchronization instruction with a certain time advance, that is, a fixed time delay (ΔT 1 / 2), and the corresponding time synchronization instruction time is T 地3 +ΔT 1 / 2, which is sent at a fixed time by the modulation equipment under the control of T 地3 ; the time synchronization instruction timing control accuracy is better than 0.1 ms. The time synchronization instruction is sent to the satellite through the satellite-ground uplink transmission channel, generating a satellite-ground uplink transmission time delay τ up ; when the digital management computer receives the time synchronization instruction, it records the remote control interruption time T 星3 , and makes a difference with the time information sent by the ground to generate a time increment ΔT 2 ; the digital management computer performs time synchronization operations according to the generated time increment. In summary, the time synchronization instruction is sent on time by the ground test equipment, and operations such as being received by the digital management computer, recording the remote control interruption time, and making a difference with the ground time generate a time increment; after calibrating with the time increment, the first satellite-ground time difference is a fixed value ΔT 3 .

[0079] Figure 4d is the data schematic diagram of the second telemetry data of the present invention. As Figure 4d shown, it includes: a telemetry frame synchronization header, a TM main header, satellite time, time delay flag, forwarding time delay and telemetry data field. Among them, the satellite time is T 星4 , and the time delay flag bit is binary "10". Then, after satellite-ground time calibration, the one-way satellite-ground transmission time delay is measured and calculated. After completing the time synchronization operation, the digital management computer normally transmits telemetry data, and sets the time delay flag to binary "00". The satellite operation management software generates a telemetry interruption when the telemetry frame is ready, and at the same time, the FPGA software performs serial data modulation and replaces the satellite time with T 星4 . The telemetry frame data is modulated and frequency-converted and then sent to the ground test equipment through the downlink transmission channel, generating a satellite-ground downlink transmission time delay τ down . The ground test equipment receives the second telemetry frame data and records the reception time T of the telemetry frame synchronization word 地4, the calibrated second satellite-ground time difference ΔT can be obtained 4 ; In summary, the satellite uplink transmission delay and the satellite downlink transmission delay can be calculated.

[0080] Figure 4e is the data schematic diagram of the third remote control data of the present invention. As Figure 4e shown, it includes: a remote control frame synchronization header, a TC main header, incremental time calibration instruction data, and a checksum. Among them, the incremental time calibration instruction data is the satellite-ground time difference (τ up -τ down ) / 2. Finally, the ground test equipment sends a time calibration instruction to the satellite. After measuring and calculating the satellite-ground transmission delay, the third satellite-ground time difference (τ up -τ down ) / 2 can be obtained. The ground test equipment sends a time difference incremental time calibration instruction to the satellite to keep the satellite-ground time difference within the synchronization requirement range.

[0081] The present invention provides a geostationary satellite satellite-ground time difference test and calibration system, including:

[0082] Module M1: According to the remote control instruction sending time (T 地1 ) when the ground test equipment sends a time delay test instruction to the satellite, the satellite's forwarding delay (τ 星 ), and the telemetry data receiving time (T 地2 ) of the first telemetry data sent by the satellite received by the ground test equipment, obtain the satellite-ground two-way transmission delay (ΔT 1 ). The forwarding delay represents the difference between the time when the satellite receives the time delay test instruction (T 星1 ) and the time when the satellite sends the first telemetry data (T 星2 ).

[0083] Preferably, the first telemetry data is used to record the forwarding delay from when the satellite receives the time delay test instruction to when it sends the first telemetry data.

[0084] Module M2: According to the satellite-ground two-way transmission delay (ΔT 1 ), the time calibration instruction sending time (T 地3 ) when the ground test equipment sends a time calibration instruction to the satellite, and the time calibration instruction receiving time (T 星3 ) when the satellite receives the time calibration instruction, set the time difference between the ground equipment and the satellite as the first satellite-ground time difference (ΔT 3 ).

[0085] Preferably, module M2 includes: sub-module M201: According to the satellite-ground two-way transmission delay (ΔT1), obtain the fixed delay (ΔT 1 / 2). The time calibration instruction includes the fixed delay (ΔT 1 / 2); Sub-module M202: The ground test equipment sends a time synchronization instruction to the satellite at the time of sending the time synchronization instruction (T 地3 ). Sub-module M203: The satellite's digital management computer receives the time synchronization instruction at the time of receiving the time synchronization instruction (T 星3 ) and sets the satellite's time to the time of the time synchronization instruction (T 地3 +ΔT 1 / 2). Sub-module M204: The digital management computer calculates the time difference (ΔT 星3 ) between the time of receiving the time synchronization instruction (T 地3 +ΔT 1 / 2) and the time of the time synchronization instruction (T 2 ). Sub-module M205: Based on the time of sending the time synchronization instruction (T 地3 ), the time of receiving the time synchronization instruction (T 星3 ) and the time difference (ΔT 2 ), obtain the first satellite-ground time difference (ΔT 3 ).

[0086] Module M3: Based on the first sending time (T 星4 ) when the satellite sends the second telemetry data to the ground test equipment and the first receiving time (T 地4 ) when the ground test equipment receives the second telemetry data, obtain the second satellite-ground time difference (ΔT 4 ) between the ground equipment and the satellite.

[0087] Module M4: Calibrate the satellite according to the first satellite-ground time difference (ΔT 3 ), the second satellite-ground time difference (ΔT 4 ) and the satellite-ground two-way transmission delay (ΔT1).

[0088] Preferably, Module M4 includes: Sub-module M401: Based on the first satellite-ground time difference (ΔT 3 ), the second satellite-ground time difference (ΔT 4 ) and the satellite-ground two-way transmission delay (ΔT 1 ), obtain the satellite uplink transmission delay (τ up ) and the satellite downlink transmission delay (τ down ); Sub-module M402: Based on the satellite uplink transmission delay (τ up ) and the satellite downlink transmission delay (τ down ), obtain the third satellite-ground time difference (τ up -τ down ) / 2; Sub-module M403: Send the third satellite-ground time difference (τ up -τ down ) / 2 to the satellite for time calibration.

[0089] Preferably, the first satellite-ground time difference (ΔT3 ) is equal to the second satellite-ground time difference (ΔT 4 ).

[0090] Compared with the prior art, the present invention has the following beneficial effects:

[0091] 1. The present invention can be used as a routine operation for satellite services, has the characteristics of being simple and fast to use, and does not require special satellite-ground ranging operations, and is fully applicable to satellite ground testing and satellite on-orbit testing.

[0092] Those skilled in the art know that in addition to implementing the system, device and its various modules provided by the present invention in the form of pure computer-readable program code, the method steps can be logically programmed to enable the system, device and its various modules provided by the present invention to be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers to implement the same program. Therefore, the system, device and its various modules provided by the present invention can be considered as a hardware component, and the modules including various implemented programs therein can also be regarded as the structure within the hardware component; the modules implementing various functions can also be regarded as either software programs implementing the method or the structure within the hardware component.

[0093] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined arbitrarily with each other.

Claims

1. A method for testing and calibrating the time difference between a geostationary satellite and the ground, characterized in that, it includes: Step 1: Obtain the two-way satellite-ground transmission delay according to the remote control instruction sending time when the ground test equipment sends a delay test instruction to the satellite, the forwarding delay of the satellite, and the telemetry data receiving time of the first telemetry data sent by the satellite received by the ground test equipment. The forwarding delay represents the difference between the delay test instruction receiving time when the satellite receives the delay test instruction and the telemetry data sending time when the satellite sends the first telemetry data; Step 2: Set the time difference between the ground test equipment and the satellite as the first satellite-ground time difference according to the two-way satellite-ground transmission delay, the time when the ground test equipment sends a timing instruction to the satellite, and the time when the satellite receives the timing instruction; Step 3: Obtain the second satellite-ground time difference between the ground test equipment and the satellite according to the first sending time when the satellite sends the second telemetry data to the ground test equipment and the first receiving time when the ground test equipment receives the second telemetry data; Step 4: Calibrate the satellite according to the first satellite-ground time difference, the second satellite-ground time difference, and the two-way satellite-ground transmission delay.

2. The method for testing and calibrating the time difference between a geostationary satellite and the ground according to claim 1, characterized in that, Step 4 includes: Step 401: Obtain the satellite uplink transmission delay and the satellite downlink transmission delay according to the first satellite-ground time difference, the second satellite-ground time difference, and the two-way satellite-ground transmission delay; Step 402: Obtain the third satellite-ground time difference according to the satellite uplink transmission delay and the satellite downlink transmission delay; Step 403: Send the third satellite-ground time difference to the satellite for calibration.

3. The method for testing and calibrating the time difference between a geostationary satellite and the ground according to claim 1, characterized in that, The first telemetry data is used to record the forwarding delay from when the satellite receives the delay test instruction to when it sends the first telemetry data.

4. The method for testing and calibrating the time difference between a geostationary satellite and the ground according to claim 1, characterized in that, Step 2 includes: Step 201: Obtain a fixed delay according to the two-way satellite-ground transmission delay. The timing instruction includes the fixed delay; Step 202: The ground test equipment sends a timing instruction to the satellite at the timing instruction sending time; Step 203: The satellite's digital management computer receives the timing instruction at the timing instruction receiving time and sets the satellite's time to the timing instruction time; Step 204: The digital management computer calculates the time difference between the timing instruction receiving time and the timing instruction time; Step 205: Obtain the first satellite-ground time difference according to the timing instruction sending time, the timing instruction receiving time, and the time difference.

5. The method for testing and calibrating the time difference between a geostationary satellite and the ground according to claim 1, characterized in that, The first satellite-ground time difference is equal to the second satellite-ground time difference.

6. A ground-satellite time difference test and time calibration system for geostationary satellites, Characterized in that, Comprising: Module M1: Obtain the ground-satellite two-way transmission time delay according to the remote control command sending time when the ground test equipment sends a time delay test command to the satellite, the forward time delay of the satellite, and the telemetry data receiving time of the first telemetry data sent by the satellite received by the ground test equipment, where the forward time delay represents the difference between the time delay test command receiving time when the satellite receives the time delay test command and the telemetry data sending time when the satellite sends the first telemetry data; Module M2: Set the time difference between the ground test equipment and the satellite as the first ground-satellite time difference according to the ground-satellite two-way transmission time delay, the time when the ground test equipment sends a time calibration command to the satellite, and the time when the satellite receives the time calibration command; Module M3: Obtain the second ground-satellite time difference between the ground test equipment and the satellite according to the first sending time when the satellite sends the second telemetry data to the ground test equipment and the first receiving time when the ground test equipment receives the second telemetry data; Module M4: Calibrate the satellite according to the first ground-satellite time difference, the second ground-satellite time difference, and the ground-satellite two-way transmission time delay.

7. The ground-satellite time difference test and time calibration system for geostationary satellites according to claim 6, Characterized in that, The module M4 includes: Sub-module M401: Obtain the ground-satellite uplink transmission time delay and the ground-satellite downlink transmission time delay according to the first ground-satellite time difference, the second ground-satellite time difference, and the ground-satellite two-way transmission time delay; Sub-module M402: Obtain the third ground-satellite time difference according to the ground-satellite uplink transmission time delay and the ground-satellite downlink transmission time delay; Sub-module M403: Send the third ground-satellite time difference to the satellite for time calibration.

8. The ground-satellite time difference test and time calibration system for geostationary satellites according to claim 6, Characterized in that, The first telemetry data is used to record the forward time delay from when the satellite receives the time delay test command to when it sends the first telemetry data.

9. The ground-satellite time difference test and time calibration system for geostationary satellites according to claim 6, Characterized in that, The module M2 includes: Sub-module M201: Obtain a fixed time delay according to the ground-satellite two-way transmission time delay, and the time calibration command includes the fixed time delay; Sub-module M202: The ground test equipment sends a time calibration command to the satellite at the time when the time calibration command is sent; Sub-module M203: The satellite's data management computer receives the time calibration command at the time when the time calibration command is received, and sets the satellite's time to the time calibration command time; Sub-module M204: The data management computer calculates the time difference between the time when the time calibration command is received and the time calibration command time; Sub-module M205: Obtain the first ground-satellite time difference according to the time when the time calibration command is sent, the time when the time calibration command is received, and the time difference.

10. The ground-satellite time difference test and time calibration system for geostationary satellites according to claim 6, Characterized in that, The first satellite-ground time difference is equal to the second satellite-ground time difference.

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