Satellite system timing function test system and method based on 1553B bus

Abstract

The invention relates to a satellite system timing function test system and method based on a 1553B bus, a test device comprises an on-satellite part and a ground part, and the on-satellite part comprises a telemetering and remote control unit, a central management unit, a GNSS and a plurality of remote terminals; the ground part comprises a 1553B bus monitor, ground telemetering and remote control equipment and integrated testing equipment; the integrated test equipment edits a test case; comprising GNSS time function test cases (GNSS pulse per second output function test and GNSS time output function check), center management unit satellite time maintenance function check cases (center management unit ground timing function test, GNSS timing function test and synchronous pulse timing function test) and remote terminal satellite time maintenance function test cases (remote terminal satellite time maintenance function test cases). A synchronous pulse signal timing function is used for testing, and a second pulse timing function is used for testing. The problem that the current satellite time test cannot meet the test requirement is solved, and the correctness of the full-chain timing function from the BC end to the RT end is verified.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of spacecraft ground testing, and relates to a satellite system time correction function test system and method based on a 1553B bus. BACKGROUND

[0002] At present, as high-orbit satellite tasks are becoming more and more complex, various types of load units need to use high-precision time information to complete tasks, and therefore a high-orbit GNSS navigation system needs to be configured for a satellite as an important unit of a time unification system, and in combination with a time management and distribution function of a central management unit, provides stable and reliable time information, orbit information and the like for various subsystems of a high-orbit satellite.

[0003] The current time scheme design of a high-orbit satellite is centered on a central management unit, receives time information from a GNSS, performs time maintenance, and distributes the system time after time correction to various lower units through a 1553B bus, and other single units mainly realize time maintenance and use through bus time correction of the central management unit + GNSS second pulse.

[0004] The last stage of the satellite development process is the whole satellite AIT stage, and in the AIT stage, the function of the system time needs to be tested to verify whether the function and performance, precision and the like of the time scheme design in the whole satellite state meet the requirements, which is one of the key projects of the whole satellite test. At present, the traditional time test scheme is that the central management unit receives time information from a GNSS, processes the time information, and distributes the time information to various lower units through a 1553B bus, and the ground judges whether the time correction is successful through time telemetry of the CMU and time telemetry of the lower units. This test method can only verify that the lower units can receive and use the time distributed by the CMU, but cannot effectively test the time precision, and this method cannot be used for testing of a satellite with high time precision. In addition, this test method depends on the telemetry design of the lower units, but for a large number of lower units that need time, there is no intuitive telemetry design, and the time cannot be tested through this method. Therefore, in view of the problems that the traditional test scheme cannot test the time precision and the lower units do not have a related time telemetry design, a satellite system time correction function test system and method based on a 1553B bus are needed to solve the problem that the current satellite time test scheme cannot meet the test requirements. SUMMARY

[0005] The application solves the technical problem of overcoming the deficiencies of the prior art, and proposes a satellite system time correction function test system and method based on a 1553B bus to solve the problems of difficult satellite time test and inability to meet the test requirements.

[0006] The technical problem is solved by a satellite system time calibration function test system based on a 1553B bus, which comprises an on-board part and a ground part.

[0007] The on-board part comprises a telemetry and remote control unit, a central management unit, a GNSS and a plurality of remote terminals.

[0008] The telemetry and remote control unit is responsible for receiving instructions input by a ground telemetry and remote control device and forwarding the instructions to the central management unit, and receiving telemetry information forwarded by the central management unit and sending the telemetry information to the ground telemetry and remote control device.

[0009] The central management unit is responsible for setting time and the software state of the unit according to the instructions forwarded by the telemetry and remote control unit, collecting telemetry information of the remote terminals and forwarding the telemetry information to the telemetry and remote control unit, receiving satellite time generated by the GNSS and / or an integrated test device, maintaining the satellite time and sending the satellite time to the remote terminals, and compensating for the deviation of the received GNSS satellite time according to the second pulse generated by the GNSS.

[0010] The GNSS is responsible for generating satellite time and sending the satellite time to the central management unit, and generating a second pulse and sending the second pulse to the central management unit and the remote terminals.

[0011] The remote terminal is responsible for receiving satellite time sent by the central management unit as the satellite time of the unit, and further correcting the satellite time of the unit according to the received second pulse.

[0012] The ground part comprises a 1553B bus monitor, a ground telemetry and remote control device and an integrated test device.

[0013] The 1553B bus monitor is a bus monitoring terminal of the bus system, which monitors various data on the bus, and realizes the functions of bus data storage, bus data interpretation and bus data analysis.

[0014] The ground telemetry and remote control device sends instructions generated by the integrated test device to the on-board telemetry and remote control unit, and receives telemetry information transmitted by the on-board telemetry and remote control unit and forwards the telemetry information to the integrated test device.

[0015] The integrated test device generates ground remote control instructions, sends the ground remote control instructions to the on-board telemetry and remote control unit through the ground telemetry and remote control device, sends satellite time to the central management unit, edits test cases and test configurations for the time calibration function of the GNSS, the central management unit and the remote terminals, receives telemetry information forwarded by the ground telemetry and remote control device and displays the telemetry information.

[0016] Further, the central management unit also sends a synchronous pulse signal to part of the remote terminals, and the part of the remote terminals can correct the satellite time of the unit according to the received second pulse or the synchronous pulse signal.

[0017] Further, the remote terminals are divided into two categories, the first category is that the remote terminal needs to print time information in the process of performing tasks, this kind of remote terminal is collectively referred to as RTI; the second category is that the remote terminal needs to obtain the center management unit star time, so that the local computer star time and the center management unit star time maintain synchronization accuracy, this kind of remote terminal is collectively referred to as RTII.

[0018] A satellite system time correction function test method based on a 1553B bus, including a GNSS time function test method;

[0019] The GNSS time function test method includes GNSS second pulse output function test and GNSS time output function check;

[0020] The GNSS second pulse output function test includes the following steps:

[0021] S1: The test system is powered on;

[0022] S2: Send an instruction to control the GNSS to normally output a second pulse through an integrated test device;

[0023] S3: According to the relevant telemetry information generated after each remote terminal receives the second pulse, check whether the function of each remote terminal receiving the second pulse is normal, and record the test results;

[0024] The GNSS time output function check includes the following steps:

[0025] S1: The test system is powered on, and the center management unit star time T1 is set through an integrated test device;

[0026] S2: Send an instruction to control the GNSS to normally output a second pulse through an integrated test device;

[0027] S3: Inhibit the center management unit from using GNSS time correction, send an instruction to the GNSS through an integrated test device to enter a time invalidation mode, observe that the GNSS time attribute telemetry is "time invalidation", and record the test results;

[0028] S4: Send an instruction to set the center management unit star time T2 through an integrated test device, and send an instruction for the GNSS to use the center management unit star time, after sending, detect the second pulse signal and record the update of the GNSS whole second information, observe that the GNSS time attribute telemetry is "center management unit time correction mode", and observe whether the GNSS time is updated to the latest time of the center management unit, if yes, the time output function is correct, otherwise, the time output function is abnormal, and record the test results;

[0029] S5: Change the center management unit star time to T3 again;

[0030] S6: send instruction to set GNSS time attribute to "real-time mode" through integrated test equipment, at this time, observe GNSS time attribute download telemetry as "real-time mode"; set the central management unit to GNSS time correction function enabled through ground remote control instruction, and observe that the central management unit time attribute is "time correction success";

[0031] S7: observe time information T4 sent by GNSS to the central management unit and time information T5 fed back by the central management unit to GNSS through the 1553B bus monitor, and record test data;

[0032] S8: send instruction to set GNSS time attribute to "extrapolation mode" through integrated test equipment, repeat the test of S5-S7 and record test results.

[0033] Further, the T1 and T2 star time difference is greater than 1 hour;

[0034] The T3 and GNSS time difference is not greater than 100S;

[0035] The time difference between T5 and T4 is less than or equal to 1 central management unit time processing period.

[0036] Further, the method further comprises a central management unit star time maintenance function test method;

[0037] The central management unit star time maintenance function test method comprises a central management unit ground time correction function test, a GNSS time correction function test and a synchronous pulse time correction function test;

[0038] The central management unit ground time correction function test comprises the following steps:

[0039] S1: power on the test system, send absolute time correction instruction to set the central management unit star time T11 through integrated test equipment, and observe whether the central management unit time telemetry information is consistent with T11; send absolute time correction instruction again to set the central management unit star time T12, and observe whether the central management unit time telemetry information is consistent with T12;

[0040] S2: send incremental time correction instruction to set the central management unit star time △T1 through integrated test equipment, and observe whether the central management unit time telemetry information differs from the last frame time by one telemetry period +△T1;

[0041] S3: send uniform time correction instruction to set the central management unit star time △T2 through integrated test equipment, and observe whether the central management unit time telemetry information is increased by one △T2 every 2 hours on the basis of the original time;

[0042] The GNSS time correction function test comprises the following steps:

[0043] S1: the test system is powered on, and an absolute time setting instruction is sent by the integrated test device to set the central management unit star time T13;

[0044] S2: an instruction is sent by the integrated test device to set the second pulse to be valid, and the central management unit is allowed to use GNSS time, and the central management unit is successfully time-set;

[0045] S3: the time information periodically sent by the central management unit to the remote terminal is judged by the 1553B bus monitor: under the condition that the second pulse is valid, the central management unit sends the star time content characterized by: the time difference data is greater than an integer second, and less than an integer second+1 central management unit time processing period, the time attribute and time setting function when the second pulse is valid are checked;

[0046] S4: an instruction is sent by the integrated test device to set the second pulse to be invalid, and the central management unit fails to be time-set;

[0047] S5: the correctness of the time information periodically sent by the central management unit to the remote terminal is judged by the 1553B bus monitor: under the condition that the second pulse is invalid, the time attribute characteristics when the second pulse is invalid are checked: the time difference data sent twice by the central management unit is equal to the actual time difference;

[0048] S6: an instruction is sent by the integrated test device to change the star time of the central management unit to T14, the test of steps S2-S3 is repeated, and the test result is recorded;

[0049] The synchronous pulse time setting function test comprises the following steps:

[0050] S1: the test system is powered on, and an absolute time setting instruction is sent by the integrated test device to set the central management unit star time T15;

[0051] S2: an instruction is sent by the integrated test device to set the second pulse to be valid, and an instruction is sent to allow the central management unit to use GNSS time, and the central management unit is successfully time-set;

[0052] S3: the sending characteristics of the central management unit after sending the synchronous pulse are checked by the 1553B bus monitor: the specific content of the two time information is different by one synchronous pulse sending period M;

[0053] S4: an instruction is sent by the integrated test device to set the second pulse to be invalid, and the central management unit fails to be time-set.

[0054] Further, the time difference between T12 and T11 is greater than 1 hour;

[0055] The time difference between T13 and GNSS time is less than 100s;

[0056] The time difference between T14 and T13 is greater than 24 hours.

[0057] Furthermore, the invention also includes a method for testing the time correction function of the remote terminal RTI using a synchronous pulse signal, comprising the following steps:

[0058] S1: The test system is connected to the 1553B bus monitor, the satellite is powered on, the central management unit, GNSS and each remote terminal are powered on, and the ground sends an absolute time calibration command to set the central management unit satellite time T16;

[0059] S2: Send a command from the ground to set the second pulse to be valid and allow the central management unit to use GNSS time. The central management unit calibrates the time successfully.

[0060] S3: The RTI task generation function under the synchronous pulse signal timing condition uses the synchronous pulse signal as the trigger condition. The test system first sets the task period and triggers the task at M / 2 + Tdelay after the synchronous pulse signal is sent, where M is the synchronous pulse transmission period and Tdelay is the inherent delay of the test system design.

[0061] S4: During the actual mission generation process, the system adjusts the satellite time, jumping from the synchronization time C to the synchronization time N, and generates the mission at (M+M / 2+Tdelay) ms after the synchronization time N. That is, the time TC of the mission generation is the synchronization time N+(M+M / 2+Tdelay) ms. The mission auxiliary telemetry information TX at the time of the jump is retrieved from the multiple groups of tasks sent to the ground by RTI. If the mission exists and its mission auxiliary telemetry information TX is consistent with the TC value, it is considered that the RTI timing function meets the design expectations.

[0062] S5: Change the task cycle, change the system time, repeat the test of steps S2 to S4, and record the test results.

[0063] Furthermore, a method for testing the time correction function of the remote terminal RTII using pulse-per-second timing is also included, comprising the following steps:

[0064] S1: The test system is connected to the 1553B bus monitor, the satellite is powered on, the central management unit, GNSS and each remote terminal are powered on, and the ground sends an absolute time calibration command to set the central management unit satellite time T17;

[0065] S2: Send a command from the ground to set the second pulse to be valid and allow the central management unit to use GNSS time. The central management unit calibrates the time successfully.

[0066] S3: The ground sends a time synchronization command, and the 1553B bus monitor records the local time Ts when the RTII receives the time synchronization command, and also records the system time Tm sent by the central management unit to the RTII at time Ts;

[0067] S4: After the RTII receives the time instruction, the time data Td of the RTII at the time Ts is sent to the ground, and the ground compares the time data Td with the time Tm of sending the time instruction, and if the time difference between Td and Tm is less than 50 ms, it is considered that the RTII is correct.

[0068] Further, the time difference between T16 and GNSS time is not greater than 100s;

[0069] The time difference between T17 and GNSS time is not greater than 100s.

[0070] The beneficial effects of the present application compared with the prior art are:

[0071] (1) The present application adopts the system time information jump mode combined with the time information monitored by the 1553B bus monitor to effectively test the time distribution function performance of the central management unit, and especially realizes the test of the time precision;

[0072] (2) The present application can also effectively test the star time maintenance function of each lower machine, and verify the correctness of the whole system from the bus control end BC to the remote terminal RT. BRIEF DESCRIPTION OF DRAWINGS

[0073] Figure 1 is the connection diagram of the test system provided by the embodiment of the present application;

[0074] Figure 2 is the time information diagram covering each stage in the whole satellite life cycle of the test case provided by the embodiment of the present application;

[0075] Figure 3 is the time diagram of the RT1 task generation function provided by the embodiment of the present application. DETAILED DESCRIPTION

[0076] The present application will be further described below in combination with the drawings and embodiments.

[0077] Embodiment 1

[0078] A satellite system time calibration function test based on 1553B bus mainly adopts the system time information jump mode to test the star time maintenance function of each remote terminal, and the test method needs to use a 1553B bus equivalent device as the bus monitoring end (MT end) of the bus system, monitors the time data on the bus, and analyzes and calculates the time data to verify the correctness of the time calibration function.

[0079] The connection diagram of the satellite system time calibration function test system based on 1553B bus of the embodiment is shown in Figure 1 The test system includes an on-board part and a ground part.

[0080] Wherein the on-board part includes telemetry and telecontrol unit, central management unit, GNSS and multiple remote terminals RT1~RTn;

[0081] Telemetry and telecontrol unit: responsible for receiving the instructions from the ground telemetry and telecontrol equipment and forwarding to the central management unit, and receiving the forwarded telemetry information from the central management unit and sending to the ground telemetry and telecontrol equipment;

[0082] Central management unit: setting the time and the software state of the unit according to the instructions forwarded by the telemetry and telecontrol unit, and forwarding the instructions to each remote terminal; collecting the telemetry information of each remote terminal and forwarding to the telemetry and telecontrol unit; receiving the satellite time generated by GNSS and / or integrated test equipment, maintaining the satellite time and sending it to each remote terminal, and compensating the received GNSS satellite time according to the second pulse sent by GNSS; sending a synchronous pulse signal to remote terminal RT1;

[0083] GNSS: generating satellite time and sending it to the central management unit, generating second pulse and sending it to the central management unit and each remote terminal RT1~RTn;

[0084] Remote terminal RT1~RTn: receiving the satellite time sent by the central management unit as the satellite time of the unit, and further correcting the satellite time of the unit according to the received second pulse; remote terminal RT1 can also correct the satellite time of the unit according to the received synchronous pulse signal.

[0085] The ground part includes 1553B bus monitor, ground telemetry and telecontrol equipment and integrated test equipment;

[0086] 1553B bus monitor: as the bus monitoring terminal (MT terminal) of the bus system, it monitors various data on the bus, realizes the functions of bus data storage, bus data interpretation and bus data analysis.

[0087] Ground telemetry and telecontrol equipment: sending the instructions generated by the integrated test equipment to the on-board telemetry and telecontrol unit, and receiving the telemetry information transmitted by the on-board telemetry and telecontrol unit and forwarding it to the integrated test equipment;

[0088] Integrated test equipment: generating ground control instructions to be sent to the on-board satellite through the ground telemetry and telecontrol equipment, sending satellite time to the central management unit; editing the test cases and test configurations for the time calibration functions of GNSS, central management unit and each remote terminal, receiving the telemetry information forwarded by the ground telemetry and telecontrol equipment and displaying.

[0089] In this embodiment, the multiple remote terminals RT1~RTn that use time can be divided into two categories. One category is that the remote terminals need to print time information during the execution of tasks. This type of remote terminals is collectively referred to as RTI; the other category is that the remote terminals need to obtain satellite system time (i.e., central management unit satellite time) to ensure that the local satellite time maintains synchronization accuracy with the satellite system time. This type of remote terminals is collectively referred to as RTII.

[0090] The time calibration function test cases edited by the integrated test equipment include GNSS time function test cases, central management unit star time maintenance function check cases, and each remote terminal star time maintenance function check cases. For the same project, comprehensive testing is required under different use cases, and its test cases cover the time information of each stage in the entire satellite life cycle. Figure 2 shown.

[0091] 1. GNSS time function test

[0092] GNSS provides satellites with time and pulse-per-second signals. The pulse-per-second output modes include time invalidation mode, real-time mode, extrapolation mode, and central management unit time calibration mode. Therefore, GNSS time function testing must cover all design conditions. Designed test cases include:

[0093] (1) GNSS second pulse output function test

[0094] S1: Test system powered on;

[0095] S2: Send instructions through the integrated test equipment to control the GNSS to normally output second pulses;

[0096] S3: The tester checks whether the function of each remote terminal to receive the second pulse is normal based on the relevant telemetry information generated after each remote terminal receives the second pulse, and records the test results.

[0097] (2) GNSS time output function check

[0098] S1: Power on the test system and set the central management unit star time T1 through the integrated test equipment;

[0099] S2: Send instructions through the integrated test equipment to control the GNSS to normally output second pulses;

[0100] S3: Disable the central management unit from using GNSS for time calibration. Send a command through the integrated test equipment to put the GNSS into time invalid mode. Observe the GNSS time attribute transmitted telemetry as "time invalid" and record the test results.

[0101] S4: send the instruction to set the central management unit star time T2 (T1 and T2 star time difference is greater than 1 hour) through the integrated test equipment, send the GNSS central management unit star time instruction at the same time, detect the second pulse signal after sending and record the GNSS whole second information update, observe the GNSS time attribute telemetry as "central management unit time correction mode", and observe whether the GNSS time is updated to the latest time of the central management unit. If yes, the time output function is correct, otherwise, the time output function is abnormal, and record the test results;

[0102] S5: change the central management unit star time to T3 again, and the time difference between T3 and GNSS is not greater than 100S;

[0103] S6: set the GNSS time attribute to "real-time mode" through the integrated test equipment, at this time, observe the GNSS time attribute telemetry as "real-time mode"; set the central management unit to GNSS time correction function enabled through the ground remote control instruction, and observe the central management unit time attribute as "time correction success";

[0104] S7: observe the time information T4 sent by GNSS to the central management unit and the time information T5 fed back by the central management unit to GNSS through the 1553B bus monitor, record the test data, and calculate T5 and T4 through data analysis. The time difference between T5 and T4 should be less than or equal to one central management unit time processing period (different satellites have different design indexes, which are determined according to the model design).

[0105] S8: set the GNSS time attribute to "extrapolation mode" through the integrated test equipment, repeat the test of S5-S7 and record the test results.

[0106] II. Central management unit star time maintenance function check

[0107] According to the central management unit time system software design function design, the time has three time correction modes: ground time correction function, GNSS time correction function and synchronous pulse time correction function; among them, the ground time correction is divided into: absolute time correction, incremental time correction and uniform time correction; therefore, the test of the central management unit time function needs to cover all the design conditions, and the test cases designed include:

[0108] (1) Central management unit ground time correction function test

[0109] S1: test system power on, set the central management unit star time T11 through the integrated test equipment by sending absolute time correction instruction, observe whether the central management unit time telemetry information is consistent with T11; set the central management unit star time T12 (T12 and T11 time difference is greater than 1 hour) by sending absolute time correction instruction again, observe whether the central management unit time telemetry information is consistent with T12;

[0110] S2: The integrated test equipment sends an incremental time setting instruction to set the central management unit star time AT1, and observes whether the central management unit time telemetry information differs from the last frame time by one telemetry cycle + AT1;

[0111] S3: The integrated test equipment sends a uniform time setting instruction to set the central management unit star time AT2, and observes whether the central management unit time telemetry information is increased by one AT2 every 2 hours on the basis of the original time.

[0112] (2) Central management unit remote terminal time function test - GNSS time function

[0113] The central management unit remote terminal time function test mainly analyzes the data characteristics through the 1553B bus monitor, and then calculates the time setting time precision to confirm the correctness and effectiveness of the time, including GNSS time function test and synchronous pulse time function test.

[0114] S1: The test system is powered on, and the integrated test equipment sends an absolute time setting instruction to set the central management unit star time T13, and the time difference between T13 and GNSS time is less than 100s;

[0115] S2: The integrated test equipment sends an instruction to set the second pulse to be valid, and at the same time, the integrated test equipment sends an instruction to allow the central management unit to use GNSS time, and the central management unit time setting is successful;

[0116] S3: Through the 1553B bus monitor, the central management unit periodically sends time information to the remote terminal: under the condition of second pulse validity, the central management unit sends star time content characteristics: the time difference data should be greater than the whole second, less than the whole second + 1 central management unit time processing period, and the time information sending period is about 1S. Check the time attribute and time function when the second pulse is valid (check the time setting period through the bus monitor);

[0117] S4: The integrated test equipment sends an instruction to set the second pulse to be invalid, and the central management unit time setting fails;

[0118] S5: Through the 1553B bus monitor, the correctness of the time information periodically sent by the central management unit to the remote terminal is judged: under the condition of second pulse invalidity, the time attribute function when the second pulse is invalid is checked, and the data characteristics are: the time difference data sent by the central management unit twice is equal to the actual sending time difference;

[0119] S6: Send instruction to change the satellite time of the central management unit to T14 (the time difference between T14 and T13 is greater than 24 hours) through the integrated test equipment, repeat the test of steps S2 and S3, and record the test results.

[0120] (3) Central management unit timing function test for remote terminal - synchronous pulse timing function

[0121] S1: The test system is powered on, and an absolute timing instruction is sent to set the satellite time T15 of the central management unit through the integrated test equipment;

[0122] S2: Send instruction to set the second pulse effective through the integrated test equipment, and send instruction to allow the central management unit to use GNSS time, and the central management unit timing is successful;

[0123] S3: Check the transmission characteristics of the central management unit after sending the synchronous pulse through the 1553B bus monitor: the specific content of the two time information differs by one synchronous pulse transmission period M;

[0124] S4: Send instruction to set the second pulse invalid through the integrated test equipment, and the central management unit timing fails.

[0125] III. Remote terminal RT satellite time maintenance function check

[0126] This check mainly tests the function of each remote terminal RT to maintain its own satellite time according to the periodic satellite time information sent by the central management unit, and checks its accuracy. This function has two working conditions: synchronous pulse signal timing condition and second pulse timing condition. Remote terminals using time can be divided into the aforementioned RTI and RTII.

[0127] (1) Synchronous pulse signal timing function test

[0128] When RTI uses synchronous pulse signal to adjust satellite time, check whether RTI satellite time is executed according to the calibration scheme of the central management unit. The satellite time of the central management unit is set to ground timing mode or GNSS timing mode, and during this period, the ground can adjust the satellite time arbitrarily by sending remote control instruction. The entire test process needs to adjust the satellite time by time hopping multiple times, and the specific time code is recorded through the bus monitor.

[0129] S1: The test system is connected to the 1553B bus monitor, the satellite is powered on, the central management unit, GNSS and each remote terminal are powered on, and the absolute timing instruction is sent to set the satellite time T16 of the central management unit, and the time difference between T16 and GNSS time is not greater than 100s;

[0130] S2: The ground sends a command to set the second pulse effective, and at the same time, the ground sends a command to allow the central management unit to use the GNSS time, and the central management unit is successfully time-synchronized;

[0131] S3: The RTI task generation function under the synchronous pulse signal time-synchronization condition is triggered by the synchronous pulse signal. The test system first sets the task period, and triggers the task at M / 2+Tdelay after the synchronous pulse signal is sent. The specific information of this time will be packaged into the auxiliary data of the task, and the task execution time is as shown in Figure 3 . Wherein, M is the synchronous pulse sending period, and Tdelay is the inherent delay designed by the test system;

[0132] S4: The task generation time should be the synchronous pulse signal time+(M / 2+Tdelay) ms. In the actual task generation process, the system adjusts the star time, and the synchronous time C jumps to the synchronous time N. The time information T of the synchronous time N can be found in the 1553B bus monitor. The task is generated at (M+M / 2+Tdelay) ms after the synchronous time N. The time of the task is (M+M / 2+Tdelay) ms after the synchronous time N, that is, the time TC of task generation=(M+M / 2+Tdelay) ms. By searching the task auxiliary telemetry information TX of the jump time in the multiple tasks sent to the ground by RTI, if the task exists and its task auxiliary telemetry information TX is consistent with the value of TC, it is considered that the RTI time-synchronization function meets the design expectation, otherwise it is incorrect. N

[0133] S5: Change the task period, change the system time, repeat the test of steps S2-S4, and record the test results.

[0134] (2) Test using second pulse time-synchronization function

[0135] RTII star time maintenance function check. This check mainly tests the maintenance function of RTII on its own star time according to the star time content of the central management unit and the pulse signal.

[0136] S1: The test system accesses the 1553B bus monitor, the satellite is powered on, the central management unit, GNSS and each remote terminal are powered on; the ground sends an absolute time-synchronization command to set the central management unit star time T17, and the time difference between T17 and GNSS time cannot be greater than 100s;

[0137] S2: The ground sends a command to set the second pulse effective, and allows the central management unit to use the GNSS time, and the central management unit is successfully time-synchronized;

[0138] ​S3: (According to the RTII software design state, when the RTII receives the time instruction, the star time Td of the RTII at the moment is packaged to the ground, and the ground adjusts the time according to the star time data and the link delay, to ensure that the star-ground time is consistent.) The ground sends the time instruction, the 1553B bus monitor records the local time Ts of the RTII receiving the time instruction, and the system time information Tm sent by the central management unit to the RTII at the Ts moment is recorded.

[0139] S4: After the RTII receives the time instruction, the star time data Td of the RTII at the Ts moment is sent to the ground, and the ground compares the sent star time Td with the time Tm (obtained through the bus monitor) of sending the time instruction, according to the software processing logic, if the time difference between the two parameters (Td and Tm) is less than 50 ms (the index is a reference value), it is considered that the RTII is correct, otherwise it is wrong.

[0140] Although the present application has been disclosed with the above preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application by using the disclosed methods and technical contents without departing from the spirit and scope of the present application, therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, which does not deviate from the technical solutions of the present application, belongs to the protection scope of the technical solutions of the present application.

[0141] The contents not described in detail in the specification of the present application are the known technology of the person skilled in the art.

Claims

1. A satellite system timing function test system based on 1553B bus, characterized in that: Including the satellite part and the ground part; The onboard part includes a telemetry and remote control unit, a central management unit, GNSS, and multiple remote terminals; Telemetry and remote control unit: responsible for receiving instructions from the ground telemetry and remote control equipment and forwarding them to the central management unit, and at the same time receiving telemetry information forwarded by the central management unit and sending it to the ground telemetry and remote control equipment; Central Management Unit: Sets the time and software status of this unit according to the instructions forwarded by the telemetry and remote control unit; collects telemetry information from each remote terminal and forwards it to the telemetry and remote control unit; receives the star time generated by GNSS and / or integrated test equipment, maintains the star time and sends it to each remote terminal, and compensates the received GNSS star time for deviation based on the second pulse sent by the GNSS; GNSS: Generates satellite time and sends it to the central management unit, generates second pulses and sends them to the central management unit and each remote terminal; Remote terminal: Receives the star time sent by the central management unit as the local star time, and further corrects the local star time based on the received second pulse; The ground segment includes 1553B bus monitor, ground telemetry and remote control equipment, and integrated test equipment; 1553B bus monitor: As the bus monitoring terminal of the bus system, it monitors various types of data on the bus and realizes bus data storage, bus data interpretation and bus data analysis functions; Ground telemetry and remote control equipment: sends the instructions generated by the integrated test equipment to the onboard remote control and telemetry unit, and receives the telemetry information transmitted from the onboard telemetry and remote control unit and forwards it to the integrated test equipment; Integrated test equipment: Generates ground remote control commands and sends them to the satellite through ground telemetry and remote control equipment, and sends satellite time to the central management unit; edits test cases and test configurations for the timing functions of GNSS, central management unit and each remote terminal, receives and displays telemetry information forwarded by ground telemetry and remote control equipment.

2. A satellite system timing function test system based on 1553B bus according to claim 1, characterized in that: The central management unit also sends a synchronization pulse signal to some remote terminals; the remote terminals can correct the local star time according to the received second pulse or the synchronization pulse signal.

3. A satellite system timing function test system based on 1553B bus according to claim 2, characterized in that: Remote terminals are divided into two categories. The first category is that which needs to print time information while executing tasks. Such remote terminals are collectively referred to as RTIs. The second category is that which needs to obtain the central management unit's star time to ensure that the local star time maintains synchronization accuracy with the central management unit's star time. Such remote terminals are collectively referred to as RTIIs.

4. A method for testing the timing function of a satellite system based on a 1553B bus based on the test system of claim 3, characterized in that: Including GNSS time function test methods; The GNSS time function test method includes a GNSS second pulse output function test and a GNSS time output function check; The GNSS pulse-per-second output function test includes the following steps: S1: Test system powered on; S2: Send instructions through the integrated test equipment to control the GNSS to normally output second pulses; S3: Based on the relevant telemetry information generated after each remote terminal receives the second pulse, check whether the function of each remote terminal receiving the second pulse is normal and record the test results; The GNSS time output function check includes the following steps: S1: Power on the test system and set the central management unit star time T1 through the integrated test equipment; S2: Send instructions through the integrated test equipment to control the GNSS to normally output second pulses; S3: Disable the central management unit from using GNSS for time calibration. Send a command through the integrated test equipment to put the GNSS into time invalid mode. Observe the GNSS time attribute transmitted telemetry as "time invalid" and record the test results. S4: Use the integrated test equipment to send a command to set the central management unit's star time T2. Simultaneously, send the GNSS command to use the central management unit's star time. After sending, detect the pulse-second signal and record the update of the GNSS whole-second information. Observe whether the GNSS time attribute is transmitted in the "central management unit time calibration mode" and whether the GNSS time is updated to the latest time of the central management unit. If so, the time output function is correct. Otherwise, the time output function is abnormal. Record the test results. S5: Change the central management unit's star time to T3; S6: Send a command from the integrated test equipment to set the GNSS time attribute to "Real-time Mode". Observe that the GNSS time attribute transmitted telemetry is in "Real-time Mode". Use a ground remote control command to enable the GNSS time synchronization function on the central management unit. Observe that the central management unit's time attribute is "Successful Synchronization". S7: Observe the time information T4 sent by the GNSS to the central management unit and the time information T5 fed back by the central management unit to the GNSS through the 1553B bus monitor, and record the test data; S8: Send a command through the integrated test device to set the GNSS time attribute to "extrapolation mode", repeat the tests of S5-S7 and record the test results.

5. The method for testing the timing function of a satellite system based on 1553B bus according to claim 4, characterized in that: The time difference between T1 and T2 is greater than 1 hour; The time difference between T3 and GNSS is no more than 100S; The time difference between T5 and T4 is less than or equal to one central management unit time processing cycle.

6. The method for testing the timing function of a satellite system based on 1553B bus according to claim 4, characterized in that: It also includes a test method for the central management unit's star-time maintenance function; The central management unit star time maintenance function test method includes a central management unit ground time calibration function test, a GNSS time calibration function test and a synchronous pulse time calibration function test; The central management unit ground time synchronization function test includes the following steps: S1: Power on the test system, send an absolute time calibration command through the integrated test equipment to set the central management unit's star time T11, and observe whether the central management unit's time telemetry information is consistent with T11; send an absolute time calibration command again to set the central management unit's star time T12, and observe whether the central management unit's time telemetry information is consistent with T12; S2: Send incremental time calibration instructions through the integrated test equipment to set the central management unit star time △T1, and observe whether the central management unit time telemetry information differs from the previous frame time by one telemetry cycle + △T1; S3: Send a uniform time calibration command through the integrated test equipment to set the central management unit's star time △T2, and observe whether the central management unit's time telemetry information adds a △T2 to the original time every 2 hours; The GNSS timing function test includes the following steps: S1: Power on the test system and send the absolute time calibration command to set the central management unit star time T13 through the integrated test equipment; S2: Send a command through the integrated test equipment to set the second pulse to be valid and allow the central management unit to use GNSS time. The central management unit calibrates the time successfully. S3: Using the 1553B bus monitor, determine the time information periodically sent by the central management unit to the remote terminal: When the second pulse is valid, the characteristics of the star time content sent by the central management unit are: the difference between two time data is greater than a whole second and less than a whole second + 1 central management unit time processing cycle. Check the time attributes and timing function when the second pulse is valid; S4: The command sent by the integrated test equipment to set the second pulse is invalid, and the central management unit fails to calibrate the time; S5: Using the 1553B bus monitor, determine the correctness of the time information periodically sent by the central management unit to the remote terminal: Under the condition where the second pulse is invalid, check that the time attribute characteristic when the second pulse is invalid is: the time difference data sent twice by the central management unit is equal to the actual time difference sent; S6: Send a command through the integrated test device to change the central management unit's star time to T14, repeat the test of steps S2 to S3, and record the test results; The synchronous pulse timing function test comprises the following steps: S1: Power on the test system and send the absolute time calibration command to set the central management unit star time T15 through the integrated test equipment; S2: Send a command through the integrated test device to set the second pulse to be valid, and at the same time send a command to allow the central management unit to use GNSS time. The central management unit successfully calibrates the time; S3: Check the transmission characteristics of the central management unit after sending the synchronization pulse through the 1553B bus monitor: the specific content of the two time information differs by a synchronization pulse sending period M; S4: The command sent through the integrated test equipment to set the second pulse is invalid, and the central management unit fails to calibrate the time.

7. The method for testing the timing function of a satellite system based on 1553B bus according to claim 6, characterized in that: The time difference between T12 and T11 is greater than 1 hour; The difference between T13 time and GNSS time is less than 100s; The time difference between T14 and T13 is greater than 24 hours.

8. The method for testing the timing function of a satellite system based on 1553B bus according to claim 6, characterized in that: The invention also includes a method for testing a time correction function of a remote terminal RTI using a synchronous pulse signal, comprising the following steps: S1: The test system is connected to the 1553B bus monitor, the satellite is powered on, the central management unit, GNSS and each remote terminal are powered on, and the ground sends an absolute time calibration command to set the central management unit satellite time T16; S2: Send a command from the ground to set the second pulse to be valid and allow the central management unit to use GNSS time. The central management unit calibrates the time successfully. S3: The RTI task generation function under the synchronous pulse signal timing condition uses the synchronous pulse signal as the trigger condition. The test system first sets the task period and triggers the task at M / 2 + Tdelay after the synchronous pulse signal is sent, where M is the synchronous pulse transmission period and Tdelay is the inherent delay of the test system design. S4: During the actual mission generation process, the system adjusts the satellite time, jumping from the synchronization time C to the synchronization time N, and generates the mission at (M+M / 2+Tdelay) ms after the synchronization time N. That is, the time TC of the mission generation is the synchronization time N+(M+M / 2+Tdelay) ms. The mission auxiliary telemetry information TX at the time of the jump is retrieved from the multiple groups of tasks sent to the ground by RTI. If the mission exists and its mission auxiliary telemetry information TX is consistent with the TC value, it is considered that the RTI timing function meets the design expectations. S5: Change the task cycle, change the system time, repeat the test of steps S2 to S4, and record the test results.

9. The method for testing the timing function of a satellite system based on 1553B bus according to claim 8, characterized in that: The invention also includes a method for testing the time correction function of the remote terminal RTII using a second pulse, including the following steps: S1: The test system is connected to the 1553B bus monitor, the satellite is powered on, the central management unit, GNSS and each remote terminal are powered on, and the ground sends an absolute time calibration command to set the central management unit satellite time T17; S2: Send a command from the ground to set the second pulse to be valid and allow the central management unit to use GNSS time. The central management unit calibrates the time successfully. S3: The ground sends a time synchronization command, and the 1553B bus monitor records the local time Ts when the RTII receives the time synchronization command, and also records the system time Tm sent by the central management unit to the RTII at time Ts; S4: After receiving the timing instruction, the RTII sends its own satellite time data Td at time Ts to the ground. The ground compares the sent satellite time Td with the time Tm when the timing instruction was sent. If the time difference between Td and Tm is less than 50ms, the RTII timing is considered correct.

10. The method for testing the timing function of a satellite system based on 1553B bus according to claim 9, characterized in that: The difference between T16 time and GNSS time is no more than 100s; The difference between T17 time and GNSS time is no more than 100s.

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