Ground test verification method for inter-satellite microwave ranging instrument with micron precision

Abstract

The application discloses a kind of micro-precision inter-satellite microwave range finder ground test verification methods, comprising: long-distance signal time delay simulation test is carried out: obtaining long baseline long time delay under the influence of biased distance measurement precision σ1, distance change rate measurement precision δ1;Long-distance signal level attenuation simulation test is carried out: obtain the system noise under the influence of biased distance measurement precision σ2 under long-distance static condition, distance change rate measurement precision δ2;Space direction and distance dynamic simulation test is carried out: obtain the biased distance measurement precision σ3 of A, B inter-satellite range finder under the condition of space direction and distance dynamic change simulation, distance change rate measurement precision δ3;According to the test results, the overall biased distance measurement precision σ and overall distance change rate measurement precision δ are calculated.The application solves the technical problem of inter-satellite range finder ground test verification, and also solves the application risk that may be caused by the true value comparison and evaluation of distance change without micron precision in orbit.

Description

Technical Field

[0001] This invention relates to a ground testing and verification method for an inter-satellite microwave rangefinder with micron precision, belonging to the technical field of inter-satellite microwave rangefinders for satellite inter-satellite measurement. Background Technology

[0002] In fields such as gravity measurement satellite micrometer-level precision ranging systems (KBR), navigation satellite high-precision signal processing, and other scientific measurement, ground-based performance testing and verification are crucial for verifying the actual performance of products. However, the coupling between various parts of extremely high-precision measurement systems is often very tight, resulting in numerous error factors. Moreover, there are no other higher-precision measurement instruments available for on-orbit application of such high-precision testing instruments to obtain true values ​​for comparison and verification. Therefore, ground-based performance testing and verification are extremely important.

[0003] my country's low-low tracking gravity measurement satellite's micrometer-level high-precision microwave inter-satellite rangefinder (ISR) is designed for measurements between two satellites at actual distances of hundreds of kilometers during orbit. The ISR's antenna beam is narrow, with no obstructions or multipath effects outside the aperture, and the antenna axes of the two satellites remain aligned and stable within a limited, small angle range over a long period. Ground testing and verification of the ISR requires evaluating the impact of the on-orbit signal incident angle on measurement accuracy. However, ground testing sites are difficult to replicate under these conditions. Therefore, verifying the ground measurement performance of the micrometer-precision microwave ISR has become a technical challenge.

[0004] In light of the application background of the GRACE low-low tracking gravity measurement satellite, the micrometer-level high-precision microwave ranging of the low-low tracking gravity measurement satellite developed by JPL in the United States also adopts a microwave dual unidirectional ranging system. However, the published literature mainly introduces the principle of its dual unidirectional ranging system and describes its ranging performance. While there are also related key technology studies in domestic published literature, the proposed test methods only focus on some error factors. Therefore, the existing technology lacks ground test methods for product measurement performance.

[0005] In summary, the existing methods have the following shortcomings: they are generally only meter-level accurate, the test simulation scenarios are different from the requirements, and the errors brought by the existing test systems far exceed the accuracy required by this invention. Summary of the Invention

[0006] The technical problem solved by this invention is to address the shortcomings of existing technologies by proposing a ground testing and verification method for an inter-satellite microwave rangefinder with micrometer precision. This method solves the technical difficulties in ground testing and verification of inter-satellite rangefinders and also mitigates the application risks that may arise from the lack of micrometer precision distance change true value comparison and evaluation in orbit.

[0007] The technical solution adopted in this invention is as follows:

[0008] A ground-based testing and verification method for a micrometer-precision inter-satellite microwave rangefinder includes:

[0009] Step 1: Conduct long-distance signal delay simulation test: Insert a high-stability delay simulator between the bidirectional signal transceiver ports of the two inter-satellite rangefinders under test, and test to obtain the biased distance measurement accuracy σ1 and the distance change rate measurement accuracy δ1 under the influence of long baseline and long delay.

[0010] Step 2: Conduct long-distance signal level attenuation simulation test: Insert a space long-distance signal level attenuation simulation device between the two satellite rangefinders to obtain the biased distance measurement accuracy σ2 and the distance change rate measurement accuracy δ2 under the influence of system noise under long-distance static conditions;

[0011] Step 3: Perform dynamic simulation test of spatial pointing and distance: Place the inter-satellite rangefinder A or B to be tested on a high-precision turntable on a high platform at one end of a large anechoic chamber. Install an inter-satellite rangefinder signal simulator on a two-dimensional position adjustable bracket on a high platform at the other end of the anechoic chamber, which is L meters away. Establish a microwave signal link between the inter-satellite rangefinder and another inter-satellite rangefinder signal simulator for testing. Test twice to obtain the biased distance measurement accuracy σ3 and the distance change rate measurement accuracy δ3 of the inter-satellite rangefinder A and B under the simulated conditions of dynamic change of spatial pointing and distance.

[0012] Step 4: Based on the above test results, calculate the overall biased distance measurement accuracy σ and the overall distance change rate measurement accuracy δ.

[0013] Furthermore, the high-stability delay simulator is a bidirectional long-baseline delay simulator, with inputs and outputs at both ends being long-delay fiber optic simulated delay lines in the microwave frequency band used by the inter-satellite rangefinder.

[0014] The high-stability delay simulator includes a laser, optoelectronic modulation and demodulation device A, an ultra-long optical fiber containing an adjustable delay optical signal delay unit, optoelectronic modulation and demodulation device B, and a real-time fiber delay measurement controller. Optoelectronic modulation and demodulation device A modulates the input microwave signal onto the laser-generated laser carrier. After transmission through the ultra-long optical fiber, the microwave signal is demodulated by optoelectronic modulation and demodulation device B to output the microwave signal, thus realizing the microwave signal transmission delay from A to B. Similarly, the reverse microwave signal transmission delay from B to A is realized, achieving bidirectional long-delay microwave signal transmission.

[0015] The real-time fiber delay measurement controller ensures that the delay simulator is stable within the micrometer accuracy required by the specification by detecting the transmission delay jitter changes of the input / output signals of the ultra-long fiber in real time and controlling the adjustable delay optical signal delay device; the length of the ultra-long fiber can be set according to the test requirements.

[0016] Furthermore, the output signal of the inter-satellite rangefinder is output to the receiving input of another inter-satellite rangefinder after passing through a high-stability time delay simulator. By configuring an attenuator, the input level is set to be no less than the minimum on-orbit distance level.

[0017] Furthermore, during the long-distance signal delay simulation test, the long-distance signal level attenuation simulation test, and the spatial pointing and distance dynamic simulation test, the ambient temperature of the test device and the test equipment is monitored and recorded in real time. The change is required to be controlled to be less than 0.1 degrees, and the environment must be kept stable during the test to avoid generating vibration sources.

[0018] Furthermore, the space long-distance signal level attenuation simulation device includes an absorbing box A facing the antenna under test, a polarized transceiver antenna A, an adjustable signal attenuator, an absorbing box B facing the antenna under test, and a polarized transceiver antenna B. After receiving the signal transmitted by the antenna of satellite A under test, the absorbing box A and the polarized transceiver antenna A transmit the signal through the adjustable signal attenuator and then through the polarized transceiver antenna B and the absorbing box B facing the antenna under test to the antenna of satellite B under test. Similarly, the reverse microwave signal transmission from satellite B to satellite A is realized. The size of the absorbing box is related to the size of the antenna aperture and the signal frequency band, and it needs to achieve effective absorption to suppress the influence of multipath signals. The attenuation range of the adjustable signal attenuator is determined according to the simulated inter-satellite microwave link spatial attenuation calculation value to achieve system noise equivalence in ground testing and on-orbit application scenarios.

[0019] Furthermore, during the long-distance signal level attenuation simulation test, the inter-satellite rangefinder was tested at the three states of the farthest, closest, and median distances required by the index. The corresponding biased distance measurement accuracy and distance change rate measurement accuracy were obtained. The test results at the three distances were analyzed. If the difference between the test results and the theoretical results met the expectations, the test results were considered valid. The test result of the farthest distance among the valid test results was selected to participate in the overall accuracy calculation.

[0020] Furthermore, in the large microwave anechoic chamber, the high-precision turntable has two-dimensional high-precision rotation in azimuth and elevation, and submicron precision translation in the forward and backward directions. The stability of the high platform where the device under test and the turntable are installed reaches the micron level; the selection of the high platform height H and the distance between the antenna aperture L meets the far-field requirements of antenna testing.

[0021] The antenna horn of the inter-satellite rangefinder signal simulator adopts a small-aperture wide-beam antenna with the same polarization design as the antenna horn under test, which reduces the impact of secondary reflection multipath on dynamic measurement. The other components of the antenna are the same as those of the inter-satellite rangefinder antenna.

[0022] Furthermore, the inter-satellite rangefinder signal simulator adopts a product with the same design baseline as the product under test. A fixed amount of signal attenuator is inserted before the transmitted signal reaches the antenna and after the received signal reaches the antenna, so that the signal level received by the inter-satellite rangefinder antenna and the signal level received by the signal simulator are both at the equivalent level of the closest distance on the track, so that the product under test and the test equipment operate under conditions of minimum system noise.

[0023] Furthermore, during the dynamic simulation test of airspace pointing and distance, the inter-satellite rangefinder was first tested under three conditions: zero angle of view, small deflection angle range, and large deflection angle range. The results of the deflected distance measurement accuracy and distance change rate measurement accuracy of the inter-satellite rangefinder were obtained and compared with the theoretical results. If the difference was within the preset range, the inter-satellite rangefinders of the two satellites obtained two test results within the deflection angle range required by the index. The larger value was taken as the final result of the dynamic simulation test of airspace pointing and distance.

[0024] Furthermore, the small translational amount of the turntable distance direction is used as the true value of the distance change. The measured distance change value of the inter-satellite rangefinder is compared with the corresponding true value to evaluate the biased distance measurement accuracy. The statistical standard deviation of the results of multiple measurement comparisons is used as the dynamic comparison biased distance measurement accuracy σ4. After testing the two satellite products separately, the maximum value of the two results is selected.

[0025] Furthermore, the calculations yield the overall biased distance measurement accuracy σ and the overall distance change rate measurement accuracy δ, specifically as follows:

[0026] Analysis of the biased distance measurement accuracy results σ1, σ2, and σ3 obtained from the three tests shows that, if the analysis verifies that the errors introduced by non-on-orbit factors on the ground are large, causing σ1, σ2, and σ3 to all be greater than three times the maximum value of the theoretical accuracy calculated for each of these three error factors, the overall biased distance measurement accuracy σ and the overall distance change rate measurement accuracy δ are calculated as follows:

[0027] σ=max(σ1, σ2, σ3, σ4)

[0028] δ = max(δ1, δ2, δ3).

[0029] Otherwise, the overall bias distance measurement accuracy σ and the overall distance change rate measurement accuracy δ are:

[0030]

[0031]

[0032] The advantages of this invention compared to the prior art are:

[0033] (1) The ground test and verification method for a micrometer-precision inter-satellite microwave rangefinder proposed in this invention designs three specific test scenarios for the three main error factors of long-distance transmission delay, system noise, and inter-satellite pointing under the on-orbit application of the DOWR system inter-satellite rangefinder. This not only ensures the testability of the performance of micrometer measurement accuracy, but also fully covers the error factors, reduces the difficulty of test implementation, and ensures good equivalence between ground test and actual on-orbit operation. It solves the technical problem of ground test and verification of inter-satellite rangefinders, and also resolves the application risks that may be caused by the lack of micrometer-precision distance change true value comparison and evaluation on-orbit.

[0034] (2) The method of the present invention can not only be directly applied to the ground test and verification of microwave inter-satellite rangefinders in fields such as low-low tracking gravity field measurement satellites, but also has a wide application prospect for the ground verification of other micron-precision microwave inter-satellite measurement payloads in some scenarios. Attached Figure Description

[0035] Figure 1 A schematic diagram of the ground testing and verification method for a microwave inter-satellite rangefinder with micrometer precision;

[0036] Figure 2 This is a schematic diagram of test scenario ①;

[0037] Figure 3 This is a schematic diagram of test scenario ②;

[0038] Figure 4 This is a schematic diagram of an example of test scenario ③. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0040] This invention proposes a ground-based testing and verification method for a micrometer-precision microwave inter-satellite rangefinder, such as... Figure 1 As shown, the inter-satellite ranging product under test underwent on-orbit multi-factor simulation testing in three ground scenarios to address factors affecting measurement performance. This included specific test steps or methods designed for three scenarios targeting long-distance transmission delay, system noise, and inter-satellite pointing—three main error factors—for on-orbit applications.

[0041] ① Distance signal delay simulation test;

[0042] ②Long-distance signal level attenuation simulation test;

[0043] ③ Dynamic simulation test of airspace pointing and distance.

[0044] Table 1 shows the on-orbit integrated simulation results under three different test scenarios.

[0045] Table 1. On-orbit simulation results under three different test scenarios.

[0046]

[0047] Detailed explanation is as follows:

[0048] Step 1: Test Scenario ① Long-distance signal delay simulation test: such as Figure 2 A high-stability time-delay simulator was inserted between the bidirectional signal transceiver ports of the two inter-satellite rangefinder active products (excluding antennas) under test. The biased distance measurement accuracy σ1 and the distance change rate measurement accuracy δ1 under the influence of long baseline and long time delay were tested and obtained. The key points of the test method in test scenario ① are:

[0049] 1) The high-stability delay simulator is a bidirectional long-baseline (or long-distance) delay simulator. Its design method is described as follows: The high-stability delay simulator is designed as a fiber optic simulation delay line with long delay in the microwave frequency band used by inter-satellite rangefinders at both ends. Its main internal components include: a laser, optoelectronic modulation and demodulation device A, an ultra-long optical fiber containing an adjustable delay optical signal delay unit, optoelectronic modulation and demodulation device B, and a real-time fiber delay measurement controller. The optoelectronic modulation and demodulation device A modulates the input microwave signal onto the laser to generate a laser carrier. After transmission through the ultra-long optical fiber, the microwave signal is demodulated by the optoelectronic modulation and demodulation device B to output the microwave signal, realizing the microwave signal transmission delay from A to B. Similarly, the reverse microwave signal transmission delay from B to A is realized, achieving bidirectional long-delay transmission of microwave signals.

[0050] Ultra-long optical fibers can simulate microwave signal transmission delays over distances of hundreds of kilometers in space. However, the use of ultra-long optical fibers results in large laser delay jitter that far exceeds the measurement accuracy requirements. Therefore, the high-stability delay simulator must be designed with a real-time optical fiber delay measurement and controller to ensure that the delay of the simulator is stable within the required micron-level accuracy. The length of the ultra-long optical fiber can be set to four lengths: near-zero (L0), small (LS), medium (LM), and large (LL) to facilitate performance testing and use. The specific length selection is basically equivalent to ground testing and on-orbit application scenarios.

[0051] 2) The output signal of the active inter-satellite ranging device (AMS) is passed through a high-stability delay simulator and then output to the receiving input of the active AMS of another satellite. A suitable attenuator is configured to ensure that the input level is not less than the minimum on-orbit distance level. The additive noise from the high-stability delay simulator must be controlled to an acceptable level.

[0052] 3) During the test, the ambient temperature of the test piece and the test equipment is monitored and recorded in real time. The change is required to be controlled to be less than 0.1 degrees Celsius, and the environment should be kept stable during the test to avoid generating vibration sources.

[0053] The obtained results are compared with theoretical analysis. If the results are reasonable, the test results that are not less than the required distance from the target state are used for the calculation and evaluation of the final results in the fourth step.

[0054] Step 2: Test Scenario ② Long-Distance Signal Level Attenuation Simulation Test: Insert a spatial long-distance signal level attenuation simulation device between two inter-satellite rangefinder products to obtain the biased distance measurement accuracy σ2 and the distance change rate measurement accuracy δ2 under the influence of system noise under long-distance static conditions; Figure 3 As shown.

[0055] The key points of the testing method in test scenario ② are:

[0056] 1) The design method of the space long-distance signal level attenuation simulation device is described as follows: The space long-distance signal level attenuation simulation device includes an absorbing box A facing the antenna under test, a polarized transceiver antenna A, an adjustable signal attenuator, an absorbing box B facing the antenna under test, and a polarized transceiver antenna B; After receiving the signal transmitted by the antenna of satellite A under test through the absorbing box A and the polarized transceiver antenna A, the signal is transmitted to the antenna of satellite B under test through the adjustable signal attenuator and then through the polarized transceiver antenna B and the absorbing box B facing the antenna under test; Similarly, the reverse microwave signal transmission from satellite B to satellite A is realized; The size of the absorbing box is related to the size of the antenna aperture and the signal frequency band, and it needs to achieve effective absorption to suppress the influence of multipath signals; The attenuation range of the adjustable signal attenuator is determined according to the simulated inter-satellite microwave link spatial attenuation calculation value to achieve system noise equivalence in ground testing and on-orbit application scenarios.

[0057] 2) During the test, the ambient temperature of the test piece and the test equipment is monitored and recorded in real time. The change is required to be controlled to be less than 0.1 degrees, and the environment should be kept stable during the test to avoid generating vibration sources.

[0058] In this scenario, the inter-satellite rangefinder needs to be tested under three conditions: the farthest distance, the closest distance, and the median distance required by the index. The corresponding biased distance measurement accuracy and distance change rate measurement accuracy results are analyzed and evaluated and compared with theoretical results. The results under the farthest distance condition are used in the calculation and evaluation of the final results in the fourth step.

[0059] Step 3: Test Scenario ③ Dynamic Simulation Test of Spatial Pointing and Distance: The single-satellite inter-satellite rangefinder product A (or B) under test is placed on a high-precision turntable on a high platform (height H) at one end of a large anechoic chamber. An inter-satellite rangefinder signal simulator is installed on a two-dimensional (up / down, left / right) adjustable bracket on the other end of the anechoic chamber, L meters away. A microwave signal link is established between the single-satellite inter-satellite rangefinder and the signal simulator of the other satellite for testing. The biased distance measurement accuracy σ3 and the distance change rate measurement accuracy δ3 of the inter-satellite rangefinder products A and B under the simulated conditions of dynamic changes in spatial pointing and distance are obtained twice. For example... Figure 4 As shown.

[0060] Key aspects of the testing method in test scenario ③ include:

[0061] 1) The high-precision turntable has two-dimensional high-precision rotation in azimuth and pitch and submicron precision translation in forward and backward directions. The stability of the high platform where the device under test is installed and the turntable must also reach the micron level.

[0062] 2) The height H of the platform and the distance L between the antenna apertures should be selected to meet the far-field requirements of the antenna test;

[0063] 3) The antenna horn of the inter-satellite rangefinder signal simulator adopts a small-aperture wide-beam antenna with the same polarization design as the antenna horn under test to reduce the influence of secondary reflection multipath on dynamic measurement. The other components of the antenna are the same as those of the inter-satellite rangefinder antenna.

[0064] 4) The active product of the inter-satellite rangefinder signal simulator adopts the same design baseline as the product under test. A fixed amount of signal attenuator is inserted before the transmitted signal to the antenna and after the received signal from the antenna, so that the signal level received by the inter-satellite rangefinder antenna of the test piece and the signal level received by the active product of the signal simulator are both at the equivalent level of the closest distance on the track, so that the product under test and the test equipment work under the condition of minimum system noise.

[0065] 5) During the test, the ambient temperature of the test piece and the test equipment shall be monitored and recorded in real time. The change shall be controlled to be less than 0.1 degrees and the environment shall be kept stable during the test to avoid generating vibration sources.

[0066] In this scenario, the inter-satellite rangefinder is first tested under three conditions: zero angle of view, a smaller required deflection angle range, and a larger deflection angle range. The results of the deflected distance measurement accuracy and distance change rate measurement accuracy of the inter-satellite rangefinder are obtained, analyzed and evaluated, and compared with the theoretical results. If the results are reasonable, two test results can be obtained for the inter-satellite rangefinder products of the two satellites within the required deflection angle range. The larger value is taken for the calculation and evaluation of the final result in the fourth step.

[0067] By using the high-precision translation of the turntable, the biased distance measurement accuracy can be evaluated by comparing the true value of the distance change with the measured distance change value of the inter-satellite rangefinder. The statistical standard deviation of the results of multiple measurements and comparisons can be used to obtain the dynamic comparison biased distance measurement accuracy σ4 and to evaluate its reasonableness with other biased distance measurement results.

[0068] Step 4: Conduct a comprehensive evaluation of the measurement results obtained from test scenarios ①, ②, and ③. The evaluation method is as follows: Based on the principle of statistical independence of the test results from the three scenarios: Overall bias in distance measurement accuracy: Accuracy of overall distance change rate measurement:

[0069] In actual testing, such high precision is difficult to achieve. However, signal multipath propagation due to close proximity is often difficult to minimize. Ground-based testing introduces multipath propagation, a significant error that is absent in orbit but easily introduced in ground testing. Therefore, [the following approach is adopted]. This synthesis method leads to a further amplification of the multipath effect in ground tests. Therefore, sometimes an alternative comprehensive evaluation result can be used: taking the maximum value σ = max(σ1, σ2, σ3, σ4), δ = max(δ1, δ2, δ3). An additional condition for choosing this comprehensive evaluation method that takes the maximum value is that the measured results in all three scenarios are significantly greater than (generally considered to be more than 3 times) the accuracy results of the inter-satellite rangefinder product design error factor analysis.

[0070] The order of the first three steps can be varied and determined based on the availability of test resources. When all conditions are met, testing in the order described above is preferable because the initial steps require less work in setting up the testing site, which can reduce the risk of increased workload due to repeated testing caused by substandard products.

[0071] Example:

[0072] The aforementioned ground-based testing and verification method was used to test a DOWR-based K / Ka band micrometer-precision inter-satellite distance measuring instrument with a ranging accuracy better than 5 micrometers and a velocity accuracy better than 0.5 micrometers / second. The inter-satellite distance measurement range was approximately 100km to 270km.

[0073] Test Scenario ①: Four fiber optic cables of length L0=10 meters, LS=60km, LM=120km, and LL=180km were selected for switching. The maximum spatial distance signal transmission delay can be simulated to 900 microseconds (equivalent distance of about 270km). The accuracy of inter-satellite offset distance measurement σ1 and the accuracy of distance change rate measurement δ1 were tested.

[0074] Test Scenario ②: The internal dimensions of the absorbing box are two 0.6m×0.6m×0.6m boxes, and the aperture of the antenna under test is about 0.15m. The attenuator was selected at three simulated equivalent time delay distances of about 90km, 180km and 270km to test the inter-satellite offset distance measurement accuracy σ2 and the distance change rate measurement accuracy δ2.

[0075] Test Scenario ③: With a platform height H of approximately 8 meters and an antenna aperture distance L of approximately 18 meters, tests were conducted on the biased distance measurement accuracy σ3 and the distance change rate measurement accuracy δ3.

[0076] A comprehensive evaluation method was adopted: Offset distance measurement accuracy: Accuracy of distance change rate measurement: Ground tests showed that the distance measurement accuracy of an inter-satellite rangefinder was approximately 2 to 3 micrometers, and the distance change rate measurement accuracy was approximately 0.2 to 0.3 micrometers per second.

[0077] The parts of this invention that are not described in detail are common knowledge to those skilled in the art.

Claims

1. A ground-based testing and verification method for a micrometer-precision inter-satellite microwave rangefinder, characterized in that... include: Long-distance signal delay simulation test: A high-stability delay simulator is inserted between the bidirectional signal transceiver ports of the two inter-satellite rangefinders under test to test and obtain the biased distance measurement accuracy under the influence of long baseline and long delay. Accuracy of distance change rate measurement ; Long-distance signal level attenuation simulation test: A space long-distance signal level attenuation simulation device was inserted between the two inter-satellite rangefinders to obtain the biased distance measurement accuracy under the influence of system noise under long-distance static conditions. Accuracy of distance change rate measurement ; Dynamic simulation test of spatial pointing and distance: The inter-satellite rangefinders A or B under test are placed on a high-precision turntable on a platform at one end of a large anechoic chamber. An inter-satellite rangefinder signal simulator is installed on a two-dimensional position-adjustable bracket on the other end of the anechoic chamber, which is L meters away. A microwave signal link is established between the inter-satellite rangefinder and the other inter-satellite rangefinder signal simulator for testing. The biased distance measurement accuracy of the inter-satellite rangefinders A and B under the simulated dynamic change of spatial pointing and distance is tested twice. Accuracy of distance change rate measurement ; Based on the above test results, the overall biased distance measurement accuracy was calculated. Accuracy of measurement of overall distance change rate ; The high-stability time delay simulator is a bidirectional long-baseline time delay simulator, with inputs and outputs at both ends being long-delay fiber optic simulated delay lines in the microwave frequency band used by the inter-satellite rangefinder. The high-stability delay simulator includes a laser, optoelectronic modulation and demodulation device A, an ultra-long optical fiber containing an adjustable delay optical signal delay unit, optoelectronic modulation and demodulation device B, and a real-time fiber delay measurement controller. Optoelectronic modulation and demodulation device A modulates the input microwave signal onto the laser-generated laser carrier. After transmission through the ultra-long optical fiber, the microwave signal is demodulated by optoelectronic modulation and demodulation device B to output the microwave signal, thus realizing the microwave signal transmission delay from A to B. Similarly, the reverse microwave signal transmission delay from B to A is realized, achieving bidirectional long-delay microwave signal transmission. The real-time fiber delay measurement controller ensures that the delay simulator maintains the required micron-level accuracy by detecting the transmission delay jitter changes of the input / output signals of the ultra-long fiber in real time and controlling the adjustable delay optical signal delay device; the length of the ultra-long fiber can be set according to the test requirements.

2. The ground testing and verification method for a micrometer-precision inter-satellite microwave rangefinder according to claim 1, characterized in that: The output signal of the inter-satellite ranging instrument is sent to the receiving input of another inter-satellite ranging instrument after passing through a high-stability time delay simulator. By configuring an attenuator, the input level is set to be no less than the minimum on-orbit distance level.

3. The ground testing and verification method for a micrometer-precision inter-satellite microwave rangefinder according to claim 1, characterized in that: During the long-distance signal delay simulation test, the long-distance signal level attenuation simulation test, and the spatial pointing and distance dynamic simulation test, the ambient temperature of the test device and the test equipment is monitored and recorded in real time. The change is required to be controlled to be less than 0.1 degrees, and the environment should be kept stable during the test to avoid the generation of vibration sources.

4. The ground testing and verification method for a micrometer-precision inter-satellite microwave rangefinder according to claim 1, characterized in that: The space long-distance signal level attenuation simulation device includes an absorbing box A facing the antenna under test, a polarized transceiver antenna A, an adjustable signal attenuator, an absorbing box B facing the antenna under test, and a polarized transceiver antenna B. After receiving the signal transmitted by the antenna of satellite A under test, the absorbing box A and the polarized transceiver antenna A transmit the signal through the adjustable signal attenuator and then through the polarized transceiver antenna B and the absorbing box B facing the antenna under test to the antenna of satellite B under test. Similarly, the reverse microwave signal transmission from satellite B to satellite A is realized. The size of the absorbing box is related to the size of the antenna aperture and the signal frequency band, and it needs to achieve effective absorption to suppress the influence of multipath signals. The attenuation range of the adjustable signal attenuator is determined according to the simulated inter-satellite microwave link spatial attenuation calculation value to achieve system noise equivalence in ground testing and on-orbit application scenarios.

5. The ground testing and verification method for a micrometer-precision inter-satellite microwave rangefinder according to claim 1, characterized in that: When conducting long-distance signal level attenuation simulation tests, the inter-satellite rangefinder is tested at the three states of the farthest, closest, and median distances required by the specifications. The corresponding biased distance measurement accuracy and distance change rate measurement accuracy are obtained. The test results at the three distances are analyzed. If the difference between the test results and the theoretical results meets the expectations, the test results are considered valid. The test result of the farthest distance among the valid test results is selected for the overall accuracy calculation.

6. The ground testing and verification method for a micrometer-precision inter-satellite microwave rangefinder according to claim 1, characterized in that: In the large microwave anechoic chamber, the high-precision turntable has two-dimensional high-precision rotation in azimuth and elevation, and submicron precision translation in the forward and backward directions. The stability of the high platform where the device under test and the turntable are installed reaches the micron level; the selection of the high platform height H and the distance between the antenna aperture L meets the far-field requirements of antenna testing. The antenna horn of the inter-satellite rangefinder signal simulator adopts a small-aperture wide-beam antenna with the same polarization design as the antenna horn under test, which reduces the impact of secondary reflection multipath on dynamic measurement. The other components of the antenna are the same as those of the inter-satellite rangefinder antenna.

7. The ground testing and verification method for a micrometer-precision inter-satellite microwave rangefinder according to claim 6, characterized in that: The inter-satellite rangefinder signal simulator uses a product with the same design baseline as the product under test. A fixed amount of signal attenuator is inserted before the transmitted signal reaches the antenna and after the received signal reaches the antenna. This ensures that the signal level received by the inter-satellite rangefinder antenna and the signal level received by the signal simulator are both at the equivalent level of the closest distance on orbit, so that the product under test and the test equipment operate under conditions of minimum system noise.

8. The ground testing and verification method for a micrometer-precision inter-satellite microwave rangefinder according to claim 7, characterized in that: When conducting dynamic simulation tests of airspace pointing and distance, the inter-satellite rangefinder is first tested under three conditions: zero angle of pointing field of view, small deflection angle range, and large deflection angle range. The results of the deflected distance measurement accuracy and distance change rate measurement accuracy of the inter-satellite rangefinder are obtained and compared with the theoretical results. If the difference is within the preset range, the inter-satellite rangefinders of the two satellites will obtain two test results within the deflection angle range required by the index. The larger value is taken as the final result of the dynamic simulation test of airspace pointing and distance.

9. The ground testing and verification method for a micrometer-precision inter-satellite microwave rangefinder according to claim 8, characterized in that: Using the minute translation of the turntable in the distance direction as the true value of the distance change, the accuracy of the biased distance measurement is evaluated by comparing the measured distance change values ​​of the inter-satellite rangefinder with the corresponding true values. The statistical standard deviation of the results of multiple measurement comparisons is used as the accuracy of the biased distance measurement in dynamic comparison. After testing the two star products separately, the maximum value of the two results is selected.

10. The ground testing and verification method for a micrometer-precision inter-satellite microwave rangefinder according to claim 9, characterized in that: The calculation yields the overall biased distance measurement accuracy. Accuracy of measurement of overall distance change rate Specifically: The biased distance measurement accuracy results obtained from three tests , , Analysis suggests that the significant error is due to non-orbiting factors on the ground. , , When all three error factors exceed three times the maximum theoretical accuracy calculated for each of the three error factors, the overall distance measurement accuracy is biased. Accuracy of measurement of overall distance change rate The calculation is as follows: ； Otherwise, the overall distance measurement accuracy will be biased. Accuracy of measurement of overall distance change rate : 。

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