Calibration device and method for inconsistency of uplink and downlink time delay of space-borne measuring equipment

Abstract

The application discloses a kind of calibrating devices and methods of inconsistency of uplink and downlink time delay of spaceborne measuring equipment, belong to spaceflight TT&C technical field.The application utilizes the difference value calculation needed in inconsistency calibration, unified ground detection equipment, unified time frequency reference and real time difference measurement reference are designed, and the to-be-calibrated quantity is obtained by simple measurement and difference value calculation, which eliminates the inconsistency of uplink and downlink time delay of ground equipment, space transmission time delay, reference drift error and the like, and meets the calibration requirement of high precision.Meanwhile, the calibrating device constructed is simple in structure, easy and fast to operate, and facilitates rapid calibration of multiple satellites.

Description

Technical Field

[0001] This invention belongs to the field of aerospace measurement and control technology, specifically relating to fixed time delay calibration technology for spaceborne measurement equipment, and in particular to a calibration device and method for inconsistency in uplink and downlink time delay difference of spaceborne measurement equipment. Background Technology

[0002] Measuring satellite-to-ground distance, relative velocity, and time difference is a crucial task in aerospace telemetry and control. Among these, satellite-to-ground time difference measurement is usually calculated in conjunction with satellite-to-ground distance measurement. The onboard equipment transmits the satellite time via downlink channel, and the ground compares the satellite time with the ground time, subtracting satellite-to-ground propagation delay and equipment processing delay to obtain the satellite-to-ground time difference.

[0003] In a multi-satellite Earth observation system, multiple satellites need to be synchronized on the same time reference to achieve precise target positioning and observation. This requires simultaneously and accurately measuring the satellite-to-ground time difference of multiple satellites and calculating the relative time difference between them. Since different onboard measurement equipment is not entirely consistent, and their processing delays also vary, this is reflected in the inconsistency of the uplink and downlink time delay differences between the satellites. Therefore, this inconsistency needs to be pre-calibrated so that the calculated relative time difference between the satellites can be corrected after they are in orbit, thereby improving measurement accuracy.

[0004] Traditional methods for calibrating the time delay of spaceborne equipment primarily involve three approaches. The first is using an oscilloscope, drawing signals from both the equipment's input and output ports. The uplink or downlink delay is obtained by comparing the occurrence times of identical bits on the oscilloscope, followed by multiple calibration calculations. This method offers high accuracy but requires signal interfaces and is complex to implement. The second method involves using the same standard ground-based survey equipment with a wired connection to measure the distance to multiple satellites and subtracting cable delays. This method only obtains the sum of the uplink and downlink delays of the spaceborne measurement equipment, as well as any inconsistencies in these delay sums. The third method still uses a wired connection, with both satellite and ground synchronized to GNSS time. The satellite time is then transmitted downlink, and the ground calculates the time by subtracting cable delays and time stamp transmission delays. This method only obtains the downlink delay, cannot directly calculate the inconsistency between the uplink and downlink delays, and has lower accuracy, failing to meet the required standards. Summary of the Invention

[0005] The purpose of this invention is to provide a calibration device and method for the inconsistency of uplink and downlink time delay difference on a spaceborne measurement device.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] According to a first aspect of the present invention, a calibration device for the inconsistency of uplink and downlink time delay difference of a spaceborne measurement device is provided. The calibration device includes a ground detection device, a signal conversion unit, a reference clock, a time unit, a counter, and a calculation unit. The signal conversion unit has a first interface for connecting to the spaceborne measurement device under test, and the time unit has a second interface for connecting to the spaceborne measurement device under test.

[0008] The reference clock output is connected to the time unit and the counter to provide a high-precision clock for the time unit and the counter; the time unit is connected to the ground detection equipment, the signal conversion unit, and the counter, and it generates second pulses according to the high-precision clock and outputs second pulses to the counter, the ground detection equipment, and the on-board measurement equipment under test.

[0009] The counter is used to measure the first time difference between the second pulse output by the time unit and the second pulse output by the ground detection equipment. The ground detection equipment directly measures the uplink and downlink loop between the counter and the onboard measurement equipment under test to obtain the second time difference.

[0010] The calculation unit is used to calculate the difference between the first time difference and the second time difference corresponding to the satellite-borne measurement device under test, and obtain the inconsistency calibrator of the uplink and downlink transmission delay difference of the satellite-borne measurement device based on the difference between the two satellite-borne measurement devices under test.

[0011] In one embodiment, the computing unit calculates the difference between the first difference corresponding to the first satellite-borne measurement device under test and the second difference corresponding to the second satellite-borne measurement device under test, so as to obtain the inconsistency calibrated value of the uplink and downlink transmission delay difference of the satellite-borne measurement device.

[0012] In one embodiment, the time unit includes: a first output terminal connected to a ground detection device for outputting a second pulse and a frequency standard to the ground detection device; a second output terminal connected to a signal conversion unit for outputting a frequency standard to the signal conversion unit; and a third output terminal connected to a counter for outputting a second pulse to the counter.

[0013] In one embodiment, when connected to the onboard measurement device under test, the time unit outputs a second pulse and a frequency standard to the onboard measurement device under test through a second interface.

[0014] In one embodiment, the signal conversion unit includes an up-converter, a down-converter, and a circulator. A time unit is connected to the up-converter and down-converter respectively to provide frequency standards to the up-converter and down-converter. The signal input terminal of the up-converter is connected to the ground detection equipment, and the signal output terminal is connected to the circulator to convert the intermediate frequency signal from the ground detection equipment into a radio frequency signal to be provided to the spaceborne measurement equipment under test. The signal input terminal of the down-converter is connected to the circulator, and the signal output terminal is connected to the ground detection equipment to convert the radio frequency signal from the spaceborne measurement equipment under test into an intermediate frequency signal to be provided to the ground detection equipment. The circulator has the first interface to connect to the spaceborne measurement equipment under test, realizing the combining and splitting of uplink and downlink radio frequency signals.

[0015] According to a second aspect of the present invention, a calibration method is provided for calibrating the inconsistency between uplink and downlink time delays of a spaceborne measurement device using the calibration apparatus described above, the method comprising:

[0016] Step S11: Connect the first spaceborne measurement device to be tested to the above-mentioned calibration device;

[0017] Step S12: Measure the first time difference Δt between the second pulse output by the time unit and the second pulse output by the ground detection equipment using a counter. counter The second time difference Δt is obtained by measuring the uplink and downlink loops between the ground-based detection equipment and the first satellite-borne measurement equipment under test. computer And calculate the first time difference Δt counter With the second time difference Δt computer The first difference Δτ between eudS ;

[0018] Step S13: Connect the second spaceborne measurement device to be tested to the above-mentioned calibration device;

[0019] Step S14: Measure the first time difference Δt between the second pulse output by the time unit and the second pulse output by the ground detection equipment using a counter. counter * The second time difference Δt is obtained by measuring the uplink and downlink loops between the ground-based detection equipment and the second satellite-borne measurement equipment under test. computer * And calculate the first time difference Δt counter * With the second time difference Δt computer * The second difference Δτ between eudS * ;

[0020] Step S15: Calculate the first difference Δτ eudS The second difference Δτ eudS *The difference between them is used to obtain the inconsistency calibrated ΔΔτ of the uplink and downlink transmission delay difference of the onboard measurement equipment. eudS .

[0021] According to a third aspect of the present invention, a method for calibrating the inconsistency between uplink and downlink time delays of a spaceborne measurement device is provided, the method comprising:

[0022] Step S21: Generate a second pulse using a reference clock;

[0023] Step S22: For the first satellite-borne measurement device under test, measure the first time difference Δt between the second pulse and the second pulse output by the ground detection device. counter And the second time difference Δt obtained by directly measuring the uplink and downlink loop between the ground detection equipment and the first satellite-borne measurement equipment under test. computer ;

[0024] Step S23: For the second satellite-borne measurement device under test, measure the first time difference Δt between the second pulse and the second pulse output by the ground detection device. counter * And the second time difference Δt obtained by directly measuring the uplink and downlink loop between the ground detection equipment and the second satellite-borne measurement equipment under test. computer * ;

[0025] Step S24: Calculate the first time difference Δt counter With the first time difference Δt counter * The first difference Δτ between eudS and the second time difference Δt computer With the second time difference Δt computer * The second difference Δτ between eudS * And calculate the first difference Δτ eudS The second difference Δτ eudS * The difference between them is used to obtain the inconsistency calibrated ΔΔτ of the uplink and downlink transmission delay difference of the onboard measurement equipment. eudS .

[0026] This invention utilizes the difference calculation required in inconsistency calibration. By designing a unified ground detection device, a unified time and frequency reference, and a real time difference measurement reference, the quantity to be calibrated is obtained through simple measurement and difference calculation. This effectively eliminates the inconsistency of uplink and downlink time delay differences of ground equipment, spatial transmission delay, reference drift error, etc., and meets the requirements of high-precision calibration.

[0027] Meanwhile, the calibration device constructed in this invention has a simple structure, is easy and quick to operate, and facilitates rapid calibration of multiple satellites.

[0028] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0029] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0030] Figure 1 This is a schematic diagram of the calibration device for the inconsistency between uplink and downlink time delays of a spaceborne measurement device according to an embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram illustrating the workflow of a calibration method for the inconsistency between uplink and downlink time delays on a spaceborne measurement device according to an embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram illustrating the workflow of a calibration method for the inconsistency between uplink and downlink time delays on a spaceborne measurement device according to another embodiment of the present invention. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0034] Figure 1 This is a schematic diagram of the calibration device for the inconsistency between uplink and downlink time delays on a spaceborne measurement device according to an embodiment of the present invention. Figure 1 As shown, the calibration device includes a ground detection device 10, a signal conversion unit 20, a reference clock 30, a time unit 40, a counter 50, and a calculation unit (not shown). The signal conversion unit 20 has a first interface for connecting to the onboard measurement device 100 under test, and the time unit 40 has a second interface for connecting to the onboard measurement device 100 under test.

[0035] The output of the reference clock 30 is connected to the time unit 40 and the counter 50 to provide a high-precision clock for the time unit 40 and the counter 50.

[0036] The time unit 40 is connected to the ground detection equipment 10, the signal conversion unit 20, and the counter 50. It generates a second pulse (Pulse Per Second, 1pps) and a frequency standard (e.g., 10MHz) according to a high-precision clock, and outputs the second pulse and frequency standard to the ground detection equipment 10 and the satellite-borne measurement equipment under test 100, outputs the frequency standard to the signal conversion unit 20, and outputs the second pulse to the counter 50.

[0037] For example, the time unit 40 includes: a first output terminal connected to the ground detection device 10, used to output a second pulse and a frequency standard to the ground detection device 10; a second output terminal connected to the signal conversion unit 20, used to output a frequency standard to the signal conversion unit 20; and a third output terminal connected to the counter 50, used to output a second pulse to the counter 50. Simultaneously, when connected to the onboard measurement device 100 under test, the time unit 40 can output a second pulse and a frequency standard to the onboard measurement device 100 under test through a second interface.

[0038] like Figure 1 As shown, in one example, the signal conversion unit 20 includes an up-converter, a down-converter, and a circulator. The timing unit 40 is connected to the up-converter and down-converter respectively to provide frequency standards to them. The up-converter's signal input is connected to the ground detection equipment 10, and its signal output is connected to the circulator to convert the intermediate frequency (IF) signal from the ground detection equipment 10 into a radio frequency (RF) signal for supply to the spaceborne measurement equipment 100 under test. The down-converter's signal input is connected to the circulator, and its signal output is connected to the ground detection equipment 10 to convert the RF signal from the spaceborne measurement equipment 100 under test into an IF signal for supply to the ground detection equipment 10. The circulator has the first interface to connect to the spaceborne measurement equipment 100 under test, enabling the combining and splitting of uplink and downlink RF signals.

[0039] Counter 50 is used to measure the first time difference between the second pulse output by time unit 40 and the second pulse output by ground detection equipment 10. Ground detection equipment 10 directly measures the second time difference.

[0040] The calculation unit is used to calculate the difference between the first time difference and the second time difference corresponding to the satellite-borne measurement equipment under test, and to obtain the inconsistency calibrator of the uplink and downlink transmission delay difference of the satellite-borne measurement equipment based on the difference between the two differences of the satellite-borne measurement equipment under test. Specifically, the difference between the first difference corresponding to the first satellite-borne measurement equipment under test and the second difference corresponding to the second satellite-borne measurement equipment under test is calculated to obtain the inconsistency calibrator of the uplink and downlink transmission delay difference of the satellite-borne measurement equipment.

[0041] Continue to refer to Figure 1 For a certain onboard measurement device A under test, two measurement quantities can be obtained: Δt counter This represents the counter's reading, specifically the time difference Δt between the second pulse provided by the time unit and the second pulse from the ground detection equipment. counter =t s -t G That is, the difference between the system time of the spaceborne measurement equipment and the system time of the ground detection equipment; Δt computerThis represents the time difference measurement value directly obtained by the ground detection equipment, that is, the time difference measurement value obtained by the ground detection equipment through direct measurement of the uplink and downlink loops between the ground detection equipment and the onboard measurement equipment.

[0042] The measurements taken by the ground-based detection equipment are calculated strictly according to the following formula:

[0043]

[0044] Where t'2 is the on-board sampled value at time t2, with the ground clock as the reference; t'3 is the ground sampled value at time t3; This represents the bidirectional transmission delay, where all parameters can be directly measured; Δτ eud Δτ represents the transmission delay difference between uplink and downlink devices, and is a quantity to be determined that needs to be calibrated. In actual measurement, Δτ... eud The values ​​are filled with already calibrated valid values, and are used in... Figure 1 When performing test calibration, this quantity is preset to zero.

[0045] Δt counter The value obtained by directly measuring two different second pulses can be considered to represent the true time difference between the onboard measurement equipment and the ground detection equipment. Therefore, if Formula 1 is corrected and the influence of various errors is not considered, its calculated value should be able to physically represent the true time difference between the satellite and the ground, i.e., Δt. computer =Δt counter However, in reality, the measured value was not corrected because the correction term was preset to zero, so Δt... computer With Δt counter They should not be equal, and the difference is equal to Δτ. eud This can be expressed as a formula:

[0046] Δt computer -Δt counter =Δτ eud / 2 (Formula 2)

[0047] Due to Δτ eud It can be broken down into spaceborne measurement equipment and ground-based testing equipment. The above formula can be written as:

[0048] Δt computer -Δt counter =Δτ eud / 2=(Δτ eudS +Δτ eudG ) / 2 (Formula 3)

[0049] Where Δτ eudS Δτ represents the uplink and downlink transmission delay difference on the satellite. eudG This indicates the difference in uplink and downlink transmission delay on the ground.

[0050] Replace the currently measured onboard measurement device A with another onboard measurement device B to be tested, and then perform the above measurements again. Assume that the second measurement obtained through the counter and ground detection equipment is Δt. computer * and Δt counter * Similarly, according to Formula 3 above, we can obtain:

[0051] Δt computer * -Δt counter * =(Δτ) eudS * +Δτ eudG * ) / 2 (Formula 4)

[0052] The inconsistency calibration of the uplink and downlink transmission delay difference between the two spaceborne measurement devices AB can be equivalent to calculating Δτ. eudS -Δτ eudS * Therefore, by subtracting Formula 3 from Formula 4, we obtain the value:

[0053] Δt computer -Δt counter -(Δt) computer * -Δt counter * )=(Δτ eudS +Δτ eudG ) / 2-

[0054] (Δτ eudS * +Δτ eudG * ) / 2(Formula 5)

[0055] Since the two measurements used exactly the same ground detection equipment and measurement conditions, it can be assumed that Δτ eudG =Δτ eudG * Therefore, formula (5) can be simplified to:

[0056] Δt computer -Δt counter -(Δt) computer * -Δt counter * )=(Δτ eudS -Δτ eudS * ) / 2 (Formula 6)

[0057] The right side of equation (6) is the required calibration value for the inconsistency between uplink and downlink transmission delays on the satellite, denoted as:

[0058] ΔΔτ eudS =Δτ eudS -Δτ eudS * =2×(Δt) computer -Δt counter -(Δt) computer * -Δt counter * )) (Formula 7)

[0059] As can be seen from Formula 7, the measurement reading Δt is obtained directly from the two measurements. computer , Δt counter , Δt computer * , Δt counter * This allows us to calculate the required inconsistency calibrated value Δτ for the uplink and downlink transmission delay difference of the onboard equipment. eudS During the two measurements, it is only necessary to connect the two different onboard measurement devices between the first and second interfaces.

[0060] Figure 2 This is a schematic diagram illustrating the workflow of a calibration method for inconsistencies in uplink and downlink time delays of a spaceborne measurement device according to an embodiment of the present invention. In this embodiment, based on the aforementioned calibration device, a calibration method for inconsistencies in uplink and downlink time delays of a spaceborne measurement device is provided, the method comprising the following steps:

[0061] Step S11: Connect the first spaceborne measurement device to be tested to the above-mentioned calibration device;

[0062] Step S12: Measure the first time difference Δt between the second pulse output by the time unit 40 and the second pulse output by the ground detection device 10 using the counter 50. counter And using ground-based detection equipment 10 to measure the second time difference Δt computer And calculate the first time difference Δt counter With the second time difference Δt computer The first difference Δτ between eudS ;

[0063] Step S13: Connect the second spaceborne measurement device to be tested to the above-mentioned calibration device;

[0064] Step S14: Measure the first time difference Δt between the second pulse output by the time unit 40 and the second pulse output by the ground detection device 10 using the counter 50. counter * And using ground-based detection equipment 10 to measure the second time difference Δtcomputer * And calculate the first time difference Δt counter * With the second time difference Δt computer * The second difference Δτ between eudS * ;

[0065] Step S15: Calculate the first difference Δτ eudS The second difference Δτ eudS * The difference between them is used to obtain the inconsistency calibrated ΔΔτ of the uplink and downlink transmission delay difference of the onboard measurement equipment. eudS .

[0066] In another embodiment of the present invention, a more general method for calibrating the inconsistency between uplink and downlink time delays on spaceborne measurement equipment is provided. This method is not strictly limited to the calibration device shown in the above embodiments; that is, one or more of the ground detection equipment, signal conversion unit, reference clock, time unit, and counter in the above calibration device can be constructed in other ways. The calibration method includes:

[0067] Step S21: Generate a second pulse using a reference clock;

[0068] Step S22: For the first satellite-borne measurement device under test, measure the first time difference Δt between the second pulse and the second pulse output by the ground detection device. counter The second time difference Δt is obtained by directly measuring the uplink and downlink loops between the ground detection equipment and the first satellite-borne measurement equipment under test. computer ;

[0069] Step S23: For the second satellite-borne measurement device under test, measure the first time difference Δt between the second pulse and the second pulse output by the ground detection device. counter * The second time difference Δt is obtained by directly measuring the uplink and downlink loops between the ground-based detection equipment and the second satellite-borne measurement equipment under test. computer * ;

[0070] Step S24: Calculate the first time difference Δt counter With the first time difference Δt counter * The first difference Δτ between eudS and the second time difference Δt computer With the second time difference Δt computer * The second difference Δτ between eudS * And calculate the first difference Δτ eudSThe second difference Δτ eudS * The difference between them is used to obtain the inconsistency calibrated ΔΔτ of the uplink and downlink transmission delay difference of the onboard measurement equipment. eudS .

[0071] In this invention, the counter is a standard measuring device with a reading accuracy reaching the sub-nanometer level. The measurement accuracy of the ground detection equipment is comparable to that of satellite-to-ground time difference measurement, at the nanosecond level. Therefore, the overall measurement accuracy can reach the nanosecond level, meeting the accuracy requirements for time difference calibration.

[0072] The measurement reference and time depend on the reference clock, and the instability of the clock causes the frequency and time reference to change over time. In this invention, since all devices use the same high-precision frequency source, the time drift of the reference clock is synchronized across all devices. After a single difference calculation using the method described above, the time drift is eliminated, thus eliminating the error that may be caused by frequency reference drift due to the difference in measurement time between two measurements.

[0073] This invention utilizes the difference calculation required in inconsistency calibration. By designing a unified ground detection device, a unified time and frequency reference, and a real time difference measurement reference, the quantity to be calibrated is obtained through simple measurement and difference calculation. This effectively eliminates inconsistencies in uplink and downlink time delays of ground equipment, spatial transmission delays, and reference drift errors, thus meeting the requirements for high-precision calibration. Furthermore, the constructed calibration device has a simple structure, is easy and quick to operate, and facilitates rapid calibration of multiple satellites.

[0074] Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific embodiments of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solution claimed in the present invention.

Claims

1. A calibration device for the inconsistency of uplink and downlink time delay difference on a spaceborne measurement device, characterized in that, The calibration device includes ground detection equipment, a signal conversion unit, a reference clock, a time unit, a counter, and a calculation unit. The signal conversion unit has a first interface for connecting to the onboard measurement equipment under test, and the time unit has a second interface for connecting to the onboard measurement equipment under test. The reference clock output is connected to the time unit and the counter to provide a high-precision clock for the time unit and the counter; the time unit is connected to the ground detection equipment, the signal conversion unit, and the counter, and it generates second pulses according to the high-precision clock and outputs second pulses to the counter, the ground detection equipment, and the on-board measurement equipment under test. The counter is used to measure the first time difference between the second pulse output by the time unit and the second pulse output by the ground detection equipment. The ground detection equipment directly measures the uplink and downlink loop between the counter and the onboard measurement equipment under test to obtain the second time difference. The calculation unit is used to calculate the difference between the first time difference and the second time difference corresponding to the satellite-borne measurement equipment under test, and to obtain the inconsistency calibration of the uplink and downlink transmission delay difference of the satellite-borne measurement equipment based on the difference between the differences of different satellite-borne measurement equipment under test. The signal conversion unit includes an up-converter, a down-converter, and a circulator. The time unit is connected to the up-converter and down-converter respectively to provide frequency standards to them. The signal input terminal of the up-converter is connected to the ground detection equipment, and the signal output terminal is connected to the circulator to convert the intermediate frequency signal from the ground detection equipment into a radio frequency signal to be provided to the spaceborne measurement equipment under test. The signal input terminal of the down-converter is connected to the circulator, and the signal output terminal is connected to the ground detection equipment to convert the radio frequency signal from the spaceborne measurement equipment under test into an intermediate frequency signal to be provided to the ground detection equipment. The circulator has the first interface to connect to the onboard measurement equipment under test, enabling the combining and splitting of uplink and downlink radio frequency signals.

2. The calibration device according to claim 1, characterized in that, The calculation unit calculates the difference between the first difference corresponding to the first satellite-borne measurement device under test and the second difference corresponding to the second satellite-borne measurement device under test, so as to obtain the inconsistency calibrator of the uplink and downlink transmission delay difference of the satellite-borne measurement device.

3. The calibration device according to claim 1, characterized in that, The time unit includes: a first output terminal, connected to the ground detection equipment, for outputting second pulses and frequency standards to the ground detection equipment; a second output terminal, connected to the signal conversion unit, for outputting frequency standards to the signal conversion unit; and a third output terminal, connected to the counter, for outputting second pulses to the calculator.

4. The calibration device according to claim 3, characterized in that, When connected to the onboard measurement device under test, the time unit outputs second pulses and frequency standards to the onboard measurement device under test through the second interface.

5. A method for calibrating the inconsistency between uplink and downlink time delays of a spaceborne measurement device using the calibration device according to any one of claims 1-4, characterized in that, The method includes: Step S11: Connect the first spaceborne measurement device to be tested to the above-mentioned calibration device; Step S12: Measure the first time difference Δt between the second pulse output by the time unit and the second pulse output by the ground detection equipment using a counter. counter The second time difference Δt is obtained by measuring the uplink and downlink loops between the ground-based detection equipment and the first satellite-borne measurement equipment under test. computer And calculate the first time difference Δt counter With the second time difference Δt computer The first difference between ; Step S13: Connect the second spaceborne measurement device to be tested to the above-mentioned calibration device; Step S14: Measure the first time difference between the second pulse output by the time unit and the second pulse output by the ground detection equipment using a counter. The second time difference is obtained by measuring the uplink and downlink loops between the ground-based detection equipment and the second satellite-borne measurement equipment under test. And calculate the first time difference. With the second time difference The second difference between ； Step S15: Calculate the first difference. The second difference The difference between them is used to obtain the inconsistency calibrator of the uplink and downlink transmission delay difference of the spaceborne measurement equipment. .

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