A calibration method and system for systematic errors of a laser ranging station

Abstract

The present invention discloses a calibration method for the systematic error of a laser ranging station system. The method includes the following steps: measuring the circuit transmission and device response delay of the station system using an optical fiber of a preset length to obtain the circuit transmission and device response delay; measuring the jitter of the response of a superconducting single-photon detector and obtaining the jitter magnitude of the superconducting single-photon detector according to the jitter of the response of the superconducting single-photon detector; selecting four positions with the same distance to the main mirror in front of the main mirror of the telescope, performing multiple groups of detections by sequentially placing a photodetector at the selected four positions to obtain the corresponding laser reception moments, and calculating according to the corresponding laser reception moments to obtain the internal optical path flight time of the station system; calibrating the laser ranging station system according to the circuit transmission and device response delay corresponding to the station system, the jitter magnitude of the superconducting single-photon detector, and the internal optical path flight time. The present invention realizes accurate calibration of the laser ranging station system.

Description

Technical Field

[0001] The present invention relates to the field of calibration of laser ranging systems, and specifically, to a method and system for calibrating systematic errors of a laser ranging station system. Background Art

[0002] Laser ranging is a means of high-precision spatial target observation. By emitting a laser and recording the time of flight of the laser pulse, the distance can be measured.

[0003] Systematic error calibration is an important step in laser ranging. The quality of systematic calibration directly determines the quality of the data generated by the laser ranging station. During the laser ranging observation task, it is necessary to frequently calibrate the systematic error to improve the quality of the ranging data.

[0004] The systematic errors of a laser ranging station are divided into two parts. One is the circuit transmission delay and the response delay of the device, and the other is the time of flight of the laser pulse in the optical path inside the laser ranging station. The former is very intuitive in understanding. Circuit transmission takes a certain amount of time, and the response of the device is not instantaneous, and there is a certain delay that needs to be deducted. And the circuit transmission and the response of the device are basically stable and will not cause large fluctuations. The latter is understood based on the use of laser ranging data. When using laser ranging data, the laser ranging station is usually equivalent to a point, that is, the fixed point of the laser ranging station telescope. If the time of flight of the laser pulse in the internal optical path of the laser ranging station is not deducted, it will bring large deviations and is not conducive to data use.

[0005] The conventional systematic calibration method for a laser ranging station is to measure a ground target. At a certain position on the ground, one or more corner reflectors are placed, the telescope is adjusted to a suitable position, and the corner reflector is used as the target to start the measurement. After obtaining the data, the measured value of the distance of the corner reflector is subtracted from the actual distance to the corner reflector, and the obtained residual can be used as the systematic error of the laser ranging system at this time.

[0006] Existing methods need to apply a gating state to the detector within the time scale of nanoseconds or microseconds. For detectors that cannot apply gating in a short time, the detector needs to be measured in a constant current mode. At this time, a large amount of stray light in the ranging station will be detected by the detector, greatly affecting the result of the ground target measurement and making it impossible to accurately judge the signal of the ground target. For detectors that can apply gating, if there is a phenomenon of afterglow in the laser, there will also be a situation where the stray light is too strong to accurately judge the position of the signal.

[0007] Generally speaking, the biggest drawback of the existing ground target measurement is that the signal of the ground target cannot always be accurately distinguished in the ranging data. This is not conducive to the systematic error calibration of the ranging station.

[0008] The Chinese invention application with the application number 201910305917.5 discloses "A High-precision Calibration System for Pulse Laser Ranging Based on Total Station". Its technical solution is as follows: By measuring the true value of the total station with a centimeter-level absolute ranging accuracy, a measurement error table of the pulse laser rangefinder with respect to the distance distribution can be obtained. By looking up the measurement error table of the distance distribution for ranging compensation, the calibration of the system can be achieved. Compared with this technical solution, the present invention calibrates the laser ranging station system by measuring the transmission of the measurement circuit and the device response delay, the jitter magnitude of the superconducting single-photon detector, and the flight time of the internal optical path. Therefore, the technical means adopted by the present invention is different from this technical solution. Summary of the Invention

[0009] To solve the technical problem that the calibration of the existing laser ranging system has poor calibration effect due to inaccurate measurement, the present invention provides a method and system for calibrating the error of the laser ranging station system. The technical solution adopted by the present invention is as follows:

[0010] In the first aspect of the present invention, a method for calibrating the error of a laser ranging station system is provided. The laser ranging station system includes a laser and a superconducting single-photon detector. The method includes the following steps:

[0011] Measure the circuit transmission and device response delay of the laser ranging station system using a fiber optic cable with a preset length to obtain the circuit transmission and device response delay;

[0012] Measure the jitter of the response of the superconducting single-photon detector, and obtain the jitter magnitude of the superconducting single-photon detector according to the jitter of the response of the superconducting single-photon detector;

[0013] Select four positions with the same distance to the main mirror in front of the main mirror of the telescope. By sequentially placing the photodetector at the selected four positions for multiple groups of detections to obtain the corresponding laser reception times, and calculating according to the corresponding laser reception times, obtain the flight time of the internal optical path of the laser ranging station system;

[0014] Calibrate the laser ranging station system according to the circuit transmission and device response delay, the jitter magnitude of the superconducting single-photon detector, and the flight time of the internal optical path corresponding to the laser ranging station system.

[0015] As a preferred solution, the method for measuring the circuit transmission and device response delay of the laser ranging station system using a fiber optic cable with a preset length to obtain the circuit transmission and device response delay includes:

[0016] Use a fiber optic cable with a calibrated delay to connect the laser and the superconducting single-photon detector. Specifically:

[0017] Place a first photodetector and several attenuation sheets at the light output port of the laser. The first photodetector is used to obtain the corresponding laser emission time. Fix one end of the optical fiber to the first attenuation sheet and the other end to the filter. Set the filter in front of the input optical path of the superconducting single-photon detector. After the measurement platform is installed, subtract the laser emission time measured by the first photodetector from the time when the laser is detected by the superconducting single-photon detector, and the circuit transmission and equipment response delay T1 of the laser ranging station system can be obtained.

[0018] As a preferred solution, the method for measuring the jitter of the response of the superconducting single-photon detector and obtaining the jitter magnitude of the superconducting single-photon detector according to the jitter of the response of the superconducting single-photon detector includes:

[0019] Set a second photodetector and several attenuation sheets at the light output port of the laser. The second photodetector is used to obtain the corresponding laser emission time. Set the beam splitter at the light output port of the first attenuation sheet among the several attenuation sheets, and set the filter in front of the input optical path of the superconducting single-photon detector. Detect through the second photodetector and the superconducting single-photon detector to obtain the detection data of the second photodetector and the detection data of the superconducting single-photon detector. According to the detection data of the second photodetector and the detection data of the superconducting single-photon detector, obtain two columns of timestamps. Taking the timestamp of the second photodetector as the standard, the magnitude of the difference obtained by subtracting the two columns of timestamps is the jitter magnitude of the superconducting single-photon detector.

[0020] As a preferred solution, the method for obtaining the flight time of the internal optical path of the laser ranging station system by selecting four positions with the same distance to the main mirror in front of the main mirror of the telescope, and performing multiple groups of detections by sequentially placing the photodetector at the selected four positions to obtain the corresponding laser reception time and calculating according to the corresponding laser reception time includes:

[0021] Obtain the corresponding laser emission time by setting a third photodetector at the light output port of the laser. Select four positions with the same distance to the main mirror in front of the main mirror of the telescope. Perform multiple groups of detections by sequentially placing the fourth photodetector at the four symmetric positions to obtain four groups of laser reception times respectively. Subtract the four groups of laser reception times from the laser emission time obtained by the third photodetector respectively to obtain the corresponding flight time of the internal optical path. Take the average value of the values measured by the four photodetectors to obtain the flight time T2 of the internal optical path.

[0022] As a preferred solution, when the laser ranging station system is a coaxial transceiver laser ranging system, it is also necessary to measure the optical path distance d1 from the laser to the rotating mirror, and the optical path distance d2 from the rotating mirror to the corresponding photodetector. Then the theoretical flight time T3 of the internal optical path = 2*(d1 + d2) / c, where c is the speed of light;

[0023] When the laser ranging station system is a non-coaxial transceiver laser ranging system, it is also necessary to use a corner reflector, and place a seventh photodetector at the transmitting telescope, the receiving telescope, and in front of the second photodetector respectively. Then measure the optical path distance d3 from the laser to the transmitting telescope, and the optical path distance d4 from the receiving telescope to the seventh photodetector. Then the theoretical flight time T3 of the internal optical path = (d3 + d4) / c, where c is the speed of light.

[0024] As a preferred solution, a method for calibrating the laser ranging station system according to the circuit transmission and device response delay, the jitter magnitude of the superconducting single-photon detector, and the flight time of the internal optical path corresponding to the laser ranging station system includes:

[0025] Add the circuit transmission and device response delay T1 and the internal optical path flight time T2, and then subtract the internal optical path theoretical flight time T3 to obtain the calibration value T1 + T2 - T3 of the laser ranging station system. Finally, calibrate the laser ranging station system according to the calibration value of the laser ranging station system and the jitter magnitude of the superconducting single-photon detector.

[0026] The second aspect of the present invention provides a calibration system for the error of a laser ranging station system. The laser ranging station system includes a laser and a superconducting single-photon detector. The system includes a circuit transmission and device response delay measurement module, a photodetector jitter magnitude measurement module, a system internal optical path flight time measurement module, and a calibration module;

[0027] The circuit transmission and device response delay measurement module is used to measure the circuit transmission and device response delay of the laser ranging station system using a fiber optic cable with a preset length to obtain the circuit transmission and device response delay;

[0028] The photodetector jitter magnitude measurement module is used to measure the jitter of the response of the superconducting single-photon detector, and obtain the jitter magnitude of the superconducting single-photon detector according to the jitter of the response of the superconducting single-photon detector;

[0029] The system internal optical path flight time measurement module is used to select four positions with the same distance to the main mirror in front of the main mirror of the telescope, and perform multiple groups of detections by sequentially placing the photodetector at the selected four positions to obtain the corresponding laser reception moments. Calculate according to the corresponding laser reception moments to obtain the internal optical path flight time of the laser ranging station system;

[0030] The calibration module is used to calibrate the laser ranging station system according to the circuit transmission and device response delay corresponding to the laser ranging station system, the jitter magnitude of the superconducting single-photon detector, and the flight time of the internal optical path.

[0031] As a preferred solution, the circuit transmission and device response delay measurement module includes a first photodetector, a fiber optic with a calibrated delay, a filter, and several attenuation sheets;

[0032] The first photodetector and several attenuation sheets are arranged at the light output port of the laser. The first photodetector is used to obtain the corresponding laser emission moment. One end of the fiber optic is connected to the first attenuation sheet among the several attenuation sheets, and the other end is connected to the filter. The filter is arranged in front of the input optical path of the superconducting single-photon detector.

[0033] As a preferred solution, the photodetector jitter magnitude measurement module includes a second photodetector, several attenuation sheets, a beam splitter, and a filter;

[0034] The first photodetector and several attenuation sheets are arranged at the light output port of the laser. The beam splitter is arranged at the light output port of the first attenuation sheet among the several attenuation sheets. The filter is arranged in front of the input optical path of the superconducting single-photon detector. The beam splitter is used to split the laser beam and direct it to the second photodetector and the filter.

[0035] As a preferred solution, the internal optical path flight time measurement module of the system includes a third photodetector, a fourth photodetector, several attenuation sheets, a beam splitter, and a telescope primary mirror;

[0036] The third photodetector and several attenuation sheets are arranged at the light output port of the laser. The beam splitter is arranged at the light output port of the first attenuation sheet among the several attenuation sheets. The beam splitter is connected to the telescope primary mirror through an optical path, and the telescope primary mirror is connected to the fourth photodetector through an optical path.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] By separately measuring the circuit transmission and device response delay, the jitter magnitude of the superconducting single-photon detector, and the flight time of the internal optical path of the laser ranging station system, the corresponding measurement data are obtained, and the laser ranging station system is calibrated according to the measurement data, achieving high-accuracy error calibration. Moreover, the present invention has no limitation on whether the high-sensitivity photon detector supports gating within a short time, and has a wide range of applications. Compared with the traditional calibration method, the technical solution of the present invention is highly feasible and has a low implementation cost. Description of the Drawings

[0039] Figure 1 Flow chart of a calibration method for systematic error of a laser ranging station provided in this embodiment;

[0040] Figure 2 Block diagram of a circuit transmission and device response delay measurement module provided in this embodiment;

[0041] Figure 3 Block diagram of a photodetector jitter magnitude measurement module provided in this embodiment;

[0042] Figure 4 Block diagram of a system internal optical path flight time measurement module provided in this embodiment. Detailed implementation manners

[0043] The accompanying drawings are only for illustrative purposes and cannot be construed as limiting the present invention;

[0044] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the embodiments of the present application.

[0045] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0046] When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application. On the contrary, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0047] In addition, in the description of the present application, unless otherwise specified, "a plurality of" means two or more. "And / or" describes the association relationship of associated objects and indicates that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after. The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0048] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0049] Embodiment 1

[0050] Please refer to Figure 1 , this embodiment provides a calibration method for the systematic error of a laser ranging station system. The laser ranging station system includes a laser and a superconducting single-photon detector;

[0051] It should be noted that the original data of laser ranging is the moment when the laser is emitted and the moment when the laser returns to the station. The former is the start of a measurement, and the latter is the end of a measurement. The time interval between the two is the distance obtained from one observation. Usually, the moment when the laser is emitted is detected by a detector placed near the laser, and the moment when the laser returns to the station is detected by a high-sensitivity photon detector.

[0052] The method includes the following steps:

[0053] S1: Measure the circuit transmission and device response delay of the laser ranging station system using a fiber optic cable with a preset length to obtain the circuit transmission and device response delay;

[0054] In a specific embodiment, the method for measuring the circuit transmission and device response delay of the laser ranging station system using a fiber optic cable with a preset length to obtain the circuit transmission and device response delay includes:

[0055] Connect the laser to the superconducting single-photon detector using a fiber optic cable with a calibrated delay. Specifically:

[0056] Place a first photodetector and several attenuation sheets at the light output port of the laser. The first photodetector is used to obtain the corresponding laser emission moment. Fix one end of the fiber optic cable to the first attenuation sheet, fix the other end of the fiber optic cable to the filter, place the filter in front of the input optical path of the superconducting single-photon detector. After the measurement platform is installed, subtract the laser emission moment measured by the first photodetector from the moment when the laser is detected by the superconducting single-photon detector to obtain the circuit transmission and device response delay T1 of the laser ranging station system.

[0057] S2: Measure the jitter of the response of the superconducting single-photon detector, and obtain the jitter magnitude of the superconducting single-photon detector based on the jitter of the response of the superconducting single-photon detector;

[0058] In a specific embodiment, the method for measuring the jitter of the response of the superconducting single-photon detector and obtaining the jitter magnitude of the superconducting single-photon detector based on the jitter of the response of the superconducting single-photon detector includes:

[0059] Set a second photodetector and a number of attenuation sheets at the light output port of the laser. The second photodetector is used to obtain the corresponding laser emission time. Set a beam splitter at the light output port of the first attenuation sheet among the number of attenuation sheets, and set a filter before the input optical path of the superconducting single-photon detector. Detect through the second photodetector and the superconducting single-photon detector to obtain the detection data of the second photodetector and the detection data of the superconducting single-photon detector. Obtain two columns of timestamps based on the detection data of the second photodetector and the detection data of the superconducting single-photon detector. Taking the timestamp of the second photodetector as the standard, the magnitude of the difference obtained by subtracting the two columns of timestamps is the jitter magnitude of the superconducting single-photon detector.

[0060] S3: Select four positions with the same distance to the main mirror in front of the main mirror of the telescope. Perform multiple groups of detections by sequentially placing a photodetector at the selected four positions to obtain the corresponding laser reception times. Calculate based on the corresponding laser reception times to obtain the internal optical path flight time of the laser ranging station system;

[0061] In a specific embodiment, the method for selecting four positions with the same distance to the main mirror in front of the main mirror of the telescope, performing multiple groups of detections by sequentially placing a photodetector at the selected four positions to obtain the corresponding laser reception times, and calculating based on the corresponding laser reception times to obtain the internal optical path flight time of the laser ranging station system includes:

[0062] Obtain the corresponding laser emission time by setting a third photodetector at the light output port of the laser. Select four positions with the same distance to the main mirror in front of the main mirror of the telescope. Perform multiple groups of detections by sequentially placing a fourth photodetector at four symmetric positions to obtain four groups of laser reception times respectively. Subtract the four groups of laser reception times from the laser emission time obtained by the third photodetector respectively to obtain the corresponding internal optical path flight times. Take the average value of the values measured by the four photodetectors to obtain the internal optical path flight time T2;

[0063] It should be noted that among the four positions with the same distance to the main mirror, the connection lines of two adjacent positions can form a square, and the center of the formed square is close to the center of the main mirror.

[0064] It should be noted that when the laser ranging station system is a coaxial transceiver laser ranging system, it is also necessary to measure the optical path distance d1 from the laser to the rotating mirror and the optical path distance d2 from the rotating mirror to the corresponding photodetector. Then, the theoretical flight time T3 of the internal optical path is 2*(d1 + d2) / c, where c is the speed of light;

[0065] When the laser ranging station system is a non-coaxial transceiver laser ranging system, it is also necessary to use a corner reflector and place a seventh photodetector at the transmitting telescope, the receiving telescope, and in front of the second photodetector respectively. Then, measure the optical path distance d3 from the laser to the transmitting telescope and the optical path distance d4 from the receiving telescope to the seventh photodetector. Then, the theoretical flight time T3 of the internal optical path is (d3 + d4) / c, where c is the speed of light.

[0066] S4: Calibrate the laser ranging station system according to the circuit transmission and device response delay corresponding to the laser ranging station system, the jitter magnitude of the superconducting single-photon detector, and the flight time of the internal optical path;

[0067] In a specific embodiment, the method for calibrating the laser ranging station system according to the circuit transmission and device response delay corresponding to the laser ranging station system, the jitter magnitude of the superconducting single-photon detector, and the flight time of the internal optical path includes:

[0068] Add the circuit transmission and device response delay T1 and the flight time T2 of the internal optical path, and then subtract the theoretical flight time T3 of the internal optical path to obtain the calibration value T1 + T2 - T3 of the laser ranging station system. Finally, calibrate the laser ranging station system according to the calibration value of the laser ranging station system and the jitter magnitude of the superconducting single-photon detector;

[0069] It should be noted that the preset theoretical flight time T3 of the internal optical path is the internal optical path distance divided by the speed of light.

[0070] Embodiment 2

[0071] The present invention provides a calibration system for the error of a laser ranging station system. The laser ranging station system includes a laser and a superconducting single-photon detector. The system includes a circuit transmission and device response delay measurement module, a photodetector jitter magnitude measurement module, a system internal optical path flight time measurement module, and a calibration module;

[0072] The circuit transmission and device response delay measurement module is used to measure the circuit transmission and device response delay of the laser ranging station system using a fiber optic cable of a preset length to obtain the circuit transmission and device response delay;

[0073] The jitter magnitude measurement module of the photodetector is used to measure the jitter of the response of the superconducting single-photon detector, and obtain the jitter magnitude of the superconducting single-photon detector according to the jitter of the response of the superconducting single-photon detector;

[0074] The internal optical path flight time measurement module of the system is used to select four positions with the same distance to the primary mirror in front of the primary mirror of the telescope. By placing the photodetector at the selected four positions in sequence for multiple groups of detections, the corresponding laser reception moments are obtained, and the internal optical path flight time of the laser ranging station system is calculated according to the corresponding laser reception moments;

[0075] The calibration module is used to calibrate the laser ranging station system according to the circuit transmission and device response delay corresponding to the laser ranging station system, the jitter magnitude of the superconducting single-photon detector, and the internal optical path flight time.

[0076] Please refer to Figure 2 , in a specific embodiment, the circuit transmission and device response delay measurement module includes a first photodetector, a fiber optic cable with a calibrated delay, a filter, and several attenuation sheets;

[0077] The first photodetector and several attenuation sheets are arranged at the light output port of the laser. The first photodetector is used to obtain the corresponding laser emission moment; one end of the fiber optic cable is connected to the first attenuation sheet among the several attenuation sheets, and the other end is connected to the filter. The filter is arranged in front of the input optical path of the superconducting single-photon detector.

[0078] Please refer to Figure 3 , in a specific embodiment, the jitter magnitude measurement module of the photodetector includes a second photodetector, several attenuation sheets, a beam splitter, and a filter;

[0079] The first photodetector and several attenuation sheets are arranged at the light output port of the laser. The beam splitter is arranged at the light output port of the first attenuation sheet among the several attenuation sheets. The filter is arranged in front of the input optical path of the superconducting single-photon detector. The beam splitter is used to split the laser beam and shoot it towards the second photodetector and the filter.

[0080] Please refer to Figure 4 , in a specific embodiment, the internal optical path flight time measurement module of the system includes a third photodetector, a fourth photodetector, several attenuation sheets, a beam splitter, and the primary mirror of the telescope;

[0081] The third photodetector and several attenuation sheets are arranged at the light output port of the laser. The beam splitter is arranged at the light output port of the first attenuation sheet among the several attenuation sheets. The beam splitter is connected to the primary mirror of the telescope through an optical path. The primary mirror of the telescope is connected to the fourth photodetector through an optical path.

[0082] In a specific embodiment, the orientation of the fourth photodetector is consistent with the laser pulse emission direction of the laser.

[0083] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A method for calibrating the error of a laser ranging station system, wherein the laser ranging station system comprises a laser and a superconducting single photon detector, characterized in that: The method comprises the following steps: The circuit transmission and device response delay of the laser ranging station system are measured using an optical fiber of a preset length to obtain the circuit transmission and device response delay; Measuring the jitter of the superconducting single-photon detector response, and obtaining the jitter magnitude of the superconducting single-photon detector according to the jitter of the superconducting single-photon detector response; Select four positions with the same distance from the primary mirror in front of the telescope, place photodetectors at the four selected positions in sequence for multiple detections, obtain corresponding laser receiving moments, and calculate based on the corresponding laser receiving moments to obtain the internal optical path flight time of the laser ranging station system; The laser ranging station system is calibrated according to the circuit transmission and equipment response delay corresponding to the laser ranging station system, the jitter magnitude of the superconducting single-photon detector, and the internal optical path flight time.

2. The method for calibrating the system error of a laser ranging station according to claim 1, characterized in that: The method for measuring the circuit transmission and device response delay of a laser ranging station system using an optical fiber of a preset length, and obtaining the circuit transmission and device response delay includes: The laser is connected to the superconducting single-photon detector using an optical fiber with a calibrated delay, specifically: A first photodetector and several attenuation plates are placed at the light outlet of the laser. The first photodetector is used to obtain the corresponding laser emission moment. One end of the optical fiber is fixed to the first attenuation plate, and the other end of the optical fiber is fixed to the filter. The filter is set in front of the input optical path of the superconducting single-photon detector. After the measurement platform is installed, the laser emission moment measured by the first photodetector is subtracted from the moment when the laser is detected by the superconducting single-photon detector, so as to obtain the circuit transmission and equipment response delay T1 of the laser ranging station system.

3. The method for calibrating the system error of a laser ranging station according to claim 1, characterized in that: The method of measuring the jitter of a superconducting single-photon detector response and obtaining the jitter magnitude of the superconducting single-photon detector according to the jitter of the superconducting single-photon detector response comprises: A second photodetector and several attenuation plates are arranged at the light outlet of the laser, the second photodetector is used to obtain the corresponding laser emission moment, a spectroscope is arranged at the light outlet of the first attenuation plate among the several attenuation plates, and a filter is arranged in front of the input optical path of the superconducting single-photon detector, and detection is performed by the second photodetector and the superconducting single-photon detector to obtain detection data of the second photodetector and the detection data of the superconducting single-photon detector. Two columns of timestamps are obtained according to the detection data of the second photodetector and the detection data of the superconducting single-photon detector. The timestamp of the second photodetector is taken as the standard, and the magnitude of the difference obtained by subtracting the two columns of timestamps is the jitter magnitude of the superconducting single-photon detector.

4. The method for calibrating the system error of a laser ranging station according to claim 1, characterized in that: A method for obtaining the internal optical path flight time of a laser ranging station system by selecting four positions with the same distance from the primary mirror in front of the primary mirror of the telescope, placing photoelectric detectors at the four selected positions in sequence for multiple detections, obtaining corresponding laser receiving moments, and calculating according to the corresponding laser receiving moments includes: A third photodetector is set at the laser light outlet to obtain the corresponding laser emission time, four positions with the same distance from the main mirror of the telescope are selected, and a fourth photodetector is placed in four symmetrical positions in sequence for multiple detections to obtain four groups of laser receiving times. The four groups of laser receiving times are subtracted from the laser emission time obtained by the third photodetector to obtain the corresponding internal light path flight time, and the values ​​measured by the four photodetectors are averaged to obtain the internal light path flight time T2.

5. The method for calibrating the system error of a laser ranging station according to claim 4, characterized in that: When the laser ranging station system is a coaxial laser ranging system, it is also necessary to measure the optical path distance d1 from the laser to the rotating mirror and the optical path distance d2 from the rotating mirror to the corresponding photodetector. Then the internal optical path theoretical flight time T3 = 2*(d1+d2) / c, where c is the speed of light; When the laser ranging station system is a non-coaxial transceiver laser ranging system, it is also necessary to use a corner cone reflector, and place a seventh photodetector at the transmitting telescope, the receiving telescope, and in front of the second photodetector, respectively. Then, the optical path distance d3 from the laser to the transmitting telescope and the optical path distance d4 from the receiving telescope to the seventh photodetector are measured. The theoretical flight time of the internal optical path is T3 = (d3 + d4) / c, where c is the speed of light.

6. A laser ranging station system error calibration system according to claim 5, characterized in that: The method for calibrating the laser ranging station system according to the circuit transmission and device response delay corresponding to the laser ranging station system, the jitter magnitude of the superconducting single photon detector and the internal optical path flight time includes: The circuit transmission and device response delay T1 and the internal optical path flight time T2 are added together and then the internal optical path theoretical flight time T3 is subtracted to obtain the laser ranging station system calibration value T1+T2-T3. Finally, the laser ranging station system is calibrated according to the laser ranging station system calibration value and the jitter level of the superconducting single-photon detector.

7. A laser ranging station system error calibration system, the laser ranging station system comprising a laser and a superconducting single photon detector, characterized in that: The system includes a circuit transmission and device response delay measurement module, a photodetector jitter magnitude measurement module, a system internal optical path flight time measurement module and a calibration module; The circuit transmission and device response delay measurement module is used to measure the circuit transmission and device response delay of the laser ranging station system using an optical fiber of a preset length to obtain the circuit transmission and device response delay; The photodetector jitter magnitude measurement module is used to measure the jitter of the superconducting single-photon detector response, and obtain the jitter magnitude of the superconducting single-photon detector according to the jitter of the superconducting single-photon detector response; The system internal optical path flight time measurement module is used to select four positions with the same distance to the primary mirror in front of the telescope, and to place photoelectric detectors in the four selected positions in turn to perform multiple groups of detection to obtain corresponding laser receiving moments, and to calculate according to the corresponding laser receiving moments to obtain the internal optical path flight time of the laser ranging station system; The calibration module is used to calibrate the laser ranging station system according to the circuit transmission and device response delay corresponding to the laser ranging station system, the jitter magnitude of the superconducting single-photon detector, and the internal optical path flight time.

8. The laser ranging station system error calibration system according to claim 7, characterized in that: The circuit transmission and device response delay measurement module includes a first photodetector, an optical fiber with a calibrated delay, an optical filter, and a plurality of attenuation sheets; The first photodetector and a plurality of attenuation plates are arranged at the light outlet of the laser, and the first photodetector is used to obtain the corresponding laser emission moment; one end of the optical fiber is connected to the first attenuation plate among the plurality of attenuation plates, and the other end is connected to a filter, which is arranged in front of the input optical path of the superconducting single-photon detector.

9. A laser ranging station system error calibration system according to claim 8, characterized in that: The photodetector jitter magnitude measurement module includes a second photodetector, a plurality of attenuation sheets, a spectroscope, and a filter; The first photodetector and several attenuation plates are arranged at the light outlet of the laser, the beam splitter is arranged at the light outlet of the first attenuation plate among the several attenuation plates, and the filter is arranged in front of the input light path of the superconducting single-photon detector; the beam splitter is used to split the laser beam and direct it to the second photodetector and the filter.

10. A laser ranging station system error calibration system according to claim 7, characterized in that: The internal optical path flight time measurement module of the system includes a third photodetector, a fourth photodetector, a plurality of attenuation plates, a beam splitter and a primary mirror of the telescope; The third photodetector and several attenuation plates are arranged at the light outlet of the laser, the beam splitter is arranged at the light outlet of the first attenuation plate among the several attenuation plates, the beam splitter is connected to the telescope primary mirror through an optical path, and the telescope primary mirror is connected to the fourth photodetector through an optical path.

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