Method and device for testing open-loop pointing of fixed star and electronic equipment

Abstract

The invention discloses a method and a device for testing open-loop pointing of a fixed star and electronic equipment. The method comprises the following steps: calibrating coordinate systems of all equipment and a conversion relation between the coordinate systems of all the equipment; obtaining first orbit attitude data of a first satellite corresponding to the laser terminal and second orbit attitude data of the second satellite, and determining laser link information of the first satellite and the second satellite according to the first orbit attitude data and the second orbit attitude data; and projecting a star map corresponding to the target star based on the conversion relationship between the laser link information and each equipment coordinate system by using a star simulator, so that the laser terminal simulates a star open-loop pointing test based on the star map. Therefore, an equivalent, transformation and unified relationship can be established between each space coordinate system involved in an on-orbit link star open-loop pointing environment of the laser terminal and each equipment coordinate system in a ground test simulation environment, deviation correction is carried out on a star map based on the relationship, and the space precision of an indoor star open-loop pointing test can be improved. And a more accurate and reliable test result can be obtained.

Description

Technical Field

[0001] The present application relates to the field of satellite communication technology, and in particular to a test method, device and electronic equipment for star open-loop pointing. Background Art

[0002] With the growing demand for high-speed data transmission, laser communication, which has advantages such as high bandwidth, strong anti-interference and low power consumption, has gradually begun to be used in the field of satellite communications.

[0003] The narrow beam characteristics of laser communications place higher demands on the open-loop stellar pointing technology of precision optical terminals. Open-loop stellar pointing calibration utilizes a star sensor coaxial with the terminal to capture stars in real time, providing a high-precision attitude reference and real-time correction of the pointing target accuracy. This eliminates the increased pointing errors of the laser terminal caused by factors such as on-orbit gravity release, thermal deformation, and long-term orbit recursion errors, providing reliable guarantees for the long-term stability and rapid re-linking of intersatellite laser links. However, the current ground-based open-loop stellar pointing calibration scenarios differ significantly from those of on-orbit open-loop stellar pointing, resulting in low verification environment equivalence. Outdoor testing scenarios are also significantly restricted by weather conditions, making high-precision and high-reliability ground-based verification difficult to achieve.

[0004] Currently, no effective solution has been proposed to the above-mentioned problem of being unable to achieve high-precision and high-reliability ground-based open-loop pointing calibration of stars. Summary of the Invention

[0005] The purpose of the embodiments of the present application is to provide a test method, device and electronic equipment for open-loop stellar pointing, which can achieve spatial equivalence between space orbits and stellar environments and ground simulation environments, and obtain more accurate and reliable test results.

[0006] In a first aspect, the present specification provides a method for testing open-loop star pointing, which is applied to a star open-loop pointing test system, wherein the star open-loop pointing test system includes at least a turntable, a laser terminal mounted on the turntable, and a star simulator. The method includes:

[0007] Calibrate the coordinate systems of each device and the conversion relationship between the coordinate systems of each device, wherein the device coordinate system includes at least the reference coordinate system of the turntable, the zero point coordinate system of the turntable, the coordinate system of the laser terminal, the coordinate system of the star simulator, and the star map coordinate system;

[0008] Obtaining and determining laser link information between the first satellite and the second satellite based on first orbital attitude data of a first satellite and second orbital attitude data of a second satellite corresponding to the laser terminal;

[0009] A star simulator is used to project a star map corresponding to the target star based on the conversion relationship between the laser link information and the coordinate systems of each device, so that the laser terminal simulates the star open-loop pointing test based on the star map.

[0010] In some embodiments of the present specification, the star map projected by the star simulator is the star background of the sky in the direction of the laser link of the first satellite and the second satellite.

[0011] In some embodiments of this specification, calibrating each device coordinate system and the conversion relationship between the device coordinate systems includes:

[0012] Calibrate the position and direction of each device coordinate system, as well as the coordinate system deviation between each device coordinate system;

[0013] The deviation correction amount between the device coordinate systems is determined based on the coordinate system deviation amount between the device coordinate systems as the conversion relationship between the device coordinate systems.

[0014] In some embodiments of this specification, calibrating the position and direction of each device coordinate system and the coordinate system deviation between each device coordinate system includes:

[0015] Installing a zero-point measurement tool at the zero-point position of the turntable, representing the reference coordinate system of the turntable by a first cubic mirror installed at the reference position of the turntable, and representing the zero-point coordinate system of the turntable by a second cubic mirror;

[0016] Performing optical measurement on the first cubic mirror and the second cubic mirror using a theodolite to determine a first coordinate system deviation between the first cubic mirror and the second cubic mirror;

[0017] The laser terminal is installed at the zero point position of the turntable, the zero point coordinate system of the turntable is represented by a third cubic mirror installed on the laser terminal, and the coordinate system of the star simulator is represented by a fourth cubic mirror installed on the star simulator;

[0018] Define the star map coordinate system projected by the star simulator, use a theodolite to perform optical measurements on the first cubic mirror and the third cubic mirror, the first cubic mirror and the fourth cubic mirror, and the fourth cubic mirror and the star map coordinate system, and determine the second coordinate system deviation between the first cubic mirror and the third cubic mirror, the third coordinate system deviation between the first cubic mirror and the fourth cubic mirror, and the fourth coordinate system deviation between the fourth cubic mirror and the star map coordinate system.

[0019] In some embodiments of this specification, determining the deviation correction amount between the device coordinate systems based on the coordinate system deviation amount between the device coordinate systems includes:

[0020] Based on the deviation of each coordinate system, the direction cosine corresponding to the deviation of each coordinate system is determined as the deviation correction amount between the corresponding device coordinate systems;

[0021] Determining a third deviation correction amount between the zero-point coordinate system and the laser terminal coordinate system based on a first deviation correction amount between the reference coordinate system and the zero-point coordinate system and a second deviation correction amount between the reference coordinate system and the coordinate system of the laser terminal;

[0022] Based on the fourth deviation correction between the reference coordinate system and the coordinate system of the star simulator, the fifth deviation correction between the coordinate system of the star simulator and the star map coordinate system, and the second deviation correction, the sixth deviation correction between the star map coordinate system and the laser terminal coordinate system is determined.

[0023] In some embodiments of the present specification, the first orbital attitude data and / or the second orbital attitude data include at least: orbital position data in an inertial coordinate system, satellite velocity data, Euler angles, and quaternions.

[0024] In some embodiments of this specification, determining laser link information between the first satellite and the second satellite according to first orbital attitude data of a first satellite and second orbital attitude data of a second satellite corresponding to the laser terminal includes:

[0025] Determining first position data of the first satellite in an inertial coordinate system and second position data of the second satellite in an inertial coordinate system based on the first orbital attitude data and the second orbital attitude data;

[0026] Based on the second position data and the second position data, a pointing vector of the first satellite to the second satellite in the inertial coordinate system is determined as the laser link information.

[0027] In some embodiments of this specification, projecting a star map corresponding to a target star based on the conversion relationship between the laser link information and the coordinate systems of each device using a star simulator includes:

[0028] Determining a star map projection control amount used by the star simulator to project the star map based on a conversion relationship between the laser link information and the coordinate systems of each device;

[0029] The star simulator is used to project the star map onto a sky region in the direction of the laser link of the first satellite and the second satellite based on the star map projection control amount.

[0030] In some embodiments of this specification, determining a star map projection control amount used by the star simulator to project the star map based on a conversion relationship between the laser link information and each device coordinate system includes:

[0031] Based on the conversion relationship between the coordinate systems of each device, convert the pointing vector from the first satellite to the second satellite in the laser link information in the inertial coordinate system to the star map coordinate system to obtain a target direction vector;

[0032] A rotation quaternion obtained by rotating the central optical axis of the star map coordinate system to the target direction vector is determined, and the rotation quaternion is used as the star map projection control quantity.

[0033] In some embodiments of this specification, the star map projection control amount is determined by the following formula:

[0034] ;

[0035] Wherein, q represents the rotation quaternion of the star map coordinate system, which represents the star map projection control quantity; represents a pointing vector from the first satellite to the second satellite in the laser link information in the star map coordinate system; represents the direction vector corresponding to the pointing vector from the first satellite to the second satellite in the laser link information in the star map coordinate system, V1 represents the unit vector of the central optical axis of the star map coordinate system, represents the pointing vector from the first satellite to the second satellite in the laser link information in the inertial coordinate system, C M4 represents the conversion relationship from the star map coordinate system to the star simulator, C 14 represents the conversion relationship from the reference coordinate system to the star simulator, C 12 Indicates the conversion relationship from the reference coordinate system to the zero-point coordinate system.

[0036] In some embodiments of this specification, after determining the rotation quaternion from the central optical axis of the star map coordinate system to the target direction vector, the method further includes:

[0037] The rotation quaternion is normalized, and the normalized rotation quaternion is used as the star map projection control quantity.

[0038] In some embodiments of this specification, the star open-loop pointing test system further includes a timing device and a data processing terminal, and the method further includes:

[0039] Use the time synchronization equipment to perform corresponding time alignment processing on the laser terminal, turntable, and star simulator;

[0040] At a first advance time point, the data processing end is used to send the orbit and attitude data with timestamps to the turntable and the laser terminal, so that the turntable and the laser terminal simulate the orbit and attitude of the first satellite and the second satellite in-orbit link establishment based on the orbit and attitude data, and simulate the star open-loop pointing test based on the star map projected by the star simulator at the target time point during the movement; wherein the orbit and attitude data include the first orbit attitude data and the second orbit attitude data at the target time point.

[0041] A second aspect of this specification provides a stellar open-loop pointing test device, which is applied to a stellar open-loop pointing test system, wherein the stellar open-loop pointing test system comprises at least: a turntable, a laser terminal mounted on the turntable, and a stellar simulator, and the device comprises:

[0042] A calibration module is used to calibrate the coordinate systems of various devices and the conversion relationship between the coordinate systems of various devices, wherein the device coordinate systems include at least the reference coordinate system of the turntable, the zero point coordinate system of the turntable, the coordinate system of the laser terminal, the coordinate system of the star simulator, and the star map coordinate system;

[0043] a processing module, configured to obtain and determine laser link information between the first satellite and the second satellite based on first orbital attitude data of the first satellite and second orbital attitude data of the second satellite corresponding to the laser terminal;

[0044] The test module is used to use a star simulator to project a star map corresponding to the target star based on the conversion relationship between the laser link information and the coordinate systems of each device, so that the laser terminal simulates the star open-loop pointing test based on the star map.

[0045] A third aspect of this specification provides an electronic device, comprising a processor and a memory for storing processor-executable instructions, wherein the processor implements the steps of the method described in the first aspect when executing the instructions.

[0046] A fourth aspect of this specification provides a computer storage medium, wherein the computer storage medium stores computer program instructions, and when the computer program instructions are executed by a processor, the steps of the method described in the first aspect are implemented.

[0047] A fifth aspect of this specification provides a computer program product, comprising a computer program, which, when executed by a processor, implements the steps of the method described in the first aspect.

[0048] The test method, device and electronic device for open-loop star pointing in the embodiments of this specification calibrate the coordinate systems of each device and the conversion relationship between the coordinate systems of each device; obtain and determine the laser link information of the first satellite and the second satellite based on the first orbital attitude data of the first satellite corresponding to the laser terminal and the second orbital attitude data of the second satellite; use a star simulator to project the star map corresponding to the target star based on the laser link information and the conversion relationship between the coordinate systems of each device, so that the laser terminal simulates the open-loop star pointing test based on the star map. By calibrating the coordinate systems of each device and the conversion relationship between the coordinate systems of each device, it is possible to establish an equivalent, transformed and unified relationship between the various spatial coordinate systems involved in the open-loop star pointing environment of the laser terminal on-orbit link and the coordinate systems of each device in the ground test simulation environment. Based on this, when projecting the star map, the star map can be combined with the conversion relationship between the device coordinate systems and the laser link information between the simulated satellites to perform deviation correction on the star map, thereby ensuring the spatial accuracy of the indoor open-loop star pointing test and obtaining more accurate and reliable test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the implementation methods or the description of the prior art. Obviously, the drawings described below are only some implementation methods recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0050] Figure 1 FIG2 is a schematic diagram of a star open-loop pointing test method provided in an embodiment of this specification;

[0051] Figure 2 FIG2 is a schematic diagram of a star open-loop pointing test system provided in an embodiment of this specification;

[0052] Figure 3 FIG2 is a schematic diagram of a method for determining a coordinate system deviation amount provided in an embodiment of this specification;

[0053] Figure 4 FIG2 is a schematic diagram of a method for determining a deviation correction amount provided in an embodiment of this specification;

[0054] Figure 5 The figure shows a schematic diagram of the coordinate system of each device provided in the embodiment of this specification;

[0055] Figure 6 The figure shows a schematic diagram of the coordinate system of each device and the satellite orbit coordinate system provided in the embodiment of this specification;

[0056] Figure 7Shown is a schematic diagram of the internal coordinate system relationship of the star simulator provided in the embodiment of this specification;

[0057] Figure 8 FIG2 is a schematic diagram of a star open-loop pointing test device provided in an embodiment of this specification;

[0058] Figure 9 Shown is a schematic diagram of an electronic device provided in an embodiment of this specification. DETAILED DESCRIPTION

[0059] In order to enable those skilled in the art to better understand the technical solutions in this application, the following will clearly and completely describe the technical solutions in the embodiments of this application in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0060] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments of the invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or device comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or devices.

[0061] This specification provides method operation steps as described in the embodiments or flowcharts, but more or fewer operation steps may be included based on routine or non-creative work. The order of steps listed in the embodiments is only one way of executing the steps among many orderings and does not represent the only execution order. When a system or device product is actually executed, the method can be executed in the order shown in the embodiments or the drawings or in parallel.

[0062] It should be noted that the information involved in this application (including but not limited to user terminal device information, user personal information, etc.) is information and data authorized by the user or fully authorized by all parties, and the acquisition, transmission, storage, use and processing of relevant data comply with the relevant laws, regulations and standards of relevant countries and regions.

[0063] It should be noted that in the embodiments of this specification, certain software, components, models and other existing solutions in the industry may be mentioned. They should be regarded as exemplary and their purpose is only to illustrate the feasibility of implementing the technical solution of the present invention, but it does not mean that the applicant has or will necessarily use the solution.

[0064] Open-loop stellar pointing involves using the laser terminal's onboard star sensor to capture real-time images of stars in the link's sky while the link is maintained. The star sensor's attitude quaternion is then calculated in real time to resolve the laser terminal's pointing error. The core of this attitude calculation involves capturing images of stars in the link's sky using the star sensor, matching the captured star's direction vector in the star sensor with the theoretical direction vector of the star in the inertial coordinate system, and calculating the rotation matrix from the satellite's coordinate system to the inertial coordinate system to obtain the attitude quaternion. The star sensor on the laser terminal follows the link's pointing direction, and the calculated attitude quaternion incorporates the laser terminal's pointing information. By combining the laser terminal's CPA theory with the actual pointing position, the star sensor's attitude quaternion, and the installation matrix, the laser terminal's pointing error can be calculated. When conducting open-loop stellar pointing verification on the ground, a verification environment in which the effective equivalent satellite orbit, attitude motion, and a star map of the link's sky that follows the dynamic changes of the orbit are crucial.

[0065] In some implementation scenarios, the status of the satellite and the ground control center during the on-orbit calibration of the laser communication payload are simulated on the ground. A target star is selected, and the position of the selected star is framed and broadcast to the laser payload through the simulation center. The laser payload is then pointed at the target star on the ground for star calibration. However, this method uses an Earth-fixed coordinate system, which is significantly different from the orbit of the laser terminal on orbit and the dynamically changing star background of the sky region pointed by the link. It cannot be equivalent to the orbit, attitude, and dynamic star map background of the sky region pointed to. In addition, since the verification is carried out outdoors, it is subject to uncontrollable weather conditions, making it difficult to guarantee the accuracy and reliability of the verification.

[0066] Taking into account the problems existing in the above-mentioned implementation scenarios, the embodiments of the present application establish an equivalent, transformed and unified relationship between the various spatial coordinate systems involved in the laser terminal on-orbit link star open-loop pointing environment and the various coordinate systems in the ground test simulation environment, so as to provide a spatial benchmark for the indoor equivalent simulation of the laser on-orbit star open-loop pointing environment and realize the laser terminal star open-loop pointing process and accuracy verification.

[0067] Based on this, an embodiment of this specification provides a star open-loop pointing test method, which can be applied to a star open-loop pointing test system, wherein the star open-loop pointing test system includes at least: a laser terminal, a turntable (such as a two-dimensional turntable, etc.), and a star simulator. Figure 1 The figure shows a schematic diagram of the star open loop pointing test method provided in the embodiment of this specification. Figure 1As shown, the star open-loop pointing test method may include:

[0068] S101: Calibrate each device coordinate system and the conversion relationship between each device coordinate system, wherein the device coordinate system at least includes the turntable's reference coordinate system, the turntable's zero point coordinate system, the laser terminal's coordinate system, the star simulator's coordinate system, and the star map coordinate system.

[0069] Correspondingly, the conversion relationship between the coordinate systems of each device may include: the conversion relationship between the reference coordinate system and the zero-point coordinate system, the conversion relationship between the reference coordinate system and the coordinate system of the laser terminal, the conversion relationship between the reference coordinate system and the coordinate system of the star simulator, the conversion relationship between the coordinate system of the star simulator and the star map coordinate system, the conversion relationship between the zero-point coordinate system and the coordinate system of the laser terminal, the conversion relationship between the coordinate system of the laser terminal and the coordinate system of the star simulator, etc.

[0070] S102: Obtain and determine laser link information between the first satellite and the second satellite based on first orbital attitude data of a first satellite and second orbital attitude data of a second satellite corresponding to the laser terminal.

[0071] It can be understood that the star open-loop pointing test may include the pointing process of the laser terminal corresponding to the local satellite pointing to the laser terminal of the target satellite, pointing deviation correction, and the corrected star open-loop pointing accuracy. Among them, the laser terminal corresponding to the local satellite can be used as the laser terminal to be tested and can be simulated by the laser terminal in the above step S102. The local satellite is the first satellite in the embodiment of this specification, the corresponding target satellite is the second satellite, and the laser terminal in step S102 is the laser terminal corresponding to the first satellite. Of course, in other embodiments, the first satellite can also be the target satellite, the second satellite can be the local satellite, and the laser terminal corresponding to the corresponding second satellite is the laser terminal in the above step S102.

[0072] It can be understood that the first orbital data and the second orbital data can be orbital data with timestamps, and the first orbital data and the second orbital data can correspond to the same timestamp, and the laser communication link between the first satellite under the first orbital data and the second satellite under the second orbital data can be captured and maintained through a laser terminal.

[0073] S103: Using a star simulator to project a star map corresponding to the target star based on the conversion relationship between the laser link information and the coordinate systems of each device, so that the laser terminal simulates a star open-loop pointing test based on the star map.

[0074] In the embodiments of this specification, by calibrating the coordinate systems of each device and the conversion relationship between each device coordinate system, it is possible to establish an equivalent, transformed and unified relationship between each spatial coordinate system involved in the open-loop star pointing environment of the laser terminal on-orbit link and each device coordinate system in the ground test simulation environment. Based on this, when projecting the star map, the star map can be corrected for deviations in combination with the conversion relationship between the device coordinate systems and the laser link information between the simulated satellites, thereby ensuring the spatial accuracy of the indoor open-loop star pointing test and obtaining more accurate and reliable test results.

[0075] The star open-loop pointing test system in the embodiment of this specification can be a system deployed indoors on the ground for simulating the star open-loop pointing verification environment of a satellite on orbit and performing star open-loop pointing tests. Figure 2 As shown, a laser terminal pointing difference star calibration test system provided in an embodiment of this specification may include at least: a turntable (such as a two-dimensional turntable), a star simulator, a laser terminal, etc.

[0076] Corresponding protocol rules, such as UDP (User Datagram Protocol), can be deployed between the turntable, the star simulator, and the laser terminal. The star simulator can be deployed correspondingly to the laser terminal.

[0077] The turntable can be used to simulate the orbital and attitude motion of the host satellite during open-loop stellar pointing testing. A laser terminal, mounted on the turntable, can simulate the motion of the laser payload on the target satellite during stellar calibration. A stellar simulator can be used to simulate the target star during stellar calibration. The laser terminal can be equipped with a laser generator, a laser receiver, and a star sensor. The stellar simulator can be equipped with a star map projection unit for projecting a star map. In implementation, the turntable control variables can be determined based on the acquired orbital and attitude data to drive the turntable's motion, providing a dynamic orbital simulation environment. The laser terminal can acquire and calculate the pointing vector based on the orbital and attitude data. Furthermore, since the driven turntable's motion cannot accurately simulate the host satellite's orbital and attitude data, the laser terminal can be used to compensate for the satellite's orbital motion in real time and point to the target star under a unified time base, providing a foundation for subsequent open-loop stellar pointing testing.

[0078] In some embodiments of the present specification, the star open-loop pointing test system also includes a timing device and a data processing end, and the method also includes: using the timing device to perform corresponding time alignment processing on the laser terminal, turntable, and star simulator respectively; using the data processing end to send the orbit and attitude data with timestamps to the turntable and the laser terminal at a first advance time point, so that the turntable and the laser terminal simulate the orbit and attitude of the first satellite and the second satellite in-orbit link based on the orbit and attitude data, and simulate the star open-loop pointing test based on the star map projected by the star simulator at the target time point during the movement; wherein the orbit and attitude data include the first orbit attitude data and the second orbit attitude data at the target time point.

[0079] Specifically, the stellar open-loop pointing test system may also include a timing device, a laser engineering data workstation, a terminal ground inspection, and a turntable controller (such as a two-dimensional state controller).

[0080] The time synchronization equipment can be connected to the laser engineering data workstation, terminal ground inspection, turntable, turntable controller, and laser terminal via wired or wireless means. The laser engineering data workstation can be connected to the terminal ground inspection and turntable controller. Corresponding protocol rules can also be deployed on the laser engineering data workstation, laser terminal, terminal ground inspection, turntable, and turntable controller. The turntable controller can be connected to the turntable. The terminal ground inspection can be connected to the laser terminal.

[0081] The laser engineering data workstation can be used to acquire or generate orbit and attitude data for the first and second satellites. This data is then transmitted to the turntable controller and to the terminal ground station according to the orbit and attitude data broadcast protocol. Furthermore, the orbit and attitude data sent to the turntable controller can be integrated with disturbance data, including but not limited to orbit and attitude disturbances, orbit extrapolation errors, and intersatellite laser pointing errors. This disturbance data can be simulated by the turntable. The turntable controller can drive the turntable based on the orbit and attitude data of the first satellite to provide a dynamic orbit simulation environment. The terminal ground station can broadcast the orbit and attitude data of the first and second satellites to the laser terminal, enabling the laser terminal to compensate for its current orbit and attitude. The terminal ground station can also calculate the pointing vector based on the orbit and attitude data of the two satellites for open-loop stellar pointing correction. A timing device can provide a unified clock source for the laser engineering data workstation, turntable controller, terminal ground station, and laser terminal.

[0082] In some embodiments of this specification, a user can select orbit and attitude data for a test period, such as the orbit and attitude data for a continuous orbital cycle, convert the orbit and attitude data for that test period into a file format recognizable by the laser engineering data workstation, such as a CSV / TXT file, and write the file to the laser engineering data workstation. The laser engineering data workstation can then retrieve the orbit and attitude data from the file. The orbit and attitude data can be simulated orbit and attitude data or in-orbit data from the first and second satellites. The orbit and attitude data may include, but is not limited to, the system's real-time time broadcast; the J2000 position, velocity, and timestamp of the local and other satellites; the local satellite's attitude quaternion; and roll, pitch, and yaw attitude angles, angular velocities, and timestamps (including four sets of attitude data: T0, T0+250 milliseconds (ms), T0+500ms, and T0+750ms); and the sun vector. The orbit and attitude data are timestamped (i.e., given timestamps), with T0 being the starting timestamp (i.e., initial time point) of the orbit and attitude data.

[0083] It is understood that the orbit and attitude data carries a given timestamp. The format of the orbit and attitude data with a given timestamp specified in the broadcast protocol for orbit and attitude data may include a transmission protocol and a file format. The transmission protocol may be the User Datagram Protocol (UDP) or other transmission protocols, and the file format may be CSV / TXT or other file formats. The broadcast protocol for orbit and attitude data may also specify a first advance time point. This first advance time point can be determined based on the transmission delay between the laser engineering data workstation and the terminal ground inspection, and the transmission delay between the laser engineering data workstation and the turntable controller. For example, the first advance time point may be 1 second (s), 2 seconds, etc. The broadcast protocol for orbit and attitude data may also specify a preset broadcast frequency. This preset broadcast frequency is determined based on the given timestamp interval of the orbit and attitude data. For example, if the given timestamp interval is 1 second, the preset broadcast frequency may be 1 / 1s = 1Hz; if the given timestamp interval is 0.1s, the preset broadcast frequency may be 1 / 0.1s = 10Hz.

[0084] In some embodiments of the present specification, a timing device is used to perform corresponding time alignment processing on devices such as a data processing terminal, a laser terminal, a ground inspection terminal, a turntable, a turntable controller, and a star simulator, which may include: using the timing device to send a preset time code to the data processing terminal, sending a preset trigger signal to the turntable, sending a preset time code and a preset trigger signal to the turntable controller, sending a preset time code, a preset trigger signal, and a preset transmission configuration signal to the ground inspection terminal, and sending a preset trigger signal and a preset transmission configuration signal to the laser terminal.

[0085] It is understood that the preset trigger signal can specifically be a 1PPS signal. 1PPS (1 Pulse Per Second) specifically refers to one pulse per second. During implementation, a preset trigger signal can be used for corresponding synchronous triggering. The preset transmission configuration signal can specifically be 10M / 100M. The 10M / 100M signal is used to define the upper limit of data transmission speed to 10Mbps (megabits per second) or 100Mbps. During implementation, the preset transmission configuration signal can be used to balance communication efficiency and network performance, ensuring the communication quality based on the laser link. The time code can specifically be used to unify the time base of different devices in the stellar open-loop pointing test system.

[0086] In the embodiments of this specification, through the use of time codes, preset trigger signals, preset transmission configuration signals, combined with orbit and attitude data carrying timestamps, the time alignment processing for the stellar open-loop pointing test system can be completed accurately and comprehensively, thereby avoiding errors caused by time delays and other problems in subsequent testing processes.

[0087] In practice, the process for verifying stellar open-loop pointing using the aforementioned open-loop stellar pointing test system is as follows: The system simulates the orbit and attitude of the binary satellites used by the on-orbit laser terminal, as well as the stellar background in the sky where the binary link is pointed, providing the laser terminal with a space environment equivalent to that used for on-orbit stellar open-loop pointing. A turntable simulates the satellite's orbit and attitude motion. A stellar simulator simulates the dynamically changing stellar background in the sky where the link is pointed based on the input binary satellite coordinates. The irradiance meets the magnitude requirements. The laser terminal under test is mounted on the turntable. Under a unified time reference, the laser terminal performs real-time compensation for its orbit and attitude. The laser terminal's star sensor is aligned with the stellar simulator to begin capturing stars and calculate the laser terminal's pointing error in real time, conducting indoor open-loop stellar pointing verification.

[0088] In some embodiments of the present specification, the star map projected by the star simulator is the star background of the sky in the direction of the laser link of the first satellite and the second satellite.

[0089] It can be understood that after calibrating the conversion relationship between the coordinate systems of each device and the coordinate systems of each device, the star map coordinate system becomes the initial coordinate system of the star map. The coordinate origin of this initial coordinate system is defined at the center of the exit pupil of the star simulator's optical system. The Z-axis is the direction of the optical axis's emission (in this case, the initial optical axis coincides with the Z-axis of the inertial coordinate system). The X-axis and Y-axis are two orthogonal axes perpendicular to the optical axis, determined by the right-hand rule. When projecting a star map, the star simulator needs to determine the central optical axis of the projected star map. To center the projected star map in the direction of the laser terminal's optical axis, the central optical axis of the star map coordinate system needs to be rotated to the direction of the laser terminal's optical axis, that is, the direction of the laser link. At this point, the star map coordinate system rotates relative to the initial coordinate system, and the projected star map is the star map of the sky in the direction of the binary laser link (that is, the stellar background).

[0090] In some embodiments of the present specification, calibrating each device coordinate system and the conversion relationship between each device coordinate system includes: calibrating the position direction of each device coordinate system and the coordinate system deviation between each device coordinate system; and determining the deviation correction amount between each device coordinate system based on the coordinate system deviation between each device coordinate system as the conversion relationship between each device coordinate system.

[0091] It can be understood that the position direction of the device coordinate system can be represented by a position vector, for example, it can include the position vector of the turntable's reference coordinate system, the position vector of the turntable's zero-point coordinate system, the position vector of the laser terminal's coordinate system, the position vector of the star simulator's coordinate system, and the position vector of the star map's initial coordinate system. Furthermore, when determining the coordinate system deviation between each coordinate system, the position vector of each device coordinate system can be calibrated, and the deviation between each position vector, such as the direction deviation, can be calibrated at the same time. The deviation correction amount between each device coordinate system can then be determined based on the deviation of the position vector. Furthermore, since the deviation of the position vector of some coordinate systems cannot be directly measured and calibrated, it can be obtained by transforming the deviation correction amount between multiple device coordinates based on measurement and calibration, thereby achieving unified spatial reference between each device.

[0092] refer to Figure 3 As shown, in some embodiments of this specification, calibrating the position and direction of each device coordinate system, as well as the coordinate system deviation between each device coordinate system, may include:

[0093] S301: Installing a zero-point measurement tool at the zero-point position of the turntable, representing the reference coordinate system of the turntable by a first cubic mirror installed at the reference position of the turntable, and representing the zero-point coordinate system of the turntable by a second cubic mirror;

[0094] S302: performing optical measurement on the first cubic mirror and the second cubic mirror using a theodolite to determine a first coordinate system deviation between the first cubic mirror and the second cubic mirror;

[0095] S303: Installing the laser terminal at the zero point position of the turntable, representing the zero point coordinate system of the turntable by a third cubic mirror installed on the laser terminal, and representing the coordinate system of the star simulator by a fourth cubic mirror installed on the star simulator;

[0096] S304: Define the star map coordinate system projected by the star simulator, use a theodolite to perform optical measurements on the first cubic mirror and the third cubic mirror, the first cubic mirror and the fourth cubic mirror, and the fourth cubic mirror and the star map coordinate system, and determine the second coordinate system deviation between the first cubic mirror and the third cubic mirror, the third coordinate system deviation between the first cubic mirror and the fourth cubic mirror, and the fourth coordinate system deviation between the fourth cubic mirror and the star map coordinate system.

[0097] It can be understood that the turntable's zero-point coordinate system is equivalent to the orbital coordinate system of the on-orbit laser terminal, the laser terminal coordinate system is equivalent to the coordinate system of the on-orbit laser terminal, and the stellar simulator's coordinate system is equivalent to the coordinate system of the on-orbit star. The coordinate system deviation can be used to characterize the overall system deviation relative to the actual stellar open-loop pointing correction of the on-orbit satellite when conducting simulated stellar open-loop pointing tests using a ground-based stellar open-loop pointing test system. Furthermore, based on the determined coordinate system deviation, the deviation correction between the coordinate systems can be further determined. Based on the deviation correction, the various spatial coordinate systems involved in the on-orbit stellar open-loop pointing environment of the laser terminal (including the J2000 inertial coordinate system, the satellite orbit coordinate system, and the laser terminal coordinate system) are equivalent, transformed, and unified with the various coordinate systems in the ground-based test simulation environment (the turntable coordinate system, the laser terminal coordinate system, and the star chart coordinate system). This provides a spatial benchmark for indoor equivalent simulation of the on-orbit stellar open-loop pointing environment of the laser terminal and for verifying the laser terminal's stellar open-loop pointing process and accuracy.

[0098] refer to Figure 4 As shown, in some embodiments of this specification, determining the deviation correction amount between each device coordinate system based on the coordinate system deviation amount between each device coordinate system includes:

[0099] S401: Based on the deviation of each coordinate system, determine the direction cosine corresponding to the deviation of each coordinate system as the deviation correction amount between the corresponding device coordinate systems;

[0100] S402: Determine a third deviation correction amount between the zero-point coordinate system and the laser terminal coordinate system based on a first deviation correction amount between the reference coordinate system and the zero-point coordinate system and a second deviation correction amount between the reference coordinate system and the coordinate system of the laser terminal;

[0101] S403: Determine the sixth deviation correction between the star map coordinate system and the laser terminal coordinate system based on the fourth deviation correction between the reference coordinate system and the coordinate system of the star simulator, the fifth deviation correction between the coordinate system of the star simulator and the star map coordinate system, and the second deviation correction.

[0102] It can be understood that since the relationship between the coordinate system of the laser terminal and the zero-point coordinate system of the turntable, and between the coordinate system of the laser terminal and the coordinate system of the star simulator cannot be accurately obtained, it is possible to define the reference coordinate system of the turntable and calibrate the conversion relationship between the reference coordinate system and the coordinate systems of each device to determine the conversion relationship between the coordinate system of the laser terminal and the zero-point coordinate system of the turntable, as well as the conversion relationship between the coordinate system of the laser terminal and the coordinate system of the star simulator, etc., to provide a basis for the subsequent unification of spatial references.

[0103] In some embodiments of this specification, the process of calibrating each device coordinate system and the conversion relationship between the device coordinate systems may be as follows:

[0104] refer to Figure 5 As shown, the orbital coordinate system of the target satellite is defined as XYZ, where X points to the direction of orbital movement, Z points to the center of the earth, and Y is the right-hand direction of X and Z. The zero-point coordinate system X2Y2Z2 of the turntable is defined to be equivalent to the satellite orbital coordinate system XYZ, and is represented by the cubic mirror 2 placed on the zero-point measurement fixture of the turntable, where X2 / / X, Y2 / / Y, and Z2 / / Z are in the same direction. The position vector of the cubic mirror 2 is ; Define the coordinate system X3Y3Z3 of the laser terminal, represented by the cubic mirror 3 on it, and the position vector of the cubic mirror 3 ; Define the reference coordinate system X1Y1Z1 of the turntable, which is represented by installing a cubic mirror 1 on the side of the turntable. The position vector of the cubic mirror 1 is , used to calibrate the initial coordinate relationship of the zero-point coordinate system of the laser terminal and the turntable. Figure 6 As shown, the coordinate system of the star simulator is established by installing a cubic mirror 4 on the star simulator, which is defined as X4Y4Z4. The position vector of the cubic mirror 4 is The initial coordinate system of the star map is defined as X5'Y5'Z5', which is equivalent to the inertial (i.e., J2000) coordinate system XJ2000YJ2000ZJ2000, where X5' / / XJ2000, Y5' / / YJ2000, and Z5' / / ZJ2000, and their directions are consistent. The coordinate system of the projected star map is defined as X5Y5Z5, where X5 is the long side of the star map projection board, Y5 is the short side of the star map projection board, and Z5 is the direction from the simulated target star to the terminal. Each coordinate system satisfies the right-hand rule.

[0105] Furthermore, calibrating the conversion relationship between the coordinate systems of each device can include: calibrating the relationship between the zero-point coordinate system of the turntable and the reference coordinate system of the turntable, calibrating the relationship between the laser terminal coordinate system and the reference coordinate system of the turntable, calibrating the relationship between the star simulator coordinate system and the reference coordinate system of the turntable, and calibrating the relationship between the star simulator coordinate system and the initial coordinate system of the star map.

[0106] In some embodiments of the present specification, the relationship between the zero-point coordinate system of the calibration turntable and the reference coordinate system of the turntable may specifically include: when the intersatellite laser terminal establishes a link at both ends, the light of the receiving optical fiber comes from the collimator, so it is necessary to calibrate the parallelism of the plane formed by the collimator camera and the two axes of the two-dimensional turntable. Specifically, the light emitted by the receiving optical fiber and the collimator will be reflected back through the zero-point cubic mirror 2 of the turntable to present a light spot on the collimator camera. The calibration equipment is used to make the light spot be at the optimal optical fiber coupling position (X0, Y0) of the collimator camera. The azimuth pointing angle and pitch pointing angle (A0, E0) of the turntable corresponding to this position are the zero-point position of the turntable, which is also the spatial zero point for the alignment of the turntable and the simulation track. Use a theodolite to calibrate the zero-point cubic mirror 2 of the turntable and the reference cubic mirror 1 of the turntable. The measurement diagram is as follows: Figure 5 As shown, the reference coordinate system position vector of the turntable is The zero-point coordinate system position vector of the turntable is And their mutual conversion relationship (for example, it can be expressed as a transformation matrix C used to characterize the transformation from the reference coordinate system to the zero point coordinate system 12 ). The parallel light tube can be arranged corresponding to the cubic mirror 2.

[0107] In some embodiments of the present specification, calibrating the relationship between the laser terminal coordinate system and the reference coordinate system of the turntable may specifically include: installing and fixing the laser terminal to be measured on the turntable; turning on the lasers of the collimator and the laser terminal, with both ends emitting light toward each other, adjusting the azimuth pointing angle and the pitch pointing angle of the laser terminal so that the optical axis of the laser terminal and the optical axis of the collimator are coaxial, which is specifically reflected in that the laser terminal and the collimator focal plane camera simultaneously observe a complete and regular circular light spot, which is located in the center of the camera's field of view. The azimuth pointing angle and the pitch pointing angle A0' and E0' of the laser terminal at this time are recorded as the zero point of the laser terminal. Use a theodolite to calibrate the cubic mirror 3 corresponding to the laser terminal and the reference cubic mirror 1 of the turntable, as shown in the figure. Figure 6 As shown, the reference coordinate system position vector of the turntable is and the laser terminal coordinate system position vector is And their mutual conversion relationship (for example, it can be expressed as a transformation matrix C used to characterize the coordinate system from the reference coordinate system to the laser terminal 13). Furthermore, based on the conversion relationship between the zero-point coordinate system of the turntable and the reference coordinate system of the turntable, the conversion relationship between the coordinate system of the laser terminal and the zero-point coordinate system of the turntable can be calculated. The collimator can be arranged corresponding to the laser terminal.

[0108] In some embodiments of the present specification, calibrating the relationship between the coordinate system of the star simulator and the reference coordinate system of the turntable may specifically include: placing the turntable and the laser terminal in the initial position pointing to the orbit (i.e., the zero position), and maintaining the zero position. Install the star simulator in front of the terminal, project the calibration star map on the star simulator, adjust the star simulator tooling to the star sensitivity of the laser terminal to be able to capture the star map and successfully solve the quaternion, and visually observe that the optical axis deflection angle is ≤3°, and determine it to be aligned. After the quaternion is solved, return the turntable to the zero point, and use the theodolite to perform precise measurements on the cubic mirror 4 corresponding to the star simulator and the cubic mirror 1 corresponding to the turntable, such as Figure 6 As shown, the position vector of the turntable's reference coordinate system is and the position vector of the star simulator is And the mutual conversion relationship (for example, it can be expressed as the transformation matrix C used to characterize the coordinate system from the reference coordinate system to the star simulator coordinate system) 14 ). Furthermore, by combining the conversion relationship between the zero-point coordinate system of the turntable and the reference coordinate system of the turntable, the conversion relationship between the coordinate system of the star simulator and the zero-point coordinate system of the turntable can be calculated.

[0109] In some embodiments of this specification, the initial coordinate system of the star map is equivalent to the inertial coordinate system. Therefore, the conversion relationship between the star simulator coordinate system and the initial coordinate system of the star map can be calibrated by measuring the conversion relationship between the cubic mirror 4 and the inertial coordinate system. Specifically, the theodolite can be used to perform non-contact optical measurement on the cubic mirror 4 and the cubic mirror representing the inertial coordinate system to determine the direction cosines between the two as the conversion relationship between the star simulator coordinate system and the initial coordinate system of the star map. The coordinate system position vector of the star simulator can be measured using the theodolite to be and the position vector of the initial coordinate system of the star map is And their mutual conversion relationship (for example, it can be expressed as a transformation matrix C used to characterize the coordinate system from the reference coordinate system to the laser terminal M4 ).

[0110] The conversion relationship between the coordinate systems of the above-mentioned devices can be shown as follows: Measure and determine the measurement matrix C of the turntable zero point coordinate system X2Y2Z2 and the turntable reference coordinate system X1Y1Z1 12 ; Measure and determine the measurement matrix C14 of the coordinate system X4Y4Z4 of the star simulator and the turntable reference coordinate system X1Y1Z1; Measure and determine the measurement matrix C of the coordinate system X3Y3Z3 of the laser terminal and the two-dimensional turntable reference coordinate system X1Y1Z1 13; Measure and determine the measurement matrix C of the star simulator coordinate system X4Y4Z4 and the star map initial coordinate system X5'Y5'Z5' M4 . Then the coordinate transformation relationship is as follows:

[0111] Formula (1)

[0112] Formula (2)

[0113] Formula (3)

[0114] Formula (4)

[0115] From the conversion relationship between the above coordinate systems, the direction vector of the laser terminal and the projected star map direction vector expressed in the turntable zero-point coordinate system can be derived:

[0116] Formula (5)

[0117] Formula (6)

[0118] In some embodiments of the present specification, the first orbital attitude data and / or the second orbital attitude data include at least: orbital position data in an inertial coordinate system, satellite velocity data, Euler angles, and quaternions.

[0119] Based on the aforementioned stellar open-loop pointing test system, before projecting the star map, it is necessary to perform orbital dynamic simulation of the local star and / or binary stars (including the local star and the target star). Then, during the orbital dynamic simulation, the binary star link establishment and tracking can be simulated, and the local star pointing error calculation, correction, and correction accuracy test can be performed based on the unified time reference star map projection.

[0120] In some embodiments of the present specification, based on the unified space reference established above, orbital dynamic simulation can be achieved by sending the orbit and attitude data of the local satellite in the inertial coordinate system and the orbital position data of the target satellite to the laser terminal and turntable.

[0121] Specifically, the data used in the orbital dynamics simulation can include the orbital position, velocity, Euler angles, and quaternions of the binary satellites in the J2000 inertial coordinate system. The position vectors of local satellite A and target satellite B in the inertial coordinate system (i.e., the J2000 system) can be set to (X1, Y1, Z1) and (X2, Y2, Z2), respectively. The pointing vector of local satellite A to target satellite B is:

[0122] Formula (7)

[0123] The pointing vector is converted to the orbital coordinate system VVLH according to the Euler angle measured under J2000 (the default orbital coordinate system coincides with the target satellite body coordinate system, 312 conversion order), and the attitude transformation matrix used is R 312 The conversion of the pointing vector in the inertial coordinate system to the orbital coordinate system can be expressed as:

[0124] Formula (8)

[0125] Among them, r VVLH It can be equivalent to the position vector of the turntable's reference coordinate system , then based on the conversion matrix mentioned above, the pointing vector in the above orbital coordinate system can be converted to the coordinate system of the laser terminal, which can be expressed as:

[0126] Formula (9)

[0127] Based on the pointing vector in the above laser terminal coordinate system, the azimuth pointing angle θ of the laser terminal can be calculated Az and the pitch pointing angle θ El , can be calculated by the following formula:

[0128] Formula (10)

[0129] Since the turntable moves in opposite directions to the laser terminal, the azimuth and elevation angles of the turntable are -θ. Az and -θ El , then the control quantity of the turntable can be expressed as:

[0130] Formula (11)

[0131] Among them, A can represent the azimuth pointing angle of the state, and E can represent the pitch pointing angle of the turntable.

[0132] Furthermore, the turntable controller can be used to drive the turntable movement based on the control quantity of the turntable to realize track dynamic simulation.

[0133] Furthermore, during the dynamic orbit simulation process, the establishment of a dual-star laser link can be simulated. In this case, a real-time dynamic star map can be projected through the star simulator, i.e., dynamic star map simulation. This allows the laser terminal star sensor to be aligned with the star simulator and begin capturing stars, calculating the laser terminal pointing error in real time, and conducting indoor open-loop star pointing verification. During the dynamic star map simulation process, it is necessary to determine the laser link information of the dual stars, such as the laser link direction. The initial star map coordinate system is then rotated to this laser link direction, so that the center of the projected star map is in the direction of the laser terminal's optical axis. The real-time dynamic star map is then projected based on the rotated star map coordinate system, achieving dynamic star map simulation.

[0134] Specifically, determining the laser link information between the first satellite and the second satellite based on the first orbital data of the first satellite corresponding to the laser terminal and the second orbital data of the second satellite can include: determining the first position data of the first satellite in the inertial coordinate system and the second position data of the second satellite in the inertial coordinate system based on the first orbital data and the second orbital data; and determining the pointing vector of the first satellite to the second satellite in the inertial coordinate system as the laser link information based on the second position data and the second position data.

[0135] It can be understood that the pointing vector in the embodiment of this specification can be expressed as the pointing vector of the local star A to the target star B in the inertial coordinate system mentioned above is r AB . The calculation process of the pointing vector in the inertial coordinate system can be implemented by using the data processing terminal, laser terminal, and control software corresponding to the star simulator in the aforementioned open-loop star pointing test system. When using devices such as data terminals and laser terminals to calculate the pointing vector, the pointing vector in the inertial coordinate system can be sent to the control software of the star simulator based on the broadcast protocol established between the devices. Furthermore, the control software of the star simulator can determine the control signal of the star simulator projecting the star map, such as the star map projection control amount, based on the pointing vector in the inertial coordinate system and the conversion relationship between the coordinate systems of each device, and send the control signal to the star simulator to drive the star simulator to project a real-time dynamic star map.

[0136] In a specific implementation scenario, the turntable controller can be time-triggered starting from T0 (i.e., the initial time point), and send corresponding control quantities to the turntable at 10Hz to control the turntable rotation to simulate the negative relative angular movement of the two stars. The turntable closed-loop control period is less than or equal to 0.12ms; the data processing end can inject the orbit and position data into the terminal ground detection at 1Hz through the UDP protocol at the first advance time point (for example, 1 second before the initial time point). After receiving the data, the terminal ground detection automatically frames and broadcasts it to the laser terminal according to the on-board format, driving the laser terminal to compensate for the satellite orbital motion and point to the corresponding laser terminal of the target star; the data processing end can be based on the position data of the local satellite and the target star in the J2000 coordinate system (the conversion matrix between the turntable zero point coordinate system and the star simulator coordinate system can be superimposed in the position data) and loaded into the star simulator control software, so that the star simulator control software determines the star map projection control quantity based on the received orbit and posture data. The star simulator software is installed in the data processing terminal, reads the system time in real time, and sends the star map projection control quantity to the star simulator at a frequency of 20Hz. The star simulator can then project a dynamic star map based on the star map projection control quantity.

[0137] In some embodiments of the present specification, using a star simulator to project a star map corresponding to a target star based on the conversion relationship between the laser link information and the coordinate systems of each device may include: determining a star map projection control quantity used by the star simulator to project the star map based on the conversion relationship between the laser link information and the coordinate systems of each device; and using the star simulator to project the star map in the sky area in the laser link direction of the first satellite and the second satellite based on the star map projection control quantity.

[0138] In some embodiments of the present specification, determining the star map projection control quantity used by the star simulator to project the star map based on the conversion relationship between the laser link information and the coordinate systems of each device may include: based on the conversion relationship between the coordinate systems of each device, converting the pointing vector from the first satellite to the second satellite in the laser link information in the inertial coordinate system to the star map coordinate system to obtain a target direction vector; determining the rotation quaternion of the central optical axis of the star map coordinate system to the target direction vector, and using the rotation quaternion as the star map projection control quantity.

[0139] Specifically, based on the above formulas (6) and (8), the conversion relationship between the pointing vector in the initial coordinate system of the star map and the inertial coordinate system can be obtained, which can be expressed by the following formula:

[0140] Formula (12)

[0141] in, represents the pointing vector from the first satellite to the second satellite in the laser link information in the inertial coordinate system, C M4 represents the conversion relationship from the star map coordinate system to the star simulator, C 14 represents the conversion relationship from the reference coordinate system to the star simulator, C 12 Indicates the conversion relationship from the reference coordinate system to the zero-point coordinate system.

[0142] After obtaining the target vector, it is necessary to rotate the optical axis of the initial coordinate system of the star map to the bidirectional link building direction to obtain the star map projection control amount. Specifically, the star map projection control amount can be determined by the following formula:

[0143] Formula (13)

[0144] Wherein, q represents the rotation quaternion of the star map coordinate system, which represents the star map projection control quantity; represents the direction vector corresponding to the pointing vector from the first satellite to the second satellite in the laser link information in the star map coordinate system, and V1 represents the unit vector of the central optical axis of the star map coordinate system. Specifically, the initial optical axis defined in the star map coincides with the Z axis of the J2000 coordinate system, and its unit vector V1 = [0; 0; 1].

[0145] In some embodiments of the present specification, after determining the rotation quaternion from the central optical axis of the star map coordinate system to the target direction vector, the method may further include: normalizing the rotation quaternion and using the normalized rotation quaternion as the star map projection control quantity.

[0146] Specifically, the normalization of the rotation quaternion can be achieved by the following formula:

[0147] Formula (14)

[0148] in, It can represent the normalized rotation quaternion, and ||q|| can represent the Euclidean norm of the rotation quaternion.

[0149] Reference Figure 7 As shown, the internal coordinate relationship of a star simulator provided by the embodiment of this specification can be as shown in the figure, and the pointing vector representing the direction of the binary star chain can be Convert to the cubic mirror 4 coordinate system (i.e., the star simulator coordinate system), and then convert from the cubic mirror 4 coordinate system to the initial star map coordinate system X5'Y5'Z5'. After calculating the rotation quaternion, the initial star map coordinate system can be rotated to the coordinate system X5Y5Z5 to obtain the digital micromirror device (DMD) star map. The star simulator can project the star map based on the rotation quaternion and the determined position of each star in the field of view of the laser terminal.

[0150] In some embodiments of this specification, when generating a star map, it is also necessary to determine the position of each star in the star map. Specifically, based on the star catalog, each star has its corresponding position in the J2000 coordinate system, and the right ascension α is used. s and declination δ s To express it, the direction vector of each star in the J2000 coordinate system is:

[0151] Formula (15)

[0152] Furthermore, the angle between the direction vector of each star in the inertial coordinate system and the pointing vector corresponding to the binary star alignment direction can be calculated, thereby determining the position of each star in the star map. Images or image identifiers of each star are then generated at the corresponding positions in the stellar coordinate system. When projecting the star map, the rotation quaternion or normalized rotation quaternion can be input into a stellar simulator. Based on the rotation quaternion or normalized rotation quaternion and the generated star map, the simulator projects a dynamic sky region in the binary star alignment direction (i.e., a real-time dynamic star map). This real-time dynamic star map projection can be time-aligned across devices using a time synchronization terminal. Based on a unified time base, the real-time dynamic star map corresponding to the alignment direction is projected simultaneously with the binary star alignment.

[0153] In practice, after the star simulator projects a real-time dynamic star map in the direction of link establishment, the laser terminal's star sensor can be aligned with the map to begin capturing stars and calculate the laser terminal's pointing error in real time, allowing for indoor open-loop star pointing verification. This includes calculating the pointing error, calculating the pointing deviation correction, correcting the laser terminal's pointing, and determining the pointing correction accuracy based on the corrected pointing deviation.

[0154] The spatial coordinate equivalence method in the embodiments of this specification is applied to indoor verification of open-loop pointing of stars, and can achieve spatial equivalence of space orbits and stellar environments with ground simulation environments. Furthermore, based on a unified spatial reference, a space environment that simulates satellite orbit attitudes and dynamic stellar backgrounds with high fidelity can be established. By superimposing the coordinate system corrections obtained by precise measurement and coordinate transformation calculations on the binary star orbit data input to the star simulator control software, the turntable zero-point coordinates can be corrected to the star model coordinate system, and the accuracy of the coordinate deviation correction can be guaranteed, thereby providing a basis for the spatial accuracy of indoor open-loop pointing verification of stars. Furthermore, by unifying the chain-building sky area and the direction of the central optical axis of the star simulator, orbit attitudes can be simulated with high fidelity and indoor open-loop pointing verification of stars can be achieved.

[0155] Based on the above-mentioned stellar open-loop pointing test method, the embodiments of this specification also provide a stellar open-loop pointing test device. It is understood that this device can be applied to a stellar open-loop pointing test system, wherein the stellar open-loop pointing test system at least includes: a turntable, a laser terminal mounted on the turntable, and a stellar simulator. Figure 8 The figure shows a schematic diagram of a star open loop pointing test device provided in an embodiment of this specification. Figure 8 As shown, the star open-loop pointing test device may include:

[0156] The calibration module 801 is used to calibrate the coordinate systems of various devices and the conversion relationship between the coordinate systems of various devices, wherein the device coordinate systems include at least the reference coordinate system of the turntable, the zero point coordinate system of the turntable, the coordinate system of the laser terminal, the coordinate system of the star simulator, and the star map coordinate system;

[0157] The processing module 802 is configured to obtain and determine the laser link information between the first satellite and the second satellite based on the first orbital attitude data of the first satellite and the second orbital attitude data of the second satellite corresponding to the laser terminal;

[0158] The test module 803 is used to use a star simulator to project a star map corresponding to the target star based on the conversion relationship between the laser link information and the coordinate systems of each device, so that the laser terminal simulates the star open-loop pointing test based on the star map.

[0159] In some embodiments of the present specification, the star map projected by the star simulator is the star background of the sky in the direction of the laser link of the first satellite and the second satellite.

[0160] In some embodiments of the present specification, the calibration module 801 can be specifically used to: calibrate the position direction of each device coordinate system, and the coordinate system deviation between each device coordinate system; determine the deviation correction amount between each device coordinate system based on the coordinate system deviation between each device coordinate system as the conversion relationship between each device coordinate system.

[0161] In some embodiments of the present specification, when calibrating the position direction of each device coordinate system and the coordinate system deviation between each device coordinate system, the calibration module 801 can be specifically used to: install the zero point measurement tool at the zero point position of the turntable, characterize the reference coordinate system of the turntable by a first cubic mirror installed at the reference position of the turntable, and characterize the zero point coordinate system of the turntable by a second cubic mirror; use a theodolite to perform optical measurement on the first cubic mirror and the second cubic mirror to determine the first coordinate system deviation between the first cubic mirror and the second cubic mirror; install the laser terminal at the zero point position of the turntable, and characterize the zero point coordinate system of the turntable by a second cubic mirror installed at the reference position of the turntable. The third cubic mirror on the end represents the zero-point coordinate system of the turntable, and the coordinate system of the star simulator is represented by the fourth cubic mirror installed on the star simulator; the star map coordinate system projected by the star simulator is defined, and the first cubic mirror and the third cubic mirror, the first cubic mirror and the fourth cubic mirror, and the fourth cubic mirror and the star map coordinate system are optically measured using a theodolite to determine the second coordinate system deviation between the first cubic mirror and the third cubic mirror, the third coordinate system deviation between the first cubic mirror and the fourth cubic mirror, and the fourth coordinate system deviation between the fourth cubic mirror and the star map coordinate system.

[0162] In some embodiments of the present specification, when the calibration module 801 determines the deviation correction amount between each device coordinate system based on the coordinate system deviation amount between each device coordinate system, it can be specifically used to: determine the direction cosine corresponding to each coordinate system deviation amount as the deviation correction amount between the corresponding device coordinate systems based on the coordinate system deviation amount; determine the third deviation correction amount between the zero-point coordinate system and the laser terminal coordinate system based on the first deviation correction amount between the reference coordinate system and the zero-point coordinate system and the second deviation correction amount between the reference coordinate system and the coordinate system of the laser terminal; determine the sixth deviation correction amount between the star map coordinate system and the laser terminal coordinate system based on the fourth deviation correction amount between the reference coordinate system and the coordinate system of the star simulator, the fifth deviation correction amount between the coordinate system of the star simulator and the star map coordinate system, and the second deviation correction amount.

[0163] In some embodiments of the present specification, the first orbital attitude data and / or the second orbital attitude data include at least: orbital position data in an inertial coordinate system, satellite velocity data, Euler angles, and quaternions.

[0164] In some embodiments of the present specification, the processing module 802 can be specifically used to: determine the first position data of the first satellite in the inertial coordinate system and the second position data of the second satellite in the inertial coordinate system based on the first orbital attitude data and the second orbital attitude data; and determine the pointing vector of the first satellite to the second satellite in the inertial coordinate system as the laser link information based on the second position data and the second position data.

[0165] In some embodiments of the present specification, the test module 803 can be specifically used to: determine the star map projection control quantity used by the star simulator to project the star map based on the conversion relationship between the laser link information and the coordinate systems of each device; and use the star simulator to project the star map in the sky area in the laser link direction of the first satellite and the second satellite based on the star map projection control quantity.

[0166] In some embodiments of the present specification, when the test module 803 determines the star map projection control quantity of the star simulator used to project the star map based on the conversion relationship between the laser link information and the coordinate systems of each device, it can be specifically used to: based on the conversion relationship between the coordinate systems of each device, convert the pointing vector from the first satellite to the second satellite in the laser link information in the inertial coordinate system to the star map coordinate system to obtain the target direction vector; determine the rotation quaternion of the central optical axis of the star map coordinate system to the target direction vector, and use the rotation quaternion as the star map projection control quantity.

[0167] In some embodiments of this specification, the star map projection control amount is determined by the following formula:

[0168] ;

[0169] Wherein, q represents the rotation quaternion of the star map coordinate system, which represents the star map projection control quantity; represents a pointing vector from the first satellite to the second satellite in the laser link information in the star map coordinate system; represents the direction vector corresponding to the pointing vector from the first satellite to the second satellite in the laser link information in the star map coordinate system, V1 represents the unit vector of the central optical axis of the star map coordinate system, represents the pointing vector from the first satellite to the second satellite in the laser link information in the inertial coordinate system, C M4 represents the conversion relationship from the star map coordinate system to the star simulator, C 14 represents the conversion relationship from the reference coordinate system to the star simulator, C 12 Indicates the conversion relationship from the reference coordinate system to the zero-point coordinate system.

[0170] In some embodiments of the present specification, the testing module 803 may also be configured to: normalize the rotation quaternion, and use the normalized rotation quaternion as the star map projection control variable.

[0171] In some embodiments of the present specification, the star open-loop pointing test system also includes a timing device and a data processing end, and the device may also include a sending module for: using the timing device to perform corresponding time alignment processing on the laser terminal, turntable, and star simulator respectively; using the data processing end to send the orbit and attitude data with timestamps to the turntable and the laser terminal at a first advance time point, so that the turntable and the laser terminal simulate the orbit and attitude of the first satellite and the second satellite in-orbit link based on the orbit and attitude data, and simulate the star open-loop pointing test based on the star map projected by the star simulator at the target time point during the movement; wherein the orbit and attitude data include the first orbit attitude data and the second orbit attitude data at the target time point.

[0172] The description and functions of the above modules can be understood by referring to the content of the Stellar Open-Loop Pointing Test Method section, which will not be repeated here.

[0173] An embodiment of the present invention further provides an electronic device, such as Figure 9As shown, electronic device 901, located on a satellite, may include one or more processors 902, such as one or more central processing units (CPUs), each of which may implement one or more hardware threads. Electronic device 901 may also include any memory 903 for storing any type of information, such as code, settings, data, and the like. For example, and without limitation, memory 903 may include any one or more combinations of the following: any type of RAM, any type of ROM, a flash memory device, a hard disk, an optical disk, and the like. More generally, any memory may use any technology to store information. Furthermore, any memory may provide volatile or non-volatile retention of information. Furthermore, any memory may represent a fixed or removable component of electronic device 901. In one embodiment, when processor 902 executes associated instructions stored in any memory or combination of memories, electronic device 901 may perform any operation of the associated instructions. Electronic device 901 also includes one or more drive mechanisms 904, such as a hard disk drive mechanism, an optical disk drive mechanism, and the like, for interacting with any memory.

[0174] The electronic device 901 may also include one or more network interfaces 905 for exchanging data with other devices via one or more communication links 906. One or more communication buses 907 couple the components described above together.

[0175] The communication link 906 can be implemented in any manner, for example, through a local area network, a wide area network (e.g., the Internet), a point-to-point connection, etc., or any combination thereof. The communication link 906 can include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0176] An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above method are executed.

[0177] An embodiment of the present invention further provides a computer-readable instruction, wherein when a processor executes the instruction, the program therein causes the processor to execute the method described in any of the aforementioned embodiments.

[0178] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0179] It should also be understood that in the embodiments of the present invention, the term "and / or" merely describes the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this invention generally indicates that the associated objects are in an "or" relationship.

[0180] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the composition and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0181] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0182] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or can be an electrical, mechanical or other form of connection.

[0183] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected according to actual needs to achieve the objectives of the embodiments of the present invention.

[0184] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0185] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for enabling an electronic device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0186] Specific embodiments are used in the present invention to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A method for testing open-loop star pointing, characterized in that: Applied to a star open-loop pointing test system, wherein the star open-loop pointing test system comprises at least: a turntable, a laser terminal mounted on the turntable, and a star simulator, the method comprising: Calibrate the coordinate systems of each device and the conversion relationship between the coordinate systems of each device, wherein the device coordinate system includes at least the reference coordinate system of the turntable, the zero point coordinate system of the turntable, the coordinate system of the laser terminal, the coordinate system of the star simulator, and the star map coordinate system; Obtaining and determining laser link information between the first satellite and the second satellite based on first orbital attitude data of a first satellite and second orbital attitude data of a second satellite corresponding to the laser terminal; A star simulator is used to project a star map corresponding to the target star based on the conversion relationship between the laser link information and the coordinate systems of each device, so that the laser terminal simulates the star open-loop pointing test based on the star map.

2. The method for testing open-loop star pointing according to claim 1, characterized in that: The star map projected by the star simulator is the star background of the sky in the direction of the laser link of the first satellite and the second satellite.

3. The method for testing open-loop star pointing according to claim 1, characterized in that: Calibrate each device coordinate system and the conversion relationship between each device coordinate system, including: Calibrate the position and direction of each device coordinate system, as well as the coordinate system deviation between each device coordinate system; The deviation correction amount between the device coordinate systems is determined based on the coordinate system deviation amount between the device coordinate systems as the conversion relationship between the device coordinate systems.

4. The method for testing open-loop star pointing according to claim 3, characterized in that: Calibrate the position and direction of each device coordinate system, as well as the coordinate system deviation between each device coordinate system, including: Installing a zero-point measurement tool at the zero-point position of the turntable, representing the reference coordinate system of the turntable by a first cubic mirror installed at the reference position of the turntable, and representing the zero-point coordinate system of the turntable by a second cubic mirror; Performing optical measurement on the first cubic mirror and the second cubic mirror using a theodolite to determine a first coordinate system deviation between the first cubic mirror and the second cubic mirror; The laser terminal is installed at the zero point position of the turntable, the zero point coordinate system of the turntable is represented by a third cubic mirror installed on the laser terminal, and the coordinate system of the star simulator is represented by a fourth cubic mirror installed on the star simulator; Define the star map coordinate system projected by the star simulator, use a theodolite to perform optical measurements on the first cubic mirror and the third cubic mirror, the first cubic mirror and the fourth cubic mirror, and the fourth cubic mirror and the star map coordinate system, and determine the second coordinate system deviation between the first cubic mirror and the third cubic mirror, the third coordinate system deviation between the first cubic mirror and the fourth cubic mirror, and the fourth coordinate system deviation between the fourth cubic mirror and the star map coordinate system.

5. The method for testing open-loop star pointing according to claim 4, characterized in that: Determining the deviation correction amount between the coordinate systems of each device based on the coordinate system deviation amount between the coordinate systems of each device includes: Based on the deviation of each coordinate system, the direction cosine corresponding to the deviation of each coordinate system is determined as the deviation correction amount between the corresponding device coordinate systems; Determining a third deviation correction amount between the zero-point coordinate system and the laser terminal coordinate system based on a first deviation correction amount between the reference coordinate system and the zero-point coordinate system and a second deviation correction amount between the reference coordinate system and the coordinate system of the laser terminal; Based on the fourth deviation correction between the reference coordinate system and the coordinate system of the star simulator, the fifth deviation correction between the coordinate system of the star simulator and the star map coordinate system, and the second deviation correction, the sixth deviation correction between the star map coordinate system and the laser terminal coordinate system is determined.

6. The method for testing open-loop star pointing according to claim 1, characterized in that: The first orbital attitude data and / or the second orbital attitude data at least include: orbital position data in an inertial coordinate system, satellite velocity data, Euler angles, and quaternions.

7. The method for testing open-loop star pointing according to claim 1 or 6, characterized in that: Determining laser link information between the first satellite and the second satellite according to first orbital attitude data of a first satellite and second orbital attitude data of a second satellite corresponding to the laser terminal, including: Determining first position data of the first satellite in an inertial coordinate system and second position data of the second satellite in an inertial coordinate system based on the first orbital attitude data and the second orbital attitude data; Based on the second position data and the second position data, a pointing vector of the first satellite to the second satellite in the inertial coordinate system is determined as the laser link information.

8. The method for testing open-loop star pointing according to claim 1, characterized in that: Projecting a star map corresponding to a target star using a star simulator based on the laser link information and the conversion relationship between the coordinate systems of each device includes: Determining a star map projection control amount used by the star simulator to project the star map based on a conversion relationship between the laser link information and the coordinate systems of each device; The star simulator is used to project the star map onto a sky region in the direction of the laser link of the first satellite and the second satellite based on the star map projection control amount.

9. The method for testing open-loop star pointing according to claim 8, characterized in that: Determining a star map projection control amount used by the star simulator to project the star map based on a conversion relationship between the laser link information and the coordinate systems of each device includes: Based on the conversion relationship between the coordinate systems of each device, convert the pointing vector from the first satellite to the second satellite in the laser link information in the inertial coordinate system to the star map coordinate system to obtain a target direction vector; A rotation quaternion obtained by rotating the central optical axis of the star map coordinate system to the target direction vector is determined, and the rotation quaternion is used as the star map projection control quantity.

10. The method for testing open-loop star pointing according to claim 8 or 9, characterized in that: The star map projection control amount is determined by the following formula: ； Wherein, q represents the rotation quaternion of the star map coordinate system, which represents the star map projection control quantity; represents a pointing vector from the first satellite to the second satellite in the laser link information in the star map coordinate system; represents the direction vector corresponding to the pointing vector from the first satellite to the second satellite in the laser link information in the star map coordinate system, V1 represents the unit vector of the central optical axis of the star map coordinate system, represents the pointing vector from the first satellite to the second satellite in the laser link information in the inertial coordinate system, C M4 represents the conversion relationship from the star map coordinate system to the star simulator, C 14 represents the conversion relationship from the reference coordinate system to the star simulator, C 12 Indicates the conversion relationship from the reference coordinate system to the zero-point coordinate system.

11. The method for testing open-loop star pointing according to claim 9, characterized in that: After determining the rotation quaternion from the central optical axis of the star map coordinate system to the target direction vector, the method further includes: The rotation quaternion is normalized, and the normalized rotation quaternion is used as the star map projection control quantity.

12. The method for testing open-loop star pointing according to claim 1, characterized in that: The star open-loop pointing test system further includes a timing device and a data processing terminal, and the method further includes: Use the time synchronization equipment to perform corresponding time alignment processing on the laser terminal, turntable, and star simulator; At a first advance time point, the data processing end is used to send the orbit and attitude data with timestamps to the turntable and the laser terminal, so that the turntable and the laser terminal simulate the orbit and attitude of the first satellite and the second satellite in-orbit link establishment based on the orbit and attitude data, and simulate the star open-loop pointing test based on the star map projected by the star simulator at the target time point during the movement; wherein the orbit and attitude data include the first orbit attitude data and the second orbit attitude data at the target time point.

13. A test device for star open-loop pointing, characterized in that: Applicable to a star open-loop pointing test system, wherein the star open-loop pointing test system comprises at least: a turntable, a laser terminal mounted on the turntable, and a star simulator, and the device comprises: A calibration module is used to calibrate the coordinate systems of various devices and the conversion relationship between the coordinate systems of various devices, wherein the device coordinate systems include at least the reference coordinate system of the turntable, the zero point coordinate system of the turntable, the coordinate system of the laser terminal, the coordinate system of the star simulator, and the star map coordinate system; a processing module, configured to obtain and determine laser link information between the first satellite and the second satellite based on first orbital attitude data of the first satellite and second orbital attitude data of the second satellite corresponding to the laser terminal; The test module is used to use a star simulator to project a star map corresponding to the target star based on the conversion relationship between the laser link information and the coordinate systems of each device, so that the laser terminal simulates the star open-loop pointing test based on the star map.

14. An electronic device, characterized in that: The method comprises a processor and a memory for storing processor-executable instructions, wherein the processor implements the steps of the method according to any one of claims 1 to 12 when executing the instructions.

15. A computer storage medium, characterized in that The computer storage medium stores computer program instructions, which implement the steps of the method according to any one of claims 1 to 12 when executed by a processor.

16. A computer program product, characterized in that The invention comprises a computer program, which implements the steps of the method according to any one of claims 1 to 12 when the computer program is executed by a processor.

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