System and method for ground-based simulation of on-orbit operating environment of laser communication terminal

Abstract

The present invention relates to a system and method for a ground-based simulation of an on-orbit operating environment of a laser communication terminal. The system comprises a plurality of subsystems, each subsystem comprising: a control unit, which performs data interaction with a timing and synchronization unit, a two-axis gimbal unit, a corresponding laser communication terminal, and a test unit; the timing and synchronization unit is configured for achieving time synchronization to a common reference between the respective subsystem and another subsystem; the two-axis gimbal unit is configured for simulating, on the basis of a satellite attitude control signal, an attitude of a satellite platform carrying a laser communication terminal, the laser communication terminal driving, on the basis of a pointing control signal of the control unit, a rotating mechanism to adjust a pose of the laser communication terminal; the test unit is configured for testing the laser communication terminal; and an optical path assembly unit configured for forming or disconnecting a free-space laser link with an optical path assembly unit of another subsystem. The present invention enables simulation of an on-orbit operating environment of a laser communication terminal, and performs comprehensive and dynamic functional testing for laser communication terminals.

Description

Systems and methods for simulating the on-orbit operating environment of ground-based laser communication terminals Technical Field

[0001] The embodiments of the present invention generally relate to satellite laser communication, and more specifically to a system and method for an on-orbit operating environment for a ground-based simulated laser communication terminal. Background Technology

[0002] Inter-satellite laser communication uses laser signals as carriers and mainly includes point-to-point communication between two terminals: Low Earth Orbit to Low Earth Orbit (LEO-LEO), Geostationary Orbit to Low Earth Orbit (GEO-LEO), and Geostationary Orbit to Geostationary Orbit (GEO-GEO). A spaceborne laser communication payload typically consists of four parts: an optical head, an integrated processor, a communication controller, and a fiber optic amplifier. High-speed data transmission between satellites is achieved via optical carriers. The application layout, functional verification, and performance testing of inter-satellite laser communication terminals in the space orbit environment all require pre-testing on a ground-based simulation platform. This allows for testing of the entire link's functional indicators and simulating on-orbit application scenarios in the space environment.

[0003] Traditional ground-based simulation platforms and methods can only simulate static functions such as satellite broadcast data transmission, telemetry and remote control data transmission and reception, or interface testing. These are insufficient to meet the on-orbit testing requirements of simulating spaceborne laser communication terminals. Furthermore, their testing functions are relatively limited and their coverage is poor, significantly hindering the improvement of on-orbit testing performance. In addition, the large distance between the two inter-satellite laser communication terminals, their high speed, the randomness of satellite platform attitude adjustments, the asynchrony of time bases between different platforms, and the frequent occurrence of solar interference all contribute to the increased difficulty of real-time, high-precision on-orbit search, acquisition, and tracking of the two inter-satellite laser communication terminals. Therefore, traditional ground-based simulation platforms cannot simulate the long-term, stable link establishment and rapid link reconstruction between two inter-satellite laser communication terminals.

[0004] In summary, the shortcomings of traditional ground simulation platforms and methods are: the testing functions for laser communication terminals are relatively simple and limited to static functions; in addition, they are difficult to meet the requirements for long-term, stable link establishment and rapid reconstruction after link loss between laser communication terminals of two satellites. Summary of the Invention

[0005] This invention provides a system and method for simulating the on-orbit operating environment of a ground-based laser communication terminal, which can simulate the on-orbit operating environment of the laser communication terminal and perform comprehensive and dynamic functional testing on the laser communication terminal.

[0006] Furthermore, the present invention can effectively meet the requirements of stable link establishment and rapid reconstruction after link loss for laser communication terminals between two satellites.

[0007] According to a first aspect of the present invention, a system for simulating the on-orbit operating environment of a ground-based laser communication terminal is provided. The system comprises at least: multiple subsystems configured to simulate the on-orbit operating environment of corresponding laser communication terminals, each subsystem comprising: a control unit configured to interact with a time synchronization unit, a two-dimensional turntable unit, the corresponding laser communication terminal, and a testing unit; a time synchronization unit including an antenna configured to achieve the same reference time synchronization between its subsystem and other subsystems; a two-dimensional turntable unit configured to simulate the attitude of the satellite platform where the laser communication terminal of its subsystem is located based on the satellite attitude control signals sent by the control unit, the laser communication terminal being mounted on the two-dimensional turntable unit, the laser communication terminal including a rotation mechanism configured to adjust the attitude of the laser communication terminal based on the pointing control signals of the control unit driving the rotation mechanism; a testing unit configured to be electrically connected to the control unit and the corresponding laser communication terminal respectively for testing the laser communication terminal; and an optical path combining unit disposed on the optical path of the laser emitted or received by the laser communication terminal, the optical path combining unit including multiple optical elements and configured to form or disconnect a space laser link with the optical path combining units of other subsystems.

[0008] In some embodiments, each subsystem further includes: a micro-perturbation simulation unit, configured between the laser communication terminal and the optical path combination unit, and in the optical path of the laser emitted or received by the laser communication terminal, the micro-perturbation simulation unit being configured to move based on a perturbation signal output by the control unit in order to interfere with the optical path between the laser communication terminal and the optical path combination unit, the perturbation signal being generated based on the NASDA power spectral density function.

[0009] In some embodiments, the remapping vector is a linear expansion of the output feature gradient points corresponding to the input feature gradients with values ​​not equal to "0" in the reverse remapping relation, and the remapping index includes a start index and an end index.

[0010] In some embodiments, the control unit is further configured to acquire the status information of the two-dimensional turntable unit in real time or at predetermined time intervals.

[0011] In some embodiments, the micro-perturbation simulation unit is a mirror rotation device, and the time synchronization unit uses the BeiDou navigation satellite as its time synchronization reference.

[0012] According to a second aspect of the invention, a method for simulating the on-orbit operation environment of a ground-based laser communication terminal is also provided. The method is executed on the system described in the first aspect of the invention, comprising multiple subsystems including at least a local satellite subsystem and an other satellite subsystem. The method includes: simultaneously timing the local satellite subsystem and the other satellite subsystem via control units of the local satellite subsystem and the other satellite subsystem, wherein the timing reference of the timing units is the same as that of the BeiDou navigation satellite; transmitting predetermined pulse signals to corresponding control units and two-dimensional turntable units via the timing units of the local satellite subsystem and the other satellite subsystem, respectively, to achieve the same reference timing for the corresponding laser communication terminal and the two-dimensional turntable unit; and transmitting predetermined pulse signals via the same reference... Under the time reference provided, the laser communication terminal in this satellite subsystem calculates the spatial coordinate difference between the laser communication terminal in this satellite subsystem and the laser communication terminal in other satellite subsystems based on satellite broadcast data, attitude data of the two-dimensional turntable unit, and coordinate transformation matrix between the two-dimensional turntable unit and the laser communication terminal. Based on the calculated spatial coordinate difference, the laser communication terminal in this satellite subsystem adjusts its azimuth and / or elevation angles so that the laser communication terminal in this satellite subsystem can establish or disconnect a space laser link with the laser communication terminal in other satellite subsystems via the corresponding optical path combination unit.

[0013] In some embodiments, satellite broadcast data includes local satellite broadcast data and other satellite broadcast data. The method further includes: generating local satellite broadcast data via a laser communication terminal in the local satellite subsystem; and generating other satellite broadcast data via a laser communication terminal in the other satellite subsystem.

[0014] In some embodiments, achieving the same reference time synchronization between the corresponding laser communication terminal and the two-dimensional turntable unit includes: in the local satellite subsystem and the other satellite subsystem, the corresponding time synchronization unit outputs a first pulse signal to the two-dimensional turntable unit and outputs a second pulse signal to the control unit; and the control unit obtains a third pulse signal based on the second pulse signal received from the time synchronization unit and outputs it to the laser communication terminal, so as to achieve the same reference time synchronization between the corresponding laser communication terminal and the two-dimensional turntable unit in the local satellite subsystem and the other satellite subsystem.

[0015] In some embodiments, forming local satellite broadcast data via a laser communication terminal in the local satellite subsystem includes: the time synchronization unit uploading the BeiDou satellite time value to the control unit; the control unit packaging the BeiDou satellite time value and the acquired attitude data of the two-dimensional turntable unit into a data packet to form local satellite attitude data, thereby sending the local satellite attitude data to the laser communication terminal; and forming local satellite broadcast data based on the BeiDou satellite time value, local satellite orbit simulation data and other satellite orbit simulation data, solar vector simulation data, and local satellite attitude data, wherein the local satellite orbit simulation data is constructed from the local satellite attitude data of the local satellite subsystem, and the other satellite orbit simulation data is constructed from the local satellite attitude data of the other satellite subsystem.

[0016] In some embodiments, forming the satellite attitude data includes: setting the initial tracking time and motion curve of the two-dimensional turntable unit's motion trajectory via a control unit; resetting the initial tracking time to zero and controlling the two-dimensional turntable unit to start moving, and recording the BeiDou satellite time value at the moment the initial tracking time is reset to zero; extracting arbitrary frame data of the two-dimensional turntable unit's return motion data to generate the initial data of the satellite attitude data, wherein the return motion data is associated with the BeiDou satellite time value at the return time; calculating the BeiDou satellite time value corresponding to the two-dimensional turntable unit's motion data based on the BeiDou satellite time value at the moment the initial tracking time is reset to zero and the BeiDou satellite time value at the return time; and re-framing the BeiDou satellite time value corresponding to the two-dimensional turntable unit's motion data, the inner frame angle value and outer frame angle value of the two-dimensional turntable unit, and the initial data of the satellite attitude data to generate the satellite attitude data.

[0017] In some embodiments, forming the local satellite attitude data further includes: before setting the initial tracking time and motion curve of the two-dimensional turntable unit's motion trajectory, powering on the time synchronization unit and outputting a predetermined second pulse signal; determining, via the control unit, whether the predetermined second pulse signal is detected; and in response to determining that the predetermined second pulse signal is detected, setting the initial tracking time of the two-dimensional turntable unit's motion trajectory.

[0018] In some embodiments, generating local satellite broadcast data includes: the control unit acquiring two-dimensional turntable unit motion data once at a first predetermined time interval, the two-dimensional turntable unit motion data including at least the inner frame angle value and the outer frame angle value of the two-dimensional turntable unit; and re-fusing the initial data corresponding to the two-dimensional turntable unit motion data, the BeiDou satellite time value, the local satellite orbit simulation data, the other satellite orbit simulation data, the solar vector simulation data, the inner frame angle value and the outer frame angle value of the two-dimensional turntable unit, and the local satellite attitude data into frames to generate local satellite broadcast data.

[0019] In some embodiments, the method for simulating the on-orbit operating environment of a ground-based laser communication terminal further includes: broadcasting local satellite attitude data at first predetermined intervals via a control unit; and broadcasting local satellite broadcast data at second predetermined intervals.

[0020] In some embodiments, the method for simulating the on-orbit operating environment of a laser communication terminal on the ground further includes: in the local satellite subsystem, the laser communication terminal continuously receives local satellite broadcast data and other satellite broadcast data; the laser communication terminal simulates solar interference avoidance operations based on solar vector simulation data in the local satellite broadcast data; based on the other satellite broadcast data, it acquires the orbital data of other satellites associated with BeiDou satellite time values, attitude data and velocity information of the two-dimensional turntable unit of the other satellite subsystem at a specific time period; based on the attitude data and velocity information of the two-dimensional turntable unit of the other satellite subsystem associated with BeiDou satellite time values, it calculates the position information of the laser communication terminal in the other satellite subsystem at the current moment; based on the position information of the laser communication terminal in the local satellite subsystem and the position information of the laser communication terminal in the other satellite subsystem at the current moment, it calculates the initial pre-pointing data of the local satellite; and based on the calculated initial pre-pointing data of the local satellite, it generates a control signal to control the rotating structure to complete the initial pre-pointing action.

[0021] The beneficial effects of this invention include at least the ability to simulate the on-orbit operating environment of a laser communication terminal, enabling comprehensive and dynamic functional testing of the laser communication terminal. Furthermore, this invention can effectively meet the needs of establishing a link between two satellites and rapidly rebuilding the link after a break.

[0022] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0023] The above and other features, advantages, and aspects of the various embodiments of the present invention will become more apparent from the accompanying drawings and the following detailed description. In the drawings, the same or similar reference numerals denote the same or similar elements.

[0024] Figure 1 schematically illustrates a system for simulating the on-orbit operating environment of a ground-based laser communication terminal according to an embodiment of the present invention.

[0025] Figure 2 schematically illustrates a flowchart of a method for simulating the on-orbit operating environment of a ground-based laser communication terminal according to an embodiment of the present invention.

[0026] Figure 3 shows a flowchart of a method 300 for generating satellite attitude data packets according to an embodiment of the present invention.

[0027] Figure 4 shows a schematic diagram of an apparatus for satellite attitude control simulation according to an embodiment of the present invention.

[0028] Figure 5 shows a flowchart of a method for generating and broadcasting local satellite broadcast data according to an embodiment of the present invention.

[0029] Figure 6 shows a flowchart of a method for controlling a rotating structure to complete an initial pre-pointing action according to an embodiment of the present invention.

[0030] Figure 7 shows a schematic diagram of a method for establishing a laser communication link between multiple laser communication terminals according to an embodiment of the present invention.

[0031] In the various figures, the same or corresponding reference numerals indicate the same or corresponding parts. Detailed Implementation

[0032] Preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0033] The term "comprising" and its variations as used herein signify open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects.

[0034] As described above, Figure 1 schematically illustrates a system for simulating the on-orbit operating environment of a ground-based laser communication terminal according to an embodiment of the present invention. As shown in Figure 1, system 100 is used to simulate the on-orbit operating environment of a ground-based laser communication terminal. For example, system 100 can simulate the on-orbit operation and testing process of an inter-satellite laser communication terminal in a laboratory environment. System 100 includes multiple (two or more) subsystems. Each subsystem, for example, simulates the on-orbit operating environment of a corresponding laser communication terminal mounted on a satellite platform for comprehensive, dynamic functional testing. Figure 1 illustrates two subsystems among the multiple subsystems. For example, the two subsystems are, for example, the local satellite subsystem indicated by label 110 and the other satellite subsystem indicated by label 130. It should be understood that system 100 may include more subsystems. The local satellite subsystem 110 and the other satellite subsystem 130 communicate via laser path 132. Each subsystem (e.g., local satellite subsystem 110 or other satellite subsystem 130) includes: a control unit 112, a test unit 114, a laser communication terminal 116, a two-dimensional turntable unit 120, a time synchronization unit 118, and an optical path combination unit 124. In some embodiments, each subsystem further includes a micro-perturbation simulation unit 122.

[0035] Regarding the control unit 112 in each subsystem, it is configured, for example, at least to interact with the time synchronization unit 118, the two-dimensional turntable unit 120, the corresponding laser communication terminal 116, and the test unit 114. In some embodiments, the control unit 112 is also configured to interact with the micro-perturbation simulation unit 122 and with the control units of other subsystems. In some embodiments, the control unit 112 may have one or more processing units, including dedicated processing units such as graphics processing units (GPUs), field programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), or general-purpose computing on graphics processing units (GPGPUs), as well as general-purpose processing units such as CPUs. In some embodiments, the control unit 112 of each subsystem, for example, realizes the transmission of telemetry and remote control data and satellite broadcast data of the laser communication terminal 116 and the extraction of engineering parameters through a data communication path formed between a communication interface (e.g., a CAN communication interface) and the communication interface (e.g., a CAN communication interface) of the test unit 114. The control unit 112 realizes the reconstruction function of the laser communication terminal 116 through a data communication path formed between its communication interface (e.g., RS422 communication interface) and the communication interface (e.g., RS422 communication interface) of the test unit 114. The control unit 112 also realizes the image data download function of the laser communication terminal 116 through a data communication path formed between its communication interface (e.g., LVDS communication interface) and the communication interface (e.g., LVDS communication interface) of the test unit 114. It should be understood that the CAN communication interface, RS422 communication interface, and LVDS communication interface in the above examples are merely illustrative of data interaction and testing via multiple communication interfaces; other communication interfaces may also be used in this invention.

[0036] The time synchronization unit 118 includes at least an antenna. In some embodiments, the time synchronization unit 118 further includes a second pulse generation unit. The time synchronization unit 118 is configured, for example, to achieve the same reference time synchronization between its own subsystem and other subsystems. In some embodiments, the control units 112 of the local satellite subsystem 110 and the other satellite subsystem 130 respectively complete simultaneous time synchronization with the time synchronization unit 118 of the local satellite subsystem 110 and the other satellite subsystem 130 through their respective network communication paths (e.g., indicated by mark 117). The time synchronization reference of the time synchronization unit 118 of the local satellite subsystem 110 and the other satellite subsystem 130 is the same Beidou navigation satellite, thereby achieving time synchronization consistency of the laser communication terminals of the local satellite subsystem 110 and the other satellite subsystem 130. In some embodiments, the timing unit 118 of the local subsystem 110 and the other subsystem 130 sends a 1PPS pulse signal to the control unit 112 and the two-dimensional turntable unit 120 to enable the laser communication terminal 116 of the local subsystem 110 and the other subsystem 130 and the two-dimensional turntable unit 120 to synchronize time based on the same time reference.

[0037] Regarding the two-dimensional turntable unit 120, it is configured, for example, to simulate the attitude of the corresponding laser communication satellite of its subsystem based on the satellite attitude control signals sent by the control unit. In some embodiments, the control unit 112 performs attitude control of the two-dimensional turntable unit 120, for example, through an RS422 communication interface, in order to simulate the attitude control of the satellite platform where the laser communication terminal 116 is located.

[0038] Regarding the laser communication terminal 116, it is mounted on the two-dimensional turntable unit 120. The laser communication terminal includes a rotation mechanism and is configured to simulate the attitude of the satellite platform where the laser communication terminal of its subsystem is located based on the satellite attitude control signals sent by the control unit. In some embodiments, under a unified time reference, the laser communication terminals 116 of the local subsystem 110 and the other subsystem 130 calculate the spatial coordinate difference between the laser communication terminals of the local subsystem and the other subsystem based on the satellite broadcast data of the local subsystem 110 and the attitude data of the two-dimensional turntable unit 120, combined with the transformation calculation of the coordinate transformation matrix; and based on the calculated spatial coordinate difference, adjust the azimuth and / or elevation angles of the laser communication terminals so that the optical path combination unit 124 of the local subsystem 110 and the other subsystem 130 can complete the real-time high-precision pointing of the laser communication terminals of the local subsystem 110 and the other subsystem 130.

[0039] The test unit 114 is configured to be electrically connected to the control unit and the corresponding laser communication terminal respectively, so as to perform tests on the corresponding laser communication terminal.

[0040] Regarding the optical path combination unit 124, it is disposed on the optical path of the laser emitted or received by the laser communication terminal. The optical path combination unit includes multiple optical elements and is configured to form or disconnect a spatial laser link with the optical path combination units of other subsystems.

[0041] Regarding the micro-perturbation simulation unit 122, it is configured, for example, between the laser communication terminal and the optical path combination unit, and in the optical path of the laser emitted or received by the laser communication terminal. The micro-perturbation simulation unit is configured to move based on a perturbation signal output by the control unit, in order to interfere with the optical path between the laser communication terminal and the optical path combination unit. The perturbation signal is generated based on the NASDA power spectral density function. In some embodiments, the control unit 112 performs real-time control of the micro-perturbation simulation unit 122 through the PZT drive control channel 121, thereby completing the real-time simulation of the perturbation signal.

[0042] Through the aforementioned methods, the system 100 of this invention can simulate the attitude of the satellite platform where the laser communication terminal is located by placing the laser communication terminal on a two-dimensional turntable unit, and enabling the two-dimensional turntable unit to simulate the attitude of the satellite platform based on the satellite attitude control signals sent by the control unit. Furthermore, the laser communication terminal can adjust its attitude based on the pointing control signals of the control unit. Therefore, this invention can simulate the on-orbit operating environment of the laser communication terminal and conduct comprehensive and dynamic functional tests on the adjustable attitude laser communication terminal on the two-dimensional turntable unit with dynamically changing attitude using a test unit. In addition, by achieving the same reference time synchronization for different subsystems through a time synchronization unit, and by forming or disconnecting space laser links between optical path combination units set on the optical paths of laser communication terminals in different subsystems, this invention can effectively meet the requirements for stable link establishment and rapid re-establishment after link loss between laser communication terminals between two satellites.

[0043] Figure 2 schematically illustrates a flowchart of a method 200 for simulating the on-orbit operation environment of a ground-based laser communication terminal according to an embodiment of the present invention. Method 200 may also include additional actions not shown and / or the actions shown may be omitted; the scope of the invention is not limited in this respect.

[0044] In step 202, the control units of the local satellite subsystem and the other satellite subsystem respectively complete the simultaneous time synchronization of the time synchronization units of the local satellite subsystem and the other satellite subsystem, and the time synchronization reference of the time synchronization units is the same as the Beidou navigation satellite.

[0045] In step 204, predetermined pulse signals are sent to the corresponding control unit and two-dimensional turntable unit via the time synchronization units of the local satellite subsystem and the other satellite subsystem, respectively, so as to complete the same reference time synchronization between the corresponding laser communication terminal and the two-dimensional turntable unit.

[0046] For example, in both the local and other satellite subsystems, the corresponding time synchronization unit outputs a first pulse signal to the two-dimensional turntable unit and a second pulse signal to the control unit. The control unit, based on the second pulse signal received from the time synchronization unit, obtains a third pulse signal and outputs it to the laser communication terminal, thus achieving the same time reference synchronization between the corresponding laser communication terminal and the two-dimensional turntable unit in both the local and other satellite subsystems. For instance, the time synchronization unit 118 outputs two pulse signals, such as two 1PPS second pulse signals. One 1PPS second pulse signal is output to the two-dimensional turntable unit 120 in the local satellite subsystem, and the other is output to the control unit 112. The control unit 112, based on the 1PPS second pulse signal received from the time synchronization unit 118, obtains the 1PPS second pulse signal for the laser communication terminal and outputs it to the laser communication terminal 116 according to interface matching requirements, thus achieving the same time reference synchronization between the corresponding laser communication terminal 116 and the two-dimensional turntable unit 120.

[0047] In step 206, under the same time reference, the laser communication terminal in this satellite subsystem calculates the spatial coordinate difference between the laser communication terminal in this satellite subsystem and the laser communication terminal in other satellite subsystems based on satellite broadcast data, attitude data of the two-dimensional turntable unit, and coordinate transformation matrix between the two-dimensional turntable unit and the laser communication terminal.

[0048] Regarding satellite broadcast data, this includes, for example, local satellite broadcast data and other satellite broadcast data. For instance, local satellite broadcast data is generated via a laser communication terminal within the local satellite subsystem. Other satellite broadcast data is generated via a laser communication terminal within another satellite subsystem. Local satellite broadcast data includes, for example, BeiDou satellite time values, local satellite orbit simulation data, other satellite orbit simulation data, solar vector simulation data, and local satellite attitude data. Similarly, local satellite broadcast data includes, for example, BeiDou satellite time values, other satellite orbit simulation data, target satellite orbit simulation data (target satellite orbit simulation data is, for example, the local satellite orbit simulation data corresponding to the local satellite subsystem; it should be understood that target satellite orbit simulation data also includes orbit simulation data from other satellite platforms that interface with other satellite platforms), solar vector simulation data, and other satellite attitude data.

[0049] Methods for generating local satellite broadcast data include, for example, the following: the time synchronization unit uploads the BeiDou satellite time value to the control unit; the control unit packages the BeiDou satellite time value and the acquired attitude data of the two-dimensional turntable unit into a data packet to generate local satellite attitude data, which is then sent to the laser communication terminal; and based on the BeiDou satellite time value, local satellite orbit simulation data, other satellite orbit simulation data, and solar vector simulation data, local satellite broadcast data is generated based on the local satellite attitude data. The local satellite orbit simulation data is constructed from the local satellite attitude data of the local satellite subsystem, and the other satellite orbit simulation data is constructed from the local satellite attitude data of the other satellite subsystem. The method 400 for generating local satellite broadcast data will be described in detail below with reference to Figure 4, and will not be repeated here.

[0050] In step 208, the laser communication terminal in the local satellite subsystem adjusts its azimuth and / or elevation angles based on the calculated spatial coordinate difference, so that the laser communication terminal in the local satellite subsystem can establish or disconnect a space laser link with the laser communication terminal in another satellite subsystem via the corresponding optical path combination unit.

[0051] In the above scheme, the time synchronization unit completes simultaneous time synchronization for the local satellite subsystem and other satellite subsystems, and completes the same reference time synchronization for the corresponding laser communication terminal and the two-dimensional turntable unit. Under the same reference time, based on satellite broadcast data, attitude data of the two-dimensional turntable unit, and coordinate transformation matrix between the two-dimensional turntable unit and the laser communication terminal, the azimuth and / or elevation angle of the laser communication terminal is adjusted so that the laser communication terminal in the local satellite subsystem can establish or disconnect a space laser link with the laser communication terminal in the other satellite subsystem via the corresponding optical path combination unit. This invention can simulate the random adjustment of the satellite platform attitude and overcome the problem of time reference asynchrony between different platforms, realizing real-time high-precision on-orbit search and acquisition of two laser communication terminals between satellites. Therefore, this invention can also effectively meet the needs of stable link establishment and rapid reconstruction after link loss between two laser communication terminals between satellites.

[0052] The method 300 for generating satellite attitude data packets according to an embodiment of the present invention will be described below with reference to Figures 3 and 4. Figure 3 shows a flowchart of the method 300 for generating satellite attitude data packets according to an embodiment of the present invention. Figure 4 shows a schematic diagram of an apparatus 400 for satellite attitude control simulation according to an embodiment of the present invention. The method 300 may also include additional actions not shown and / or the actions shown may be omitted, and the scope of the present invention is not limited in this respect.

[0053] In step 302, the tracking initial time and motion curve of the two-dimensional turntable unit motion trajectory are set via the control unit.

[0054] As shown in Figure 4, the two-dimensional turntable unit 120 can interact with the control unit 112 via a sixth communication interface 420 (e.g., an RS422 communication interface) and a communication protocol. The control unit 112 is configured to support the transmission of motion data from the two-dimensional turntable unit 120 and the real-time reception of status information (e.g., motion data) from the two-dimensional turntable unit 120. The two-dimensional turntable unit 120 is also equipped with a fifth communication interface 418 (e.g., a second pulse interface) for data interaction with the time synchronization unit 118. As shown in Figure 4, the control unit 112 interacts with the laser communication terminal 116 via a first communication interface 410 and a second communication interface 412. The control unit 112 interacts with the time synchronization unit 118 via a third communication interface 414 and a fourth communication interface 416.

[0055] In some embodiments, after the control unit 112 confirms that the predetermined second pulse signal input of the two-dimensional turntable unit is valid, it sets the initial tracking time and motion curve of the motion trajectory of the two-dimensional turntable unit.

[0056] A method for confirming the validity of a predetermined second pulse signal input for a two-dimensional turntable unit includes, for example, powering on a time synchronization unit and outputting a predetermined second pulse signal before setting the initial tracking time and motion curve of the two-dimensional turntable unit's motion trajectory; determining, via a control unit, whether the predetermined second pulse signal is detected; and setting the initial tracking time of the two-dimensional turntable unit's motion trajectory in response to the determination that the predetermined second pulse signal has been detected. For example, after powering on, the time synchronization unit 120 outputs a 1PPS second pulse signal (e.g., the time synchronization unit 120 outputs two 1PPS second pulse signals, one of which is output to the two-dimensional turntable unit 120 via a fifth communication interface 418, and the other is output to the control unit 112 via a third communication interface 414); the control unit 112 determines, for example, whether the predetermined second pulse signal is detected via a second pulse query command to ensure that the predetermined second pulse signal input is valid. If the predetermined second pulse signal is detected, it is determined that the time synchronization of the two-dimensional turntable unit 120, the control unit 112, and the time synchronization unit is consistent, and that the BeiDou satellite time update is complete. If it is determined that the predetermined second pulse signal is not detected, the system continues to determine whether the predetermined second pulse signal has been detected via a second pulse query command. It should be understood that the predetermined second pulse signal and the transmitted time value appear in pairs. Through the above means, the present invention can ensure the validity of the predetermined second pulse signal and its associated time value input in the two-dimensional turntable unit.

[0057] Regarding the motion curve, it is, for example, pre-set by the control unit to indicate the motion data of the satellite platform to be simulated by the two-dimensional turntable platform. This motion curve can be, for example, a sine wave motion curve, a cosine wave motion curve, or a square wave motion curve, or other motion curves. The frequency of the motion curve is, for example, but not limited to, 10 Hz. Additionally, the amplitude of the motion curve frequency can also be pre-set by the control unit. The file format of the motion curve is, for example, but not limited to, ".xlsx".

[0058] In step 304, the initial tracking time is reset to zero, the two-dimensional turntable unit is controlled to start moving, and the BeiDou satellite time value at the moment the initial tracking time is reset to zero is recorded.

[0059] Regarding the BeiDou satellite time value at the initial time reset, it is, for example, the whole second value of the BeiDou satellite time at the initial time reset.

[0060] For example, the control unit 112 resets the initial tracking time to zero and sends the set motion curve to the two-dimensional turntable unit 120 so as to control the two-dimensional turntable unit to start running, and to obtain the status information (e.g., "motion data" or "attitude data") and BeiDou satellite time value of the two-dimensional turntable unit 120 at the time when the initial tracking time is reset to zero.

[0061] Regarding the BeiDou satellite time value, it comes from, for example, the time synchronization unit 118. As shown in Figure 4, the time synchronization unit 118 outputs the BeiDou satellite time value to the control unit 112 via the fourth communication interface 416 (e.g., a communication network port). The transmission protocol of the time synchronization unit 118 is, for example, NTP format.

[0062] In step 306, arbitrary frame data of the return motion data of the two-dimensional turntable unit is extracted to generate the initial data of the satellite attitude data. The return motion data is associated with the BeiDou satellite time value at the time of return.

[0063] The return motion data of the two-dimensional turntable unit is, for example, the attitude data of the two-dimensional turntable unit returned every 10ms.

[0064] For example, the control unit sends a tracking command and extracts the return motion data (i.e., attitude data) of the 2D turntable unit. The control unit also checks whether the flag indicating whether the received current frame attitude data is valid is "1". If the flag indicates that the received current frame attitude data is valid, the received current frame attitude data is stored. The current frame attitude data includes, for example, the inner frame angle value of the 2D turntable unit (the inner frame angle value indicates pitch angle data), the outer frame angle value of the 2D turntable unit (the outer frame angle value indicates azimuth angle data), and the BeiDou satellite time value T2 of the return motion data of the 2D turntable unit.

[0065] In step 308, based on the BeiDou satellite time value at the initial tracking time reset moment and the BeiDou satellite time value at the return moment, the BeiDou satellite time value corresponding to the motion data of the two-dimensional turntable unit is calculated.

[0066] Regarding the BeiDou satellite time value corresponding to the motion data of the two-dimensional turntable unit, it is determined based on the following formula (1): T1=T0+T2 (1)

[0067] In the above formula (1), T1 represents the BeiDou satellite time value corresponding to the motion data of the two-dimensional turntable unit. T0 represents the BeiDou satellite time value at the initial time reset, that is, the integer second value of the control unit 112 at the initial time reset. T2 represents the BeiDou satellite time value at the return time of the return motion data of the two-dimensional turntable unit (the BeiDou satellite time value at the return time is, for example, the sum of the second time and the sequence number in the return motion data).

[0068] In step 310, the motion data of the two-dimensional turntable unit corresponding to the Beidou satellite time value, the inner frame angle value and outer frame angle value of the two-dimensional turntable unit, and the initial data of the satellite attitude data are re-framed in order to generate the satellite attitude data.

[0069] The initial data of the satellite's attitude data (i.e., the first frame data) is used, for example, as a check value in the satellite's attitude data.

[0070] The control unit 112 reframes the motion data of the two-dimensional turntable unit corresponding to the Beidou satellite time value T1, the inner frame angle value and outer frame angle value of the two-dimensional turntable unit, and the initial data of the satellite attitude data, in order to generate the satellite attitude data packet.

[0071] In some embodiments, the control unit 112 further transmits the generated local satellite attitude data to the laser communication terminal of the same subsystem at a frequency of 1 Hz, and further forms and broadcasts local satellite broadcast data based on the local satellite attitude data.

[0072] By employing the above methods, the present invention can utilize each subsystem to simulate the local satellite attitude data of each laser communication terminal operating in orbit on the ground.

[0073] The following description, in conjunction with FIG5, describes a method 500 for generating and broadcasting local satellite broadcast data according to an embodiment of the present invention. FIG5 shows a flowchart of a method 500 for generating and broadcasting local satellite broadcast data according to an embodiment of the present invention. Method 500 may also include additional actions not shown and / or the actions shown may be omitted, and the scope of the present invention is not limited in this respect.

[0074] In step 502, the control unit acquires the motion data of the two-dimensional turntable unit once at a first predetermined time interval. The motion data of the two-dimensional turntable unit includes at least the inner frame angle value and the outer frame angle value of the two-dimensional turntable unit.

[0075] Regarding the first scheduled time, it is, for example, 250ms.

[0076] For example, the control unit 112 of each subsystem captures the return motion data (i.e., attitude data) of the two-dimensional turntable unit every 250ms, and discards the rest of the return motion data.

[0077] The method for acquiring the two-dimensional turntable unit includes, for example, the two-dimensional turntable unit returning its attitude data every 10ms, and incrementing a counter by "1" each time the attitude data is returned, until a predetermined number is reached (the predetermined number is, for example, 25). If the predetermined number is reached, the control unit acquires the returned motion data of the two-dimensional turntable unit once.

[0078] In step 504, the motion data of the two-dimensional turntable unit corresponding to the Beidou satellite time value, the local satellite orbit simulation data, the orbit simulation data of other satellites, the solar vector simulation data, the inner frame angle value and outer frame angle value of the two-dimensional turntable unit, and the initial data of the local satellite attitude data are re-framed and fused to generate local satellite broadcast data.

[0079] Regarding the local satellite orbit simulation data, such as the local satellite attitude data, such as the local satellite attitude data packet of the first satellite.

[0080] Regarding the orbital simulation data of other satellites, this includes, for example, the attitude data of this satellite generated by the control unit of another satellite (e.g., a second satellite) to establish a laser communication link with this satellite. The orbital simulation data of other satellites is, for example, acquired by the control unit of this satellite's subsystem from the control unit of the other satellite's subsystem.

[0081] Regarding solar vector simulation data, it indicates, for example, the position information of the sun.

[0082] For example, the control unit 112 frames the BeiDou satellite time value, the local satellite orbit simulation data, the other satellite orbit simulation data, the solar vector simulation data, and the return motion data of the two-dimensional turntable unit obtained in step 502, so as to generate local satellite broadcast data.

[0083] At step 506, the local satellite attitude data is broadcast at a first predetermined time interval via the control unit; and the local satellite broadcast data is broadcast at a second predetermined time interval.

[0084] Regarding the first scheduled time, it is, for example, but not limited to, 250ms.

[0085] Regarding the second predetermined time, it is, for example, but not limited to, 1 second.

[0086] For example, the control unit 112 broadcasts local satellite broadcast data once every 1 second and broadcasts the return motion data of the two-dimensional turntable unit every 250ms, so that the laser communication terminal of the local satellite subsystem can obtain all the data required to establish a laser communication link with other satellites.

[0087] By employing the above methods, the present invention can utilize each subsystem to generate and broadcast the local satellite broadcast data of the simulated on-orbit satellite, so as to simulate the establishment of laser communication links between multiple laser communication terminals.

[0088] The following description, in conjunction with Figures 6 and 7, describes a method 600 for controlling a rotating structure to complete an initial pre-pointing action according to an embodiment of the present invention. Figure 6 shows a flowchart of the method 600 for controlling a rotating structure to complete an initial pre-pointing action according to an embodiment of the present invention. Figure 7 shows a schematic diagram of a method for establishing a laser communication link between multiple laser communication terminals according to an embodiment of the present invention. Method 600 may also include additional actions not shown and / or the actions shown may be omitted; the scope of the present invention is not limited in this respect.

[0089] At step 602, in the local satellite subsystem, the laser communication terminal continuously receives local satellite broadcast data and other satellite broadcast data.

[0090] The local satellite subsystem, for example, simulates the local satellite platform. The other satellite subsystem, for example, simulates a other satellite platform that needs to establish a laser communication link with the local satellite platform.

[0091] As shown in Figure 7, label 710 indicates the orbits of the local satellite platform and other satellite platforms. Label 712 indicates the direction of movement of the local satellite platform and other satellite platforms. The local satellite platform carries its own laser communication terminal. Label 720 indicates the position of the local satellite platform at time T0. Label 722 indicates the position of the local satellite platform at time T. At time T, the laser communication terminal of the local satellite platform is pointing, for example, in the direction indicated by label 724. It should be understood that during its movement, the local satellite platform will transmit its broadcast data to other satellite platforms, and other satellite platforms will also transmit data to the local satellite platform.

[0092] For example, each satellite platform transmits local satellite broadcast data for simulating its own satellite platform at the falling edge of each 1PPS second pulse. This local satellite broadcast data includes, for example, on-board time (e.g., BeiDou satellite time), local satellite orbit simulation data, other satellite orbit simulation data, solar vector simulation data, and local satellite attitude data.

[0093] At step 604, the laser communication terminal simulates solar outage avoidance operations based on solar vector simulation data in the local satellite broadcast data.

[0094] For example, the laser communication terminal of the local satellite subsystem used to simulate the local satellite platform simulates solar interference avoidance operations based on solar vector simulation data in the acquired local satellite broadcast data.

[0095] Regarding the method for simulating solar outage avoidance, for example, the laser communication terminal calculates in real time the angle between its own laser emission or reception vector data and the simulated solar vector data indicated in the satellite's broadcast data. If the angle indicates that the satellite's laser emission or reception vector and the solar vector are about to converge to the same straight line (e.g., the angle is less than 3°), an early warning is issued so that the azimuth and / or elevation angles of the laser transmitting terminal of the satellite can be adjusted to deviate from the azimuth and / or elevation angles at the time of the warning. If the angle indicates that the satellite's laser emission or reception vector is gradually deviating from the same straight line as the solar vector, the elevation angle of the laser transmitting terminal of the satellite can be restored to the elevation angle at the time of the warning. Thus, the present invention can simulate solar outage avoidance operations.

[0096] In step 606, based on the satellite broadcast data, the orbital data of the satellite associated with the BeiDou satellite time value, the attitude data and velocity information of the two-dimensional turntable unit of the satellite subsystem are obtained during a specific time period.

[0097] For example, through the data acquisition channel of another satellite subsystem, orbital data of another satellite associated with BeiDou satellite time values, attitude data and velocity information of the two-dimensional turntable unit of the other satellite subsystem are acquired during a specific time period. Then, through the data upload channel of the other satellite subsystem, the local satellite broadcast data (i.e., other satellite broadcast data) of the other satellite subsystem is uploaded to the local satellite subsystem. The local satellite subsystem forwards the data to the laser communication terminal of the local satellite subsystem through the telemetry and remote control (CAN communication interface) channel.

[0098] At step 608, based on the attitude data and velocity information of the two-dimensional turntable unit of the other satellite subsystem associated with the BeiDou satellite time value, the position information of the laser communication terminal in the other satellite subsystem at the current moment is calculated.

[0099] As shown in Figure 7, label 730 indicates the position of the other satellite platform at time T0. Label 732 indicates the position of the other satellite platform at time T. At time T, the laser communication terminal of the other satellite platform is pointing, for example, in the direction indicated by label 734. Label 736 indicates the position information of the laser communication terminal in the other satellite subsystem at the current time, calculated by the local subsystem. Label 726 indicates the position information of the laser communication terminal in the local subsystem at the current time, calculated by the other satellite subsystem.

[0100] In step 610, based on the position information of the laser communication of this satellite subsystem and the position information of the laser communication terminal in the other satellite subsystem at the current moment, the initial pre-pointing data of this satellite is calculated.

[0101] As shown in Figure 7, based on the position information 724 of the laser communication in the local satellite subsystem at time T and the position information 734 of the laser communication terminal in the other satellite subsystem at time T, the initial pre-pointing data 728 of the local satellite is calculated. Similarly, based on the position information 734 of the laser communication in the other satellite subsystem at time T and the position information 724 of the laser communication terminal in the local satellite subsystem at time T, the initial pre-pointing data 738 of the other satellite is calculated.

[0102] At step 612, a control signal is generated based on the calculated initial pre-pointing data of the local satellite to control the rotating structure to complete the initial pre-pointing action.

[0103] For example, the control unit of the local satellite subsystem uses the calculated initial pre-pointing data 728 of the local satellite as a control signal to drive the rotation mechanism of the laser communication terminal of the local satellite subsystem to complete the initial pre-pointing action of the local satellite. The control unit of another satellite subsystem generates a control signal based on the calculated initial pre-pointing data 738 of the other satellite to drive the rotation mechanism of the laser communication terminal of the other satellite subsystem to complete the initial pre-pointing action of the other satellite.

[0104] By employing the above methods, the present invention can complete the dual-terminal on-orbit mutual pointing operation of the simulated local satellite platform and other satellite platforms in a laboratory environment.

[0105] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps loaded in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this application can be achieved, and this is not limited herein.

[0106] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors.

Claims

1. A system for simulating the on-orbit operating environment of a ground-based laser communication terminal, characterized in that, The system includes at least: multiple subsystems configured to simulate the on-orbit operating environment of corresponding laser communication terminals, each subsystem including at least a local satellite subsystem and other satellite subsystems, each subsystem including: The control unit is configured to interact with the time synchronization unit, the two-dimensional turntable unit, the corresponding laser communication terminal, and the test unit. The control unit transmits telemetry and remote control data and satellite broadcast data to the laser communication terminal through the data communication path formed between its communication interface and the communication interface of the test unit. The satellite broadcast data includes local satellite broadcast data and other satellite broadcast data. The time synchronization unit includes an antenna and is configured to achieve the same reference time synchronization between its own subsystem and other subsystems. A two-dimensional turntable unit is configured to simulate the attitude of the satellite platform where the laser communication terminal of its subsystem is located based on the satellite attitude control signal sent by the control unit. The laser communication terminal is mounted on the two-dimensional turntable unit and includes a rotation mechanism. The laser communication terminal is configured to drive the rotation mechanism to adjust the position and attitude of the laser communication terminal based on the pointing control signal of the control unit. The test unit is configured to be electrically connected to both the control unit and the corresponding laser communication terminal for testing the laser communication terminal; and An optical path combining unit is disposed on the optical path of the laser emitted or received by the laser communication terminal. The optical path combining unit includes multiple optical elements and is configured to form or disconnect a spatial laser link with the optical path combining units of other subsystems. The local satellite broadcast data is generated by the laser communication terminal in the local satellite subsystem based on the BeiDou satellite time value, the local satellite orbit simulation data, the orbit simulation data of other satellites, the solar vector simulation data, and the local satellite attitude data.

2. The system according to claim 1, characterized in that, Each subsystem also includes: A micro-perturbation simulation unit is configured between the laser communication terminal and the optical path combination unit, and in the optical path of the laser emitted or received by the laser communication terminal, the micro-perturbation simulation unit is configured to move based on a perturbation signal output by the control unit in order to interfere with the optical path between the laser communication terminal and the optical path combination unit, the perturbation signal being generated based on the NASDA power spectral density function.

3. The system according to claim 1, characterized in that, The control unit is also configured to acquire the status information of the two-dimensional turntable unit in real time or at predetermined time intervals.

4. The system according to claim 1, characterized in that, The micro-perturbation simulation unit is a mirror rotation device, and the time synchronization unit uses the BeiDou navigation satellite as its time synchronization reference.

5. A method for simulating the on-orbit operating environment of a ground-based laser communication terminal, said method being performed on a system according to any one of claims 1-4, characterized in that, The method includes: Through the control units of the local satellite subsystem and other satellite subsystems, the time synchronization units of the local satellite subsystem and other satellite subsystems are simultaneously synchronized, and the time synchronization reference of the time synchronization units is the Beidou navigation satellite. The time synchronization units of this satellite subsystem and other satellite subsystems respectively send predetermined pulse signals to the corresponding control unit and two-dimensional turntable unit in order to complete the same reference time synchronization of the corresponding laser communication terminal and two-dimensional turntable unit; Under the same time reference, the laser communication terminal in this satellite subsystem calculates the spatial coordinate difference between the laser communication terminal in this subsystem and the laser communication terminals in other satellite subsystems based on satellite broadcast data, attitude data of the two-dimensional turntable unit, and the coordinate transformation matrix between the two-dimensional turntable unit and the laser communication terminal; and Based on the calculated spatial coordinate difference, the laser communication terminal in this satellite subsystem adjusts its azimuth and / or elevation angles so that it can establish or disconnect a space laser link with the laser communication terminal in another satellite subsystem via the corresponding optical path combination unit.

6. The method according to claim 5, characterized in that, The method further includes: Local satellite broadcast data is generated via laser communication terminals within the local satellite subsystem; and Data is broadcast from another satellite via a laser communication terminal in the satellite subsystem.

7. The method according to claim 5, characterized in that, The process of achieving the same reference time synchronization for the corresponding laser communication terminal and two-dimensional turntable unit includes: In this satellite subsystem and other satellite subsystems, the corresponding time synchronization unit outputs a first pulse signal to the two-dimensional turntable unit and a second pulse signal to the control unit; and The control unit obtains a third pulse signal based on the second pulse signal received from the time synchronization unit and outputs it to the laser communication terminal so as to complete the same reference time synchronization between the corresponding laser communication terminals and two-dimensional turntable units in this satellite subsystem and other satellite subsystems.

8. The method according to claim 6, characterized in that, The local satellite broadcast data, generated via the laser communication terminal in the local satellite subsystem, includes: The time synchronization unit uploads the BeiDou satellite time value to the control unit; The control unit packages the BeiDou satellite time value and the acquired attitude data of the two-dimensional turntable unit into a data packet to form the local satellite attitude data, and then sends the local satellite attitude data to the laser communication terminal. The orbital simulation data of this satellite is constructed from the attitude data of this satellite subsystem, while the orbital simulation data of other satellites is constructed from the attitude data of other satellite subsystems.

9. The method according to claim 8, characterized in that, The attitude data of this satellite includes: The initial tracking time and motion curve of the two-dimensional turntable unit's motion trajectory are set via the control unit; The initial tracking time is reset to zero, and the two-dimensional turntable unit is controlled to start moving, and the BeiDou satellite time value at the moment the initial tracking time is reset to zero is recorded; Extract arbitrary frame data of the return motion data from the two-dimensional turntable unit to generate initial data of the satellite attitude data. The return motion data is associated with the BeiDou satellite time value at the time of return. Based on the BeiDou satellite time values ​​at the initial tracking time reset and the return time, the corresponding BeiDou satellite time values ​​for the motion data of the two-dimensional turntable unit are calculated; and The motion data of the two-dimensional turntable unit is reframed to correspond to the BeiDou satellite time value, the inner frame angle value and the outer frame angle value of the two-dimensional turntable unit, and the initial data of the satellite attitude data, so as to generate the satellite attitude data.

10. The method according to claim 9, characterized in that, The local satellite attitude data also includes: Before setting the initial tracking time and motion curve of the two-dimensional turntable unit's motion trajectory, the time synchronization unit is powered on and outputs a predetermined second pulse signal; The control unit determines whether a predetermined second pulse signal has been detected; and In response to the detection of a predetermined second pulse signal, the initial tracking time of the two-dimensional turntable unit's motion trajectory is set.

11. The method according to claim 8, characterized in that, The data that forms the local satellite broadcast data includes: The control unit acquires motion data of the two-dimensional turntable unit once at a first predetermined time interval. The motion data of the two-dimensional turntable unit includes at least the inner frame angle value and the outer frame angle value of the two-dimensional turntable unit; and The motion data of the two-dimensional turntable unit, corresponding to the Beidou satellite time value, the local satellite orbit simulation data, the orbit simulation data of other satellites, the solar vector simulation data, the inner and outer frame angle values ​​of the two-dimensional turntable unit, and the initial data of the local satellite attitude data are re-fused and framed to generate local satellite broadcast data.

12. The method according to claim 11, characterized in that, Also includes: The control unit broadcasts the satellite's attitude data at predetermined intervals; and The satellite broadcasts data at the second scheduled interval.

13. The method according to claim 6, characterized in that, Also includes: In this satellite subsystem, the laser communication terminal continuously receives broadcast data from this satellite and broadcast data from other satellites; The laser communication terminal simulates solar interference avoidance operations based on solar vector simulation data from the local satellite broadcast data. Based on satellite broadcast data, acquire satellite orbit data associated with BeiDou satellite time values, attitude data and velocity information of two-dimensional turntable units of satellite subsystems during specific time periods; Based on the attitude data and velocity information of the two-dimensional turntable unit of the other satellite subsystem that is associated with the BeiDou satellite time value, the position information of the laser communication terminal in the other satellite subsystem at the current moment is calculated. Based on the location information of the laser communication in this satellite subsystem and the location information of the laser communication terminals in other satellite subsystems at the current moment, calculate the initial pre-pointing data of this satellite; as well as Based on the calculated initial pre-pointing data of the local satellite, a control signal is generated to control the rotating structure to complete the initial pre-pointing action.

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