A laser pointing determination method based on fixed light emission time

Abstract

This invention relates to the field of aerospace technology, and particularly to a laser pointing method based on a fixed laser emission time. Addressing the need for optical payloads to periodically and accurately point to specific ground stations, a laser pointing method is designed, consisting of two main steps: prediction and search. In the prediction phase, the satellite extrapolates its orbit based on pre-loaded orbital parameters from the ground station. Based on the satellite's three-axis attitude when the laser payload points to the ground station, the optimal emission time for the future phase is obtained. In the precise search phase, near the predicted optimal emission time, the satellite updates its optimal emission time and attitude based on real-time acquired orbital parameters, further improving accuracy, and generates commands in advance to initiate attitude maneuvers. The method proposed in this invention significantly improves the satellite's calculation efficiency for the optimal laser emission time and the pointing accuracy of the payload when pointing to the ground station, solving practical problems in on-orbit satellite applications and demonstrating practicality.

Description

Technical Field

[0001] This invention relates to the field of aerospace technology, and in particular to a method for determining laser pointing based on a fixed light emission time. Background Technology

[0002] The satellite is in a sun-synchronous orbit with a descending node local time of 10:30 AM, at an altitude of approximately 505 km. It is equipped with a ground-based laser ranging payload, which operates at a fixed frequency in orbit. Ground users periodically calibrate the laser payload's direction. During calibration, the ground-based laser receiver is activated in advance, and the satellite controls the laser to point towards the ground calibration field at a specific moment.

[0003] During the satellite's operation in orbit, it is necessary to perform ground-based fixed calibration field calculations for pre-designated ground stations. During this process, the onboard computer needs to obtain the optimal observation time and attitude of the satellite for the ground station based on the real-time extrapolated predicted orbital position. Before the optimal observation time arrives, the satellite's attitude maneuver is initiated in advance to keep the laser payload carried by the satellite pointing in a fixed direction relative to the orbital coordinate system. This ensures that at the optimal observation time calculated by the control subsystem, the laser payload carried by the satellite can accurately and stably point to the designated ground station. Summary of the Invention

[0004] This invention provides a method, apparatus, electronic device, and storage medium for determining laser direction based on a fixed emission time, which can simulate the radiation characteristics of multi-layered clouds.

[0005] In a first aspect, embodiments of the present invention provide a method for determining laser pointing based on a fixed light emission time, comprising: Step 100: After receiving the ground station forecast permission instruction, mark the current time as the forecast initial time, and determine the optimal forecast time based on the forecast initial time, computer calculation cycle, number of prediction iterations and forecast time length; Step 102: Determine the search time starting point based on the optimal forecast time, the deviation of the laser emission time from whole seconds, and the search limit; and determine the optimal emission time based on the search time starting point, the computer calculation cycle, and the number of search iterations. Step 104: Based on the optimal light emission time, orbital parameters, ground station position, and the installation matrix of the laser payload relative to the satellite body, determine the three-axis attitude angles of the satellite body when the laser payload points to the ground station position at the optimal light emission time. Step 106: Output the optimal light emission time and initiate attitude maneuvering to adjust the three-axis attitude angle of the satellite body to the three-axis attitude angle obtained in step 104.

[0006] Secondly, embodiments of the present invention also provide a laser pointing determination device based on a fixed light emission time, used to implement the method described in any embodiment of this specification, the device comprising: After receiving the command to allow the ground station to forecast, the forecast module marks the current time as the initial forecast time and determines the optimal forecast time based on the initial forecast time, the computer calculation cycle, the number of prediction iterations, and the forecast time length. The light emission calculation module determines the search time starting point based on the optimal prediction time, the deviation of the laser light emission time from the whole second, and the search limit, and determines the optimal light emission time based on the search time starting point, the computer calculation cycle, and the number of search iterations. The attitude calculation module determines the three-axis attitude angles of the satellite body when the laser payload points to the ground station position at the optimal light emission time, based on the optimal light emission time, orbital parameters, ground station position, and the installation matrix of the laser payload relative to the satellite body. The output module outputs the optimal light emission time and initiates attitude maneuvers to adjust the three-axis attitude angle of the satellite body to the three-axis attitude angle obtained in step 104.

[0007] Thirdly, embodiments of the present invention also provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the method described in any embodiment of this specification.

[0008] Fourthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the methods described in any embodiment of this specification.

[0009] Compared with the prior art, the present invention has at least the following beneficial effects: This patent proposes a method for determining the laser pointing on a satellite based on a fixed emission time. Under the constraint of the onboard computer's computing power, it can iteratively extrapolate the satellite orbit step by step and calculate the optimal emission time and pointing attitude of the satellite relative to the ground station. Furthermore, it considers the influence of factors such as a transparent Earth and the emission frequency of the laser payload on the optimal emission time. Simulation and on-orbit practice results show that the algorithm has high accuracy and strong engineering practicality. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a flowchart of a method provided in an embodiment of this patent. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0013] Please refer to Figure 1 This invention provides a method for determining laser pointing based on a fixed light emission time, comprising: Step 100: After receiving the ground station forecast permission instruction, mark the current time as the forecast initial time, and determine the optimal forecast time based on the forecast initial time, computer calculation cycle, number of prediction iterations and forecast time length; Step 102: Determine the search time starting point based on the optimal forecast time, the deviation of the laser emission time from whole seconds, and the search limit; and determine the optimal emission time based on the search time starting point, the computer calculation cycle, and the number of search iterations. Step 104: Based on the optimal light emission time, orbital parameters, ground station position, and the installation matrix of the laser payload relative to the satellite body, determine the three-axis attitude angles of the satellite body when the laser payload points to the ground station position at the optimal light emission time. Step 106: Output the optimal light emission time and initiate attitude maneuvering to adjust the three-axis attitude angle of the satellite body to the three-axis attitude angle obtained in step 104.

[0014] In this embodiment, for optical payloads on an on-orbit agile satellite that require periodic precise pointing to specific ground stations, a laser pointing determination method based on fixed laser times is designed, consisting of two main steps: prediction and search. In the prediction phase, the satellite extrapolates its orbit based on pre-loaded orbital parameters from the ground station, and obtains the optimal laser emission time for the future period based on the satellite's three-axis attitude when the laser payload points to the ground station. In the precise search phase, near the predicted optimal emission time, the satellite updates its optimal emission time and attitude based on real-time acquired orbital parameters, further improving accuracy, and generates commands in advance to initiate attitude maneuvers. The proposed method for calculating the optimal laser emission time and attitude significantly improves the satellite's efficiency in calculating the optimal laser emission time and the pointing accuracy of the payload when pointing to the ground station, solving practical problems in on-orbit satellite applications and demonstrating practicality.

[0015] Below, each step will be explained in detail.

[0016] Before step 100, the relevant information is initialized, specifically including: Upon receiving ground commands, the satellite begins preparations for the optimal observation time prediction procedure for the designated ground station and performs initialization. Initialization information includes: Orbital information: including the satellite's current orbital elements, the satellite's precession nutation matrix, the Earth's polar motion angle, etc. Laser payload information: the angle between the line of sight and the three axes of the satellite body (Pay.ang_opb), and the deviation relative to whole seconds (Cali.Δt_Emit).

[0017] Ground station information: Define the latitude, longitude, and altitude of the ground station: Cali.lamda_Station, Cali.delta_Station, Cali.h_Station; Configuration parameters: forecast duration, forecast success threshold, etc.

[0018] Regarding step 100, after receiving the ground station's forecast permission instruction, the current time is marked as the forecast initial time. Based on the forecast initial time, computer calculation cycle, prediction iteration number, and forecast duration, the optimal forecast time is determined, specifically including:

[0019] Best forecast timing iteration

[0020] tmpt1=Cali.t0+Cali.Cnt_Forecast*Tc+Cali.Δt_Forecast; Cali.t0 is the time when the ground station's forecast permission flag is received; Tc is the computer's calculation cycle, which is typically 125ms. Cali.Cnt_Forecast is the iteration count; Cali.Δt_Forecast is the forecast time length, which is usually fixed at 86400 or 43200s.

[0021] Step 201: Based on the optimal forecast time, orbital parameters, ground station location, and the installation matrix of the laser payload relative to the satellite body, determine the inferred latitude and longitude of the nadir point trajectory at the optimal forecast time, as well as the three-axis attitude angles of the satellite body when the laser payload points to the ground station location.

[0022] In this step, according to the obtained optimal prediction time, as well as the known orbital parameters, the ground station position, and the installation matrix of the laser payload relative to the satellite body, the predicted latitude and longitude of the sub-satellite point trajectory, and the three-axis attitude angles of the satellite body when the laser payload points to the ground station position can be determined at the optimal prediction time.

[0023] The obtained predicted latitude, predicted longitude, and three-axis attitude angles may not necessarily meet the requirements. If they do not meet the requirements, it is necessary to recalculate the optimal prediction time iteratively. Therefore, the following judgment is made: Step 202: Determine whether the deviation between the predicted latitude, the predicted longitude and the latitude and longitude of the ground station exceeds a preset threshold, and determine whether the roll angle and pitch angle in the three-axis attitude angles exceed the maximum values of the satellite attitude roll angle and the satellite attitude pitch angle. If both judgments are negative, execute step 102; otherwise, after adding 1 to the prediction iteration count, execute step 100 again.

[0024] It is determined whether the obtained optimal prediction time is reasonable by judging whether the predicted latitude and longitude (tmpLon, tmpLat) are too far from the ground station position (Cali.lamda_Station, Cali.delta_Station, Cali.h_Station), and whether the roll angle and pitch angle exceed the maximum values set for the satellite. The specific process includes: When the following four conditions are simultaneously satisfied, the predicted tmpt1 moment is the predicted fixed light emission moment, and the prediction of the fixed light emission moment of the satellite to the ground station ends. Output the predicted optimal observation time Cali.T0 = tmpt1, and enter the next step to judge whether to start the precise fixed light emission search program; otherwise, the prediction iteration count Cali.Cnt_Forecast = Cali.Cnt_Forecast + 1, and return to execute step 100; , is the maximum value of the satellite attitude roll angle allowed when the satellite performs laser pointing to the specified ground station at the tmpt1 moment; |tmptheta| < Cali.Lmtθ_Forecast, where Cali.Lmtθ_Forecast is the maximum value of the satellite attitude pitch angle allowed when the satellite performs laser pointing to the specified ground station at the tmpt1 moment; | tmpLon - Cali.lamda_Station | < Cali.Lmtλ_Forecast, where Cali.Lmtλ_Forecast is the maximum range allowed between the longitude of the sub-satellite point coordinate of the satellite and the longitude of the ground station at the tmpt1 moment; | tmpLat-Cali.delta_Station | <Cali.Lmtδ_Forecast, where Cali.Lmtδ_Forecast is the maximum allowable range of the latitude of the satellite's sub-satellite point coordinate and the latitude of the ground station at tmpt1 moment.

[0025] Step 301: Determine whether the current satellite time is greater than the difference obtained by subtracting the reserved attitude maneuver time and the search limit from the best forecast moment in sequence. If it is greater, execute Step 102; otherwise, repeat Step 301. The specific process is as follows: When the following conditions are met, the precise search program for the best light emission moment of the satellite to the ground station is started, and Step 102 is entered; otherwise, Step 301 is repeated. Cali.T0 = tmpt1, t > Cali.T0 - Cali.Δt_Mnv - Cali.Δt_Search, where t is the current satellite time, Cali.Δt_Mnv is the reserved attitude maneuver time of the satellite, and Cali.Δt_Search is the search limit, which is related to the prediction accuracy of the best fixed light emission moment Cali.T0, and generally takes 60s.

[0026] Step 102: Determine the search time start point according to the best forecast moment, the deviation of the laser emission moment relative to the whole second, and the search limit. Determine the best light emission moment according to the search time start point, the computer calculation period, and the number of search iterations. The specific process includes the following: Update the search time start point tmpt0 of the best light emission moment according to the predicted best observation moment Cali.T0, tmpt0 = round(Cali.T0 - Cali.Δt_Search) + Cali.Δt_Emit, where Cali.Δt_Emit is the deviation of the laser emission moment relative to the whole second. After the search time start point tmpt0 of the best light emission moment is determined, calculate the time point tmpt2 of the best laser emission moment for each search iteration, tmpt2 = tmpt0 + Cali.Cnt_Search * Tc, where Cali.Cnt_Search is the number of search iterations. Synchronously update the orbit information of the current moment for the orbit extrapolation prediction at tmpt2 moment. <​​​​ Step 401: Compare the pitch angle from the three-axis attitude angles obtained in step 104 with the roll angle from the historical three-axis attitude angles. If the pitch angle is smaller than the roll angle, delete the historical data and use the three-axis attitude angles obtained in step 104 and the corresponding optimal light emission time as new historical data. Specifically, this includes: The pitch angle tmptheta obtained at the current search time tmpt2 is compared with the historically stored minimum roll angle Cali.Minθ. If tmptheta is less than Cali.Minθ, then Cali.Minθ = tmptheta, and the attitude angle corresponding to time tmpt2 is updated. Cali.Minθ= tmptheta Cali.Minθ_T0=tmpt2 Cali.фt_Mnv=tmphi Cali. θt_Mnv=tmptheta Cali.Ψt_Mnv= tmppsi.

[0028] Step 402: Determine whether the number of search iterations is not less than a preset value obtained based on the search limit and the computer calculation cycle; determine whether the pitch angle in the three-axis attitude angle corresponding to the optimal light emission time obtained in the current search iteration is opposite in sign to the pitch angle in the three-axis attitude angle corresponding to the optimal light emission time obtained in the previous search iteration. If at least one determination result is yes, determine the optimal light emission time and three-axis attitude angle in the historical data as output values ​​and execute step 106; otherwise, increment the number of search iterations by one and execute step 102, which specifically includes: If any of the following three conditions are met, the satellite's precise search for the fixed light emission time of the ground station ends and proceeds to step 106; otherwise, the predicted iteration count is Cali.Cnt_Search = Cali.Cnt_Search + 1, and the process returns to step 102.

[0029] Cali.Cnt_Search≥round(2*Cali.Δt_Search / Tc); Cali.Signθt is negative, and Cali.Signθt_Lst is positive; Cali.Signθt is a positive number, and Cali.Signθt_Lst is a negative number; Where Cali.Signθt is the sign of the elevation angle tmptheta of the satellite pointing to the ground station at the search time tmpt2 corresponding to the current iteration number Cali.Cnt_Search; Cali.Signθt_Lst is the sign of the elevation angle tmptheta of the satellite pointing to the ground station at the search time tmpt2 corresponding to the previous iteration period, i.e., the iteration number Cali.Cnt_Search-1.

[0030] Step 106: Output the optimal light emission time and initiate attitude maneuvers to adjust the satellite's three-axis attitude angles to the three-axis attitude angles obtained in step 104. Specifically, this includes: During several iterations, the minimum roll angle Cali.Minθ and its corresponding light emission time Cali.T0 = Cali.Minθ_T0 are stored to obtain the attitude angle at the optimal light emission time. ,Cali.θt_Mnv,Cali.θt_Mnv, where Cali.Minθ is equal to Cali.θt_Mnv.

[0031] The desired posture to be obtained The output of Cali.θt_Mnv is sent to the satellite management system to generate attitude maneuver commands and initiate attitude maneuvers.

[0032] This invention provides a laser pointing device based on a fixed emission time. The device can be implemented via software, hardware, or a combination of both. From a hardware perspective, the hardware architecture diagram of the electronic device housing the laser pointing device based on a fixed emission time provided in this invention includes, in addition to the processor, memory, network interface, and non-volatile memory, other hardware such as a forwarding chip for processing messages. Taking software implementation as an example, as a logical device, it is formed by the CPU of the electronic device reading the corresponding computer program from the non-volatile memory into memory and running it. The laser pointing device based on a fixed emission time provided in this embodiment includes: After receiving the command to allow the ground station to forecast, the forecast module marks the current time as the initial forecast time and determines the optimal forecast time based on the initial forecast time, the computer calculation cycle, the number of prediction iterations, and the forecast time length. The light emission calculation module determines the search time starting point based on the optimal prediction time, the deviation of the laser light emission time from the whole second, and the search limit, and determines the optimal light emission time based on the search time starting point, the computer calculation cycle, and the number of search iterations. The attitude calculation module determines the three-axis attitude angles of the satellite body when the laser payload points to the ground station position at the optimal light emission time, based on the optimal light emission time, orbital parameters, ground station position, and the installation matrix of the laser payload relative to the satellite body. The output module outputs the optimal light emission time and initiates attitude maneuvers to adjust the three-axis attitude angle of the satellite body to the three-axis attitude angle obtained in step 104.

[0033] It is understood that the structures illustrated in the embodiments of the present invention do not constitute a specific limitation on a laser pointing device based on a fixed emission time. In other embodiments of the present invention, a laser pointing device based on a fixed emission time may include more or fewer components than illustrated, or combine some components, or split some components, or arrange different components. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0034] The information interaction and execution process between the modules in the above-mentioned device are based on the same concept as the method embodiment of the present invention, and the specific details can be found in the description of the method embodiment of the present invention, and will not be repeated here.

[0035] This invention also provides an electronic device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements a laser pointing determination method based on a fixed light emission time according to any embodiment of this invention.

[0036] This invention also provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program causes the processor to perform a laser pointing determination method based on a fixed light emission time according to any embodiment of this invention.

[0037] Specifically, a system or apparatus equipped with a storage medium may be provided, on which software program code implementing the functions of any of the embodiments described above is stored, and the computer (or CPU or MPU) of the system or apparatus may read and execute the program code stored in the storage medium.

[0038] In this case, the program code read from the storage medium can itself implement the function of any of the above embodiments, and therefore the program code and the storage medium storing the program code constitute part of the present invention.

[0039] Storage media embodiments for providing program code include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, program code can be downloaded from a server computer via a communication network.

[0040] Furthermore, it should be clear that not only can the program code read by the computer be executed, but also the operating system or other components operating on the computer can be instructed based on the program code to perform some or all of the actual operations, thereby realizing the function of any of the embodiments described above.

[0041] Furthermore, it is understood that the program code read from the storage medium is written to the memory set in the expansion board inserted into the computer or to the memory set in the expansion module connected to the computer. Then, based on the instructions of the program code, the CPU or other components installed on the expansion board or expansion module execute some and all of the actual operations, thereby realizing the function of any of the above embodiments.

[0042] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0043] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as ROM, RAM, magnetic disk, or optical disk.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining laser pointing based on a fixed light emission time, characterized in that, include: Step 100: After receiving the ground station forecast permission instruction, mark the current time as the forecast initial time, and determine the optimal forecast time based on the forecast initial time, computer calculation cycle, number of prediction iterations and forecast time length; Step 102: Determine the search time starting point based on the optimal forecast time, the deviation of the laser emission time from whole seconds, and the search limit; and determine the optimal emission time based on the search time starting point, the computer calculation cycle, and the number of search iterations. Step 104: Based on the optimal light emission time, orbital parameters, ground station position, and the installation matrix of the laser payload relative to the satellite body, determine the three-axis attitude angles of the satellite body when the laser payload points to the ground station position at the optimal light emission time. Step 106: Output the optimal light emission time and initiate attitude maneuvering to adjust the three-axis attitude angle of the satellite body to the three-axis attitude angle obtained in step 104.

2. The method according to claim 1, characterized in that, After step 100 and before step 102, the following is also included: Step 201: Based on the optimal forecast time, orbital parameters, ground station location, and the installation matrix of the laser payload relative to the satellite body, determine the inferred latitude and longitude of the nadir point trajectory at the optimal forecast time, as well as the three-axis attitude angles of the satellite body when the laser payload points to the ground station location. Step 202: Determine whether the predicted latitude and longitude deviate from the latitude and longitude of the ground station by more than a preset threshold, and determine whether the roll angle and pitch angle in the three-axis attitude angle exceed the maximum values ​​of the satellite attitude roll angle and satellite attitude pitch angle. If both determinations are negative, then proceed to step 102; otherwise, increment the prediction iteration number by one and proceed to step 100 again.

3. The method according to claim 1, characterized in that, After step 100 and before step 102, the following is also included: Step 301: Determine whether the current satellite time is greater than the difference between the optimal forecast time and the reserved attitude maneuver time and the search limit. If it is greater, proceed to step 102; otherwise, repeat step 301.

4. The method according to claim 1, characterized in that, After step 104 and before step 106, the following is also included: Step 401: Compare the pitch angle in the three-axis attitude angles obtained in step 104 with the roll angle in the three-axis attitude angles of the historical data. If it is less than the pitch angle, delete the historical data and use the three-axis attitude angles obtained in step 104 and the corresponding optimal light emission time as the new historical data. Step 402: Determine whether the number of search iterations is not less than a preset value obtained based on the search limit and the computer calculation cycle; determine whether the pitch angle in the three-axis attitude angle corresponding to the best light emission time obtained in the current search iteration is opposite in sign to the pitch angle in the three-axis attitude angle corresponding to the best light emission time obtained in the previous search iteration; if at least one determination result is yes, determine the best light emission time and three-axis attitude angle in the historical data as output values ​​and execute step 106; otherwise, increment the number of search iterations by one and execute step 102.

5. The method according to claim 1, characterized in that, The optimal forecast time is calculated using the following formula: tmpt1=Cali.t0+Cali.Cnt_Forecast*Tc+Cali.Δt_Forecast Where tmpt1 is the optimal forecast time, Cali.t0 is the time when the ground station forecast instruction is received, Tc is the computer calculation cycle, Cali.Cnt_Forecast is the number of forecast iterations, and Cali.Δt_Forecast is the forecast time length.

6. The method according to claim 1, characterized in that, In step 102, the starting point of the search time is calculated using the following formula: tmpt0=round(Cali.T0-Cali.Δt_Search)+Cali.Δt_Emit Where tmpt0 is the starting point of the search time, Cali.T0 = tmpt1 is the optimal prediction time, Cali.Δt_Search is the search limit, and Cali.Δt_Emit is the deviation of the laser emission time from the whole second.

7. The method according to claim 1, characterized in that, In step 102, the optimal light emission time is calculated using the following formula: tmpt2= tmpt0+Cali.Cnt_Search* Tc Where tmpt2 is the optimal light emission time, tmpt0 is the starting point of the search time, Cali.Cnt_Search is the number of search iterations, and Tc is the computer calculation cycle.

8. A laser pointing determination device based on a fixed light emission time, characterized in that, The apparatus for implementing the method as described in any one of claims 1-7 comprises: After receiving the command to allow the ground station to forecast, the forecast module marks the current time as the initial forecast time and determines the optimal forecast time based on the initial forecast time, the computer calculation cycle, the number of prediction iterations, and the forecast time length. The light emission calculation module determines the search time starting point based on the optimal prediction time, the deviation of the laser light emission time from the whole second, and the search limit, and determines the optimal light emission time based on the search time starting point, the computer calculation cycle, and the number of search iterations. The attitude calculation module determines the three-axis attitude angles of the satellite body when the laser payload points to the ground station position at the optimal light emission time, based on the optimal light emission time, orbital parameters, ground station position, and the installation matrix of the laser payload relative to the satellite body. The output module outputs the optimal light emission time and initiates attitude maneuvers to adjust the three-axis attitude angle of the satellite body to the three-axis attitude angle obtained in step 104.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor, when executing the computer program, implements the method as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the method of any one of claims 1-7.

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