Acceleration Method for Satellite Observation Orbit Calculation

Abstract

The present invention belongs to the technical field of satellite observation orbit calculation, and particularly relates to an acceleration method for satellite observation orbit calculation. It includes: S1: Obtain the two-line orbital elements of all satellites to be observed, and store all satellites to be observed in the telescope control system; S2: Query the number of cores of the CPU of the computer used by the telescope control system, and allocate n calculation threads according to the number of cores of the CPU; S3: Arrange all satellites to be observed in order into the calculation queue; S4: Start all calculation threads, and the calculation threads in the idle state sequentially obtain the satellites to be observed in the calculation queue, and calculate the observation orbits of the satellites to be observed according to the variable step size method until there are no satellites to be observed in the calculation queue. The present invention can greatly reduce the time-consuming of satellite observation orbit calculation, which is beneficial to improving the working efficiency of astronomical observation research experiments and the user experience of operators.

Description

Technical Field

[0001] The present invention belongs to the technical field of satellite observation orbit calculation, and particularly relates to an acceleration method for satellite observation orbit calculation. Background Art

[0002] The horizon telescope has the function of tracking and observing artificial satellites, which plays an important role in the attitude monitoring, astronomical positioning, and orbit measurement of artificial satellites. Satellite tracking usually uses the Two-Line Element Set (TLE) to calculate the observable orbit of an artificial satellite and guides the telescope for tracking and observing. The Two-Line Element Set is an orbit coding method. At a given epoch, using a suitable prediction model, the position and velocity of the target at any point on the orbit can be calculated with a certain accuracy. The calculation models corresponding to the Two-Line Element Set are Simplified Perturbations Models (SPG), and usually, the SGP4 model and the SDP4 model are used to calculate the motion trajectory of the artificial satellite in the observable time period. The satellite calculation parameters mentioned later refer to the Two-Line Element Set.

[0003] The currently commonly used satellite orbit calculation method is as follows: Given a set of satellite calculation parameters and a time period for calculating the orbit. For each satellite, calculate the observation pointing (azimuth and elevation) for each second within this time period. If the elevation angle is greater than 0°, then the satellite is in an observable state; if the elevation angle is less than 0°, then the satellite is in an unobservable state. Arrange the consecutive pointings with an elevation angle greater than 0° in chronological order, which is called an observable arc segment. For a certain site, a satellite may have 0, 1, or multiple observable arc segments within a time period. Calculating the observable arc segments of satellites according to the existing method takes a long time, especially when calculating the observable arc segments based on multiple sites and multiple satellites, this problem is particularly prominent. Summary of the Invention

[0004] In view of this, the present invention aims to provide an acceleration method for satellite observation orbit calculation to solve the problem that the existing method takes a long time to calculate the observable arc segments of satellites. When the telescope control system needs to calculate the observation orbits of a large number of satellites, the present invention can significantly reduce the orbit calculation time, which is beneficial to improving the work efficiency of astronomical observation research experiments and the user experience of operators.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows:

[0006] An acceleration method for satellite observation orbit calculation specifically includes the following steps:

[0007] S1: Obtain the two-line orbital elements of all satellites to be observed, and store all satellites to be observed in the telescope control system;

[0008] S2: Query the number of cores of the CPU of the computer used by the telescope control system, and allocate n computing threads according to the number of cores of the CPU;

[0009] S3: Arrange all satellites to be observed in order into the computing queue;

[0010] S4: Start all computing threads. The computing threads in the idle state obtain the satellites to be observed in the computing queue in order, and calculate the observation orbits of the satellites to be observed according to the variable step size method until there are no satellites to be observed in the computing queue.

[0011] Further, in the computing queue, medium and high orbit satellites are sorted first, and low orbit satellites are sorted later.

[0012] Further, in step S2, the number of computing threads is less than the number of cores of the CPU.

[0013] Further, step S4 specifically includes the following steps:

[0014] S41: Start all computing threads;

[0015] S42: The computing threads in the idle state obtain the satellites to be observed with the highest priority in the computing queue, and calculate the observation orbits of the satellites to be observed according to the variable step size method;

[0016] S43: Check whether there are satellites to be observed in the computing queue. If so, execute step S42; otherwise, end the computing task.

[0017] Further, in step S42, the specific steps for a single idle computing thread to calculate the observation orbit of the satellite to be observed according to the variable step size method include:

[0018] S421: Set the start time for calculating the satellite to be observed as and the end time as ;

[0019] S422: Calculate the azimuth pointing and elevation pointing of the satellite to be observed at the current time t, set the initial value of t as and set the azimuth pointing of the satellite to be observed as and the elevation pointing of the satellite to be observed as ;

[0020] S423: Update the current time t according to the variable step size method;

[0021] S424: If after being updated in step S423 , then step S422 is executed based on the updated t, otherwise the calculation of the observation orbit of the satellite to be observed ends.

[0022] Further, step S423 specifically includes the following steps:

[0023] Set the reference calculation step size to , and the unit of the reference calculation step size value is seconds;

[0024] When the satellite to be observed is a medium-high orbit satellite, if the pitch pointing , then the calculation step size , where , if the pitch pointing , then set the calculation step size in minutes;

[0025] When the satellite to be observed is a low-orbit satellite, if the pitch pointing , then , if the pitch pointing , then set the calculation step size in seconds, if the pitch pointing , then set the calculation step size in minutes.

[0026] Further, during the process of a single calculation thread obtaining the satellite to be observed, if the calculation queue is empty, then the current calculation thread is destroyed.

[0027] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0028] The acceleration method for calculating the satellite observation orbit according to the present invention uses multi-threaded calculation to improve the utilization rate of the CPU, changing the original single-core serial calculation to multi-core parallel calculation; adopts the variable step size method to greatly shorten the orbit calculation time of a single satellite; when using the variable step size method, due to the particularity of the medium-high orbit satellite observation orbit, the difference in its calculation time is large, while the calculation time of the low-orbit satellite observation orbit is relatively stable. The present invention adopts the method of preferentially processing medium-high orbit satellites, which is beneficial to making the calculation loads of each calculation thread more balanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0030] Figure 1 is a schematic flow chart of the acceleration method for calculating the satellite observation orbit according to the embodiment of the present invention;

[0031] Figure 2 is a schematic flow chart of accelerating the calculation of the orbits of multiple satellites according to the embodiment of the present invention;

[0032] Figure 3 Schematic flow diagram of single-satellite orbit calculation according to an embodiment of the present invention

[0033] Figure 4 Schematic structural diagram of the calculation queue arrangement mode according to an embodiment of the present invention Detailed implementation manners

[0034] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0035] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0036] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0037] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0038] The present invention will be described in detail below with reference to the drawings and in combination with embodiments.

[0039] As Figure 1 - Figure 2As shown in the figure, the acceleration method for satellite observation orbit calculation proposed by the present invention specifically includes the following steps: S1: Obtain the two-line orbital elements of all satellites to be observed, and store all satellites to be observed in the telescope control system; S2: Query the number of cores of the CPU of the computer used by the telescope control system, and allocate n calculation threads according to the number of cores of the CPU; S3: Arrange all satellites to be observed in order into the calculation queue; S4: Start all calculation threads, and the idle calculation threads sequentially obtain the satellites to be observed in the calculation queue, and calculate the observation orbits of the satellites to be observed according to the variable step size method until there are no satellites to be observed in the calculation queue.

[0040] The acceleration method for satellite observation orbit calculation of the present invention is applicable to altazimuth telescopes, and solves the problem of long time-consuming for batch calculation of satellite observation orbits in the telescope control system. The present invention accelerates the calculation of the orbit of a single satellite through the variable step size method, uses multi-thread technology to realize the parallel calculation of the orbits of multiple satellites, and sorts the calculation order of the satellites to be observed in advance, and dynamically allocates the satellites to be observed to each calculation thread during the calculation, so that the load of multiple calculation threads is balanced, and the total time-consuming for satellite observation orbit calculation is greatly shortened.

[0041] The main principle of the present invention is outlined as follows: First, query the number of cores of the CPU (Central Processing Unit) of the computer used by the telescope control system, and allocate calculation threads according to the number of cores; then, divide all satellites to be observed into two categories, one is medium and high orbit satellites, and the other is low orbit satellites, and arrange them in order into the calculation queue; finally, each calculation thread takes the calculation parameters of a satellite to be measured from the head of the calculation queue when it is idle, and calculates the observation orbit of the satellite to be measured according to the variable step size method until the calculation queue is emptied.

[0042] It should be noted that the two-line orbital elements used in the calculation of the present invention are taken from the publicly available database on the Internet; the simplified perturbation model (SPG) for calculating the satellite observation orbit is a publicly available technology and has open source code; the observation site (longitude, latitude and elevation) of the telescope can be measured by the instrument. In addition, the present invention only needs to discuss the acceleration method for orbit generation at a single site. For multiple sites, only the orbit generation steps at a single site need to be repeated. In the present invention, due to the significant reduction in the orbit generation time at a single site, the improvement in the orbit generation efficiency for multiple sites is also very remarkable.

[0043] In some embodiments, in the calculation queue, medium and high orbit satellites are sorted first, and low orbit satellites are sorted later.

[0044] In some embodiments, the number of calculation threads is less than the number of cores of the CPU.

[0045] In some embodiments, step S4 specifically includes the following steps: S41: Start all computing threads; S42: The computing threads in the idle state obtain the satellites to be observed with the earliest order in the computing queue, and calculate the observation orbits of the satellites to be observed according to the variable step size method; S43: Check whether there are satellites to be observed in the computing queue. If so, execute step S42; otherwise, end the computing task.

[0046] It should be noted that in step S42, if the number of computing threads in the idle state is greater than or equal to 2, taking two as an example, the two computing threads obtain the two satellites to be observed with the earliest order in the computing queue for calculation. Further, each computing thread randomly assigns one of the two satellites to be observed for calculation, and the satellites assigned to the two computing threads are different. There is no absolute order of acquisition for the computing threads.

[0047] In some embodiments, during the process of a single computing thread obtaining the satellites to be observed, if the computing queue is empty, the current computing thread is destroyed and the resources are released.

[0048] The traditional satellite trajectory calculation method is to calculate the pointing of the satellite to the station location for each whole second within a specified time period, and then connect all the pointings with a continuous pitch angle greater than 0° to form several observable arc segments. However, calculating all the whole second times will obviously cause serious waste of time.

[0049] In the present invention, taking a geosynchronous satellite as an example, the height of the geosynchronous satellite is about 36,000 km, and the changes in its azimuth and pitch pointings are both less than . If the geosynchronous satellite is within the observable range (pitch angle greater than 0°) at a certain time point, the calculation step size of its observation trajectory can be appropriately increased, and the observation pointings at the remaining non-calculation time points can be calculated using the trajectory fitting method. If the satellite is outside the observable range (pitch angle less than or equal to 0°) at a certain time point, it is very likely that it will not enter the observable range for a long time. At this time, the calculation step size can be set to a larger value.

[0050] Taking a low-earth orbit satellite as an example, the orbital height of the low-earth orbit satellite is about 500 km, and the changes in its azimuth and pitch pointings are usually relatively fast. If the low-earth orbit satellite is within the observable range (pitch angle greater than 0°) at a certain time point, the pointings of all whole seconds of this low-earth orbit satellite are still calculated. If the low-earth orbit satellite is outside the observable range (pitch angle less than 0°) at a certain time point, its calculation step size can be dynamically adjusted according to the pitch angle of the pointing at this time point to ensure finding the next observable start time in a shorter time.

[0051] For the above reasons, the present invention adopts different variable step size calculation methods for medium-high orbit and low-earth orbit satellites.

[0052] In some embodiments, such as Figure 3 shown, in step S42, the specific steps for a single computing thread in the idle state to calculate the observation orbit of the satellite to be observed according to the variable step size method include: S421: Set the start time of calculating the satellite to be observed as , and the end time as ; S422: Calculate the azimuth pointing and elevation pointing of the satellite to be observed at the current time t, set the initial value of t as , set the azimuth pointing of the satellite to be observed as , and the elevation pointing of the satellite to be observed as ; S423: Update the current time t according to the variable step size method; S424: If after being updated in step S423, then execute step S422 based on the updated t, otherwise end the calculation of the observation orbit of the satellite to be observed.

[0053] Set the reference calculation step size as , and the unit of the reference calculation step size value is seconds;

[0054] When the satellite to be observed is a medium-high orbit satellite, if the elevation pointing , then the calculation step size , where , if the elevation pointing , then set the calculation step size in the order of minutes;

[0055] It should be noted that the value of n is related to the satellite orbit altitude (i.e., the pointing movement speed). The larger the satellite orbit altitude, the smaller its pointing movement speed, and the larger n can be taken. The smaller the satellite orbit altitude, the larger its pointing movement speed, and the smaller n can be taken. To ensure the tracking accuracy, the value range of n is . Through experimental statistics, it is found that for all medium-high orbit satellites used in the experiment, setting n = 10 can not only meet the tracking accuracy, but also greatly reduce the calculation amount and the complexity of program writing.

[0056] When the satellite to be observed is a low-orbit satellite, if the elevation pointing , then , if the elevation pointing , then set the calculation step size in the order of seconds, if the elevation pointing , then set the calculation step size in the order of minutes.

[0057] It should be noted that the elevation pointing , indicating that the satellite has moved below the horizon and is in an unobservable state. When the satellite to be observed is a medium- to high-earth orbit satellite, since the medium- to high-earth orbit satellite moves slowly, the satellite will be in an unobservable state for a relatively long period of time in the future. Therefore, its calculation step size is set in minutes to reduce the number of calculations. When the satellite to be observed is a low-earth orbit satellite, during the process from the satellite moving below the horizon this time to moving above the horizon next time, the pitch pointing may experience one or more processes of first decreasing and then increasing. During this process, the pitch pointing satisfies . And during this process, as decreases, the calculation step size is gradually increased, and as increases, the calculation step size is gradually decreased, which can achieve the purpose of variable step size.

[0058] In some embodiments, when the satellite to be observed is a medium- to high-earth orbit satellite, the following method is used to update the calculation step size: If the pitch pointing , then ; if the pitch pointing , then .

[0059] When the satellite to be observed is a low-earth orbit satellite, the following method is used to update the calculation step size:

[0060] If the pitch pointing , then ;

[0061] If the pitch pointing satisfies , then ;

[0062] If the pitch pointing satisfies , then ;

[0063] If the pitch pointing satisfies , then ;

[0064] If the pitch pointing satisfies , then ;

[0065] If the pitch pointing , then .

[0066] If the above strategy is used, the orbital calculation time of a single satellite will be significantly shortened. Taking the calculation of the satellite orbit within 24 hours at a certain site as an example, for different satellites, the optimization effect of the number of calculations is as follows:

[0067] 1) If calculating medium and high orbit satellites and they are all within the observable range during all time periods, the number of calculations before optimization is 86,400, the number of calculations after optimization is 8,640, and the reduction rate is 90%.

[0068] 2) If calculating medium and high orbit satellites and they are all not within the observable range during all time periods, the number of calculations before optimization is 86,400, the number of calculations after optimization is 144, and the reduction rate is 99.8%.

[0069] 3) If calculating low orbit satellites, taking 100 randomly selected low orbit satellites as an example, the number of calculations for each satellite is counted. Before optimization, the number of calculations for each satellite is 86,400, and after optimization, the average number of calculations for each satellite is 4,383, and the reduction rate is 94.9%.

[0070] Medium and high orbit satellites are not completely stationary. Especially, the movement speed of medium orbit satellites is greater than that of high orbit satellites. Medium and high orbit satellites may be observable for some time and unobservable for some time during the calculation time period. Here, only the extreme cases are discussed, which have little impact on the overall performance optimization.

[0071] In this invention, multi-thread load balancing mainly means that the total execution time of each calculation thread should be as close as possible. Since this invention uses a variable step size method to calculate the observation orbit of a single satellite, it is impossible to predict the number of observations that need to be calculated for a satellite before calculating its observation orbit. If based on the principle of evenly distributing satellite calculation parameters among all calculation threads, and exactly the calculation threads calculate all high orbit satellites within the observable range, while the calculation threads calculate all high orbit satellites outside the observable range, then the high load of the calculation thread will lead to an increase in the overall orbit calculation time.

[0072] Considering the characteristics that the number of calculations for a single medium and high orbit satellite fluctuates greatly, while the number of calculations for a single low orbit satellite fluctuates little, this invention puts all satellite calculation parameters into the calculation queue in the order of medium and high orbit first and then low orbit, and the arrangement is as Figure 4 . Each calculation thread takes the calculation parameters of a satellite from the queue during the calculation idle time, so as to ensure the load balance of all calculation threads.

[0073] Generally speaking, the generation time of the satellite observation orbit is greatly shortened. Taking 10 different station sites as an example, all observable arcs of 200 satellites within 24 hours are calculated.

[0074] Using the existing method, when calculating with a computer with an Intel(R) Core(TM) i9-11900K @3.50GHz CPU, the average calculation time for the pointing of a single satellite at each whole second point for a single site is 0.0012 ms. The total time taken for the pointing at each whole second point of 200 satellites at 10 sites within 24 hours is 207 seconds.

[0075] When calculating with a computer with an Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz, the average calculation time for the pointing of a single satellite at each whole second point for a single site is 0.0026 ms. The total time taken for the pointing at each whole second point of 200 satellites at 10 sites within 24 hours is 449 seconds.

[0076] Using the present invention, when the computer CPU model is Intel(R) Core(TM) i9-11900K @3.50GHz and 8 threads are used for calculation, the total calculation time is 2.8 seconds, with a reduction rate of up to 98.6%.

[0077] When the computer CPU model is Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz and 4 threads are used for calculation, the total calculation time is 18.3 seconds, with a reduction rate of up to 95.9%.

[0078] This shows that using the present invention to accelerate the generation of satellite observation orbits can not only utilize multi-core processors to accelerate the calculation of orbits of multiple satellites, but also significantly reduce the orbit calculation time of a single satellite in each calculation thread. Therefore, in the case of generating observation orbits for hundreds of satellites at multiple sites, the user experience and work efficiency of the operator will be greatly improved.

[0079] In the existing method for accelerating the calculation of satellite orbits by combining a CPU and a GPU, NVIDIA graphics cards are usually used for acceleration in terms of device selection. However, in the deployment plan of an optoelectronic telescope, the computers used for calculating satellite orbits rarely have high-end graphics cards configured. In most cases, they do not have the conditions for GPU accelerated computing, and the GPU acceleration effect of using low-end graphics cards cannot meet the expectations, which greatly increases the device cost. Currently, multi-core CPUs have become the standard configuration of computers. The optimization scheme based on the CPU proposed in the present invention can significantly save the device cost and improve the portability of the software. Secondly, from the perspective of the professional skills of software R & D personnel, usually R & D personnel in the field of image processing or artificial intelligence are proficient in using programming methods based on CUDA or OpenCL parallel computing. However, the calculation of satellite observation orbits usually belongs to the work content of control software R & D personnel, who need to have a certain understanding of principles such as two-line orbital elements and orbit determination. It is relatively demanding for R & D personnel to have both the above capabilities. However, R & D personnel can use the method proposed in the present invention to achieve satellite observation orbit calculation with relatively low difficulty and a short R & D cycle. Moreover, the prior art does not propose the specific use of solving satellite orbits. They all solve satellite orbits with a step size of 1 s. However, the present invention solves satellite orbits for a ground-based optoelectronic telescope and only focuses on the arc segment with an elevation angle greater than 0°. When the elevation angle is less than 0°, in order to quickly find the next observable arc segment, not all whole second points are calculated, which greatly reduces the time cost of calculation.

[0080] It should be understood that various forms of the processes shown above can be used, with steps reordered, added, or deleted. For example, the steps recorded in the disclosure of the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution disclosed in the present invention can be achieved. No limitation is imposed herein.

[0081] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. 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. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for accelerating satellite observation orbit calculation, characterized in that: The specific steps include: S1: Obtain the two-row orbit elements of all satellites to be observed, and store all satellites to be observed in the telescope control system; S2: Query the number of CPU cores of the computer used by the telescope control system, and allocate n computing threads according to the number of CPU cores; S3: Put all satellites to be observed into the calculation queue in order; S4: Start all computing threads. The computing threads in the idle state sequentially obtain the satellites to be observed in the computing queue and calculate the observation orbits of the satellites to be observed according to the variable step size method until there are no satellites to be observed in the computing queue. The steps of the computing thread in an idle state sequentially acquiring the satellites to be observed in the computing queue and calculating the observation orbits of the satellites to be observed according to the variable step length method include: S421: Set the starting time for calculating the satellite to be observed to , the end time is ; S422: Calculate the azimuth and elevation of the satellite to be observed at the current time t, and set the initial value of t to , set the azimuth of the satellite to be observed to , the elevation direction of the satellite to be observed is ; S423: Update the current time t according to the variable step size method; Step S423 specifically includes the following steps: Set the benchmark calculation step size to , the unit of the benchmark calculation step value is seconds; When the satellite to be observed is a medium-orbit satellite, if the pitch direction , then calculate the step length ,in , if the pitch is pointing , then set the calculation step size in minutes; When the satellite to be observed is a low-orbit satellite, if the pitch direction ,but , if the pitch is pointing , then set the calculation step size in seconds. If the pitch direction , then set the calculation step size in minutes; S424: If the updated , then execute step S422 based on the updated t, otherwise terminate the observation orbit calculation of the satellite to be observed.

2. The method for accelerating satellite observation orbit calculation according to claim 1, characterized in that: In the calculation queue, medium and high orbit satellites are sorted first, and low orbit satellites are sorted later.

3. The method for accelerating satellite observation orbit calculation according to claim 1, characterized in that: In step S2, the number of computing threads is less than the number of CPU cores.

4. The method for accelerating satellite observation orbit calculation according to claim 1, characterized in that: Step S4 specifically includes the following steps: S41: Start all computing threads; S42: the computing thread in the idle state obtains the first-ordered satellite to be observed from the computing queue, and calculates the observation orbit of the satellite to be observed according to the variable step size method; S43: Check whether there are satellites to be observed in the calculation queue. If so, execute step S42; otherwise, end the calculation task.

5. The method for accelerating satellite observation orbit calculation according to claim 1, characterized in that: When a single computing thread is in the process of acquiring satellites to be observed, if the computing queue is empty, the current computing thread will be destroyed.

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