A Method for Time Allocation of Remote Sensing Satellite Compression Tasks

Abstract

A method for allocating the time of a remote sensing satellite compression task belongs to the field of satellite mission planning, and solves the problems of consuming energy at all times during the operation of the satellite and insufficient satellite storage space. The present invention selects to perform compression in the sunlit area after imaging, and deletes the original imaging data after compression, so as to achieve the purpose of solving the energy and storage problems at the same time. According to the statistics of daily business applications, the results obtained by using the method for allocating the time of a remote sensing satellite compression task are relatively accurate and reasonable, and basically meet the requirements of business applications. If this method is not adopted, the satellite benefits will be discounted.

Description

Technical Field

[0001] The present invention belongs to the field of satellite mission planning, and relates to a method for allocating the time of a compression task for a remote sensing satellite. Background Art

[0002] The mission planning system is an important part of the operation and management platform of an imaging satellite, and is in the position of the nerve center in the ground service application system of the imaging satellite. Its main function is to solve the problems of resource contention and task conflict in the process of imaging satellite task management, and to optimize the utilization efficiency of the satellite. There are some constraints in the process of mission planning for imaging satellites, among which satellite energy and storage capacity are two basic constraints. Due to the increasing data transmission resources, the imaging ability of the satellite has been released, and the energy and storage constraints of the satellite have become more prominent. Therefore, it is necessary to solve the problems of insufficient energy and insufficient storage space in the planning process.

[0003] The satellite operates alternately in the sunlit area and the shadow area. When the satellite is in the sunlit area, it charges to supplement energy. The satellite consumes energy at all times during operation. Among them, compared with the energy consumed during on-orbit standby, the energy consumption during the imaging task, compression task, and data transmission task is higher. Since the time of the imaging task and the data transmission task is fixed, the time selection of the compression task becomes the key to solving the problem of insufficient satellite energy.

[0004] The data generated by the satellite includes the original data generated by the imaging task and the compressed data generated by the compression task. Among them, the amount of original data is several times that of the compressed data. The compressed data is downlinked during data transmission. When the daily generated data volume exceeds the capacity of the on-board memory, how to process the data is the key to solving the problem of insufficient storage space. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a method for allocating the time of a compression task for a remote sensing satellite, which solves the problems of continuous energy consumption during satellite operation and insufficient satellite storage space.

[0006] The technical solution adopted by the present invention to solve the technical problems is as follows:

[0007] A method for allocating the time of a compression task for a remote sensing satellite, the method comprising the following steps:

[0008] Step 1: Obtain the sunlit intervals and shadow intervals within the next week, and arrange them in chronological order;

[0009] Step 2: In the set I of imaging tasks and the set W of data transmission windows that are set, select the imaging tasks and data transmission tasks corresponding to the sunlit intervals and shadow intervals described in Step 1, and form a sunlit interval set S and a shadow interval set P from the corresponding sunlit intervals and shadow intervals;

[0010] Step 3: Sequentially loop through each sunlight interval in the sunlight interval set S, and for the imaging set I within the interval s allocate the compression time and the time to delete the original file, obtaining the compression time set C and the deletion time set D;

[0011] Step 4: Determine whether all the sunlight intervals in the sunlight area set S have been looped through; if so, execute Step 5; if not, return to Step 3;

[0012] Step 5: Determine whether the unassigned imaging task set N is empty; if so, output the allocation result and end the allocation; if not, execute Step 6;

[0013] Step 6: Sort the imaging tasks in the unassigned imaging task set N in ascending order of imaging time, and allocate the compression time and the time to delete the original file for the imaging tasks.

[0014] Preferably, in Step 2, according to the earliest imaging start time in the imaging task set I and the latest data transmission start time in the data transmission window set W select the sunlight interval set and the shadow interval set within the interval as the available sunlight interval set S and the available shadow interval set P.

[0015] Preferably, Step 3 further includes the following steps:

[0016] Step A: Calculate the corresponding compression duration t s for all the imaging I 1 ={I 2 , I k}, imaging quantity is k, imaging duration is Δt c , i∈(1, k), compression time ratio constant is g, task interval duration is t; the calculation formula is: i

[0017]

[0018] Step B: The end time of the last imaging task is The end time of the sunlight interval is The compression start time The compression end time is

[0019]

[0020]

[0021] Step C: When is true, execute Step D; when When it is time, execute step E;

[0022] Step D: When the sunny interval can cover the compression duration, sort the imaging tasks in ascending order of imaging duration; the compression start time is The start time for deleting the original file is The time interval between the end of compression and the start of deletion is d, and the calculation formula is:

[0023]

[0024]

[0025]

[0026] Add the compression start time of each imaging task to set C, add the deletion time to set D, and update the start time of the current sunny interval in set S to

[0027] Step E: When the available sunny interval cannot cover the compression duration, the duration needs to be reduced It is:

[0028]

[0029] Let the number of imaging tasks to be reduced be x, and the minimum reduction imaging duration that meets the conditions It is:

[0030]

[0031] The imaging task set I s ″ = {I 1 , I 2 ,..., I k-x}, the compression data ratio is a constant c less than 1, the constant amount of data written by the satellite per second is w, and the calculation formula for the storage space U used is:

[0032]

[0033] In order to release the storage space to the maximum extent, select a non-empty subset I s in the imaging task set I that satisfies the sum of task durations being greater than s ′ and the minimum task duration of x elements.

[0034] I s ″ = I s - I s ′

[0035] Sort the imaging tasks in I s ″ in ascending order of imaging duration; the compression start time is The start time of deleting the original file is The time interval between the end of compression and the start of deletion is d, and the deletion duration is d′. The calculation formula is:

[0036]

[0037]

[0038]

[0039] Add the compression start time of each imaging task to set C, add the deletion time to set D, and update the start time of the current sunlit interval in set S to Add the imaging tasks in I s ′ to set N.

[0040] Preferably, step six includes the following steps:

[0041] Step a: Take the first imaging task in set N. According to the imaging start time and the data transmission start time Select the intervals in sets S and P that are in the interval as the available sunlit interval S′ and the set of available shaded interval P′. The duration set T s ′ of all m available sunlit intervals in set S′ = {t 1 , t 2 ,..., t m}; The duration set T p ′ of all l available shaded intervals in set P′ = {t 1 , t 2 ,..., t l};

[0042] Step b: The imaging duration Δt of the imaging task n , and the compression time The calculation formula is:

[0043]

[0044] Step c: Determine whether there is a duration of a sunlit interval in set T s ′ that is greater than the compression time . If so, execute step d; if not, execute step e;

[0045] Step d: The earliest sunlit interval S′ that meets the conditions x , the start time of the sunlit area The compression time The start time of deleting the original file is The calculation formula is:

[0046]

[0047]

[0048] Add the compression start time of the imaging task to set C, add the deletion time to set D, and update the sunlit area S′ x The start time of the mid-sunlit interval is At the same time, update set S, and return to step five;

[0049] Step e: When , select the earliest sunlit interval S′ 1 and its connected shaded area P′ x , the start time of the sunlit area The calculation formula is:

[0050]

[0051]

[0052] Add the compression start time of the imaging task to set C, add the deletion time to set D, and delete S′ from set S 1 , update the shaded area P′ x The start time of the shaded interval is Return to step five;

[0053] When , select the earliest shaded interval P′ 1 , the start time of the sunlit area The calculation formula is:

[0054]

[0055]

[0056] Add the compression start time of the imaging task to set C, add the deletion time to set D, and update the shaded area P′ 1 The start time of the shaded interval is Return to step five.

[0057] The beneficial effects of the present invention are as follows: A method for allocating the time of the compression task of a remote sensing satellite is proposed in this paper. Compression is performed in the sunlit area after imaging, and the original data of the imaging is deleted after compression, so as to achieve the purpose of solving the energy and storage problems simultaneously. According to the statistics of daily business applications, the results obtained by using the method for allocating the time of the compression task of a remote sensing satellite are relatively accurate and reasonable, and basically meet the requirements of business applications. Description of the Drawings

[0058] Figure 1 Flow chart of a method for allocating compression task time of a remote sensing satellite in the present invention Specific implementation mode

[0059] To make the above features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings, but the protection scope of the present invention should not be limited thereby

[0060] As Figure 1 shown, a method for allocating compression task time of a remote sensing satellite, the method includes the following steps

[0061] Step 1: Obtain the sunlit intervals and shadow intervals within the next week and arrange them in chronological order

[0062] Step 2: In the set of imaging tasks I and the set of data transmission windows W that are set, select the imaging tasks and data transmission tasks corresponding to the sunlit intervals and shadow intervals described in Step 1, and form the sunlit interval set S and the shadow interval set P for the corresponding sunlit intervals and shadow intervals; among them, according to the earliest imaging start time in the set of imaging tasks I and the latest data transmission start time in the set of data transmission windows W select the sunlit interval set and the shadow interval set in the interval as the available sunlit interval set S and the available shadow interval set P

[0063] Step 3: Loop through each sunlit interval in the sunlit interval set S in turn, and allocate compression time and time for deleting original files for the imaging set I within the interval, to obtain the compression time set C and the deletion time set D; specifically, it includes the following steps s Step A: Calculate the corresponding compression duration t

[0064] for all imaging I s ={I 1 , I 2 ,..., I k} within the current sunlit interval, the number of imaging is k, the imaging duration is Δt c , i∈(1, k), the compression time ratio constant is g, and the task interval duration is t; the calculation formula is i Step B: The end time of the last imaging task is

[0065]

[0066] The sunlit interval end time is The compression start time The compression end time is

[0067] ​

[0068]

[0069] Step C: When happens, execute Step D; when happens, execute Step E;

[0070] Step D: When the sunny interval can cover the compression duration, sort the imaging tasks in ascending order of the imaging duration; the compression start time is The start time for deleting the original file is The time interval between the compression end and the deletion start is d, and the calculation formula is:

[0071]

[0072]

[0073]

[0074] Add the compression start time of each imaging task to set C, add the deletion time to set D, and update the start time of the current sunny interval in set S to

[0075] Step E: When the available sunny interval cannot cover the compression duration, the duration needs to be reduced to:

[0076]

[0077] Let the number of imaging tasks to be reduced be x, and the minimum reduction imaging duration that meets the conditions is:

[0078]

[0079] The imaging task set I s ″ = {I 1 , I 2 ,..., I k-x}, the compression data ratio is a constant c less than 1, the constant amount of data written by the satellite per second is w, and the calculation formula for the storage space U used is:

[0080]

[0081] In order to release the storage space to the maximum extent, select a non-empty subset I s in the imaging task set I that satisfies the sum of the task durations being greater than s ′ and the minimum task duration for x elements.

[0082] Is ″ = I s -I s ′

[0083] Sort the imaging tasks in I s ″ in ascending order of imaging duration; the compression start time is The start time for deleting the original file is The time interval between the end of compression and the start of deletion is d, and the deletion duration is d′. The calculation formula is:

[0084]

[0085]

[0086]

[0087] Add the compression start time of each imaging task to set C, add the deletion time to set D, and update the start time of the current sunny interval in set S to Add the imaging tasks in I s ′ to set N.

[0088] Step 4: Determine whether all sunny intervals in the sunny area set S have cycled; if so, execute Step 5; if not, return to Step 3;

[0089] Step 5: Determine whether the set N of unassigned imaging tasks is empty; if so, output the allocation result and end the allocation; if not, execute Step 6;

[0090] Step 6: Sort the imaging tasks in the set N of unassigned imaging tasks in ascending order of imaging time, and allocate compression time and original file deletion time for the imaging tasks. Specifically, it includes the following steps:

[0091] Step a: Take the first imaging task in set N, and according to the imaging start time and the data transmission start time Select the intervals in sets S and P that are in the interval as the available sunny interval S′ and the set P′ of available shaded intervals. The duration set T s ′ = {t 1 , t 2 ,..., t m} of all m available sunny intervals in set S′; the duration set T p ′ = {t 1 , t 2 ,..., t l} of all l available shaded intervals in set P′;

[0092] Step b: The imaging duration Δt of the imaging taskn , compression time The calculation formula is:

[0093]

[0094] Step c: Determine the set T s ′ to check if there is a duration of the sunny interval greater than the compression time . If so, execute Step d; if not, execute Step e;

[0095] Step d: The earliest sunny interval S′ that meets the conditions x , the start time of the sunny area compression time Delete the start time of the original file as The calculation formula is:

[0096]

[0097]

[0098] Add the compression start time of the imaging task to set C, add the deletion time to set D, and update the sunny area S′ x in which the start time of the sunny interval is At the same time, update set S and return to Step Five;

[0099] Step e: When , select the earliest sunny interval S′ 1 and its connected shaded area P′ x , the start time of the sunny area The calculation formula is:

[0100]

[0101]

[0102] Add the compression start time of the imaging task to set C, add the deletion time to set D, and delete S′ from set S 1 , update the shaded area P′ x The start time of the shaded interval is Return to Step Five;

[0103] When , select the earliest shaded interval P′ 1 , the start time of the sunny area The calculation formula is:

[0104]

[0105]

[0106] Add the compression start time of the imaging task to set C, add the deletion time to set D, and update the shaded area P'. 1 The start time of the shaded interval is Return to Step 5.

[0107] The selected task time for the instance is: from 05:00:00 on January 14, 2021 to 05:00:00 on January 15, 2021. The planned duration is 24 hours.

[0108] First, select a satellite to complete the matching of the imaging task and the data transmission task, and obtain all the imaging durations and the corresponding data transmission start times.

[0109] Then, select the sunlit intervals and shaded intervals located between the earliest imaging time and the latest data transmission time. As shown in Table 1.

[0110] Table 1 Satellite task times and sunlit intervals

[0111]

[0112] Finally, allocate the compression time and deletion time according to the method in this paper.

[0113] Table 2 shows the satellite compression task execution times and deletion task execution times with a planned duration of 24 hours obtained according to the method in this paper. As shown in Table 2, all the compression task execution periods allocated using the method in this paper are within the sunlit intervals, and when the satellite storage space limit is 900 seconds, the imaging duration on the same day is 1285 seconds, simultaneously solving the energy problem and the storage problem. The method in this paper can well meet the daily business applications. If this method is not adopted, the satellite benefits will be discounted.

[0114] Table 2 Satellite compression task times and deletion task times

[0115]

[0116] The above are only the preferred embodiments of the present invention. Obviously, the above embodiments are only examples for clearly illustrating the designed lens and are not limitations on the implementation manners; for those of ordinary skill in the art in the technical field, other different forms of changes or variations can be made based on the above description; it is not necessary and impossible to enumerate all the implementation manners here; and the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for allocating the time of a remote sensing satellite compression task, characterized in that, the method comprises the following steps: Step 1: Obtain the sunlit intervals and shadow intervals within the next week and arrange them in chronological order; Step 2: In the set of imaging tasks I and the set of data transmission windows W that are set, select the imaging tasks and data transmission tasks corresponding to the sunlit intervals and shadow intervals described in Step 1, and form the corresponding sunlit interval set S and shadow interval set P from the sunlit intervals and shadow intervals; Step 3: Sequentially loop through each sunlight interval in the sunlight interval set S, and for the imaging set I within the interval s Allocate compression time and original file deletion time to obtain a compression time set C and a deletion time set D; Step 4: Determine whether all the sunlit intervals in the sunlit area set S have cycled through; If so, execute Step 5; if not, return to Step 3; Step 5: Determine whether the set N of unallocated imaging tasks is empty; if so, output the allocation result and end the allocation; if not, execute Step 6; Step 6: Sort the imaging tasks in the set N of unallocated imaging tasks in ascending order of imaging time, and allocate compression time and original file deletion time for the imaging tasks; The said Step 3 further comprises the following steps: Step A: According to all the images I within a current sunlight interval s ={I 1 , I 2 ,..., I k}, calculate its corresponding compressed duration as t c , the number of images is k, the imaging duration is Δt i , i ∈ (1, k), the compression time ratio constant is g, the task interval duration is t; the calculation formula is: Step B: The end time of the last imaging task is The end time of the sunny illumination interval is The start time of compression The end time of compression is Step C: When occurs, execute Step D; when occurs, execute Step E; Step D: When the sunlight interval can cover the compression duration, sort the imaging tasks in ascending order of imaging duration; the compression start time is The start time for deleting the original file is The time interval between the end of compression and the start of deletion is d, and the calculation formula is: Add the compression start time of each imaging task to set C, add the deletion time to set D, and update the start time of the current sunny interval in set S to Step E: When the available sunny interval cannot cover the compressed duration, the duration needs to be reduced. It is: Let the number of imaging tasks to be reduced be x, and the minimum reduced imaging duration that meets the conditions is as follows: Imaging task set I s ″ = {I 1 , I 2 ,..., I k-x}, where the compression data ratio is a constant c less than 1, the constant amount of data written by the satellite per second is w, and the calculation formula for the storage space U used is: To maximize the release of storage space, among the imaging task set I s select a non-empty subset I ' of x elements that satisfy the sum of task durations being greater than s ' and having the minimum task duration; I s ″ = I s -I s ′ Sort the imaging tasks in ascending order of imaging duration; the compression start time is s ″ The start time for deleting the original file is The time interval between the end of compression and the start of deletion is d, and the deletion duration is d′. The calculation formula is: Add the compression start time of each imaging task to set C, add the deletion time to set D, and update the start time of the current sunny interval in set S to Add the imaging tasks in s I' to set N.

2. A method for allocating the time of a remote sensing satellite compression task according to claim 1, characterized in that, In the second step, according to the earliest imaging start time in the imaging task set I and the latest data transmission start time in the data transmission window set W select the set of sunlit intervals and the set of shaded intervals in the interval as the available sunlit interval set S and the available shaded interval set P.

3. A method for allocating the time of a remote sensing satellite compression task according to claim 1, characterized in that, The said Step 6 comprises the following steps: Step a: Take the first imaging task in set N and calculate the imaging start time And data transmission start time In the set S, P, select The intervals are used as the available sunshine intervals S′ and the available shadow intervals set P′, and the duration set T′ of all m available sunshine intervals in the set S′ s ={t 1 , t 2 , ..., t m }; The duration set T of all l available sunshine intervals in the set P′ p ′={t 1 , t 2 , ..., t l }; Step b: Imaging duration Δt of the imaging task n , compression time The calculation formula is as follows: Step c: Determine the set T s ′ to see if there is a duration of the sunny interval greater than the compression time . If so, execute Step d; if not, execute Step e; Step d: The earliest sunlight interval S' that meets the conditions x , start time of the sunlight area compression time The start time for deleting the original file is The calculation formula is: Add the compression start time of the imaging task to set C, add the deletion time to set D, and update the sunny area S′ x The start time of the mid-sunny interval is At the same time, update set S and return to step five; Step e: When occurs, select the earliest sunlight interval S′ 1 and its connected shaded area P′ x . The calculation formula for the start time of the sunlight area is as follows: Add the compression start time of the imaging task to set C, add the deletion time to set D, and delete S′ from set S 1 , and update the shadow area P′ x The start time of the shadow interval is Return to step five; When the earliest shaded interval P' selected 1 the start time of the sunlit area is calculated as follows: Add the compression start time of the imaging task to set C, add the deletion time to set D, and update the shadow area P'. 1 The start time of the shadow interval is Return to step five.

Images