阅读说明：本技术 多星多站数据下传调度方法和系统 (Multi-satellite multi-station data downloading scheduling method and system ) 是由 胡笑旋 唐玉芳 靳鹏 夏维 马华伟 唐奕城 罗贺 王国强 孙海权 王俊 程一玲 于 2020-12-09 设计创作，主要内容包括：本发明提供一种多星多站数据下传调度方法和系统,涉及卫星调度技术领域。本发明根据用户要求的成像请求截止时间要求,计算任务最晚下传结束时间,定义任务成像权重,并依据卫星下传时间窗进行聚类,选择可用的地面站进行数据下传。不同于以往研究中基于贪婪等规则进行数据下传调度,提出基于任务截止时间的下传调度策略,使得当前已规划任务下传时间灵敏度较低,提高了求解效率和效果。(The invention provides a multi-satellite multi-station data downloading scheduling method and system, and relates to the technical field of satellite scheduling. According to the imaging request deadline required by a user, the latest downloading end time of the task is calculated, the imaging weight of the task is defined, clustering is carried out according to a satellite downloading time window, and an available ground station is selected for data downloading. Different from data downloading scheduling based on greedy and other rules in the past research, a downloading scheduling strategy based on task deadline is provided, so that the sensitivity of the downloading time of the currently planned task is low, and the solving efficiency and effect are improved.)

1. A multi-satellite multi-station data downloading scheduling method is characterized by comprising the following steps:

s1, determining the latest downloading end time of the task according to the deadline of the imaging request required by the user;

s2, setting the imaging weight of the tasks to be planned, arranging in a descending order, and storing in a task set;

s3, selecting tasks from the task set according to the arrangement order for planning, determining the latest observation end time of the selected tasks according to the latest downloading end time of the tasks, and selecting an observation satellite based on the latest observation end time of the tasks;

s4, calculating a download time window of the observation satellite;

and S5, clustering the planned observation tasks by pressing down the time window to obtain the time window meeting the task deadline requirement.

2. The multi-satellite multi-station data download scheduling method of claim 1, wherein the multi-satellite multi-station data download scheduling method further comprises:

s6, calculating the number of download time windows of observation satellites which are not planned to be downloaded according to the download time windows meeting the task deadline requirement, and arranging a download interval for the observation satellites with less download time windows;

s7, when the number of the download time windows of the observation satellites which are not planned to be downloaded is the same, calculating the competition degree of the download time windows of the observation satellites which are not planned to be downloaded, and arranging a download interval for the observation satellites with low competition degree of the download time windows;

s8, checking whether enough conversion time exists when the same ground station successively receives data downloadings of different satellites, and if so, generating a download scheduling scheme; otherwise, the process proceeds to step S6.

3. The multi-satellite multi-station data downloading scheduling method of claim 1, wherein the imaging weight of the observation task to be planned is set in step S2, and is calculated by using the following formula:

wherein, w_iRepresenting the task weight, p_iIndicating the priority of the observation task to be planned, p_i∈[1,10]，N_TRepresenting the total number of imaging requests from the user request.

4. The multi-satellite multi-station data downloading scheduling method of claim 1, wherein the imaging weights of a plurality of observation tasks to be planned in the task set are the same, the downloading time sensitivities of the currently planned observation tasks are calculated after being respectively selected, and a task corresponding to the minimum sensitivity is selected for planning.

5. The multi-satellite multi-station data download scheduling method of claim 4, wherein the download time sensitivity is expressed by the following formula:

wherein the content of the first and second substances,representing the sensitivity of the drop time, n_TIndicating the number of currently planned observation tasks,Lde_irepresenting a task t_iLatest download end time, Loe_iRepresenting a task t_iThe end time is observed at the latest and,w represents observing the satellite S by a certain step length_jFor task t on the k-th track turn_iIs discretized into a number of visible time windows,representation and task t_iAt satellite S_jThe ith visible time window on the kth track turn.

6. The multi-satellite multi-station data downloading scheduling method of claim 1, wherein the step S5 clusters the scheduled observation tasks by downloading time windows to obtain downloading time windows meeting the task deadline requirement, and specifically comprises:

push down the scheduled observation task for a time window DW_mj ^k＝(ds^k _mj,de^k _mj) Clustering is carried out, and the clustering meets the following conditions:so that the number of grouped classes does not exceed the observation satellite S_jThe number of the downloading time windows of the ground station; if the task is not satisfied, sequentially deleting the tasks with the lowest imaging weight until the task satisfies the requirements, and obtaining a download time window satisfying the task deadline requirements;

wherein ds^k _mj、de^k _mjRespectively representing a download time window start time and a download time window end time, Lde_iRepresenting a task t_iLatest download end time, Loe_iRepresenting a task t_iThe end time was observed latest.

7. The multi-satellite multi-station data download scheduling method of claim 2, wherein the step S6 of calculating the number of download time windows of observation satellites not planned to be downloaded according to the download time windows meeting the task deadline includes:

calculating unplanned downloaded satellite S_jThe number of the downloading time windows is arranged in ascending order; satellite S_jThe number of download time windows is expressed as:

wherein z is_jRepresenting a satellite S_jNumber of download time windows, N_GIndicating the number of ground stations, O_j ^NIndicating that the planning period T is stepped by T/O_j ^NDivision into O_j ^NNumber of track turns, y_k ^mjRepresenting a binary variable, taking 1 indicates the satellite S_jData can be downloaded to the ground station m in the kth orbit, 0 is taken to indicate that the data is not downloaded, and N is_SIndicating the number of observed satellites.

8. The multi-satellite multi-station data download scheduling method of claim 2, wherein the download time window contention level in step S7 is expressed by the following formula:

wherein, Con_t(DW_mj ^k) Indicates the contention of the download time window, D_t(DW_mj′ ^k′) Indicating the satellite S at the current time t_jAll possible downloaded satellites S in the data downloading time interval of the ground station m_j′Of the download task set, y_k′ ^mj′Representing a binary variable, representing a satellite S when 1_j′Data is downloaded to ground station m on the k' th orbital turn.

9. The multi-satellite multi-station data download scheduling method of claim 2, wherein in step S8, it is checked whether there is enough conversion time when the same ground station successively receives data downloads of different satellites, and if so, a download scheduling scheme is generated, which specifically includes:

when the same ground station m receives data of two different satellites before and after downloading, enough conversion time is needed:

wherein p is_mjj′Representing a binary variable, 1, representing the satellite S_j′Following satellite S_jData is downloaded at the mth ground station, otherwise, the data is 0,the transition time for the ground station m to receive the downlinks of two different satellites is de^k _mj、ds^k′ _mj′Respectively representing a download time window DW_mj ^kEnd and download time window DW_mj′ ^k′The start time of (c).

10. A multi-satellite multi-station data downloading scheduling system is characterized by comprising:

the determining module is used for determining the latest downloading end time of the task according to the deadline of the imaging request required by the user;

the sequencing module is used for setting the imaging weight of the tasks to be planned, arranging in a descending order and storing in the task set;

the selection module is used for selecting tasks from the task set according to the arrangement order to plan, determining the latest observation end time of the selected tasks according to the latest downloading end time of the tasks, and selecting an observation satellite based on the latest observation end time of the tasks;

the calculation module is used for calculating a download time window of the observation satellite;

and the clustering module is used for clustering the planned observation tasks by pressing down the downloading time window to obtain the downloading time window meeting the task deadline requirement.

Technical Field

The invention relates to the technical field of satellite scheduling, in particular to a multi-satellite multi-station data downloading scheduling method and system.

Background

The multi-satellite and multi-station integrated scheduling relates to a plurality of satellites, a plurality of observation tasks and a plurality of ground stations, and means that on the basis of comprehensively considering satellite resource capacity, ground receiving station resource capacity and user requirements, resources are allocated to imaging tasks and data downloading tasks corresponding to a plurality of competing requirements without conflict, and starting and stopping time of each task is determined so as to meet the requirements of users to the maximum extent.

Compared with single-satellite scheduling, the multi-satellite and multi-station integrated scheduling has the main difference that multiple satellites can image the same observation task, so that more choices are available for arrangement of the observation tasks. Compared with the limitation that the non-agile satellite can only form images when flying over the target, the agile satellite has flexible attitude mobility and can form images of the target under the conditions of forward sight, front sight and back sight, so that the selection of the imaging time is more possible. Due to limited on-satellite storage, a data downloading scheme must be planned, and in general, multiple satellites may be visible to the same ground station, visible time windows overlap, the downloading sequence of the satellites needs to be determined, and even part of downloading opportunities needs to be abandoned. Certain antenna conversion time is also needed for receiving data of different satellites by the same ground station and downloading, so that the problem solving is complex, and new requirements are provided for solving efficiency and effect.

The data downloading activity is that after the observation activity, the satellite has limited on-satellite storage capacity, and when the on-satellite storage reaches a certain capacity, a data downloading task needs to be arranged; and the data downloading task consumes energy but can not bring benefits, so the data downloading times are controlled, on-satellite energy is consumed as little as possible on the premise of meeting the user requirements, and more opportunities are provided for satellite observation activities.

However, the existing data downloading technology is mainly performed after the satellite observation task planning is completed, and the situation that the ground station load is too high is easy to occur.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a multi-satellite multi-station data downloading scheduling method and a multi-satellite multi-station data downloading scheduling system, which solve the technical problem that the load of a ground station is easily overhigh when the existing data downloading technology is carried out after the satellite observation task planning is finished.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme:

a multi-satellite multi-station data downloading scheduling method comprises the following steps:

s1, determining the latest downloading end time of the task according to the deadline of the imaging request required by the user;

s2, setting the imaging weight of the tasks to be planned, arranging in a descending order, and storing in a task set;

s3, selecting tasks from the task set according to the arrangement order for planning, determining the latest observation end time of the selected tasks according to the latest downloading end time of the tasks, and selecting an observation satellite based on the latest observation end time of the tasks;

s4, calculating a download time window of the observation satellite;

and S5, clustering the planned observation tasks by pressing down the time window to obtain the time window meeting the task deadline requirement.

Preferably, the multi-satellite multi-station data downloading scheduling method further includes:

s6, calculating the number of download time windows of observation satellites which are not planned to be downloaded according to the download time windows meeting the task deadline requirement, and arranging a download interval for the observation satellites with less download time windows;

s7, when the number of the download time windows of the observation satellites which are not planned to be downloaded is the same, calculating the competition degree of the download time windows of the observation satellites which are not planned to be downloaded, and arranging a download interval for the observation satellites with low competition degree of the download time windows;

s8, checking whether enough conversion time exists when the same ground station successively receives data downloadings of different satellites, and if so, generating a download scheduling scheme; otherwise, the process proceeds to step S6.

Preferably, in step S2, the imaging weight of the observation task to be planned is set, and is calculated by using the following formula:

wherein, w_iRepresenting the task weight, p_iIndicating the priority of the observation task to be planned, p_i∈[1，10]，N_TRepresenting the total number of imaging requests from the user request.

Preferably, when the imaging weights of a plurality of observation tasks to be planned in the task set are the same, the descending time sensitivity of the currently planned observation task is calculated after the imaging weights are respectively selected, and the task corresponding to the minimum sensitivity is selected for planning.

Preferably, the download time sensitivity is expressed by the following formula:

wherein the content of the first and second substances,representing the sensitivity of the drop time, n_TIndicating the number of currently planned observation tasks,Lde_irepresenting a task t_iLatest download end time, Loe_iRepresenting a task t_iThe end time is observed at the latest and,w represents observing the satellite S by a certain step length_jFor task t on the k-th track turn_iIs discretized into a number of visible time windows,representation and task t_iAt satellite S_jThe ith visible time window on the kth track turn.

Preferably, in step S5, clustering the planned observation tasks by using the download time window to obtain the download time window meeting the task deadline requirement, specifically including:

push down the scheduled observation task for a time window DW_mj ^k＝(ds^k _mj，de^k _mj) Clustering is carried out, and the clustering meets the following conditions:so that the number of grouped classes does not exceed the observation satellite S_jThe number of the downloading time windows of the ground station; if the task is not satisfied, sequentially deleting the tasks with the lowest imaging weight until the task satisfies the requirements, and obtaining a download time window satisfying the task deadline requirements;

wherein ds^k _mj、de^k _mjRespectively representing a download time window start time and a download time window end time, Lde_iRepresenting a task t_iLatest download end time, Loe_iRepresenting a task t_iThe end time was observed latest.

Preferably, the step S6, according to the download time window meeting the task deadline requirement, of calculating the number of download time windows of the observation satellites not scheduled to be downloaded, specifically including:

calculating unplanned downloaded satellite S_jThe number of the downloading time windows is arranged in ascending order; satellite S_jThe number of download time windows is expressed as:

wherein z is_jRepresenting a satellite S_jNumber of download time windows, N_GIndicating the number of ground stations, O_j ^NIndicating that the planning period T is stepped by T/O_j ^NDivision into O_j ^NNumber of track turns, y_k ^mjRepresenting a binary variable, taking 1 indicates the satellite S_jData can be downloaded to the ground station m in the kth orbit, 0 is taken to indicate that the data is not downloaded, and N is_SIndicating the number of observed satellites.

Preferably, the contention level of the downlink time window in step S7 is expressed by the following formula:

wherein, Con_t(DW_mj ^k) Indicates the contention of the download time window, D_t(DW_mj′ ^k′) Indicating the satellite S at the current time t_jAll possible downloaded satellites S in the data downloading time interval of the ground station m_j′Of the download task set, y_k′ ^mj′Representing a binary variable, representing a satellite S when 1_j′Data is downloaded to ground station m on the k' th orbital turn.

Preferably, in step S8, when it is checked that the same ground station successively receives data downloadings of different satellites, whether sufficient conversion time exists or not is determined, and if yes, a download scheduling scheme is generated, which specifically includes:

when the same ground station m receives data of two different satellites before and after downloading, enough conversion time is needed:

wherein p is_mjj′Representing a binary variable, 1, representing the satellite S_j′Following satellite S_jData is downloaded at the mth ground station, otherwise, the data is 0,the transition time for the ground station m to receive the downlinks of two different satellites is de^k _mj、ds^k′ _mj′Respectively representing a download time window DW_mj ^kEnd and download time window DW_mj′ ^k′The start time of (c).

A multi-satellite multi-station data downloading scheduling system comprises:

the determining module is used for determining the latest downloading end time of the task according to the deadline of the imaging request required by the user;

the sequencing module is used for setting the imaging weight of the tasks to be planned, arranging in a descending order and storing in the task set;

the selection module is used for selecting tasks from the task set according to the arrangement order to plan, determining the latest observation end time of the selected tasks according to the latest downloading end time of the tasks, and selecting an observation satellite based on the latest observation end time of the tasks;

the calculation module is used for calculating a download time window of the observation satellite;

and the clustering module is used for clustering the planned observation tasks by pressing down the downloading time window to obtain the downloading time window meeting the task deadline requirement.

(III) advantageous effects

The invention provides a multi-satellite multi-station data downloading scheduling method and system. Compared with the prior art, the method has the following beneficial effects:

according to the imaging request deadline required by a user, the latest downloading end time of the task is calculated, the imaging weight of the task is defined, clustering is carried out according to a satellite downloading time window, and an available ground station is selected for data downloading. Different from data downloading scheduling based on greedy and other rules in the past research, a downloading scheduling strategy based on task deadline is provided, so that the sensitivity of the downloading time of the currently planned task is low, and the solving efficiency and effect are improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic flow chart of a multi-satellite multi-station data downloading scheduling method according to an embodiment of the present invention;

fig. 2 is a block diagram of a multi-satellite multi-station data downloading scheduling system according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the application provides a multi-satellite and multi-station data downloading scheduling method and system, solves the technical problem that the ground station load is high easily because the existing data downloading technology is carried out after the satellite observation task planning is finished, and improves the solving efficiency and effect of multi-satellite and multi-station data downloading scheduling.

In order to solve the technical problems, the general idea of the embodiment of the application is as follows:

according to the imaging request deadline required by a user, the latest downloading end time of the task is calculated, the imaging weight of the task is defined, clustering is carried out according to a satellite downloading time window, and an available ground station is selected for data downloading. Different from data downloading scheduling based on greedy and other rules in the past research, a downloading scheduling strategy based on task deadline is provided, so that the sensitivity of the downloading time of the currently planned task is low, and the solving efficiency and effect are improved.

In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.

The embodiment of the invention provides a multi-satellite multi-station data downloading and scheduling method, which comprises the following steps:

s1, determining the latest downloading end time of the task according to the deadline of the imaging request required by the user;

s2, setting the imaging weight of the tasks to be planned, arranging in a descending order, and storing in a task set;

s3, selecting tasks from the task set according to the arrangement order for planning, determining the latest observation end time of the selected tasks according to the latest downloading end time of the tasks, and selecting an observation satellite based on the latest observation end time of the tasks;

s4, calculating a download time window of the observation satellite;

and S5, clustering the planned observation tasks by pressing down the time window to obtain the time window meeting the task deadline requirement.

The embodiment of the invention is different from the data downloading scheduling based on greedy and other rules in the previous research, and provides a downloading scheduling strategy based on the task deadline, so that the sensitivity of the downloading time of the currently planned task is lower, and the solving efficiency and effect are improved.

Example 1:

in a first aspect, as shown in fig. 1, an embodiment of the present invention provides a multi-satellite and multi-station data downloading scheduling method, which specifically includes:

and S1, determining the latest downloading end time of the task according to the deadline of the imaging request required by the user.

Deadline dt of imaging request requested by user_iSet as the latest download ending time Lde of the observation task_iHas an upper bound of, i.e. Lde_i≤dt_i。

And S2, setting the imaging weight of the tasks to be planned, arranging in a descending order, and storing in the task set.

The imaging weight of the observation task to be planned is set, and the following formula is adopted for calculation:

wherein, w_iRepresenting the task weight, p_iIndicating the priority of the observation task to be planned, p_i∈[1,10]Task priority is usually directly obtained according to user requirements, p_iThe larger the more important the task, N_TRepresenting the total number of imaging requests from the user request.

S3, selecting tasks from the task set according to the arrangement order for planning, determining the latest observation end time of the selected tasks according to the latest downloading end time of the tasks, and selecting observation satellites based on the latest observation end time of the tasks.

Selecting tasks t from task set Q according to arrangement order_iComputing task t_iLast observed end time Loe_i，Loe_i＜Lde_iAccording to Loe_iSelecting a satellite S_jAnd calculating an observation time window.

And when the imaging weights of a plurality of observation tasks to be planned in the task set are the same, respectively selecting and then calculating the downloading time sensitivity of the currently planned observation task, and selecting the task corresponding to the minimum sensitivity for planning.

The download time sensitivity is expressed by the following formula:

wherein the content of the first and second substances,representing the sensitivity of the drop time, n_TIndicating the number of currently planned observation tasks,Lde_irepresenting a task t_iLatest download end time, Loe_iRepresenting a task t_iThe end time is observed at the latest and,w represents observing the satellite S by a certain step length_jFor task t on the k-th track turn_iIs discretized into a number of visible time windows,representation and task t_iAt satellite S_jThe ith visible time window on the kth track turn.

And S4, calculating the download time window of the observation satellite.

Calculating an observation satellite S_jAnd arranged in ascending order according to the download start time. The planning period T is divided into steps T/O_j ^NDivision into O_j ^NThe orbit turns are counted to obtain an observation satellite S_j(j＝1，...，N_S) At k (k ═ 1.., O.)_j ^N) The m (m 1, N) th track cycle is paired_G) Download time window DW of individual ground station_mj ^k＝(ds^k _mj，de^k _mj) Wherein ds^k _mj、de^k _mjRespectively a download time window start time and a download time window end time.

S5, clustering the planned observation tasks by pressing down the time window to obtain a down time window meeting the task deadline requirement, which specifically comprises:

push down the scheduled observation task for a time window DW_mj ^k＝(ds^k _mj，de^k _mj) Clustering is carried out, and the clustering meets the following conditions:so that the number of the collected classes does not exceed the observation satelliteStar S_jThe number of the downloading time windows of the ground station; if the task is not satisfied, sequentially deleting the tasks with the lowest imaging weight until the task satisfies the requirements, and obtaining a download time window satisfying the task deadline requirements;

wherein ds^k _mj、de^k _mjRespectively representing a download time window start time and a download time window end time, Lde_iRepresenting a task t_iLatest download end time, Loe_iRepresenting a task t_iThe end time was observed latest.

The data downloading of the ground station to the satellite needs to be carried out in a downloading time window, and the situation that the same ground station is visible to a plurality of satellites can occur, so that the number of collisions is large, and the load of a single ground station is high. The embodiment of the invention considers the number of the downloading time windows and the competition degree of the downloading time windows, so the multi-satellite and multi-station data downloading scheduling method provided by the embodiment of the invention further comprises the following steps:

and S6, calculating the number of download time windows of observation satellites which are not planned to be downloaded according to the download time windows meeting the task deadline requirement, and arranging a download interval for the observation satellites with less download time windows.

The calculating the number of the download time windows of the observation satellites which are not planned to be downloaded according to the download time windows meeting the task deadline requirements specifically comprises the following steps:

calculating unplanned downloaded satellite S_jThe number of the downloading time windows is arranged in ascending order; satellite S_jThe number of download time windows is expressed as:

wherein z is_jRepresenting a satellite S_jNumber of download time windows, N_GIndicating the number of ground stations, O_j ^NIndicating that the planning period T is stepped by T/O_j ^NDivision into O_j ^NNumber of track turns, y_k ^mjRepresenting a binary variable, taking 1 indicates the satellite S_jCan be paired at the k track turnThe ground station m downloads data, 0 is taken out to indicate that the data is not downloaded, and N is_SIndicating the number of observed satellites.

Observation satellite S_jThe fewer the number of the download time windows, the less the opportunity for satellite data to be downloaded, and therefore, the observation satellite S with the smaller number of the download time windows is preferred_jAnd arranging a downloading interval.

And S7, calculating the competition degree of the download time windows of the unplanned download observation satellites when the download time windows of the unplanned download observation satellites are the same in number, and arranging a download interval for the observation satellites with low competition degree of the download time windows.

The downlink time window competition degree is expressed by the following formula:

wherein, Con_t(DW_mj ^k) Indicates the contention of the download time window, D_t(DW_mj′ ^k′) Indicating the satellite S at the current time t_jAll possible downloaded satellites S in the data downloading time interval of the ground station m_j′Of the download task set, y_k′ ^mj′Representing a binary variable, representing a satellite S when 1_j′Data is downloaded to ground station m on the k' th orbital turn.

S8, checking whether the same ground station has enough conversion time, if so, generating a downloading scheduling scheme; otherwise, the process proceeds to step S6. The method specifically comprises the following steps:

when the same ground station m receives data of two different satellites before and after downloading, enough conversion time is needed:

wherein p is_mjj′Representing a binary variable, 1, representing the satellite S_j′Following satellite S_jData is downloaded at the mth ground station, otherwise, the data is 0,the transition time for the ground station m to receive the downlinks of two different satellites is de^k _mj、ds^k′ _mj′Respectively representing a download time window DW_mj ^kEnd and download time window DW_mj′ ^k′The start time of (c).

Aiming at the phenomena of time overlapping between the downloading time windows and ground station competition, the embodiment of the invention provides the definition of the competition degree of the downloading time windows, quantifies the downloading conflict time windows, preferentially arranges the downloading time windows with low competition degree, is favorable for avoiding the condition of unbalanced load of different ground stations and improves the utilization rate of ground resources.

In a second aspect, as shown in fig. 2, an embodiment of the present invention provides a multi-satellite and multi-station data downloading scheduling system, including:

the determining module is used for determining the latest downloading end time of the task according to the deadline of the imaging request required by the user;

the sequencing module is used for setting the imaging weight of the tasks to be planned, arranging in a descending order and storing in the task set;

the selection module is used for selecting tasks from the task set according to the arrangement order to plan, determining the latest observation end time of the selected tasks according to the latest downloading end time of the tasks, and selecting an observation satellite based on the latest observation end time of the tasks;

the calculation module is used for calculating a download time window of the observation satellite;

and the clustering module is used for clustering the planned observation tasks by pressing down the downloading time window to obtain the downloading time window meeting the task deadline requirement.

It can be understood that, the explanation, examples, and beneficial effects of the related contents of the multi-satellite and multi-station data download scheduling system provided in the embodiment of the present invention correspond to those of the multi-satellite and multi-station data download scheduling method provided in the embodiment of the present invention, and reference may be made to the corresponding parts in the multi-satellite and multi-station data download scheduling method, which are not described herein again.

In summary, compared with the prior art, the method has the following beneficial effects:

1. according to the imaging request deadline required by a user, the latest downloading end time of the task is calculated, the imaging weight of the task is defined, clustering is carried out according to a satellite downloading time window, and an available ground station is selected for data downloading. Different from data downloading scheduling based on greedy and other rules in the past research, a downloading scheduling strategy based on task deadline is provided, so that the sensitivity of the downloading time of the currently planned task is low, and the solving efficiency and effect are improved.

2. Aiming at the phenomena of time overlapping between the downloading time windows and ground station competition, the embodiment of the invention provides the definition of the competition degree of the downloading time windows, quantifies the downloading conflict time windows, preferentially arranges the downloading time windows with low competition degree, is favorable for avoiding the condition of unbalanced load of different ground stations and improves the utilization rate of ground resources.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.