Satellite-to-ground quantum key distribution system and task automatic planning method thereof

Abstract

The application discloses a satellite-ground quantum key distribution system and a task automatic planning method thereof, which comprises the following steps: acquiring weather and satellite orbit prediction data to calculate an available time window for a satellite-ground docking task, and screening a ground station list available for the satellite-ground docking task in the latest period of time; and establishing a shortage dynamic simulation calculation model of the satellite-ground quantum key distribution system based on a key pool threshold and a current available key amount, so as to automatically simulate and calculate the key pool shortage change of the ground station under different docking states, and obtain a quantitative ranking of docking efficiency by evaluating the key pool shortage, so that the optimal ground station can be accurately selected to perform the docking task, thereby realizing the automatic planning of the satellite-ground docking task.

Description

Technical Field

[0001] This invention relates to the field of quantum communication, specifically to an automatic task planning method for satellite-to-ground quantum key distribution, and a quantum key distribution system based on this method. Background Technology

[0002] Since the successful launch of the quantum science experimental satellite "Micius" in 2016, my country has successfully built multiple usable quantum satellite ground stations. These ground stations are able to accurately capture and track the quantum satellite and complete quantum satellite-to-ground docking missions.

[0003] The satellite-to-ground docking mission primarily utilizes the docking between a quantum satellite and a ground station to perform quantum key distribution or quantum key relay tasks. Quantum key distribution involves the ground station efficiently coupling the quantum signals transmitted by the satellite and negotiating to generate a quantum key. Quantum key relay involves XORing the quantum keys stored on the quantum satellite with those of the two ground stations to encrypt the key, and then transmitting it to the ground station using laser communication.

[0004] Because quantum satellites and ground stations are limited by weather, orbit and other conditions, they cannot perform satellite-to-ground docking missions at any time to achieve key preparation or key relay. Therefore, it is necessary to establish a key pool to store the quantum keys or paired keys generated for each mission, so that they can be used whenever needed.

[0005] In existing technologies, satellite-to-ground docking missions typically include the following steps:

[0006] 1. Manually check whether the number of available keys in the current key pool of the ground station is scarce, for example, whether the key pool is empty or nearly empty.

[0007] 2. Manually check weather forecasts and satellite orbit forecasts to determine if there is a suitable time window for the satellite-to-ground docking mission. If multiple ground stations are available for docking, manually select one for docking and execute the corresponding key tasks.

[0008] The primary criterion for judging satellite-to-ground docking missions is the availability of the ground station, which includes weather conditions (sunny or rainy, cloud cover, visibility) during the satellite's transit period, orbital conditions (orbital altitude, visibility duration), and whether the ground station is malfunctioning.

[0009] If multiple ground stations are available for satellite-to-ground docking, a specific station needs to be selected for the docking mission. Currently, this selection is primarily achieved through manual intervention. For example, a person subjectively assesses the key pool availability at each ground station, checks weather and corresponding satellite orbit forecasts, and ultimately decides which ground station to choose for docking with the quantum satellite to perform the corresponding key task. Therefore, in existing technology, frequent checks of the key pool availability are necessary, along with monitoring weather and orbit forecasts. Furthermore, the lack of a relatively objective and reasonable judgment standard can lead to wasted satellite-to-ground docking windows or inefficient scheduling of docking missions. Summary of the Invention

[0010] To address the shortcomings of existing technologies that rely on manual intervention for satellite-to-ground docking mission planning, this invention proposes a satellite-to-ground quantum key distribution system and its automatic mission planning method. This system automatically acquires weather and satellite orbit forecast data to calculate the available time window for satellite-to-ground docking missions, filtering out a list of ground stations available for such missions in the near future. Based on a key pool threshold and the current available key quantity, a dynamic simulation model of the key pool scarcity of the satellite-to-ground quantum key distribution system is established to automatically simulate and calculate the changes in key pool scarcity at ground stations under different docking states. By evaluating the key pool scarcity, a quantitative ranking of docking efficiency is derived, allowing for precise selection of the optimal ground station to execute the docking mission, thereby achieving automatic planning of satellite-to-ground docking missions.

[0011] The first aspect of this invention relates to an automatic task planning method for a satellite-to-ground quantum key distribution system, comprising a query step, a simulation calculation step, and a task planning step; wherein,

[0012] The query step is used to determine the ground station available for docking mission on day n by querying weather forecast data and satellite orbit forecast data, where n = 1, 2, ..., N, and N is a natural number;

[0013] The simulation calculation step is used to simulate the total system scarcity score of each of the ground stations available for the docking mission on day n when performing the docking mission, and to calculate the efficiency value of each of the ground stations available for the docking mission on day n when performing the docking mission based on the initial values ​​of the simulated total system scarcity score and the total system scarcity score on day n.

[0014] The mission planning step is used to select the ground station with the highest efficiency value from the ground stations available for the docking mission on day n to perform the docking mission, in order to generate the docking mission plan.

[0015] The total system scarcity score is calculated based on the current available key quantity, high threshold, and low threshold of the key pool in the satellite-to-ground quantum key distribution system. Specifically: the initial value of the total system scarcity score for the first day is calculated based on the current available key quantity, high threshold, and low threshold of the key pool in the satellite-to-ground quantum key distribution system before the docking mission is executed on the first day; the total system scarcity score calculated by simulation for the ground station selected to perform the docking mission on day n is used as the initial value of the total system scarcity score for day n+1.

[0016] Furthermore, it can be based on the relational formula Calculate the scarcity score S for each key pool in the satellite-to-ground quantum key distribution system, where ks, ht, and lt represent the current available key quantity, high threshold, and low threshold of the key pool, respectively.

[0017] The total system scarcity score is obtained by using the scarcity scores S of each key pool in the satellite-to-ground quantum key distribution system and performing a weighted summation operation.

[0018] Furthermore, the simulation calculation steps also include a relay allocation sub-step, used to simulate the relay allocation between ground stations of the satellite-to-ground quantum key distribution system during the execution of the docking mission;

[0019] In the relay distribution sub-step, the key quantity ks of the adjacent key pool NP of satellite S1 and ground station A, which are used to perform the docking mission and are implemented with quantum key distribution, is calculated. S1-A =n1+n2, where: n1 is the key quantity of the adjacent key pool NP before the docking mission is performed on the same day, and n2 is the key quantity of the adjacent key pool NP increased by quantum key distribution on the same day. The adjacent key pool NP is used to store the shared quantum key between the satellite and the ground station.

[0020] Calculate the missing key amount in the paired key pool CP in both directions between ground station A and other ground stations i in the satellite-to-ground quantum key distribution system. Ai =MA×{ht A→i -ks A→i ,0}+MA×{ht i→A -ks i→A ,0}, where:ht A→i and ks A→i These represent the high threshold and current key quantity of the paired key pool CP in the direction from ground station A to ground station i, respectively. i→A and ks i→A These are the high threshold and current key quantity of the paired key pool CP in the direction from ground station i to ground station A, respectively.

[0021] Calculate the maximum key quantity Y that can be relayed from ground station i to ground station A. Ai =MIN{ksS1-i X Ai}, ks S1-i Let be the key amount of the adjacent key pool NP between satellite S1 and ground station i;

[0022] Where: if ks S1-A >∑ i Y Ai The key amount ks of the paired key pool CP in both directions between ground station A and ground station i. Ai Set as ks Ai =ht A→i +ht i→A If ks S1-A <∑ i Y Ai According to the preset relay allocation strategy, the key amount ks of the paired key pool CP between ground station A and ground station i in both directions is set. Ai .

[0023] Preferably, if ks S1-A <∑ i Y Ai This ensures that the paired key pools (CP) in both directions between ground stations in the satellite-to-ground quantum key distribution system have the same number of keys.

[0024] Furthermore, the effectiveness value is the difference between the initial value of the total system scarcity score and the simulated total system scarcity score.

[0025] Furthermore, when there are multiple ground stations with the highest efficiency value, the ground station with the fewest currently available keys is selected to perform the docking task on day n.

[0026] Furthermore, the automatic mission planning method of the present invention may also include the step of sending the docking mission plan for the most recent two days to the satellite and ground station to execute the docking mission.

[0027] A second aspect of the present invention relates to a satellite-to-ground quantum key distribution system, comprising one or more satellites, multiple ground stations, and a mission scheduling center; wherein,

[0028] The task scheduling center is configured to generate docking task plans based on the above-mentioned automatic task planning method;

[0029] The satellite and ground station are configured to perform docking missions according to the docking mission plan, which include quantum key distribution and / or quantum key relay missions.

[0030] Furthermore, the mission scheduling center is configured to generate docking mission plans for the past seven days, and to send docking mission plans for the past two days to the satellite and ground station.

[0031] Furthermore, the mission scheduling center is configured to collect and summarize the current available key quantity, high threshold, and low threshold of adjacent key pools (NP) and paired key pools (CP) in the ground station. Attached Figure Description

[0032] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 A flowchart illustrating an example of an automated task planning method for satellite-to-ground quantum key distribution according to the present invention is shown. Detailed Implementation

[0035] In the following description, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example in order to fully convey the spirit of the invention to those skilled in the art. Therefore, the invention is not limited to the embodiments disclosed herein.

[0036] In a satellite-to-ground quantum key distribution system, the satellite-to-ground docking task includes a quantum key distribution task and a quantum key relay task.

[0037] Quantum key distribution (QKD) refers to the process of efficiently coupling quantum signals transmitted by a satellite to a ground station and negotiating to generate a quantum key. In QKD, a shared quantum key is generated between the satellite and the ground station. Since the satellite and the ground station can be considered a pair of adjacent nodes, the key pool used to store this shared quantum key in the satellite and the ground station is called the adjacent key pool (NP).

[0038] Quantum key relay refers to a process where a satellite acts as a relay node. For example, using a one-word-one-key method, the quantum keys stored on the satellite at two ground stations are XORed together and then sent to one of the ground stations. This ground station then performs a de-XOR operation based on the XOR value of the quantum key to obtain a shared quantum key (i.e., a paired key) between the two ground stations. Correspondingly, the key pool at the ground station used to store the paired key between the two ground stations is called the paired key pool (CP).

[0039] To address this, the present invention proposes a scarcity efficiency model based on dynamic simulation of the current available key quantity in the ground station pairing key pool. This model is used to automatically select the optimal ground station to perform the satellite-to-ground docking task according to the improvement of the scarcity, thereby realizing the automatic planning of satellite-to-ground docking tasks in the quantum key distribution system.

[0040] The satellite-to-ground quantum key distribution system of the present invention may include a satellite, a ground station, and a mission scheduling center. The mission scheduling center is used to generate satellite-to-ground docking mission plans, and the satellite and ground station can execute the corresponding satellite-to-ground docking missions using free-space channels according to the docking mission plans issued by the mission scheduling center.

[0041] In the satellite-to-ground quantum key distribution system and automatic mission planning method of the present invention, the mission scheduling center can collect relevant data of the key pool in each ground station (such as the current available key quantity ks, high threshold ht, and low threshold lt, etc.) and generate a large monitoring table.

[0042] For example, quantum key distribution devices at various ground stations can automatically report the current available key quantity (ks) of adjacent key pools (NP) and paired key pools (CP) to the mission scheduling center. The paired key pools (CP) between two ground stations are divided into two opposite directions: the quantum keys in one direction's CP are used for encryption (for transmission), and the quantum keys in the opposite direction's CP are used for decryption (for reception). This design prevents two ground stations from simultaneously requesting a key for encryption and decryption, thus avoiding key synchronization issues. Since the adjacent key pools (NP) are paired keys between the satellite and the ground stations, and the use of satellite keys is strictly limited by the mission scheduling center, there is no issue of simultaneous requests for a key causing key synchronization problems; therefore, two key pools (NP) in opposite directions are not required.

[0043] For example, taking a satellite-to-ground quantum key distribution system with two satellites S1 and S2 and six ground stations A, B, C, D, E, and F as an example, examples of monitoring tables generated by the mission scheduling center for adjacent key pools (NP) and paired key pools (CP) are shown:

[0044]

[0045] (Table 1: Monitoring table for adjacent key pools NP)

[0046]

[0047] (Table 2: Monitoring table for paired key pools CP)

[0048] Furthermore, the task scheduling center can compare the current available key quantity ks of each key pool with the high threshold ht (i.e., upper limit) and low threshold lt (i.e., lower limit) of that key pool to evaluate the key scarcity S of that key pool. Specifically, the closer the key quantity ks is to the low threshold lt, the more scarce the keys (high scarcity); the closer the key quantity ks is to the high threshold ht, the less scarce the keys (low scarcity); reaching or exceeding the high threshold indicates that the current key quantity is sufficient and no replenishment is needed.

[0049] According to the present invention, functions of ks, ht, and lt can be constructed to characterize the scarcity S of the key pool, i.e., S = f(ks, ht, lt).

[0050] In a preferred example, the scarcity level S can be calculated using the following piecewise function:

[0051]

[0052] In this invention, the scarcity degree S of adjacent key pools NP and paired key pools CP can be calculated separately, and then a weighted sum can be performed to obtain the total system scarcity degree score of the entire satellite-to-ground quantum key distribution system.

[0053] Therefore, this invention can simulate and calculate the total system scarcity score when different ground stations are selected to perform docking tasks, thereby obtaining the docking performance of different ground stations and selecting the optimal ground station for performing the docking task accordingly. For example, it is preferable to perform the docking task using the ground station that reduces the scarcity score the most (high docking performance value).

[0054] To this end, the mission scheduling center can first simulate the relay allocation process when different ground stations are used to perform docking missions, so as to simulate the key quantity of each key pool, the total score of system scarcity and its changes after the docking mission.

[0055] First, it is necessary to simulate the changes in the key pool key quantity achieved by satellite S1 and ground station A using a quantum key distribution task to perform the docking mission.

[0056] It is known that before docking, the adjacent key pool NP of satellite S1 and ground station A already has n1 units of key; then, based on the performance of the satellite and ground station, the amount of key generation is estimated, and it is determined that quantum key distribution can add n2 units of key to the adjacent key pool NP.

[0057] Therefore, before performing the key relay task, the key quantity ks of the adjacent key pool NP between satellite S1 and ground station A is... S1-A for:

[0058] ks S1-A =n1+n2

[0059] Considering the use of one-key-one-key relay, for ground station A to relay one unit of key with other ground station i, it requires consuming one unit of key from the adjacent key pool NP between satellite S1 and ground station A, and one unit of key from the adjacent key pool NP between satellite S1 and ground station i.

[0060] Therefore, the total missing key amount X in the paired key pool CP between ground station A and other ground stations i in both directions can be calculated according to the following relationship. Ai :

[0061] X Ai =MAX{ht A→i -ks A→i ,0}+MAX{ht i→A -ks i→A ,0},

[0062] Among them, ht i→A and ks i→A These represent the high threshold and current key quantity of the paired key pool CP in the direction from ground station i to ground station A, respectively.

[0063] Without considering the key quantities in adjacent key pools NP between satellite S1 and ground station A, the maximum key quantity Y that can be relayed from ground station i to ground station A is... Ai :

[0064] Y Ai =MIN{ks S1-i X Ai},

[0065] Among them, ks S1-i Let be the key amount of the adjacent key pool NP of satellite S1 and ground station i.

[0066] Therefore, when ground station A is selected to perform the docking task, the total amount of relay keys Y is:

[0067] The total number of keys ks in pool NP S1-A for:

[0068] ks S1-A =n1+n2-Y

[0069] Therefore, when ks S1-A >∑ i Y Ai At that time, all Y can be completed. Ai Key relay of key quantity. At this point, the key quantity ks of the paired key pool CP in both directions between ground station A and ground station i can be relayed. Ai Set as: ks Ai =ht A→i+ht i→A .

[0070] When ks S1-A <∑ i Y Ai This indicates that the amount of keys in the adjacent key pool NP between satellite S1 and ground station A is insufficient to support all Y keys. Ai Key relay of key quantity. At this point, partial key relay can be completed according to a preset strategy, thereby determining the key quantity ks of the paired key pool CP in both directions between ground station A and ground station i. Ai .

[0071] In the preferred example, if ks S1-A <∑ i Y Ai A relay allocation strategy can be selected to ensure that the paired key pools (CP) in both directions between ground stations in the satellite-to-ground quantum key distribution system have the same number of keys.

[0072] By simulating the changes in the key quantity of each key pool after selecting ground station A to perform the docking task, the corresponding total score of system scarcity can be calculated.

[0073] By using simulation calculations to obtain the total system scarcity score when different ground stations perform docking tasks, and reducing the initial value of the total system scarcity score before performing docking tasks, we can obtain the efficiency value of different ground stations when performing docking tasks, that is, the quantified value of the ideal efficiency after using the ground station as the docking station.

[0074] At this point, the ground station that can achieve the maximum efficiency (even with the greatest reduction in system scarcity) can be selected to perform the current satellite-to-ground docking mission, thereby improving the overall mission scheduling efficiency of the system.

[0075] Considering that there may be multiple ground stations with the same maximum efficiency value, the ground station with the fewest currently available keys can be selected to perform the satellite-to-ground docking task for the day. This generates the docking task plan.

[0076] The automatic task planning method for a satellite-to-ground quantum key distribution system of the present invention will be further described below to provide a clearer understanding of the working principle of the present invention.

[0077] The automatic task planning method for a satellite-to-ground quantum key distribution system according to the present invention may include a query step, a simulation calculation step, and a task planning step.

[0078] In the query step, weather forecast data and satellite orbit forecast data for the most recent N days (e.g., 7 days) can be used to determine the available ground stations for the docking mission on each day n within those N days, where n = 1, 2, ..., N, and N is a natural number. When determining available ground stations, the availability of fault information can also be taken into account.

[0079] In the simulation calculation step, for each day n in N days, the initial value of the total system scarcity score for that day can be calculated, and the total system scarcity score of each of the ground stations available for the docking mission on that day can be simulated and calculated when performing the docking mission. In order to determine the effectiveness value of each available ground station when performing the docking mission based on the difference between the initial value of the total system scarcity score and the simulated total system scarcity score.

[0080] This allows the selection of the ground station with the highest efficiency value from the available ground stations for that day during the mission planning step, thereby generating a docking mission plan.

[0081] After this, you can prepare to calculate the next day or end the current automatic planning calculation. If all N days have been calculated, the current planning ends; otherwise, the key pool state matrix after the simulated docking of the currently selected ground station is used as the initial state for the planning calculation of the next day, and the process jumps to the simulation calculation step to plan for the next day, and so on.

[0082] Therefore, in this invention, the initial value of the total system scarcity score for day 1 can be calculated by using the current available key quantity, high threshold, and low threshold of each key pool before executing the docking task on day 1. At the same time, the total system scarcity score of the ground station selected for executing the docking task on day n, which is simulated and calculated in the task planning step, is used as the initial value of the total system scarcity score for day n+1.

[0083] Furthermore, for example, considering the accuracy and precision of satellite orbits and weather forecasts, as well as satellite telemetry and control resources, the docking mission plan for the most recent two days can be sent to the satellite and ground station to execute the docking mission. The plans for the following days are generally used as a reference. Since the planning for the next 7 days is calculated every day, if the calculated ground station and orbital orbit count for that day are inconsistent with the information originally calculated for that day, the latest calculation will be used as the standard.

[0084] Figure 1 A flowchart is shown as an example of an automatic task planning method for a satellite-to-ground quantum key distribution system.

[0085] In this example, it is assumed that the current satellite-to-ground quantum key distribution system includes a quantum satellite S and ground stations A, B, C, D, E, and F. The key unit of the key pool is a bucket, and the low threshold for triggering a task by pairing key pools (CP) is 100 buckets.

[0086] In the query step, by querying weather forecast data and satellite orbit forecast data for the past 7 days, the system filters out ground stations that can be used for docking missions on each of the last 7 days. For example, on day 1, which requires planning, ground stations A, C, and D can be used to locate the ground stations.

[0087] Then, in the simulation calculation step, the initial value of the total system scarcity score for day 1 is calculated first.

[0088]

[0089] (Table 3)

[0090] Table 3 shows the initial status and scarcity S of the key pools in each ground station before the docking task is performed on day 1. In the left-hand matrix, column S represents the current available key quantity in the key pools of each ground station, and the other columns represent the current available key quantity in each paired key pool (CP). (In the left-hand column, the ground station represents the starting end, and the top row represents the ending end.)

[0091] Based on this, by calculating the scarcity S of all paired key pools CP, the initial value of the total system scarcity score for the first day can be obtained by summing them up, which is 791.

[0092] Next, the total system scarcity score under ideal conditions was simulated when docking missions were performed using each available ground station A, C, and D on the same day.

[0093]

[0094] (Table 4)

[0095]

[0096] (Table 5)

[0097]

[0098]

[0099] (Table 6)

[0100] As can be seen from Tables 4-6, through simulation calculations, the total system shortage scores obtained when ground stations A, C, and D perform docking missions are 464.5, 757, and 567, respectively.

[0101] Therefore, based on the initial system shortage score of 791 for that day, the efficiency values ​​for performing docking missions with ground stations A, C, and D can be calculated to be 326.5, 34, and 224, respectively. Therefore, ground station A, which can achieve maximum efficiency when performing docking missions, can be selected to perform the satellite-to-ground docking mission for that day (i.e., day one).

[0102] Subsequently, the docking task planning for the second day continued. The total system scarcity score (464.5) simulated during the docking task performed by ground station A on the first day was used as the initial value for the total system scarcity score calculated on the second day. That is, the key pool state simulated during the docking task performed by ground station A on the first day was used as the initial state for the calculation on the next day.

[0103]

[0104] (Table 7)

[0105] The entire planning process can be completed once the 7-day task plan has been calculated.

[0106] In summary, the satellite-to-ground quantum key distribution system and its automatic mission planning method disclosed in this invention automatically acquires weather and satellite orbit forecast data to calculate the available time window for satellite-to-ground docking missions, and filters out a list of ground stations that can be used for satellite-to-ground docking missions in the near future. Furthermore, a dynamic simulation calculation model of the scarcity of the satellite-to-ground quantum key distribution system is established based on the key pool threshold and the current available key quantity. This model is used to automatically simulate and calculate the changes in the key pool scarcity of ground stations under different docking states. By evaluating the key pool scarcity, a quantitative ranking of docking efficiency is obtained, allowing for the precise selection of the optimal ground station to perform the docking mission, thereby achieving automatic planning of satellite-to-ground docking missions.

[0107] Although the present invention has been described above with reference to the accompanying drawings and specific embodiments, those skilled in the art will readily recognize that the above embodiments are merely exemplary and used to illustrate the principles of the present invention. They do not limit the scope of the present invention. Those skilled in the art can make various combinations, modifications and equivalent substitutions to the above embodiments without departing from the spirit and scope of the present invention.

Claims

1. An automatic task planning method for a satellite-to-ground quantum key distribution system, comprising a query step, a simulation calculation step, and a task planning step; wherein, The query step is used to determine the ground station available for docking mission on day n by querying weather forecast data and satellite orbit forecast data, where n = 1, 2, ..., N, and N is a natural number; The simulation calculation step is used to simulate the total system scarcity score of each of the ground stations available for the docking mission on day n when performing the docking mission, and to calculate the efficiency value of each of the ground stations available for the docking mission on day n when performing the docking mission based on the initial values ​​of the simulated total system scarcity score and the total system scarcity score on day n. The mission planning step is used to select the ground station with the highest efficiency value from the ground stations available for the docking mission on day n to perform the docking mission, in order to generate the docking mission plan. The total system scarcity score is calculated based on the current available key quantity, high threshold, and low threshold of the key pool in the satellite-to-ground quantum key distribution system. Specifically, the initial value of the total system scarcity score for the first day is calculated based on the current available key quantity, high threshold, and low threshold of the key pool in the satellite-to-ground quantum key distribution system before the docking task is performed on the first day. The total system scarcity score calculated by simulation for the ground station selected to perform the docking mission on day n will be used as the initial value for the total system scarcity score on day n+1.

2. The automatic task planning method as described in claim 1, wherein: According to the relation Calculate the scarcity score S for each key pool in the satellite-to-ground quantum key distribution system, where ks, ht, and lt represent the current available key quantity, high threshold, and low threshold of the key pool, respectively. The total system scarcity score is obtained by using the scarcity scores S of each key pool in the satellite-to-ground quantum key distribution system and performing a weighted summation operation.

3. The automatic task planning method as described in claim 2, wherein, The simulation calculation steps also include a relay allocation sub-step, which is used to simulate the relay allocation between ground stations of the satellite-to-ground quantum key distribution system during the execution of the docking mission; In the relay distribution sub-step, the key quantity ks of the adjacent key pool NP of satellite S1 and ground station A, which are used to perform the docking mission and are implemented with quantum key distribution, is calculated. S1-A =n1+n2, where: n1 is the key quantity of the adjacent key pool NP before the docking mission is performed on the same day, and n2 is the key quantity of the adjacent key pool NP increased by quantum key distribution on the same day. The adjacent key pool NP is used to store the shared quantum key between the satellite and the ground station. Calculate the missing key amount X in the paired key pool CP in both directions between ground station A and other ground stations i in the satellite-to-ground quantum key distribution system. Ai =MAX{ht A→i -ks A→i ,0}+MAX{ht i→A -ks i→A ,0}, where: ht A→i and ks A→i These represent the high threshold and current key quantity of the paired key pool CP in the direction from ground station A to ground station i, respectively. i→A and ks i→A These are the high threshold and current key quantity of the paired key pool CP in the direction from ground station i to ground station A, respectively. Calculate the maximum key quantity Y that can be relayed from ground station i to ground station A. Ai =MIN{ks S1-i ,X Ai }, ks S1-i Let be the key amount of the adjacent key pool NP between satellite S1 and ground station i; Where: if ks S1-A >∑ i Y Ai The key amount ks of the paired key pool CP in both directions between ground station A and ground station i. Ai Set as ks Ai =ht A→i +ht i→A If ks S1-A <∑ i Y Ai According to the preset relay allocation strategy, the key amount ks of the paired key pool CP between ground station A and ground station i in both directions is set. Ai .

4. The automatic task planning method as described in claim 3, wherein, If kS S1-A <∑ i Y Ai This ensures that the paired key pools (CP) in both directions between ground stations in the satellite-to-ground quantum key distribution system have the same number of keys.

5. The automatic task planning method as described in claim 2, wherein, The effectiveness value is the difference between the initial value of the total system scarcity score and the simulated total system scarcity score.

6. The automatic task planning method as described in claim 1, wherein, When there are multiple ground stations with the highest efficiency value, the ground station with the fewest currently available keys is selected to perform the docking task on day n.

7. The automatic mission planning method as described in claim 1, further comprising the step of sending the docking mission plan for the most recent two days to the satellite and ground station to execute the docking mission.

8. A satellite-to-ground quantum key distribution system, comprising one or more satellites, multiple ground stations, and a mission scheduling center; wherein, The task scheduling center is configured to generate docking task plans according to the automatic task planning method as described in any one of claims 1-7; The satellite and ground station are configured to perform docking missions according to the docking mission plan, which include quantum key distribution and / or quantum key relay missions.

9. The satellite-to-ground quantum key distribution system as described in claim 8, wherein, The mission scheduling center is configured to generate docking mission plans for the next seven days, and to send docking mission plans for the next two days to the satellite and ground station.

10. The satellite-to-ground quantum key distribution system as described in claim 8, wherein, The task scheduling center is set up to collect and summarize the current available key quantity, high threshold, and low threshold of adjacent key pools (NP) and paired key pools (CP) in the ground station.

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