Quantum Key Distribution Method Based on Tethered UAV and Related Devices

Abstract

The present application provides a quantum key distribution method and related devices based on a tethered drone. A tethered drone deployment plan between a source node and its corresponding satellite ground station and a tethered drone deployment plan between a destination node and its corresponding satellite ground station are determined according to the deployment cost from low to high. According to the space link occlusion situation between the source node and its corresponding satellite ground station and the space link occlusion situation between the destination node and its corresponding satellite ground station, an optimal target relay link between the source node and the destination node is further determined in the above-mentioned tethered drone deployment plan, so that quantum key distribution is carried out between the source node and the destination node based on the target relay link. The present application takes into account factors such as deployment cost and geographical conditions, can select the optimal relay link for quantum key distribution between the source node and the destination node according to the priority, ensures the security and efficiency of the quantum key distribution service, and improves the flexibility of the relay link setting.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and in particular, to a quantum key distribution method based on a tethered drone and related devices. Background Art

[0002] Quantum Key Distribution (QKD) can enable two communication parties point-to-point to share symmetric quantum keys. Its information-theoretic security is guaranteed by the principles of quantum physics and is not affected by computational complexity. With the improvement of the practical level of quantum key distribution technology, it will gradually develop from local and metropolitan areas to wide areas. By providing quantum key distribution services for wide-area users, it can effectively guarantee the end-to-end secure communication of wide-area users.

[0003] However, since the physical distance between wide-area users can reach thousands of kilometers, the cost required to implement quantum key distribution services only relying on optical fibers and the technical difficulties faced are relatively high. For some regions, complex geographical conditions and harsh natural environments may make it difficult to lay optical fibers. Usually, it is necessary to use a quantum satellite as a relay node to negotiate quantum keys between a pair of fixed satellite ground stations, and further distribute the quantum keys to wide-area users through the metropolitan area optical fiber quantum key distribution link between the fixed satellite ground station and the wide-area users; or deploy a pair of movable quantum satellite ground stations at the source and destination nodes of the quantum key distribution services of wide-area users respectively to achieve their docking with the quantum satellite. However, the source and destination nodes of the quantum key distribution services of wide-area users may not have optical fiber connections to the fixed satellite ground station due to geographical conditions, and due to factors such as weather environment and transit time, it may cause the movable quantum satellite ground station to be unable to meet the quantum key distribution service requirements in a timely manner. Summary of the Invention

[0004] In view of this, the purpose of this application is to propose a quantum key distribution method based on a tethered drone and related devices to solve the problem of effective communication between the source and destination nodes of the quantum key distribution services of wide-area users and their corresponding satellite ground stations.

[0005] Based on the above purpose, this application provides a quantum key distribution method based on a tethered drone, which is applied to a quantum key distribution system composed of a source node, a destination node, a tethered drone, multiple satellite ground stations, a target quantum satellite, and a drone ground station. The method includes:

[0006] In response to receiving a quantum key distribution request sent by a target user, determine the source node and the destination node according to the quantum key distribution request;

[0007] Calculate the distances between the source node and multiple satellite ground stations within its metropolitan area, and determine the satellite ground station with the shortest distance to the source node among the multiple satellite ground stations as the first satellite ground station; calculate the distances between the destination node and multiple satellite ground stations within its metropolitan area, and determine the satellite ground station with the shortest distance to the destination node among the multiple satellite ground stations as the second satellite ground station;

[0008] Determine a first deployment plan list of the tethered drone between the source node and the first satellite ground station according to the deployment cost; wherein, the first deployment plan list includes multiple first deployment plans sorted in ascending order of the deployment cost; determine a second deployment plan list of the tethered drone between the destination node and the second satellite ground station according to the deployment cost; wherein, the second deployment plan list includes multiple second deployment plans sorted in ascending order of the deployment cost;

[0009] Determine a first target deployment plan from the multiple first deployment plans according to the space link occlusion situation between the source node and the first satellite ground station; determine a second target deployment plan from the multiple second deployment plans according to the space link occlusion situation between the destination node and the second satellite ground station;

[0010] Determine a target relay link between the source node and the destination node according to the first target deployment plan and the second target deployment plan, so that quantum key distribution is performed between the source node and the destination node based on the target relay link.

[0011] Based on the same concept, the present application further provides a quantum key distribution device based on a tethered drone, which is applied to a quantum key distribution system composed of a source node, a destination node, a tethered drone, multiple satellite ground stations, a target quantum satellite, and a drone ground station. The device includes:

[0012] A node determination module, configured to determine the source node and the destination node according to the quantum key distribution request in response to receiving a quantum key distribution request sent by a target user;

[0013] A parameter determination module, configured to calculate the distances between the source node and multiple satellite ground stations within its metropolitan area, and determine the satellite ground station with the shortest distance to the source node among the multiple satellite ground stations as the first satellite ground station; calculate the distances between the destination node and multiple satellite ground stations within its metropolitan area, and determine the satellite ground station with the shortest distance to the destination node among the multiple satellite ground stations as the second satellite ground station;

[0014] A first determination module, configured to determine a first list of deployment plans for the tethered drone between the source node and the first satellite ground station according to the deployment cost; wherein, the first list of deployment plans includes a plurality of first deployment plans sorted from low to high according to the deployment cost; determine a second list of deployment plans for the tethered drone between the destination node and the second satellite ground station according to the deployment cost; wherein, the second list of deployment plans includes a plurality of second deployment plans sorted from low to high according to the deployment cost;

[0015] A second determination module, configured to determine a first target deployment plan from the plurality of first deployment plans according to the space link occlusion condition between the source node and the first satellite ground station; determine a second target deployment plan from the plurality of second deployment plans according to the space link occlusion condition between the destination node and the second satellite ground station;

[0016] A key distribution module, configured to determine a target relay link between the source node and the destination node according to the first target deployment plan and the second target deployment plan, so that quantum key distribution is performed between the source node and the destination node based on the target relay link.

[0017] Based on the same concept, the present application also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the program, it implements the method described in any one of the above.

[0018] Based on the same concept, the present application also provides a non-transitory computer-readable storage medium, and the non-transitory computer-readable storage medium stores computer instructions for causing the computer to implement the method described in any one of the above.

[0019] As can be seen from the above, a quantum key distribution method and related devices provided by the present application are applied to a quantum key distribution system composed of a source node, a destination node, a tethered drone, multiple satellite ground stations, a target quantum satellite, and a drone ground station. The method includes: in response to receiving a quantum key distribution request issued by a target user, determining the source node and the destination node according to the quantum key distribution request; calculating the distances between the source node and multiple satellite ground stations within its metropolitan area, and determining the satellite ground station with the shortest distance from the source node among the multiple satellite ground stations as the first satellite ground station; calculating the distances between the destination node and multiple satellite ground stations within its metropolitan area, and determining the satellite ground station with the shortest distance from the destination node among the multiple satellite ground stations as the second satellite ground station; determining a first deployment plan list of the tethered drone between the source node and the first satellite ground station according to the deployment cost; the first deployment plan list includes multiple first deployment plans sorted in ascending order of deployment cost; determining a second deployment plan list of the tethered drone between the destination node and the second satellite ground station according to the deployment cost; the second deployment plan list includes multiple second deployment plans sorted in ascending order of deployment cost; determining a first target deployment plan from multiple first deployment plans according to the space link occlusion situation between the source node and the first satellite ground station; determining a second target deployment plan from multiple second deployment plans according to the space link occlusion situation between the destination node and the second satellite ground station; determining a target relay link between the source node and the destination node according to the first target deployment plan and the second target deployment plan, so that quantum key distribution is performed between the source node and the destination node based on the target relay link. The present application determines the deployment plan of the tethered drone between the source node and its corresponding satellite ground station and the deployment plan of the tethered drone between the destination node and its corresponding satellite ground station in ascending order of deployment cost. Further, according to the space link occlusion situation between the source node and its corresponding satellite ground station and the space link occlusion situation between the destination node and its corresponding satellite ground station, the optimal target relay link between the source node and the destination node is further determined from the above deployment plans of the tethered drone, so that quantum key distribution is performed between the source node and the destination node based on the target relay link. The present application considers factors such as deployment cost and geographical conditions, and can select the optimal relay link for quantum key distribution between the source node and the destination node according to the priority, ensuring the security and efficiency of the quantum key distribution service and improving the flexibility of the relay link setting. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only those of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic flowchart of the quantum key distribution method based on a tethered drone provided by an embodiment of the present application;

[0022] Figure 2 It is a schematic diagram of the first deployment plan list provided by an embodiment of the present application;

[0023] Figure 3 It is a schematic diagram of the second deployment plan list provided by an embodiment of the present application;

[0024] Figure 4 It is the first schematic diagram of one of the target relay links provided by an embodiment of the present application;

[0025] Figure 5 It is the second schematic diagram of one of the target relay links provided by an embodiment of the present application;

[0026] Figure 6 It is the third schematic diagram of one of the target relay links provided by an embodiment of the present application;

[0027] Figure 7 It is the fourth schematic diagram of one of the target relay links provided by an embodiment of the present application;

[0028] Figure 8 It is the fifth schematic diagram of one of the target relay links provided by an embodiment of the present application;

[0029] Figure 9 It is the sixth schematic diagram of one of the target relay links provided by an embodiment of the present application;

[0030] Figure 10 It is the seventh schematic diagram of one of the target relay links provided by an embodiment of the present application;

[0031] Figure 11 It is the eighth schematic diagram of one of the target relay links provided by an embodiment of the present application;

[0032] Figure 12 It is the ninth schematic diagram of one of the target relay links provided by an embodiment of the present application;

[0033] Figure 13 It is a schematic diagram of the quantum key distribution device based on a tethered drone provided by an embodiment of the present application;

[0034] Figure 14 This is a schematic diagram of the hardware structure of the electronic device provided by the embodiment of the present application. Specific embodiments

[0035] In order to make the purpose, technical solutions and advantages of the present disclosure clearer and more understandable, the following further describes the present disclosure in detail with reference to specific embodiments and the accompanying drawings.

[0036] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in this application should have the ordinary meaning understood by those of ordinary skill in the art to which the present disclosure belongs. The "first", "second" and similar terms used in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this term cover the elements or objects listed after this term and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0037] As described in the background art section, the existing methods for providing QKD services for wide-area users mainly include the following three: First, use optical fibers to connect the QKD service source, destination nodes and fixed satellite ground stations, and provide QKD services by configuring the connection of source node - (optical fiber) - satellite ground station - (free space) - quantum satellite - (free space) - satellite ground station - (optical fiber) - destination node. However, the laying of optical fibers is easily restricted by geographical conditions, and under some special geographical conditions, the QKD service source and destination nodes cannot be connected to the fixed satellite ground station through optical fibers, which limits the flexibility of QKD service provision.

[0038] Second, rely on classical key distribution methods, such as obtaining the quantum key negotiated between satellite ground stations at the satellite ground station using a USB flash drive or memory card and manually transporting it to the QKD service source and destination nodes, or using classical cryptography, physical layer security and other key distribution technologies to transmit the quantum key of the satellite ground station to the QKD service source and destination nodes. However, these methods are difficult to ensure the security of quantum keys.

[0039] Thirdly, deploy movable quantum satellite ground stations at the source and destination nodes of the QKD service. Provide the QKD service by configuring the connection of movable quantum satellite ground station - (free space) - quantum satellite - (free space) - movable quantum satellite ground station. However, the cost of the movable quantum satellite ground station is relatively high, and currently, the transit time of the quantum satellite passing through each movable quantum satellite ground station is usually several minutes (not exceeding ten minutes). The amount of quantum keys negotiated to meet the QKD service requirements is affected by factors such as weather conditions and transit time, resulting in low efficiency in providing the QKD service. Therefore, the existing methods for providing QKD services to wide-area users have problems such as low flexibility, difficult-to-guarantee security, or high costs. Moreover, factors such as geographical conditions, weather environment, and time are likely to cause low efficiency in providing QKD services, making it difficult to achieve efficient and flexible provision of QKD services for wide-area users.

[0040] In view of the above actual situation, the embodiments of the present application provide a quantum key distribution method based on a tethered drone and related devices. This method can flexibly provide QKD services for wide-area users. Considering the deployment cost of the tethered drone, it can meet the end-to-end dynamic negotiation requirements of quantum keys between QKD service source and destination nodes under complex geographical conditions.

[0041] Hereinafter, the technical solutions of the present disclosure will be further described in detail through specific embodiments.

[0042] Reference Figure 1 , is a schematic flowchart of the quantum key distribution method based on a tethered drone provided by the embodiments of the present application.

[0043] Step S101, in response to receiving a quantum key distribution request sent by a target user, determine the source node and the destination node according to the quantum key distribution request.

[0044] In a specific implementation, when a wide-area user sends a QKD service request, the QKD service source node and the QKD service destination node of the wide-area user can be queried according to the QKD service request, hereinafter referred to as the source node and the destination node for short. The QKD service can negotiate quantum keys between the source node and the destination node to ensure end-to-end secure communication for wide-area users.

[0045] Step S102, calculate the distances between the source node and multiple satellite ground stations within its metropolitan area, and determine the satellite ground station with the shortest distance from the source node among the multiple satellite ground stations as the first satellite ground station; calculate the distances between the destination node and multiple satellite ground stations within its metropolitan area, and determine the satellite ground station with the shortest distance from the destination node among the multiple satellite ground stations as the second satellite ground station.

[0046] In the specific implementation, after the source node and the destination node are determined, the satellite ground station within the metropolitan area of the source node and the destination node is further searched. The satellite ground station can connect with the quantum satellite when it passes by to realize the satellite-to-ground quantum key distribution service, and the quantum satellite relay can be used to realize the sharing of keys between satellite ground stations.

[0047] There are multiple satellite ground stations within the metropolitan area of the source node and the destination node. The most suitable one needs to be selected from the multiple satellite ground stations to perform the quantum key distribution task. Therefore, the multiple satellite ground stations need to be prioritized. Specifically, the horizontal distance between the source node and the destination node and the multiple satellite ground stations within their metropolitan area is calculated. This distance is the metropolitan communication distance, which is usually several kilometers to tens of kilometers, generally not exceeding 100km, where the horizontal distance is the straight-line distance between the two points without taking into account the height difference.

[0048] Furthermore, multiple satellite ground stations are prioritized from low to high according to the horizontal distance between the source node and the destination node and their satellite ground stations. The shorter the distance, the higher the signal transmission efficiency between the source node and the destination node and their satellite ground stations, which is conducive to the implementation of quantum key distribution services. The satellite ground station among the multiple satellite ground stations that is closest to the source node is preferentially selected as the first satellite ground station corresponding to the source node, and the satellite ground station among the multiple satellite ground stations that is closest to the destination node is preferentially selected as the second satellite ground station corresponding to the destination node.

[0049] As an optional implementation, the selection of the optimal satellite ground station can also be determined by combining the real-time quantum key remainder based on the relay of a single quantum satellite between the satellite ground station corresponding to the source node and the satellite ground station corresponding to the destination node. Specifically, a single quantum satellite is used as a relay node (such as a trusted relay node or an untrusted relay node), and key relay or quantum signal relay is performed at the quantum satellite. A quantum key can be negotiated between satellite ground stations located in two places, and stored in the key storage of the satellite ground station for subsequent use. After traversing multiple satellite ground stations, multiple quantum key remainder values corresponding to multiple satellite ground stations can be obtained. The optimal source node and satellite ground station corresponding to the destination node can be selected according to the priority of the multiple quantum key remainder values from most to least, combined with the horizontal distance between the source node and the destination node and multiple satellite ground stations within their metropolitan area.

[0050] As an optional implementation, after determining the optimal satellite ground stations corresponding to the source node and the sink node respectively, the target quantum satellite can also be determined according to the quantum key residue, specifically:

[0051] This can be determined by:

[0052] Determine a relay quantum satellite group between a first satellite ground station and a second satellite ground station; wherein, the relay quantum satellite group includes at least one relay quantum satellite;

[0053] Calculate the quantum key margin corresponding to each relay quantum satellite in the relay quantum satellite group between the first satellite ground station and the second satellite ground station;

[0054] Determine the relay quantum satellite with the most quantum key margin as the target quantum satellite.

[0055] Wherein, the relay quantum satellites in the relay quantum satellite group can be used as relay nodes (such as trusted relay nodes or untrusted relay nodes), perform key relay or quantum signal relay at the quantum satellite, and can negotiate quantum keys between satellite ground stations located in two different places.

[0056] Step S103, determine a first deployment plan list of the tethered drone between the source node and the first satellite ground station according to the deployment cost.

[0057] Reference Figure 2 , which is a schematic diagram of the first deployment plan list provided by the embodiment of the present application.

[0058] Wherein, the first deployment plan list includes multiple first deployment plans sorted from low to high according to the deployment cost; determine a second deployment plan list of the tethered drone between the sink node and the second satellite ground station according to the deployment cost; wherein, the second deployment plan list includes multiple second deployment plans sorted from low to high according to the deployment cost.

[0059] Specifically, after determining the optimal first satellite ground station corresponding to the source node, further set the deployment plan of the tethered drone between the source node and the first satellite ground station. Among them, the deployment plan of the tethered drone can be formulated in advance according to the actual situation, and multiple deployment plans of the tethered drone are sorted from low to high according to the deployment cost to obtain the first deployment plan list; wherein, the first deployment plan list includes multiple first deployment plans sorted from low to high according to the deployment cost.

[0060] As an optional embodiment, the multiple first deployment plans include: a first-level deployment plan, a second-level deployment plan, and a third-level deployment plan, wherein:

[0061] The first-level deployment plan includes: deploying a tethered drone above the source node and deploying a corresponding tethered drone ground station at the first satellite ground station; to realize the quantum key distribution service between the tethered drone and the ground.

[0062] The two - level deployment plan includes: deploying a tethered drone above the first satellite ground station, and deploying a corresponding tethered drone ground station at the source node; to implement the quantum key distribution service between the tethered drone and the ground.

[0063] The three - level deployment plan includes: deploying a first tethered drone above the source node, and deploying a second tethered drone corresponding to the first tethered drone above the first satellite ground station; to implement the quantum key distribution service between the tethered drones.

[0064] For the same purpose, after determining the optimal second satellite ground station corresponding to the destination node, a tethered drone deployment plan between the destination node and the second satellite ground station is further set. Among them, the deployment plan of the tethered drone can be formulated in advance according to the actual situation, and multiple tethered drone deployment plans are sorted from low to high according to the deployment cost to obtain a second deployment plan list; among them, the second deployment plan list includes multiple second deployment plans sorted from low to high according to the deployment cost.

[0065] Reference Figure 3 , which is a schematic diagram of the second deployment plan list provided by the embodiment of the present application.

[0066] As an optional embodiment, multiple second deployment plans include: a four - level deployment plan, a five - level deployment plan, and a six - level deployment plan, where:

[0067] The four - level deployment plan includes: deploying a tethered drone above the destination node, and deploying a corresponding tethered drone ground station at the second satellite ground station; to implement the quantum key distribution service between the tethered drone and the ground.

[0068] The five - level deployment plan includes: deploying a tethered drone above the second satellite ground station, and deploying a corresponding tethered drone ground station at the destination node; to implement the quantum key distribution service between the tethered drone and the ground.

[0069] The six - level deployment plan includes: deploying a third tethered drone above the destination node, and deploying a fourth tethered drone corresponding to the third tethered drone above the second satellite ground station; to implement the quantum key distribution service between the tethered drones.

[0070] It should be noted that the free - space signal transmission paths of the one - level deployment plan, two - level deployment plan, three - level deployment plan, four - level deployment plan, five - level deployment plan, and six - level deployment plan are differently blocked by obstacles. The three - level deployment plan and the six - level deployment plan usually have higher costs than other plans because they require more tethered drones and related equipment.

[0071] It should be noted that, in order to minimize the probability that the free-space signal transmission path is blocked by obstacles, the set height of the tethered UAV is the maximum hovering height supported by the tethered UAV.

[0072] Step S104, determine a first target deployment plan from the multiple first deployment plans according to the space link occlusion situation between the source node and the first satellite ground station; determine a second target deployment plan from the multiple second deployment plans according to the space link occlusion situation between the sink node and the second satellite ground station.

[0073] In a specific implementation, the first deployment plan list includes a first-level deployment plan, a second-level deployment plan, and a third-level deployment plan sorted by priority according to the deployment cost from low to high, and the second deployment plan list includes a fourth-level deployment plan, a fifth-level deployment plan, and a sixth-level deployment plan sorted by priority according to the deployment cost from low to high.

[0074] Furthermore, determine a first target deployment plan from the multiple first deployment plans according to the space link occlusion situation between the source node and the first satellite ground station;

[0075] As an optional embodiment, first determine whether there is an occlusion in the space link between the tethered UAV deployed above the source node in the first-level deployment plan and the tethered UAV ground station deployed at the first satellite ground station;

[0076] If there is no occlusion in the space link between the tethered UAV deployed above the source node in the first-level deployment plan and the tethered UAV ground station deployed at the first satellite ground station, determine the first-level deployment plan as the first target deployment plan;

[0077] If there is an occlusion in the space link between the tethered UAV deployed above the source node in the first-level deployment plan and the tethered UAV ground station deployed at the first satellite ground station, further determine whether there is an occlusion in the space link between the tethered UAV ground station deployed at the source node in the second-level deployment plan and the tethered UAV deployed above the first satellite ground station;

[0078] If there is no occlusion in the space link between the tethered UAV ground station deployed at the source node in the second-level deployment plan and the tethered UAV deployed above the first satellite ground station, determine the second-level deployment plan as the first target deployment plan;

[0079] If there is an occlusion in the space link between the tethered UAV ground station deployed at the source node in the second-level deployment plan and the tethered UAV deployed above the first satellite ground station, determine whether there is an occlusion in the space link between the first tethered UAV deployed above the source node in the third-level deployment plan and the second tethered UAV deployed above the first satellite ground station;

[0080] If there is no occlusion in the space link between the first tethered drone deployed above the source node in the three - level deployment scheme and the second tethered drone deployed above the first satellite ground station, determine that the three - level deployment scheme is the first target deployment scheme.

[0081] Further, determine the second target deployment scheme from multiple second deployment schemes according to the occlusion situation of the space link between the sink node and the second satellite ground station;

[0082] As an optional embodiment, first determine whether there is occlusion in the space link between the tethered drone deployed above the sink node in the four - level deployment scheme and the tethered drone ground station deployed at the second satellite ground station;

[0083] If there is no occlusion in the space link between the tethered drone deployed above the sink node in the four - level deployment scheme and the tethered drone ground station deployed at the second satellite ground station, determine that the four - level deployment scheme is the second target deployment scheme;

[0084] If there is occlusion in the space link between the tethered drone deployed above the sink node in the four - level deployment scheme and the tethered drone ground station deployed at the second satellite ground station, further determine whether there is occlusion in the space link between the tethered drone ground station deployed at the sink node in the five - level deployment scheme and the tethered drone deployed above the second satellite ground station;

[0085] If there is no occlusion in the space link between the tethered drone ground station deployed at the sink node in the five - level deployment scheme and the tethered drone deployed above the second satellite ground station, determine that the five - level deployment scheme is the second target deployment scheme;

[0086] If there is occlusion in the space link between the tethered drone ground station deployed at the sink node in the five - level deployment scheme and the tethered drone deployed above the second satellite ground station, determine whether there is occlusion in the space link between the third tethered drone deployed above the sink node in the six - level deployment scheme and the fourth tethered drone deployed above the second satellite ground station;

[0087] If there is no occlusion in the space link between the third tethered drone deployed above the sink node in the six - level deployment scheme and the fourth tethered drone deployed above the second satellite ground station, determine that the six - level deployment scheme is the second target deployment scheme.

[0088] It should be noted that if there are obstructions in the space links of both the first deployment plan list and the second deployment plan list, it indicates that the geographical conditions between the source node and the first satellite ground station and between the destination node and the second satellite ground station are relatively poor. The first satellite ground station and the second satellite ground station may be unavailable and there is no feasible tethered drone deployment plan. It may be necessary to adopt other methods to implement the quantum key distribution service.

[0089] Step S105, determine the target relay link between the source node and the destination node according to the first target deployment plan and the second target deployment plan, so that quantum key distribution is performed between the source node and the destination node based on the target relay link.

[0090] Reference Figure 4 , is the first schematic diagram of one of the target relay links provided by the embodiments of the present application.

[0091] As an optional embodiment, the target relay link may be composed of the first target deployment plan and the second target deployment plan. When the first target deployment plan is a first-level deployment plan and the second target deployment plan is a fourth-level deployment plan, the deployment of the target relay link is as follows: deploy a tethered drone above the source node, deploy a tethered drone ground station corresponding to the tethered drone at the first satellite ground station, deploy a tethered drone above the destination node, and deploy a tethered drone ground station corresponding to the tethered drone at the second satellite ground station. Among them, the direction indicated by the arrow is the quantum signal transmission direction.

[0092] Reference Figure 5 , is the second schematic diagram of one of the target relay links provided by the embodiments of the present application.

[0093] As an optional embodiment, the target relay link may be composed of the first target deployment plan and the second target deployment plan. When the first target deployment plan is a first-level deployment plan and the second target deployment plan is a fifth-level deployment plan, the deployment of the target relay link is as follows: deploy a tethered drone above the source node, deploy a tethered drone ground station corresponding to the tethered drone at the first satellite ground station, deploy a tethered drone above the second satellite ground station, and deploy a tethered drone ground station corresponding to the tethered drone at the destination node. Among them, the direction indicated by the arrow is the quantum signal transmission direction.

[0094] Reference Figure 6 , is the third schematic diagram of one of the target relay links provided by the embodiments of the present application.

[0095] As an alternative embodiment, the target relay link may consist of a first target deployment scheme and a second target deployment scheme. When the first target deployment scheme is a first-level deployment scheme and the second target deployment scheme is a sixth-level deployment scheme, the deployment of the target relay link is as follows: A tethered drone is deployed above the source node, a tethered drone ground station corresponding to the tethered drone is deployed at the first satellite ground station, a third tethered drone is deployed above the destination node, and a fourth tethered drone corresponding to the third tethered drone is deployed above the second satellite ground station. Among them, the direction indicated by the arrow is the quantum signal transmission direction.

[0096] Reference Figure 7 , which is the fourth schematic diagram of one of the target relay links provided by the embodiments of the present application.

[0097] As an alternative embodiment, the target relay link may consist of a first target deployment scheme and a second target deployment scheme. When the first target deployment scheme is a second-level deployment scheme and the second target deployment scheme is a fourth-level deployment scheme, the deployment of the target relay link is as follows: A tethered drone is deployed above the first satellite ground station, a tethered drone ground station corresponding to the tethered drone is deployed at the source node, a tethered drone is deployed above the destination node, and a tethered drone ground station corresponding to the tethered drone is deployed at the second satellite ground station. Among them, the direction indicated by the arrow is the quantum signal transmission direction.

[0098] Reference Figure 8 , which is the fifth schematic diagram of one of the target relay links provided by the embodiments of the present application.

[0099] As an alternative embodiment, the target relay link may consist of a first target deployment scheme and a second target deployment scheme. When the first target deployment scheme is a second-level deployment scheme and the second target deployment scheme is a fifth-level deployment scheme, the deployment of the target relay link is as follows: A tethered drone is deployed above the first satellite ground station, a tethered drone ground station corresponding to the tethered drone is deployed at the source node, a tethered drone is deployed above the second satellite ground station, and a tethered drone ground station corresponding to the tethered drone is deployed at the destination node. Among them, the direction indicated by the arrow is the quantum signal transmission direction.

[0100] Reference Figure 9 , which is the sixth schematic diagram of one of the target relay links provided by the embodiments of the present application.

[0101] As an alternative embodiment, the target relay link may consist of a first target deployment scheme and a second target deployment scheme. When the first target deployment scheme is a secondary deployment scheme and the second target deployment scheme is a sixth-level deployment scheme, the deployment of the target relay link is as follows: A tethered drone is deployed above the first satellite ground station, a tethered drone ground station corresponding to the tethered drone is deployed at the source node, a third tethered drone is deployed above the destination node, and a fourth tethered drone corresponding to the third tethered drone is deployed above the second satellite ground station. Among them, the direction indicated by the arrow is the quantum signal transmission direction.

[0102] Reference Figure 10 , which is the seventh schematic diagram of one of the target relay links provided by the embodiments of the present application.

[0103] As an alternative embodiment, the target relay link may consist of a first target deployment scheme and a second target deployment scheme. When the first target deployment scheme is a tertiary deployment scheme and the second target deployment scheme is a quaternary deployment scheme, the deployment of the target relay link is as follows: A first tethered drone is deployed above the source node, a second tethered drone corresponding to the first tethered drone is deployed above the first satellite ground station, a tethered drone is deployed above the destination node, and a tethered drone ground station corresponding to the tethered drone is deployed at the second satellite ground station. Among them, the direction indicated by the arrow is the quantum signal transmission direction.

[0104] Reference Figure 11 , which is the eighth schematic diagram of one of the target relay links provided by the embodiments of the present application.

[0105] As an alternative embodiment, the target relay link may consist of a first target deployment scheme and a second target deployment scheme. When the first target deployment scheme is a tertiary deployment scheme and the second target deployment scheme is a fifth-level deployment scheme, the deployment of the target relay link is as follows: A first tethered drone is deployed above the source node, a second tethered drone corresponding to the first tethered drone is deployed above the first satellite ground station, a tethered drone is deployed above the second satellite ground station, and a tethered drone ground station corresponding to the tethered drone is deployed at the destination node. Among them, the direction indicated by the arrow is the quantum signal transmission direction.

[0106] Reference Figure 12 , which is the ninth schematic diagram of one of the target relay links provided by the embodiments of the present application.

[0107] As an optional embodiment, the target relay link may be composed of a first target deployment scheme and a second target deployment scheme. When the first target deployment scheme is a three-level deployment scheme and the second target deployment scheme is a six-level deployment scheme, the deployment of the target relay link is as follows: a first tethered drone is deployed above the source node, a second tethered drone corresponding to the first tethered drone is deployed above the first satellite ground station, a third tethered drone is deployed above the destination node, and a fourth tethered drone corresponding to the third tethered drone is deployed above the second satellite ground station. Among them, the direction indicated by the arrow is the quantum signal transmission direction.

[0108] Further, after determining the target intermediate link, it is necessary to deploy the required tethered drones equipped with corresponding optical fibers and free-space QKD devices above the source node, the first satellite ground station, the destination node, and the second satellite ground station according to the deployment scheme of the tethered drones. The tethered drones are connected to the corresponding source node, destination node, or satellite ground station through tethered optical fibers and are docked with the drone ground station or other tethered drones through free space. Therefore, optical fibers and free-space QKD devices are required.

[0109] The QKD device includes a pair of QKD transmitters and QKD receivers. The tethered drone can choose to carry a QKD transmitter or a QKD receiver. Deploy the required fiber QKD devices and drone ground stations for accommodating the corresponding free-space QKD devices at the source node, destination node, and their respective corresponding satellite ground stations according to the tethered drone deployment scheme. The drone ground station docks with the tethered drone through free space, and it is necessary to place the free-space QKD device (QKD transmitter or QKD receiver) matching the tethered drone. In addition, the fiber QKD devices deployed at the QKD service source / destination node or satellite ground station need to match the fiber QKD devices of the tethered drone above them.

[0110] It should be noted that the fiber QKD connection between the tethered drone and its corresponding source / destination node or satellite ground station can be configured within the idle time window of the satellite ground station, that is, by connecting the corresponding fiber QKD transmitter and QKD receiver through the tethered optical fiber. There is no quantum satellite passing through during the idle time window of the satellite ground station.

[0111] Configure a free-space QKD connection between a tethered drone and its corresponding tethered drone or drone ground station within the idle time window of the satellite ground station, that is, connect the corresponding free-space QKD transmitter and receiver through free space. Configure an end-to-end QKD connection between the QKD service source node and its sink node within the idle time window of the satellite ground station. This connection consumes the real-time quantum key margin between the satellite ground stations corresponding to the QKD service source and sink nodes. Currently, the transit time of the quantum satellite through each satellite ground station is usually a few minutes (not exceeding ten minutes). When the quantum satellite transits through the satellite ground station, the quantum satellite and the satellite ground station perform satellite-ground QKD, and the satellite ground stations relay through the quantum satellite, and the corresponding quantum key amounts are replenished.

[0112] The QKD receiver and the QKD transmitter can be dynamically removed according to the actual situation. During the non-quantum satellite transit time (i.e., within the idle time window of the satellite ground station), dynamically establishing relevant connections can avoid the mutual influence between the tethered drone and satellite-ground QKD or the quantum satellite relay. Based on the end-to-end QKD connection of the tethered drone, quantum keys can be negotiated between the source and sink nodes to complete the QKD service provision for wide-area users.

[0113] As can be seen from the above, a quantum key distribution method and related devices provided by the present application are applied to a quantum key distribution system composed of a source node, a destination node, a tethered drone, multiple satellite ground stations, a target quantum satellite, and a drone ground station. The method includes: in response to receiving a quantum key distribution request sent by a target user, determining the source node and the destination node according to the quantum key distribution request; calculating the distances between the source node and multiple satellite ground stations within its metropolitan area, and determining the satellite ground station with the shortest distance from the source node among the multiple satellite ground stations as the first satellite ground station; calculating the distances between the destination node and multiple satellite ground stations within its metropolitan area, and determining the satellite ground station with the shortest distance from the destination node among the multiple satellite ground stations as the second satellite ground station; determining a first deployment plan list of the tethered drone between the source node and the first satellite ground station according to the deployment cost; the first deployment plan list includes multiple first deployment plans sorted in ascending order of deployment cost; determining a second deployment plan list of the tethered drone between the destination node and the second satellite ground station according to the deployment cost; the second deployment plan list includes multiple second deployment plans sorted in ascending order of deployment cost; determining a first target deployment plan from multiple first deployment plans according to the space link occlusion situation between the source node and the first satellite ground station; determining a second target deployment plan from multiple second deployment plans according to the space link occlusion situation between the destination node and the second satellite ground station; determining a target relay link between the source node and the destination node according to the first target deployment plan and the second target deployment plan, so that quantum key distribution is performed between the source node and the destination node based on the target relay link. The present application determines the deployment plan of the tethered drone between the source node and its corresponding satellite ground station and the deployment plan of the tethered drone between the destination node and its corresponding satellite ground station in ascending order of deployment cost. Further, according to the space link occlusion situation between the source node and its corresponding satellite ground station and the space link occlusion situation between the destination node and its corresponding satellite ground station, the optimal target relay link between the source node and the destination node is further determined from the above-mentioned deployment plans of the tethered drone, so that quantum key distribution is performed between the source node and the destination node based on the target relay link. The present application takes into account factors such as deployment cost and geographical conditions, and can select the optimal relay link for quantum key distribution between the source node and the destination node according to the priority, ensuring the security and efficiency of the quantum key distribution service and improving the flexibility of the relay link setting.

[0114] It should be noted that the method of the embodiment of the present application can be executed by a single device, such as a computer or a server. The method of the embodiment of the present application can also be applied to a distributed scenario and completed by multiple devices cooperating with each other. In this case of a distributed scenario, one of the multiple devices can only execute one or more steps of the method of the embodiment of the present application, and these multiple devices will interact with each other to complete the described method.

[0115] It should be noted that the above specific embodiments of the present application have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the above embodiments and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the specific order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0116] Based on the same concept, corresponding to the method of any of the above embodiments, the present application further provides a quantum key distribution device based on a tethered unmanned aerial vehicle.

[0117] Reference Figure 13 , is a schematic diagram of the quantum key distribution device based on a tethered unmanned aerial vehicle provided by the embodiment of the present application.

[0118] The quantum key distribution device based on a tethered unmanned aerial vehicle is applied to a quantum key distribution system composed of a source node, a destination node, a tethered unmanned aerial vehicle, multiple satellite ground stations, a target quantum satellite, and an unmanned aerial vehicle ground station. The device includes:

[0119] A node determination module 1301, configured to, in response to receiving a quantum key distribution request issued by a target user, determine the source node and the destination node according to the quantum key distribution request;

[0120] A parameter determination module 1302, configured to calculate the distances between the source node and multiple satellite ground stations within its metropolitan area, and determine the satellite ground station with the shortest distance to the source node among the multiple satellite ground stations as the first satellite ground station; calculate the distances between the destination node and multiple satellite ground stations within its metropolitan area, and determine the satellite ground station with the shortest distance to the destination node among the multiple satellite ground stations as the second satellite ground station;

[0121] The first determination module 1303 is configured to determine a first deployment plan list of the tethered drone between the source node and the first satellite ground station according to the deployment cost; wherein, the first deployment plan list includes a plurality of first deployment plans sorted from low to high according to the deployment cost; determine a second deployment plan list of the tethered drone between the destination node and the second satellite ground station according to the deployment cost; wherein, the second deployment plan list includes a plurality of second deployment plans sorted from low to high according to the deployment cost;

[0122] The second determination module 1304 is configured to determine a first target deployment plan from the plurality of first deployment plans according to the space link occlusion condition between the source node and the first satellite ground station; determine a second target deployment plan from the plurality of second deployment plans according to the space link occlusion condition between the destination node and the second satellite ground station;

[0123] The key distribution module 1305 is configured to determine a target relay link between the source node and the destination node according to the first target deployment plan and the second target deployment plan, so that quantum key distribution is performed between the source node and the destination node based on the target relay link.

[0124] For the convenience of description, when describing the above device, various modules are described separately according to their functions. Of course, when implementing the embodiments of the present application, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0125] The device in the above embodiment is used to implement the corresponding quantum key distribution method based on the tethered drone in the foregoing embodiment, and has the beneficial effects of the corresponding method embodiment, which will not be repeated here.

[0126] Based on the same concept, corresponding to the method in any of the above embodiments, the present application further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor implements the quantum key distribution method based on the tethered drone as described in any of the above embodiments when executing the program.

[0127] Figure 14 FIG. shows a more specific schematic diagram of the hardware structure of the electronic device provided in this embodiment. The device may include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. Among them, the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are communicatively connected to each other inside the device through the bus 1050.

[0128] The processor 1010 can be implemented in the form of a general-purpose CPU (Central Processing Unit), a microprocessor, an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits, etc., and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0129] The memory 1020 can be implemented in the form of a ROM (Read Only Memory), a RAM (Random Access Memory), a static storage device, a dynamic storage device, etc. The memory 1020 can store an operating system and other application programs. When implementing the technical solutions provided in the embodiments of this specification through software or firmware, the relevant program codes are stored in the memory 1020 and are called and executed by the processor 1010.

[0130] The input / output interface 1030 is used to connect to the input / output module to achieve information input and output. The input / output module can be configured as a component in the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Among them, the input device can include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device can include a display, a speaker, a vibrator, an indicator light, etc.

[0131] The communication interface 1040 is used to connect to a communication module (not shown in the figure) to achieve communication and interaction between this device and other devices. Among them, the communication module can achieve communication through a wired method (such as USB, network cable, etc.) or through a wireless method (such as a mobile network, WIFI, Bluetooth, etc.).

[0132] The bus 1050 includes a path for transmitting information between various components of the device (such as the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040).

[0133] It should be noted that although only the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040, and the bus 1050 are shown in the above device, in the specific implementation process, this device may also include other components necessary for normal operation. In addition, those skilled in the art can understand that the above device may also only include the components necessary to implement the solutions of the embodiments of this specification and do not have to include all the components shown in the figure.

[0134] The electronic device of the above embodiment is used to implement the corresponding quantum key distribution method based on a tethered drone in any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be elaborated herein.

[0135] Based on the same concept, corresponding to the method of any of the above embodiments, the present application also provides a non-transitory computer-readable storage medium storing computer instructions for causing the computer to execute the quantum key distribution method based on a tethered drone as described in any of the above embodiments.

[0136] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette tapes, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device.

[0137] The computer instructions stored in the storage medium of the above embodiment are used to cause the computer to execute the quantum key distribution method based on a tethered drone as described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be elaborated herein.

[0138] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the present application (including the claims) is limited to these examples; under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of brevity.

[0139] In addition, for simplicity of explanation and discussion, and so as not to make the embodiments of the present application difficult to understand, well-known power / ground connections to integrated circuit (IC) chips and other components may or may not be shown in the provided drawings. Further, the devices may be shown in block diagram form in order to avoid making the embodiments of the present application difficult to understand, and this also takes into account the fact that details regarding the implementation of these block diagram devices are highly dependent on the platform on which the embodiments of the present application are to be implemented (i.e., these details should be fully within the understanding of those skilled in the art). In cases where specific details (such as circuits) are set forth to describe exemplary embodiments of the present application, it will be apparent to those skilled in the art that the embodiments of the present application may be practiced without these specific details or with variations of these specific details. Accordingly, these descriptions should be regarded as illustrative rather than restrictive.

[0140] Although the present application has been described in connection with specific embodiments thereof, many alternatives, modifications, and variations of these embodiments will be apparent to those of ordinary skill in the art based on the foregoing description. For example, other memory architectures (such as dynamic RAM (DRAM)) may be used with the embodiments discussed.

[0141] Embodiments of the present application are intended to cover all such alternatives, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of the present application shall be included within the protection scope of the present application.

Claims

1. A quantum key distribution method based on a tethered drone, characterized in that, Applied to a quantum key distribution system composed of a source node, a destination node, a tethered unmanned aerial vehicle (UAV), multiple satellite ground stations, a target quantum satellite, and a UAV ground station, the method includes: In response to receiving a quantum key distribution request sent by a target user, determining the source node and the destination node according to the quantum key distribution request; Calculating the distances between the source node and multiple satellite ground stations within its metropolitan area, and determining the satellite ground station with the shortest distance to the source node among the multiple satellite ground stations as the first satellite ground station; calculating the distances between the destination node and multiple satellite ground stations within its metropolitan area, and determining the satellite ground station with the shortest distance to the destination node among the multiple satellite ground stations as the second satellite ground station; Determining a first deployment plan list of the tethered UAV between the source node and the first satellite ground station according to the deployment cost; wherein, the first deployment plan list includes multiple first deployment plans sorted from low to high according to the deployment cost; determining a second deployment plan list of the tethered UAV between the destination node and the second satellite ground station according to the deployment cost; wherein, the second deployment plan list includes multiple second deployment plans sorted from low to high according to the deployment cost; Determining a first target deployment plan from the multiple first deployment plans according to the space link occlusion situation between the source node and the first satellite ground station; determining a second target deployment plan from the multiple second deployment plans according to the space link occlusion situation between the destination node and the second satellite ground station; Determining a target relay link between the source node and the destination node according to the first target deployment plan and the second target deployment plan, so that quantum key distribution is performed between the source node and the destination node based on the target relay link.

2. The method according to claim 1, wherein The multiple first deployment plans include: a first-level deployment plan, a second-level deployment plan, and a third-level deployment plan, wherein: The first-level deployment plan includes: deploying a tethered UAV above the source node and deploying a corresponding tethered UAV ground station at the first satellite ground station; The second-level deployment plan includes: deploying a tethered UAV above the first satellite ground station and deploying a corresponding tethered UAV ground station at the source node; The third-level deployment plan includes: deploying a first tethered UAV above the source node and deploying a second tethered UAV corresponding to the first tethered UAV above the first satellite ground station.

3. The method according to claim 1, wherein The multiple second deployment plans include: a fourth-level deployment plan, a fifth-level deployment plan, and a sixth-level deployment plan, wherein: The fourth-level deployment plan includes: deploying a tethered UAV above the destination node and deploying a corresponding tethered UAV ground station at the second satellite ground station; The fifth-level deployment plan includes: deploying a tethered UAV above the second satellite ground station and deploying a corresponding tethered UAV ground station at the destination node; The six-level deployment plan includes: deploying a third tethered drone above the host node and deploying a corresponding fourth tethered drone above the second satellite ground station.

4. The method according to claim 2, characterized in that, Determining a first target deployment plan from the multiple first deployment plans according to the space link occlusion situation between the source node and the first satellite ground station includes: Judging whether there is occlusion in the space link between the tethered drone deployed above the source node in the first-level deployment plan and the tethered drone ground station deployed at the first satellite ground station; In response to there being no occlusion in the space link between the tethered drone deployed above the source node in the first-level deployment plan and the tethered drone ground station deployed at the first satellite ground station, determining the first-level deployment plan as the first target deployment plan.

5. The method according to claim 4, characterized in that Determining a first target deployment plan from the multiple first deployment plans according to the space link occlusion situation between the source node and the first satellite ground station further includes: In response to there being occlusion in the space link between the tethered drone deployed above the source node in the first-level deployment plan and the tethered drone ground station deployed at the first satellite ground station, judging whether there is occlusion in the space link between the tethered drone ground station deployed at the source node in the second-level deployment plan and the tethered drone deployed above the first satellite ground station; In response to there being no occlusion in the space link between the tethered drone ground station deployed at the source node in the second-level deployment plan and the tethered drone deployed above the first satellite ground station, determining the second-level deployment plan as the first target deployment plan.

6. The method according to claim 5, wherein Determining a first target deployment plan from the multiple first deployment plans according to the space link occlusion situation between the source node and the first satellite ground station further includes: In response to there being occlusion in the space link between the tethered drone ground station deployed at the source node in the second-level deployment plan and the tethered drone deployed above the first satellite ground station, judging whether there is occlusion in the space link between the first tethered drone deployed above the source node in the third-level deployment plan and the second tethered drone deployed above the first satellite ground station; In response to there being no occlusion in the space link between the first tethered drone deployed above the source node in the third-level deployment plan and the second tethered drone deployed above the first satellite ground station, determining the third-level deployment plan as the first target deployment plan.

7. The method according to claim 3, wherein Determining a second target deployment plan from the multiple second deployment plans according to the space link occlusion situation between the host node and the second satellite ground station includes: Judging whether there is occlusion in the space link between the tethered drone deployed above the host node in the fourth-level deployment plan and the tethered drone ground station deployed at the second satellite ground station; In response to there being no occlusion in the space link between the tethered drone deployed above the host node in the fourth-level deployment plan and the tethered drone ground station deployed at the second satellite ground station, determining the fourth-level deployment plan as the second target deployment plan.

8. The method according to claim 7, wherein Determining the second target deployment plan from the multiple second deployment plans according to the space link occlusion situation between the host node and the second satellite ground station further includes: In response to occlusion of the space link between the tethered drone deployed above the host node in the four-level deployment plan and the tethered drone ground station deployed at the second satellite ground station, determining whether there is occlusion of the space link between the tethered drone ground station deployed at the host node in the five-level deployment plan and the tethered drone deployed above the second satellite ground station; In response to there being no occlusion of the space link between the tethered drone ground station deployed at the host node in the five-level deployment plan and the tethered drone deployed above the second satellite ground station, determining the five-level deployment plan as the second target deployment plan.

9. The method according to claim 8, wherein Determining the second target deployment plan from the multiple second deployment plans according to the space link occlusion situation between the host node and the second satellite ground station further includes: In response to there being occlusion of the space link between the tethered drone ground station deployed at the host node in the five-level deployment plan and the tethered drone deployed above the second satellite ground station, determining whether there is occlusion of the space link between the third tethered drone deployed above the host node in the six-level deployment plan and the fourth tethered drone deployed above the second satellite ground station; In response to there being no occlusion of the space link between the third tethered drone deployed above the host node in the six-level deployment plan and the fourth tethered drone deployed above the second satellite ground station, determining the six-level deployment plan as the second target deployment plan.

10. The method according to claim 1, characterized in that, The target quantum satellite is determined by the following method: Determining a relay quantum satellite group between the first satellite ground station and the second satellite ground station; wherein, the relay quantum satellite group includes at least one relay quantum satellite; Calculating the quantum key margin corresponding to each relay quantum satellite in the relay quantum satellite group between the first satellite ground station and the second satellite ground station; Determining the relay quantum satellite with the most quantum key margin as the target quantum satellite.

11. A quantum key distribution device based on a tethered drone, which is applied to a quantum key distribution system composed of a source node, a host node, a tethered drone, multiple satellite ground stations, a target quantum satellite, and a drone ground station. The device includes: A node determination module, configured to, in response to receiving a quantum key distribution request sent by a target user, determine the source node and the host node according to the quantum key distribution request; A parameter determination module, configured to calculate the distances between the source node and multiple satellite ground stations within its metropolitan area, and determine the satellite ground station with the shortest distance from the source node among the multiple satellite ground stations as the first satellite ground station; Calculating the distances between the host node and multiple satellite ground stations within its metropolitan area, and determining the satellite ground station with the shortest distance from the host node among the multiple satellite ground stations as the second satellite ground station; A first determination module, configured to determine a first deployment plan list of the tethered drone between the source node and the first satellite ground station according to the deployment cost; wherein, the first deployment plan list includes a plurality of first deployment plans sorted from low to high according to the deployment cost; determine a second deployment plan list of the tethered drone between the sink node and the second satellite ground station according to the deployment cost; wherein, the second deployment plan list includes a plurality of second deployment plans sorted from low to high according to the deployment cost; A second determination module, configured to determine a first target deployment plan from the plurality of first deployment plans according to the spatial link occlusion condition between the source node and the first satellite ground station; determine a second target deployment plan from the plurality of second deployment plans according to the spatial link occlusion condition between the sink node and the second satellite ground station; A key distribution module, configured to determine a target relay link between the source node and the sink node according to the first target deployment plan and the second target deployment plan, so that quantum key distribution is performed between the source node and the sink node based on the target relay link.

12. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, the method described in any one of claims 1 to 10 is implemented.

13. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to cause the computer to execute the method described in any one of claims 1 to 10.

Images