Communication method of uav satellite base station and uav satellite base station

Abstract

This application provides a communication method for an unmanned aerial vehicle (UAV) satellite base station and the UAV satellite base station itself, belonging to the field of communication technology. The communication method first determines the optimal hovering position of the UAV satellite base station based on the geographical information of the target area and the ephemeris information of the target satellite, thereby increasing the direct connection availability window and reducing the probability of terrain / building obstruction. Next, it determines the first time period during which the UAV satellite base station cannot establish a direct communication link with the target satellite from the optimal hovering position, and determines an alternative communication link based on this first time period. Finally, it controls the UAV satellite base station to communicate with the target satellite through the alternative communication link during the first time period, and through the direct communication link during mission periods outside the first time period, achieving orderly switching and reverting according to time periods. This ensures the stability of the communication link between the UAV satellite base station and the target satellite, thereby guaranteeing the communication continuity of the terminal equipment.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a communication method and a drone satellite base station. Background Technology

[0002] In disaster relief, major event security, and remote area coverage scenarios, the communication method of using drones carrying base stations and transmitting data back via satellite has been widely adopted. In this method, the drone hovers at a specified altitude to provide access to terminal devices, while the satellite handles data transmission. Although this method offers mobility and rapid deployment, in areas with undulating terrain or dense buildings, the direct communication link between the drone satellite base station and the satellite is easily affected by environmental factors.

[0003] When existing drone satellite base stations rely on satellites for data transmission, the direct communication link between the drone satellite base station and the satellite is prone to attenuation or interruption when the satellite elevation angle is too low or is blocked by surrounding mountains or buildings. This cannot guarantee the communication continuity of terminal devices and affects the user experience.

[0004] Therefore, when terminal devices communicate through UAV satellite base stations, the direct communication link between the UAV satellite base station and the satellite is prone to interruption, making it difficult to ensure the communication continuity of the terminal devices, which has become an urgent problem to be solved. Summary of the Invention

[0005] This application provides a communication method and a UAV satellite base station to solve the problem that the direct communication link between the UAV satellite base station and the satellite is prone to interruption in the prior art, making it difficult to ensure the communication continuity of terminal equipment.

[0006] Firstly, this application provides a communication method for a UAV satellite base station, the method comprising:

[0007] The system acquires geographic information of the target area and ephemeris information of the target satellite, wherein the target area is the area where the UAV satellite base station performs this mission; the geographic information includes the location and altitude information of the target object within the target area, and the target object is an object that prevents the UAV satellite base station from establishing a direct communication link with the target satellite;

[0008] Based on the geographic information and the ephemeris information, multiple candidate hovering positions are filtered to determine the optimal hovering position of the UAV satellite base station; wherein, the candidate hovering position is a position on the UAV's flight path where the UAV is allowed to hover.

[0009] Based on the optimal hovering position, the geographic information, and the ephemeris information, determine whether the UAV satellite base station can always establish a direct communication link with the target satellite at the optimal hovering position;

[0010] When the UAV satellite base station can always establish a direct communication link with the target satellite at the optimal hovering position, the UAV satellite base station is controlled to communicate with the target satellite through the direct communication link.

[0011] When the UAV satellite base station cannot consistently establish a direct communication link with the target satellite at the optimal hovering position, a first time period in which the UAV satellite base station cannot establish a direct communication link with the target satellite at the optimal hovering position is determined;

[0012] Based on the first time period, an alternative communication link for the UAV satellite base station is determined; wherein, the alternative communication link is associated with a suboptimal hovering position or at least one relay base station;

[0013] The drone satellite base station is controlled to communicate with the target satellite through the alternative communication link during the first time period.

[0014] In one possible design, the step of filtering multiple candidate hovering locations based on the geographic information and the ephemeris information to determine the optimal hovering location for the UAV satellite base station includes:

[0015] Determine the minimum transmission angle corresponding to the target satellite;

[0016] Based on the ephemeris information and the geographic information, the transmission angle corresponding to each candidate hovering position among the plurality of candidate hovering positions is determined; wherein, the transmission angle is the angle between the target line and the horizontal line, the target line is the line connecting the candidate hovering position to the target satellite, and the target line does not pass through the target object;

[0017] The candidate hovering position corresponding to the transmission angle that is greater than or equal to the minimum transmission angle and has the smallest difference from the minimum transmission angle is determined as the optimal hovering position.

[0018] In one possible design, the step of filtering multiple candidate hovering locations based on the geographic information and the ephemeris information to determine the optimal hovering location for the UAV satellite base station includes:

[0019] Determine the minimum transmission angle corresponding to the target satellite;

[0020] Based on the ephemeris information and the geographic information, the transmission angle corresponding to each candidate hovering position among the plurality of candidate hovering positions is determined;

[0021] Based on the minimum transmission angle and the transmission angle corresponding to each candidate hovering position, the obstacle blocking angle corresponding to each candidate hovering position is determined; wherein, the obstacle blocking angle is the total azimuth angle at the minimum transmission angle, due to the obstruction of the target object, a direct communication link cannot be established with the target satellite;

[0022] The candidate hovering position corresponding to the smallest obstacle blocking angle among the multiple obstacle blocking angles is determined as the optimal hovering position.

[0023] In one possible design, the step of filtering multiple candidate hovering locations based on the geographic information and the ephemeris information to determine the optimal hovering location for the UAV satellite base station includes:

[0024] For each of the multiple candidate hovering locations, based on the candidate hovering location, the geographic information, and the ephemeris information, a second time period is determined in which the UAV satellite base station cannot establish a direct communication link with the target satellite at the candidate hovering location;

[0025] The candidate hovering position corresponding to the shortest second time period among multiple second time periods is determined as the optimal hovering position.

[0026] In one possible design, determining the alternative communication link for the UAV satellite base station based on the first time period includes:

[0027] Based on the first time period, the geographical information, and the ephemeris information, the multiple candidate hovering positions are filtered to determine the suboptimal hovering position of the UAV satellite base station; wherein, the suboptimal hovering position is the candidate hovering position in which the UAV satellite base station can establish a direct communication link with the target satellite within the first time period;

[0028] Based on the suboptimal hovering position, the alternative communication link is determined; wherein, the alternative communication link is a direct communication link established between the UAV satellite base station and the target satellite when the UAV satellite base station is located in the suboptimal hovering position.

[0029] In one possible design, determining the alternative communication link for the UAV satellite base station based on the first time period includes:

[0030] Obtain target list information, which includes identification information and location information corresponding to multiple first candidate base stations, as well as the task time period; wherein, the first candidate base station is an unmanned aerial vehicle (UAV) satellite base station;

[0031] Based on the first time period and the target list information, at least one relay base station is determined from the plurality of first candidate base stations, and the union of the task time periods of the at least one relay base station covers the first time period; wherein, the relay base station is a first candidate base station that can simultaneously communicate with the UAV satellite base station and the target satellite during the first time period;

[0032] Based on the at least one relay base station, the alternative communication link is determined; wherein, the alternative communication link is the communication path established by the UAV satellite base station with the target satellite through the at least one relay base station.

[0033] In one possible design, determining the alternative communication link for the UAV satellite base station based on the first time period includes:

[0034] A first message is broadcast to multiple second candidate base stations. The first message includes the first location information of the UAV satellite base station within the first time period and the identification information of the target satellite. The second candidate base station is the UAV satellite base station. The first location information is the location information of the optimal hovering position.

[0035] If the UAV satellite base station receives a response message within a preset time period, the second candidate base station that sent the response message will be identified as the relay base station; the response message is used to indicate that the second candidate base station can simultaneously communicate with the UAV satellite base station and the target satellite within the first time period.

[0036] If the UAV satellite base station does not receive the response message within the preset time period, it broadcasts a second message to the plurality of second candidate base stations. The second message includes the second location information of the UAV satellite base station within the first time period and the identification information of the target satellite. The second location information is the location information of any of the candidate hovering positions other than the optimal hovering position among the plurality of candidate hovering positions.

[0037] Treat the second message as the first message, and repeat the step of broadcasting the first message to multiple second candidate base stations until the relay base station is determined;

[0038] Based on the relay base station, the alternative communication link is determined; wherein, the alternative communication link is the communication path established between the UAV satellite base station and the target satellite through the relay base station.

[0039] In one possible design, the number of alternative communication links is multiple, and controlling the UAV satellite base station to communicate with the target satellite through the alternative communication links during the first time period includes:

[0040] Based on the communication quality of multiple alternative communication links in the first time period, a target alternative communication link is determined, wherein the target alternative communication link is the alternative communication link with the best communication quality among the multiple alternative communication links;

[0041] The UAV satellite base station is controlled to communicate with the target satellite through the target alternative communication link during the first time period.

[0042] In one possible design, controlling the UAV satellite base station to communicate with the target satellite via the alternative communication link during the first time period includes:

[0043] Before the start of the first time period, the UAV satellite base station is controlled to communicate with the target satellite through the alternative communication link;

[0044] After the end of the first time period, the UAV satellite base station is controlled to communicate with the target satellite through the direct communication link.

[0045] Secondly, this application provides a drone satellite base station, including: a memory and at least one processor;

[0046] The memory stores computer-executed instructions;

[0047] The at least one processor executes the computer execution instructions stored in the memory, causing the at least one processor to perform the method in the first aspect and / or any possible design of the first aspect.

[0048] Thirdly, this application provides a communication device, comprising: a module for performing the method embodiment of the first aspect or any possible design of the first aspect.

[0049] Fourthly, this application provides a communication system comprising: a target satellite and an unmanned aerial vehicle (UAV) satellite base station for performing the methods described in the first aspect or any possible design of the first aspect.

[0050] Fifthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed, implement the method described in the first aspect or various possible designs of the first aspect.

[0051] Sixthly, this application provides a computer program product including computer program code, which, when run on a computer, causes the computer to implement the method described in the first aspect or various possible designs of the first aspect.

[0052] In a seventh aspect, this application provides a chip, comprising: an interface circuit and a logic circuit, wherein the interface circuit is configured to receive signals from other chips outside the chip and transmit them to the logic circuit, or to send signals from the logic circuit to other chips outside the chip, and the logic circuit is configured to implement the method described in the first aspect or various possible designs of the first aspect.

[0053] This application provides a communication method and a UAV satellite base station. The method involves: first, determining the optimal hovering position of the UAV satellite base station based on the geographic information of the target area and the ephemeris information of the target satellite, thereby increasing the direct communication availability window and reducing the probability of terrain / building obstruction; second, determining whether the UAV satellite base station can consistently establish a direct communication link with the target satellite from the optimal hovering position. If the UAV satellite base station can consistently establish a direct communication link from the optimal hovering position, it is controlled to communicate with the target satellite through the direct communication link; if the UAV satellite base station cannot consistently establish a direct communication link from the optimal hovering position, a first time period during which the UAV satellite base station cannot establish a direct communication link from the optimal hovering position is determined, and an alternative communication link is determined based on the first time period, so as to pre-set an available communication link for the UAV satellite base station during the limited direct communication period from the optimal hovering position; finally, the UAV satellite base station communicates with the target satellite through the alternative communication link during the first time period, and communicates with the target satellite through the direct communication link during mission periods outside the first time period, achieving orderly switching and reverting according to time periods. The method provided in this application can transform the potential direct connection interruption of the UAV satellite base station into a foreseeable and avoidable short-window event in environments where the satellite elevation angle changes over time and is easily obstructed. This ensures the stability of the communication link between the UAV satellite base station and the target satellite, thereby guaranteeing the communication continuity of the terminal device and improving the user experience. Attached Figure Description

[0054] Figure 1 A schematic diagram of the network structure of an existing cellular communication system;

[0055] Figure 2 This is a schematic diagram of the structure of a satellite communication system applicable to the embodiments of this application;

[0056] Figure 3A flowchart illustrating a communication method for a UAV satellite base station provided in an embodiment of this application;

[0057] Figure 4 A timing diagram for communication between a UAV satellite base station and a target satellite via a direct communication link and an alternative communication link, provided for embodiments of this application;

[0058] Figure 5 A flowchart illustrating another communication method for a UAV satellite base station provided in an embodiment of this application;

[0059] Figure 6 A flowchart illustrating another communication method for a UAV satellite base station provided in an embodiment of this application;

[0060] Figure 7 A flowchart illustrating another communication method for a UAV satellite base station provided in an embodiment of this application;

[0061] Figure 8 A flowchart illustrating another communication method for a UAV satellite base station provided in an embodiment of this application;

[0062] Figure 9 This application provides a schematic diagram illustrating the positional relationship between a UAV satellite base station and a target satellite.

[0063] Figure 10 A flowchart illustrating another communication method for a UAV satellite base station provided in an embodiment of this application;

[0064] Figure 11 A flowchart illustrating another communication method for a UAV satellite base station provided in this application embodiment;

[0065] Figure 12 This is a schematic diagram of the structure of a UAV satellite base station provided in an embodiment of this application;

[0066] Figure 13 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0068] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and drawings of this application are intended to cover non-exclusive inclusion.

[0069] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0070] In this article, the term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists, A and B can exist simultaneously, and B exists. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0071] Furthermore, the terms "first," "second," etc., in the specification and claims of this application or in the aforementioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0072] In the description of this application, unless otherwise stated, "multiple" and "at least two" mean two or more (including two), and similarly, "multiple groups" and "at least two groups" mean two or more (including two groups).

[0073] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, "connected" or "linked" can refer not only to a physical connection, but also to an electrical connection or a signal connection. For instance, it can be a direct connection, i.e., a physical connection, or an indirect connection through at least one intermediate component, as long as the circuit is connected. It can also refer to the internal connection between two components. A signal connection can refer not only to a signal connection through a circuit, but also to a signal connection through a medium, such as radio waves. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0074] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, different technical features in this application can be combined with each other.

[0075] First, the terms and concepts used in one or more embodiments of this specification will be explained.

[0076] A drone satellite base station refers to a type of mobile base station that mounts a backpack base station on a drone platform and transmits data back via a satellite link. A backpack base station is a portable / mobile base station (also called a "portable backpack base station" or "mobile backpack base station") that relies on high-throughput satellites as transmission carriers to provide communication between user equipment and the satellite. The backpack base station communicates with the core network of the communication network via satellite. The mobile communication system can be a Wideband Code Division Multiple Access (WCDMA) system, a Frequency Division Multiple Access (FDMA) system, an Orthogonal Frequency Division Multiple Access (OFDMA) system, a General Packet Radio Service (GPRS) system, a Long Term Evolution (LTE) system, or a 5th Generation Mobile Communication Technology (5G) system, as well as other similar communication systems.

[0077] Terminal equipment can be a wireless terminal, which can be a device that provides voice and / or other service data connectivity to a user, a handheld device with wireless connectivity, or other processing device connected to a wireless modem. The wireless terminal can communicate with one or more core networks via a Radio Access Network (RAN). The wireless terminal can be a mobile terminal, such as a mobile phone (or "cellular" phone) and a computer with a mobile terminal, for example, a portable, pocket-sized, handheld, computer-embedded, or vehicle-mounted mobile device, which exchanges voice and / or data with the radio access network.

[0078] The following section introduces the implementation background of the technical solutions provided in the embodiments of this application.

[0079] Figure 1 This is a schematic diagram of the network architecture of an existing cellular communication system. (Example:) Figure 1As shown, the UE connects to the base station via a wireless interface, and the base station connects to the core network via a fiber optic interface. However, in the event of natural disasters such as earthquakes or floods, the fiber optic interface is easily damaged, leading to an interruption of the connection between the base station and the core network, thus creating a temporary communication island where the UE cannot communicate normally. Furthermore, in naturally formed temporary communication islands such as deserts or open oceans, although there may be multiple terminal devices with communication needs within a small area, traditional solutions are ineffective due to the difficulty and high cost of laying fiber optic cables.

[0080] To address these issues, drone satellite base stations have emerged. Figure 2 This is a schematic diagram of the structure of a satellite communication system applicable to an embodiment of this application. Figure 2 As shown, the UAV satellite base station connects to the satellite via a wireless interface, and the satellite then connects to the core network elements on the ground via a wireless interface, enabling terminal devices within the coverage area of ​​the UAV satellite base station to communicate normally. Even when traditional communication infrastructure is damaged or difficult to build, reliable communication services can still be provided.

[0081] In existing airborne emergency communication solutions, a common practice is to deploy a complete base station protocol stack on a drone satellite base station. According to relevant flight management requirements, the drone operates at an altitude of approximately 200 meters and can hover over the target area (the area where the drone performs its mission) to provide wireless network coverage; once the ground communication network is repaired and services in the area are restored, the drone satellite base station is immediately deactivated and ceases service.

[0082] Due to limitations in flight altitude and operational location, as well as environmental factors such as surrounding terrain and buildings, and the changing elevation and azimuth of satellites in the sky over time, the UAV satellite base station and the satellite do not always maintain line-of-sight (LOS) conditions during the operation of the UAV satellite base station. During certain periods, they may be in a non-line-of-sight (NLOS) state. In this case, the direct communication link between the UAV satellite base station and the satellite is interrupted, which in turn leads to communication interruption of terminal devices in the target area, resulting in a poor user experience.

[0083] To address the problems existing in related technologies, this application provides a communication method for a UAV satellite base station. First, the optimal hovering position of the UAV satellite base station is determined based on the geographical information of the target area and the ephemeris information of the target satellite. This allows the UAV satellite base station to obtain a larger direct communication window and reduce the probability of being obstructed by terrain / buildings. Second, it is determined whether the UAV satellite base station can consistently establish a direct communication link with the target satellite from the optimal hovering position. If the UAV satellite base station can consistently establish a direct communication link with the target satellite from the optimal hovering position, it is controlled to communicate with the target satellite through the direct communication link. If the UAV satellite base station cannot consistently establish a direct communication link with the target satellite from the optimal hovering position, a first time period during which the UAV satellite base station cannot establish a direct communication link with the target satellite from the optimal hovering position is determined. An alternative communication link is determined based on the first time period to pre-set an available communication link for the period when direct communication is limited at the optimal hovering position. Finally, the UAV satellite base station communicates with the target satellite through the alternative communication link during the first time period and through the direct communication link during mission periods outside the first time period, achieving orderly switching and reverting according to time periods. The method provided in this application can transform the potential direct connection interruption of the UAV satellite base station into a foreseeable and avoidable short-window event in environments where the satellite elevation angle changes over time and is easily obstructed. This ensures the stability of the communication link between the UAV satellite base station and the target satellite, thereby guaranteeing the communication continuity of the terminal device and improving the user experience.

[0084] Next, through some specific embodiments and accompanying drawings, this application will describe in detail how it solves the problem that the direct communication link between the UAV satellite base station and the satellite is prone to interruption, making it difficult to ensure the communication continuity of the terminal equipment.

[0085] Figure 3 This is a flowchart illustrating a communication method for a UAV satellite base station provided in an embodiment of this application. Figure 3 As shown, the communication method of the UAV satellite base station provided in this application embodiment specifically includes S301 to S305, and S301 to S305 will be described in detail below.

[0086] It should be noted that the communication method of the UAV satellite base station provided in this application embodiment is executed by the UAV satellite base station.

[0087] S301. Obtain the geographic information of the target area and the ephemeris information of the target satellite.

[0088] The target area is the region where the drone satellite base station will carry out this mission.

[0089] The geographic information of the target area includes the location and altitude information of the target object within the target area. The target object is the object that prevents the UAV satellite base station from establishing a direct communication link with the target satellite.

[0090] It should be noted that the target objects are objects such as mountains, buildings, towers, bridges, and wind turbines that obstruct the establishment of a direct communication link between the UAV satellite base station and the target satellite.

[0091] The location information of the target object includes the latitude and longitude or planar coordinates of the target object.

[0092] The height information of the target object includes the top elevation of the target object relative to the ground.

[0093] Before the UAV satellite base station performs this mission, the ground control center of the UAV satellite base station first determines the boundary of the target area, and then acquires and aggregates the geographic information related to the target area.

[0094] Among them, the ephemeris information of the target satellite is a set of parameters broadcast by the target satellite about its position in space. Based on the ephemeris information of the target satellite, the precise position of the target satellite in space over a period of time can be calculated, that is, the satellite position of the target satellite.

[0095] S302. Based on geographic and ephemeris information, multiple candidate hovering positions are screened to determine the optimal hovering position for the UAV satellite base station.

[0096] Among them, the candidate hovering position is the location on the UAV's flight path where the UAV is allowed to hover. The optimal hovering position is the candidate hovering position where the UAV's satellite base station is most advantageous for establishing a direct communication link with the target satellite during this mission period.

[0097] It should be noted that the candidate hovering locations are the locations where the UAV satellite base station is allowed to hover during this mission. The location information for each candidate hovering location includes the longitude and latitude of the candidate hovering location, as well as the hovering altitude of the UAV satellite base station at the candidate hovering location.

[0098] Based on ephemeris information, the changes in the azimuth and elevation angles of the target satellite over time during the current mission period of the UAV satellite base station can be calculated.

[0099] Based on geographic information, it can be determined whether the line connecting the candidate hovering position to the target satellite is obstructed by the target object in the target area.

[0100] S303. Based on the optimal hovering position, geographic information, and ephemeris information, determine whether the UAV satellite base station can always establish a direct communication link with the target satellite at the optimal hovering position.

[0101] It should be noted that the UAV satellite base station can calculate the azimuth and elevation angles of the target satellite at various times during the mission period based on ephemeris information, and combine this with the digital elevation model / building model to determine the line-of-sight, forming the LOS sequence and NLOS sequence for the mission period.

[0102] If the NLOS sequence is empty, it means that the UAV satellite base station can always establish a direct communication link with the target satellite at the optimal hovering position. In this case, the method steps shown in S304 are executed. If the NLOS sequence is not empty, it means that the UAV satellite base station cannot always establish a direct communication link with the target satellite at the optimal hovering position. In this case, the method steps shown in S305 are executed.

[0103] S304. When the UAV satellite base station can always establish a direct communication link with the target satellite at the optimal hovering position, control the UAV satellite base station to communicate with the target satellite through the direct communication link.

[0104] When the UAV satellite base station can continuously meet the direct line-of-sight conditions with the target satellite at the optimal hovering position, the UAV satellite base station uses the direct communication link established with the target satellite to carry out service and control interaction, thereby achieving end-to-end communication without relying on ground relays or other satellite forwarding, reducing resource consumption and latency accumulation caused by multi-level forwarding.

[0105] S305. When the UAV satellite base station cannot consistently establish a direct communication link with the target satellite while hovering at the optimal position, determine the first time period during which the UAV satellite base station cannot establish a direct communication link with the target satellite while hovering at the optimal position.

[0106] The start and end times of the first time period are determined based on the changes in the azimuth and elevation angles of the target satellite at the UAV satellite base station during this mission period, as well as the obstruction of the target object.

[0107] The first time period can be a continuous interval or multiple discontinuous intervals; this embodiment does not impose any specific limitations on this.

[0108] It should be noted that the continuous time interval corresponding to the LOS sequence during this task period is the third time interval, and the continuous time interval corresponding to the NLOS sequence is the first time interval.

[0109] Specifically, the line-of-sight determination is used to determine whether the UAV satellite base station can directly "see" the target satellite and establish a direct communication link at a certain moment.

[0110] During the third time period, the drone satellite base station is able to establish a direct communication link with the target satellite at the optimal hovering position.

[0111] S306. Based on the first time period, determine the alternative communication link for the UAV satellite base station.

[0112] The alternative communication link is associated with the suboptimal hovering location or at least one relay base station.

[0113] It should be noted that the alternative communication link is used to provide the UAV satellite base station with a communication link to the target satellite during the first time period.

[0114] The second-best hovering position is the candidate hovering position where the UAV satellite base station can establish a direct communication link with the target satellite within the first time period.

[0115] A relay base station is a drone satellite base station that can establish a communication link with both the drone satellite base station and the target satellite simultaneously within the first time period.

[0116] S307: Control the UAV satellite base station to communicate with the target satellite through an alternative communication link during the first time period.

[0117] In one possible embodiment, before the start of the first time period, the control drone satellite base station communicates with the target satellite via an alternative communication link; after the end of the first time period, the control drone satellite base station communicates with the target satellite via a direct communication link.

[0118] Among them, near the start of the first time period Previously, the ground control center of the UAV satellite base station triggered the establishment and verification of alternative communication links based on pre-calculated timing parameters.

[0119] It should be noted that the timing parameters include at least the lead time for pre-establishing alternative communication links. and the hold duration used for cutback determination .

[0120] advance duration The time required for establishing an alternative communication link can be comprehensively determined based on the steps involved (search and alignment, authentication and encryption establishment, routing / bearer establishment, uplink / downlink synchronization, etc.), with a security margin.

[0121] Duration Used to confirm the stability of the direct communication link quality when switching back from an alternative communication link to a direct communication link, thus avoiding frequent jitter switching.

[0122] Specifically, in ( At that moment, the drone's satellite base station initiates an establishment process with the alternative communication link and completes availability verification; When the time arrives, the drone's satellite base station has already communicated with the target satellite through an alternative communication link, and in the subsequent... From the time to the end of the first time period The drone satellite base station continuously communicates with the target satellite through an alternative communication link, and user plane data is carried by the alternative communication link; After a certain time, the UAV satellite base station initiates a switchback control based on the quality assessment result of the direct communication link, so that the UAV satellite base station switches back to the direct communication link between the optimal hovering position and the target satellite, and releases the alternative communication link after the switchback is completed.

[0123] It should be noted that, After a certain time, if the quality assessment result of the direct communication link by the UAV satellite base station is that the quality meets the standard, the UAV satellite base station will initiate a back-switch control; if the quality assessment result of the direct communication link by the UAV satellite base station is that the quality does not meet the standard, the UAV satellite base station will not initiate a back-switch control.

[0124] In one possible embodiment, the drone satellite base station determines whether the quality of the direct communication link meets the standards by detecting and thresholding key quality indicators of the direct communication link.

[0125] Key quality indicators for direct communication links include received signal strength, signal-to-noise ratio, block error rate, and packet loss rate.

[0126] The key quality indicators of the direct communication link obtained by the UAV satellite base station are compared with preset compliance thresholds. When all key quality indicators of the direct communication link meet the preset compliance thresholds, and the duration for which all key quality indicators meet the preset compliance thresholds is greater than the maintenance duration, the comparison is made. If the quality is satisfactory, the quality of the direct communication link is determined to be up to standard; otherwise, the quality of the direct communication link is determined to be substandard.

[0127] Optionally, to address time deviations caused by ephemeris errors or environmental disturbances, the UAV satellite base station can also be configured with a maximum waiting time and a retry strategy; if the UAV satellite base station is in If an alternative communication link cannot be successfully established before a certain time, a preset fallback procedure is executed (e.g., switching between alternative communication links or adjusting establishment parameters); if... If the quality of the direct communication link fails to meet the standard after a certain time, the duration of the alternative communication link is extended and the quality of the direct communication link is periodically re-evaluated.

[0128] Figure 4 This document presents a timing diagram illustrating communication between a UAV satellite base station and a target satellite via a direct communication link and an alternative communication link, as provided in an embodiment of this application. Figure 4As shown, the start time of this mission for the UAV satellite base station is T1, and the end time is T6. During the first time period (start time T3, end time T4) at the optimal hovering position, the UAV satellite base station cannot establish a direct communication link with the target satellite. From T1 to T3, and from T4 to T6, the UAV satellite base station can establish direct communication links with the target satellite at the optimal hovering position. In this situation, to ensure service continuity, the UAV satellite base station initiates the establishment process and completes availability verification at time T2 (T1 < T2 < T3), which is before time T3. Upon arrival at time T3, it switches the communication link carrying the service from the direct communication link to the alternative communication link. At time T5 (T4 < T5 < T6), after time T4, if the direct communication link is available, the UAV satellite base station switches back to the direct communication link between the optimal hovering position and the target satellite. Therefore, from time T1 to time T2, and from time T5 to time T6, the UAV satellite base station is located in the optimal hovering position and communicates with the target satellite through the direct communication link between the optimal hovering position and the target satellite; from time T2 to time T5, the UAV satellite base station communicates with the target satellite through an alternative communication link.

[0129] In this embodiment, by pre-establishing an alternative communication link before the start of the first time period and carrying services through the alternative communication link, and then restoring to the direct communication link after the end of the first time period, the timing control of the communication link of the UAV satellite base station is realized, which is to establish and then switch back to the point. This transforms the originally unpredictable communication interruption window into a controllable switching process, effectively reducing the downtime and data loss of the UAV satellite base station, and improving the continuity and stability of the connection between the UAV satellite base station and the target satellite during the execution of this mission.

[0130] This application provides a communication method for a UAV satellite base station. First, the optimal hovering position of the UAV satellite base station is determined based on the geographical information of the target area and the ephemeris information of the target satellite, so that the UAV satellite base station obtains a larger direct communication availability window and reduces the probability of being blocked by terrain / buildings. Second, it is determined whether the UAV satellite base station can always establish a direct communication link with the target satellite at the optimal hovering position. If the UAV satellite base station can always establish a direct communication link with the target satellite at the optimal hovering position, the UAV satellite base station is controlled to communicate with the target satellite through the direct communication link. If the UAV satellite base station cannot always establish a direct communication link with the target satellite at the optimal hovering position, a first time period in which the UAV satellite base station cannot establish a direct communication link with the target satellite at the optimal hovering position is determined, and an alternative communication link is determined based on the first time period, so as to pre-set an available communication link for the UAV satellite base station during the limited direct communication period at the optimal hovering position. Finally, the UAV satellite base station communicates with the target satellite through the alternative communication link during the first time period, and communicates with the target satellite through the direct communication link during the mission period outside the first time period, so as to realize orderly switching and switching back according to the time period. The method provided in this application can transform the potential direct connection interruption of the UAV satellite base station into a foreseeable and avoidable short-window event in environments where the satellite elevation angle changes over time and is easily obstructed. This ensures the stability of the communication link between the UAV satellite base station and the target satellite, thereby guaranteeing the communication continuity of the terminal device and improving the user experience.

[0131] In the above embodiments, the UAV satellite base station needs to filter multiple candidate hovering positions based on geographic information and ephemeris information to determine the optimal hovering position of the UAV satellite base station. Next, the specific process of filtering multiple candidate hovering positions based on geographic information and ephemeris information to determine the optimal hovering position of the UAV satellite base station will be described in detail.

[0132] Figure 5 This is a flowchart illustrating another communication method for a UAV satellite base station provided in an embodiment of this application. Figure 5 As shown, in one possible embodiment, the method steps shown in S302 can be implemented by Sa1 to Sa3, which will be described in detail below.

[0133] Sa1, Determine the minimum transmission angle corresponding to the target satellite.

[0134] Among them, the minimum transmission angle is the criterion for whether the UAV satellite base station and the target satellite can establish a direct communication link.

[0135] It should be noted that the minimum transmission angle refers to the lower limit of the angle between the line connecting the UAV satellite base station and the target satellite and the horizon at the location of the UAV satellite base station.

[0136] In practical applications, the minimum transmission angle can be determined by the ground control center before the start of the mission and then sent to the UAV satellite base station.

[0137] The minimum transmission angle can be set according to actual needs, and this embodiment does not impose specific limitations on it.

[0138] For example, the minimum transmission angle is 20 degrees.

[0139] Sa2. Based on ephemeris information and geographic information, determine the transmission angle corresponding to each candidate hovering position among multiple candidate hovering positions.

[0140] The transmission angle is the angle between the target line and the horizontal line. The target line is the line from the candidate hovering position to the target satellite. The target line does not pass through the target object.

[0141] It should be noted that ephemeris information is used to obtain the spatial position of the target satellite during the mission period of the UAV satellite base station.

[0142] Geographic information is used to determine whether the line connecting the candidate hovering position to the target satellite is obstructed by the target object.

[0143] Specifically, for each candidate hovering position, the spatial position of the target satellite at the corresponding time is determined based on the ephemeris information, so as to construct the target line corresponding to the candidate hovering position, and the angle between the target line and the horizon is used as the transmission angle of the candidate hovering position.

[0144] If there is no target line connecting the candidate hovering position and the target satellite (the line connecting the candidate hovering position and the target satellite must pass through a target object), the transmission angle of the candidate hovering position is considered to be 0; if there is a target line connecting the candidate hovering position and the target satellite, the transmission angle corresponding to the candidate hovering position is recorded for subsequent comparison.

[0145] Sa3. Among multiple transmission angles, the candidate hovering position corresponding to the transmission angle that is greater than or equal to the minimum transmission angle and has the smallest difference from the minimum transmission angle is determined as the optimal hovering position.

[0146] It should be noted that the minimum transmission angle is an engineering lower limit criterion set to ensure that line-of-sight and link budget are met.

[0147] For any candidate hovering position, if the transmission angle at the candidate hovering position is less than the minimum transmission angle, the line connecting the candidate hovering position and the target satellite is more likely to be closer to the horizon and more easily blocked by target objects such as mountains and buildings. Even if it is not blocked, the path through the atmosphere is longer and the attenuation is greater, making it difficult to meet the link budget. Therefore, when determining the optimal hovering position, the transmission angle corresponding to the optimal hovering position must be greater than the minimum transmission angle.

[0148] For example, in a target area A, there are candidate hovering positions A, B, and C. The transmission angle corresponding to candidate hovering position A is 30 degrees, that of candidate hovering position B is 15 degrees, and that of candidate hovering position C is 45 degrees. At this time, the transmission angle corresponding to candidate hovering position B is less than the minimum transmission angle, while the transmission angles corresponding to candidate hovering positions A and C are both greater than the minimum transmission angle (20 degrees). Since the difference between candidate hovering position A and the minimum transmission angle is the smallest, candidate hovering position A is determined as the optimal hovering position.

[0149] When multiple candidate hovering positions have the same minimum transmission angle difference, an optimal hovering position can be determined according to a pre-set priority (e.g., energy consumption, flight safety buffer, mission radius, etc.), or any one of them can be selected as the optimal hovering position.

[0150] In this embodiment, the minimum transmission angle is used as the criterion for whether the UAV satellite base station can establish direct communication with the target satellite from a candidate hovering position. The candidate hovering position corresponding to the transmission angle greater than or equal to the minimum transmission angle, and with the smallest difference from the minimum transmission angle, is selected as the optimal hovering position. This ensures direct communication between the UAV satellite base station and the target satellite while also considering the flight and energy consumption constraints of the UAV satellite base station, avoiding unnecessary excessive elevation or long-distance maneuvers. Therefore, the method in this embodiment enables the UAV satellite base station to more accurately select a target hovering position that is more conducive to direct communication with the target satellite, reducing the probability of communication interruption caused by obstruction or insufficient elevation angle, and improving the stability and continuity of the communication process.

[0151] Figure 6 This is a flowchart illustrating another communication method for a UAV satellite base station provided in an embodiment of this application. Figure 6 As shown, in another possible embodiment, the method steps shown in S302 can be implemented by Sc1 to Sc4, which will be described in detail below.

[0152] Sc1. Determine the minimum transmission angle corresponding to the target satellite.

[0153] The implementation of the method steps shown in Sc1 is the same as that shown in Sa1, and will not be described again in this embodiment.

[0154] Sc2. Based on ephemeris information and geographic information, determine the transmission angle corresponding to each candidate hovering position among multiple candidate hovering positions.

[0155] The implementation of the method steps shown in Sc2 is the same as that shown in Sa2, and will not be described again in this embodiment.

[0156] Sc3. Based on the minimum transmission angle and the transmission angle corresponding to each candidate hovering position, determine the obstacle blocking angle corresponding to each candidate hovering position.

[0157] Among them, the obstacle blocking angle is the total azimuth angle at which a direct communication link cannot be established with the target satellite due to the obstruction of the target object under the minimum transmission angle.

[0158] It should be noted that the obstacle obstruction angle corresponding to the candidate hovering position is used to measure the total azimuth width within the horizontal azimuth range where the UAV satellite base station cannot directly communicate with the target satellite due to the obstruction of the target object when it is located at the candidate hovering position under the minimum transmission angle.

[0159] Specifically, for any candidate hovering position, the line connecting the candidate hovering position to the target satellite is checked azimuthally within the range of 0° to 360° to see if it meets the line-of-sight condition. When the line connecting the candidate hovering position to the target satellite is obstructed by the target object, or when the transmission angle corresponding to the line connecting the candidate hovering position to the target satellite is lower than the minimum transmission angle, it is recorded as an unconnectable azimuth. The intervals of all unconnectable azimuths are unioned to obtain at least one non-intersecting azimuth sector. The azimuth widths of all azimuth sectors are then summed to obtain the obstruction angle of the candidate hovering position.

[0160] Sc4. Determine the candidate hovering position corresponding to the smallest obstacle blocking angle among multiple obstacle blocking angles as the optimal hovering position.

[0161] It should be noted that the smaller the obstacle obstruction angle of the candidate hovering position, the more visible azimuths that the candidate hovering position can be used for direct communication with the target satellite, which is more conducive to maintaining the direct communication link between the UAV satellite base station and the target satellite during the mission period. Therefore, the candidate hovering position corresponding to the smallest obstacle obstruction angle among multiple obstacle obstruction angles is determined as the optimal hovering position.

[0162] For example, in a target area B, there are candidate hovering positions D and E, where the transmission angle corresponding to candidate hovering position D is 30 degrees and the transmission angle corresponding to candidate hovering position E is 40 degrees. For candidate hovering position D, when the transmission angle is 30 degrees, there are no obstructions between the UAV satellite base station and the target satellite. If the transmission angle changes to 20 degrees, the UAV satellite base station cannot directly communicate with the target satellite within a horizontal range of 45 degrees; that is, the obstruction angle of candidate hovering position D is 45 degrees. For candidate hovering position E, when the transmission angle is 40 degrees, there are no obstructions between the UAV satellite base station and the target satellite. If the transmission angle changes to 20 degrees, the UAV satellite base station cannot directly communicate with the target satellite within a horizontal range of 10 degrees; that is, the obstruction angle of candidate hovering position E is 10 degrees. Since the obstruction angle of candidate hovering position E is smaller than that of candidate hovering position D, candidate hovering position E is determined as the optimal hovering position.

[0163] When multiple candidate hovering positions have the same obstacle angle and all are minimum, an optimal hovering position can be determined according to a preset priority (such as flight safety buffer, energy consumption, mission radius or regulatory height limit, etc.), or any one of them can be selected as the optimal hovering position.

[0164] In this embodiment, by quantifying the situation where the candidate hovering position is occluded by the target object in a 360° circumference at the minimum transmission angle into a comparable obstacle obstruction angle, and determining the candidate hovering position corresponding to the minimum obstacle obstruction angle as the optimal hovering position, a longer direct connection availability window and higher link stability are obtained when the azimuth of the target satellite changes over time. This reduces the probability and duration of communication interruptions caused by target object obstruction or insufficient elevation angle of the target satellite, and improves the continuity of the communication link between the UAV satellite base station and the target satellite.

[0165] Figure 7 This is a flowchart illustrating another communication method for a UAV satellite base station provided in an embodiment of this application. Figure 7 As shown, in another possible embodiment, the method steps shown in S302 can be implemented by Sd1 and Sd2, which are described in detail below.

[0166] Sd1. For each candidate hovering position among multiple candidate hovering positions, based on the candidate hovering position, geographic information, and ephemeris information, determine the second time period in which the UAV satellite base station cannot establish a direct communication link with the target satellite at the candidate hovering position.

[0167] For any candidate hovering position, the second time period corresponding to the candidate hovering position is used to indicate the time interval during which the UAV satellite base station cannot establish a direct communication link with the target satellite at that candidate hovering position.

[0168] It should be noted that the method for determining the second time period in which the UAV satellite base station cannot establish a direct communication link with the target satellite at the candidate hovering position is the same as the method for determining the first time period in which the UAV satellite base station cannot establish a direct communication link with the target satellite at the optimal hovering position in the above embodiment, and will not be repeated in this embodiment.

[0169] Sd2. Determine the candidate hovering position corresponding to the shortest second time period among multiple second time periods as the optimal hovering position.

[0170] It should be noted that the shorter the total duration of the second time period, the less time the UAV satellite base station is unable to meet the direct connection conditions during the mission period, which is more conducive to maintaining a direct communication link between the UAV satellite base station and the target satellite. Therefore, by comparing the total duration of the second time period corresponding to each candidate hovering position, the candidate hovering position corresponding to the second time period with the shortest total duration is selected as the optimal hovering position.

[0171] In this embodiment, for each candidate hovering position, a second time period in which a direct communication link cannot be established with the target satellite during the mission period is directly calculated based on ephemeris information and geographic information. The candidate hovering position corresponding to the second time period with the shortest total duration is determined as the optimal hovering position. This transforms the selection of the optimal hovering position from static spatial comparison to time-dimensional evaluation oriented towards the mission period, maximizing the direct connection availability time of the optimal hovering position, reducing the expected interruption window, and decreasing the number and duration of activating alternative communication links or maneuvering handover.

[0172] In the above embodiments, the drone satellite base station needs to determine the alternative communication link based on a first time period. The specific process of determining the alternative communication link based on the first time period will be described in detail below.

[0173] Figure 8 This is a flowchart illustrating another communication method for a UAV satellite base station provided in an embodiment of this application. Figure 8 As shown, in one possible embodiment, the method steps shown in S306 can be implemented by Se1 and Se2, which are described in detail below.

[0174] Se1. Based on the first time period, geographic information, and ephemeris information, multiple candidate hovering positions are screened to determine the suboptimal hovering position of the UAV satellite base station.

[0175] It should be noted that the suboptimal hovering position is used to provide the UAV satellite base station with a direct communication link to the target satellite during the first time period.

[0176] Specifically, after determining the first time period, the ground control center of the UAV satellite base station obtains the changes in azimuth and elevation angles of the target satellite within the first time period based on ephemeris information, and determines whether the lines connecting each candidate hovering position to the target satellite meet the line-of-sight condition and the minimum transmission angle criterion based on geographic information.

[0177] For any candidate hovering position, if the candidate hovering position can establish a direct communication link with the target satellite within the first time period, the candidate hovering position is marked as "available"; if the candidate hovering position does not meet the line-of-sight condition or the minimum transmission angle criterion, the candidate hovering position is marked as "unavailable". Based on this, a suboptimal hovering position is selected from the set of candidate hovering positions marked as "available"; when there are multiple candidate hovering positions in the set, the candidate hovering position with the closest maneuvering distance to the optimal hovering position can be selected as the suboptimal hovering position.

[0178] Se2. Based on the suboptimal hovering position, determine the alternative communication link.

[0179] The alternative communication link is the direct communication link established between the UAV satellite base station and the target satellite when the UAV satellite base station is in a suboptimal hovering position.

[0180] It should be noted that when the UAV satellite base station determines an alternative communication link based on a suboptimal hovering position, the UAV satellite base station generates an alternative communication link establishment scheme. The alternative communication link establishment scheme includes, but is not limited to: a pre-set establishment timing before the start of the first time period, a hold strategy during the first time period, and a switchback arrangement after the end of the first time period.

[0181] Specifically, after the UAV satellite base station maneuvers to the suboptimal hovering position, it completes the pointing and tracking of the target satellite based on the ephemeris information, and completes the access and establishment of the alternative communication link according to the parameters of the UAV satellite base station, so that the alternative communication link is available at the beginning of the first time period; after the end of the first time period, it restores the direct communication link at the optimal hovering position according to the back-switch strategy.

[0182] In this embodiment, for the first time period where direct communication is not possible, based on ephemeris and geographic information, a suboptimal hovering position is selected from candidate hovering positions. This suboptimal hovering position allows for direct communication between the UAV satellite base station and the target satellite during the first time period. An alternative communication link is then defined as the direct communication link between the UAV satellite base station and the target satellite when the UAV satellite base station is in the suboptimal hovering position. This ensures that the UAV satellite base station can directly communicate with the target satellite from the suboptimal hovering position during the time period when direct communication is limited at the optimal hovering position. In this embodiment, the alternative communication link is shorter, has lower latency, more predictable stability and throughput, and a simpler control process. Simultaneously, the maneuverability is controlled, and energy consumption and airspace constraints are more easily met, effectively reducing the downtime window of the UAV satellite base station and improving the connection continuity and service quality of the UAV satellite base station during this mission.

[0183] In other embodiments, the UAV satellite base station can also communicate wirelessly with the target satellite through a multi-point dynamic networking method during the first time period, ensuring the communication continuity of terminal devices accessing the UAV satellite base station.

[0184] Figure 9 This is a schematic diagram illustrating the positional relationship between a UAV satellite base station and a target satellite, provided as an embodiment of this application. Figure 9 As shown, Figure 9 As shown, at a certain moment t during the current mission period of UAV satellite base station A (UAV satellite base station), UAV satellite base station A needs to provide wireless network coverage for the target area from its current location. However, due to the obstruction of the target object, the direct communication link between UAV satellite base station A at its current location and the target satellite ( Figure 9 Path 1) is unreachable. In this case, UAV satellite base station A can communicate indirectly with the target satellite via UAV satellite base station B (relay base station), that is, UAV satellite base station A via... Figure 9 The relay link consisting of paths 2-1 and 2-2 communicates with the target satellite. The combination of paths 2-1 and 2-2 constitutes the alternative communication link at time t.

[0185] Because the azimuth and elevation angles of the target satellite change over time, and the location of the UAV satellite base station can be adjusted according to mission requirements, the time period during which the UAV satellite base station and the target satellite can directly communicate is time-varying. To ensure service continuity, the UAV satellite base station needs to determine the timing for establishing / breaking links with the relay base station. The following section details the specific process by which the UAV satellite base station determines the timing for establishing / breaking links with the relay base station.

[0186] Figure 10 This is a flowchart illustrating another communication method for a UAV satellite base station provided in an embodiment of this application. Figure 10As shown, in one possible embodiment, the method steps shown in S306 can be implemented by Sf1 to Sf3, which will be described in detail below.

[0187] Sf1. Obtain target list information, which includes the identification and location information of multiple first candidate base stations, as well as the task time period.

[0188] The first candidate base station is a drone satellite base station.

[0189] It should be noted that the target list information is used to provide a data basis for the subsequent selection of relay base stations.

[0190] After determining the first time period, the ground control center obtains a target list information related to the target area from the operation and maintenance management platform. The target list information includes at least: the identification information, location information, and task time period for each first candidate base station.

[0191] The identification information of the first candidate base station includes an identifier used to uniquely identify the first candidate base station.

[0192] The location information of the first candidate base station includes its longitude, latitude, and operating altitude.

[0193] The task period of the first candidate base station refers to the available time window in which the first candidate base station can provide relay services. The task period of the first candidate base station can consist of one or more discontinuous sub-time periods.

[0194] To facilitate the selection of relay base stations from multiple candidate base stations by UAV satellite base stations, the location information of different candidate base stations in the target list information is recorded using a unified coordinate reference, the task time period information of different candidate base stations is recorded using a unified time reference, and the capability parameters of the candidate base stations are optionally included.

[0195] The capability parameters of the first candidate base station can be its operating frequency band, antenna gain, rated throughput, etc.

[0196] Sf2. Based on the first time period and target list information, at least one relay base station is determined among multiple first candidate base stations, and the union of the task time periods of at least one relay base station covers the first time period.

[0197] Among them, the relay base station is the first candidate base station that can simultaneously communicate with the UAV satellite base station and the target satellite within the first time period.

[0198] It should be noted that for each first candidate base station in the target list information, the UAV satellite base station determines whether the connection between the first candidate base station and the UAV satellite base station, and the connection between the first candidate base station and the target satellite, simultaneously meet the line-of-sight condition during the fourth time period. When both the connection between the first candidate base station and the UAV satellite base station, and the connection between the first candidate base station and the target satellite, simultaneously meet the line-of-sight condition, it is considered that the first candidate base station can simultaneously communicate with both the UAV satellite base station and the target satellite during the fourth time period. The fourth time period is the intersection of the first candidate base station's mission time period and the first time period.

[0199] The intersection of the fourth time period of the first candidate base station that can simultaneously communicate with the UAV satellite base station and the target satellite with the first time period is obtained to obtain the effective time period for the first candidate base station to be used for relay. Based on the first time period and the effective time period for each first candidate base station to be used for relay, at least one first candidate base station is selected as a relay base station. The union of the effective time periods for at least one first candidate base station to be used for relay covers the first time period.

[0200] Specifically, when the effective time period available for relaying by a single relay base station cannot cover the first time period, multiple relay base stations can be selected to cover the first time period in segments.

[0201] Sf3. Based on at least one relay base station, determine alternative communication links.

[0202] Among them, the alternative communication link is the communication path established by the UAV satellite base station with the target satellite through at least one relay base station.

[0203] It should be noted that when there is only one relay base station, and the effective time period for this relay base station to be used for relaying can cover the first time period, the communication link between the UAV satellite base station at the optimal hovering position and the relay base station, as well as the communication link between the relay base station and the target satellite, are determined as alternative communication links.

[0204] When there are multiple relay base stations, meaning the union of the effective time periods available for relay by these multiple relay base stations covers the first time period, the first time period is divided into multiple sub-time periods based on the effective time periods available for relay by each relay base station, and a corresponding relay base station is assigned to each sub-time period. For any sub-time period of the first time period, the communication link between the UAV satellite base station at its optimal hovering position and the corresponding relay base station for that sub-time period, as well as the communication link between the corresponding relay base station for that sub-time period and the target satellite, are determined as the alternative sub-communication links for that sub-time period. The set of all alternative sub-communication links corresponding to all sub-time periods of the first time period is the alternative communication link.

[0205] In this embodiment, referring to the first time period, one or more relay base stations whose effective time periods can cover the first time period are quickly selected from the statically configured target list information. Then, according to the effective time periods of the multiple relay base stations within the first time period, the UAV satellite base station is controlled to communicate with the target satellite through the multiple relay base stations respectively within the first time period. This method can still complete the handover as planned even in weak network or obstructed environments, reducing the handover failure rate, thereby achieving communication between the UAV satellite base station and the target satellite within the first time period with lower control overhead.

[0206] Figure 11 This is a flowchart illustrating another communication method for a UAV satellite base station provided in an embodiment of this application. Figure 11 As shown, in another possible embodiment, the method steps shown in S306 can be implemented by Sg1 to Sg6, which are described in detail below.

[0207] Sg1, broadcast the first message to multiple second candidate base stations. The first message includes the first location information of the UAV satellite base station in the first time period, as well as the identification information of the target satellite.

[0208] Among them, the second candidate base station is the UAV satellite base station; the first location information is the location information of the optimal hovering position.

[0209] It should be noted that the first message is used to notify the second candidate base station, the drone satellite base station, of the target situation and coordination requirements within the first time period.

[0210] During the execution of this mission by the UAV satellite base station, before the UAV satellite base station enters the first time period, the UAV satellite base station broadcasts a first message to multiple second candidate base stations. The first message carries at least the start time of the first time period, the end time of the first time period, the first location information, the identification information of the target satellite, and suggestions for communication link parameters.

[0211] Communication link parameters can include minimum transmission angle, expected bandwidth of UAV satellite base station, etc.

[0212] Upon receiving the first message, the second candidate base station performs a self-check based on its location and mission capabilities to determine whether it can simultaneously communicate with both the UAV satellite base station and the target satellite within the first time period. If the second candidate base station determines that it can communicate with both the UAV satellite base station and the target satellite simultaneously within the first time period, it sends a response message to the UAV satellite base station, allowing the UAV satellite base station to determine the relay base station based on this response message. If the second candidate base station determines that it cannot communicate with both the UAV satellite base station and the target satellite simultaneously within the first time period, it does not send a response message to the UAV satellite base station.

[0213] For example, the first message broadcast by the UAV satellite base station to multiple second candidate base stations could be: "During the time period from T3 to T4, this base station is located at A (location A is the optimal hovering position of this base station), and wishes to communicate with satellite B (satellite B is the target satellite). Is there a relay base station? Please return a response message within the preset time."

[0214] Sg2. Determine whether the drone satellite base station has received a response message within a preset time period.

[0215] The response message is used to instruct the second candidate base station to simultaneously communicate with the UAV satellite base station and the target satellite during the first time period.

[0216] It should be noted that the preset duration is the time window during which the drone satellite base station waits for the response from the second candidate base station. The preset duration can be set by the administrator, and this embodiment does not impose specific limitations on it.

[0217] For example, the preset duration is 30 seconds.

[0218] In one possible embodiment, after broadcasting the first message, the UAV satellite base station starts a timer for a preset duration. If the UAV satellite base station receives a response message from any second candidate base station before the preset duration is reached, the UAV satellite base station executes the method steps shown in Sg3. If the UAV satellite base station still does not receive any response message after the preset duration is reached, the UAV satellite base station executes the method steps shown in Sg4.

[0219] Sg3. If the UAV satellite base station receives a response message within a preset time period, the second candidate base station that sent the response message will be identified as the relay base station.

[0220] If the UAV satellite base station receives only one response message from a second candidate base station within a preset time period, the UAV satellite base station directly determines the second candidate base station that sent the response message as the relay base station; if the UAV satellite base station receives response messages from multiple second candidate base stations within a preset time period, the UAV satellite base station selects one of the multiple second candidate base stations that sent the response message as the relay base station according to a preset priority (such as expected link quality, coverage duration, energy consumption, etc.), and records the second candidate base station that was not selected as the relay base station among the multiple second candidate base stations that sent the response message as a backup relay base station.

[0221] It should be noted that after the UAV satellite base station determines the second candidate base station that sends the response message as the relay base station, the method steps shown in Sg6 are executed.

[0222] Sg4. If the UAV satellite base station does not receive a response message within a preset time period, broadcast a second message to multiple second candidate base stations. The second message includes the second location information of the UAV satellite base station within the first time period and the identification information of the target satellite.

[0223] The second position information is the position information of any candidate hovering position other than the optimal hovering position among multiple candidate hovering positions.

[0224] It should be noted that the second message is used to re-initiate the coordination request based on other candidate hovering positions when the drone satellite base station cannot obtain a response message at the optimal hovering position.

[0225] The UAV satellite base station or ground control center selects a second location (from the candidate hovering position set and different from the optimal hovering position) and rebroadcasts it to multiple second candidate base stations. The structure of the second message is consistent with that of the first message, except that the first location information in the first message is updated to the second location information. Upon receiving the second message, the second candidate base station performs a self-check based on the second message, and if it can communicate with both the UAV satellite base station and the target satellite simultaneously within the first time period, it sends a response message to the UAV satellite base station.

[0226] For example, the second message broadcast by the UAV satellite base station to multiple second candidate base stations could be: "During the time period from T3 to T4, this base station is located at C (location C is a candidate hovering position of this base station), and wishes to communicate with satellite B (satellite B is the target satellite). Is there a relay base station? Please return a response message within the preset time."

[0227] Sg5. Treat the second message as the first message and repeat the steps shown in Sg1 until the relay base station is determined.

[0228] It should be noted that the drone satellite base station processes the second message logically as equivalent to the first message, and can execute it iteratively multiple times. During these multiple iterations, the second location information included in each second message will differ.

[0229] If the UAV satellite base station successfully receives the response message and completes the determination of the relay base station in a certain round of iteration, the iteration is terminated; if the relay base station is not determined in several consecutive rounds, rollback measures can be triggered according to the task strategy (such as adjusting the waiting time or reducing the bandwidth target).

[0230] Sg6. Based on the relay base station, determine the alternative communication link.

[0231] Among them, the alternative communication link is the communication path established between the UAV satellite base station and the target satellite through a relay base station.

[0232] It should be noted that after the drone satellite base station determines the relay base station from the second candidate base stations, the drone satellite base station generates an alternative communication link for the first time period based on the relay base station.

[0233] In this embodiment, a dynamic discovery mechanism is used to broadcast queries to multiple second candidate base stations, requiring them to respond within a preset time limit. If a second candidate base station does not respond, the mechanism iteratively retryes using the second location information. Without relying on statically configured target list information, the mechanism quickly determines relay base stations that can communicate with both the UAV satellite base station and the target satellite based on the actual situation in the first time period. This makes the link establishment decision between the UAV satellite base station and the target satellite controllable in time, shortens the establishment delay, and automatically switches to other candidate hovering positions when the optimal hovering position is unavailable. This improves the success rate of finding a feasible relay base station, reduces the interruption window caused by the unavailability of direct communication links, enhances the continuity and robustness of communication services, and reduces reliance on prior configuration and manual scheduling.

[0234] In the above embodiments, the UAV satellite base station can determine the alternative communication links for the UAV satellite base station within the first time period using different methods. Therefore, the number of alternative communication links determined by the UAV satellite base station may be multiple. Next, the specific process by which the UAV satellite base station controls the UAV satellite base station to communicate with the target satellite through the alternative communication links within the first time period when there are multiple alternative communication links will be described in detail.

[0235] In another possible embodiment, the method steps shown in S307 can be implemented by S3071 and S3072, which are described in detail below.

[0236] S3071. Based on the communication quality of multiple alternative communication links in the first time period, determine the target alternative communication link.

[0237] Among them, the target alternative communication link is the alternative communication link with the best communication quality among multiple alternative communication links.

[0238] It should be noted that the multiple alternative communication links are the alternative communication links determined in the aforementioned steps, and are related to the suboptimal hovering position or relay base station.

[0239] Before the start of the first time period, the ground control center evaluates and compares the communication quality indicators of each alternative communication link, and prioritizes the alternative communication link with higher stability, lower latency and packet loss during the first time period as the target alternative communication link.

[0240] Communication quality indicators can be obtained through a combination of prediction and measurement: prediction is based on link budget results (such as available elevation angle, expected throughput, and expected latency) formed by ephemeris information, geographic information, and system parameters; measurement can come from link probing, short-term connection tests, or historical statistics (such as received power / signal-to-noise ratio, round-trip time, jitter, packet loss rate, available time coverage ratio, etc.).

[0241] S3072, Control the UAV satellite base station to communicate with the target satellite through the target alternative communication link in the first time period.

[0242] It should be noted that the method of controlling the UAV satellite base station to communicate with the target satellite through the target alternative communication link in the first time period is similar to the method of controlling the UAV satellite base station to communicate with the target satellite through the target alternative communication link in the first time period in the above embodiment, and will not be described again in this embodiment.

[0243] In this embodiment, by evaluating the key communication quality indicators of multiple alternative communication links, the target alternative communication link with the best communication quality is selected. This allows the use of the better-performing alternative communication link to achieve communication between the UAV satellite base station and the target satellite in the first time period, reducing the occupation of low-quality alternative communication links, improving the stability of the connection between the UAV satellite base station and the target satellite during periods when the direct communication link is unavailable, and ensuring the service continuity of the UAV satellite base station during this mission.

[0244] Figure 12 This is a schematic diagram of the structure of a UAV satellite base station provided in an embodiment of this application. Figure 12 As shown, the UAV satellite base station 1200 includes an acquisition module 1201, a first determination module 1202, a judgment module 1203, a first control module 1204, a second determination module 1205, a third determination module 1206, and a second control module 1207.

[0245] The acquisition module 1201 is used to acquire the geographic information of the target area and the ephemeris information of the target satellite. The target area is the area where the UAV satellite base station performs this mission. The geographic information includes the location information and altitude information of the target object within the target area. The target object is the object that prevents the UAV satellite base station from establishing a direct communication link with the target satellite.

[0246] The first determining module 1202 is used to filter multiple candidate hovering positions based on geographic information and ephemeris information to determine the optimal hovering position of the UAV satellite base station; wherein, the candidate hovering position is the position on the UAV's flight path where the UAV is allowed to hover.

[0247] The judgment module 1203 is used to determine, based on the optimal hovering position, geographic information and ephemeris information, whether the UAV satellite base station can always establish a direct communication link with the target satellite at the optimal hovering position.

[0248] The first control module 1204 is used to control the UAV satellite base station to communicate with the target satellite through the direct communication link when the UAV satellite base station can always establish a direct communication link with the target satellite at the optimal hovering position.

[0249] The second determining module 1205 is used to determine the first time period in which the UAV satellite base station cannot establish a direct communication link with the target satellite in the optimal hovering position, when the UAV satellite base station cannot always establish a direct communication link with the target satellite in the optimal hovering position.

[0250] The third determining module 1206 is used to determine alternative communication links for UAV satellite base stations based on a first time period; wherein the alternative communication links are associated with a suboptimal hovering position or at least one relay base station.

[0251] The second control module 1207 is used to control the UAV satellite base station to communicate with the target satellite through an alternative communication link during the first time period.

[0252] It should be understood that the corresponding processes performed by each module have been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0253] Figure 13 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 13 As shown, the electronic device 1300 provided in this embodiment includes a memory 1301 and a processor 1302.

[0254] The memory 1301 can be a separate physical unit, connected to the processor 1302 via a bus 1303. Alternatively, the memory 1301 and processor 1302 can be integrated and implemented in hardware. The memory 1301 stores program instructions, which the processor 1302 calls to execute the operations performed by the UAV satellite base station in any of the above method embodiments.

[0255] Optionally, when some or all of the methods in the above embodiments are implemented by software, the electronic device 1300 may also include only the processor 1302. The memory 1301 for storing programs is located outside the electronic device 1300, and the processor 1302 is connected to the memory via circuits / wires to read and execute the programs stored in the memory. The processor 1302 may be a central processing unit (CPU), a network processor (NP), or a combination of a CPU and an NP. The processor 1302 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0256] The memory 1301 may include volatile memory, such as random-access memory (RAM); the memory may also include non-volatile memory, such as flash memory, hard disk drive (HDD) or solid-state drive (SSD); the memory may also include a combination of the above types of memory.

[0257] For example, this application provides a chip including: an interface circuit and a logic circuit. The interface circuit is used to receive signals from other chips outside the chip and transmit them to the logic circuit, or to send signals from the logic circuit to other chips outside the chip. The logic circuit is used to perform the operations performed by the UAV satellite base station in the above method embodiments.

[0258] For example, this application provides a computer-readable storage medium storing computer program instructions thereon, which are executed by the processor of an electronic device to cause the electronic device to perform the operations performed by the UAV satellite base station in the above method embodiments.

[0259] For example, this application provides a computer program product that, when run on an electronic device, causes the electronic device to perform the operations performed by the UAV satellite base station in the above method embodiments.

[0260] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A communication method for a UAV satellite base station, applied to a UAV satellite base station, characterized in that, The method includes: The system acquires geographic information of the target area and ephemeris information of the target satellite, wherein the target area is the area where the UAV satellite base station performs this mission; the geographic information includes the location and altitude information of the target object within the target area, and the target object is an object that prevents the UAV satellite base station from establishing a direct communication link with the target satellite; Based on the geographic information and the ephemeris information, multiple candidate hovering positions are filtered to determine the optimal hovering position of the UAV satellite base station; wherein, the candidate hovering position is a position on the UAV's flight path where the UAV is allowed to hover. Based on the optimal hovering position, the geographic information, and the ephemeris information, determine whether the UAV satellite base station can always establish a direct communication link with the target satellite at the optimal hovering position; When the UAV satellite base station can always establish a direct communication link with the target satellite at the optimal hovering position, the UAV satellite base station is controlled to communicate with the target satellite through the direct communication link. When the UAV satellite base station cannot consistently establish a direct communication link with the target satellite at the optimal hovering position, a first time period in which the UAV satellite base station cannot establish a direct communication link with the target satellite at the optimal hovering position is determined; Based on the first time period, an alternative communication link for the UAV satellite base station is determined; wherein, the alternative communication link is associated with a suboptimal hovering position or at least one relay base station; Control the UAV satellite base station to communicate with the target satellite through the alternative communication link during the first time period; The step of filtering multiple candidate hovering positions based on the geographic information and the ephemeris information to determine the optimal hovering position of the UAV satellite base station includes: For each of the multiple candidate hovering locations, based on the candidate hovering location, the geographic information, and the ephemeris information, a second time period is determined in which the UAV satellite base station cannot establish a direct communication link with the target satellite at the candidate hovering location; The candidate hovering position corresponding to the shortest second time period among multiple second time periods is determined as the optimal hovering position; The control of the UAV satellite base station to communicate with the target satellite via the alternative communication link during the first time period includes: Before the start of the first time period, the UAV satellite base station is controlled to communicate with the target satellite through the alternative communication link; After the end of the first time period, the UAV satellite base station is controlled to communicate with the target satellite through the direct communication link.

2. The method according to claim 1, characterized in that, The step of filtering multiple candidate hovering locations based on the geographic information and the ephemeris information to determine the optimal hovering location for the UAV satellite base station includes: Determine the minimum transmission angle corresponding to the target satellite; Based on the ephemeris information and the geographic information, the transmission angle corresponding to each candidate hovering position among the plurality of candidate hovering positions is determined; wherein, the transmission angle is the angle between the target line and the horizontal line, the target line is the line connecting the candidate hovering position to the target satellite, and the target line does not pass through the target object; The candidate hovering position corresponding to the transmission angle that is greater than or equal to the minimum transmission angle and has the smallest difference from the minimum transmission angle is determined as the optimal hovering position.

3. The method according to claim 1, characterized in that, The step of filtering multiple candidate hovering locations based on the geographic information and the ephemeris information to determine the optimal hovering location for the UAV satellite base station includes: Determine the minimum transmission angle corresponding to the target satellite; Based on the ephemeris information and the geographic information, the transmission angle corresponding to each candidate hovering position among the plurality of candidate hovering positions is determined; Based on the minimum transmission angle and the transmission angle corresponding to each candidate hovering position, the obstacle blocking angle corresponding to each candidate hovering position is determined; wherein, the obstacle blocking angle is the total azimuth angle at the minimum transmission angle, due to the obstruction of the target object, a direct communication link cannot be established with the target satellite; The candidate hovering position corresponding to the smallest obstacle blocking angle among the multiple obstacle blocking angles is determined as the optimal hovering position.

4. The method according to claim 1, characterized in that, The step of determining the alternative communication link for the UAV satellite base station based on the first time period includes: Based on the first time period, the geographical information, and the ephemeris information, the multiple candidate hovering positions are filtered to determine the suboptimal hovering position of the UAV satellite base station; wherein, the suboptimal hovering position is the candidate hovering position in which the UAV satellite base station can establish a direct communication link with the target satellite within the first time period; Based on the suboptimal hovering position, the alternative communication link is determined; wherein, the alternative communication link is a direct communication link established between the UAV satellite base station and the target satellite when the UAV satellite base station is located in the suboptimal hovering position.

5. The method according to claim 1, characterized in that, The step of determining the alternative communication link for the UAV satellite base station based on the first time period includes: Obtain target list information, which includes identification information and location information corresponding to multiple first candidate base stations, as well as the task time period; wherein, the first candidate base station is an unmanned aerial vehicle (UAV) satellite base station; Based on the first time period and the target list information, at least one relay base station is determined from the plurality of first candidate base stations, and the union of the task time periods of the at least one relay base station covers the first time period; wherein, the relay base station is a first candidate base station that can simultaneously communicate with the UAV satellite base station and the target satellite during the first time period; Based on the at least one relay base station, the alternative communication link is determined; wherein, the alternative communication link is the communication path established by the UAV satellite base station with the target satellite through the at least one relay base station.

6. The method according to claim 1, characterized in that, The step of determining the alternative communication link for the UAV satellite base station based on the first time period includes: A first message is broadcast to multiple second candidate base stations. The first message includes the first location information of the UAV satellite base station within the first time period and the identification information of the target satellite. The second candidate base station is the UAV satellite base station. The first location information is the location information of the optimal hovering position. If the UAV satellite base station receives a response message within a preset time period, the second candidate base station that sent the response message will be identified as the relay base station; the response message is used to indicate that the second candidate base station can simultaneously communicate with the UAV satellite base station and the target satellite within the first time period. If the UAV satellite base station does not receive the response message within the preset time period, it broadcasts a second message to the plurality of second candidate base stations. The second message includes the second location information of the UAV satellite base station within the first time period and the identification information of the target satellite. The second location information is the location information of any of the candidate hovering positions other than the optimal hovering position among the plurality of candidate hovering positions. Treat the second message as the first message, and repeat the step of broadcasting the first message to multiple second candidate base stations until the relay base station is determined; Based on the relay base station, the alternative communication link is determined; wherein, the alternative communication link is the communication path established between the UAV satellite base station and the target satellite through the relay base station.

7. The method according to claim 1, characterized in that, The number of alternative communication links is multiple, and controlling the UAV satellite base station to communicate with the target satellite through the alternative communication links during the first time period includes: Based on the communication quality of multiple alternative communication links in the first time period, a target alternative communication link is determined, wherein the target alternative communication link is the alternative communication link with the best communication quality among the multiple alternative communication links; The UAV satellite base station is controlled to communicate with the target satellite through the target alternative communication link during the first time period.

8. A satellite base station for unmanned aerial vehicles (UAVs), characterized in that, include: Memory and at least one processor; The memory stores computer-executed instructions; The at least one processor executes computer execution instructions stored in the memory, causing the at least one processor to perform the method as described in any one of claims 1 to 7.

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