A multi-fixed-wing unmanned aerial vehicle far-domain chain relay communication planning method

Abstract

The application discloses a kind of multi fixed wing unmanned aerial vehicle far field chain type relay communication planning method, comprising: according to communication coverage requirement, the model parameter of the fixed wing unmanned aerial vehicle is selected, and the communication terminal carried thereby is selected;The fixed wing unmanned aerial vehicle is selected and is released and is recovered site, and ground communication base station is set in its nearby preset range, and the base station has air laser communication and microwave communication capability;The route of the fixed wing unmanned aerial vehicle is planned, and the total number of unmanned aerial vehicle is determined;During relay communication process, flight control is carried out;During the relay communication task process, the route distance of adjacent unmanned aerial vehicle is controlled and the influence of sunlight on laser communication is coped with by adjusting the communication terminal carried by unmanned aerial vehicle.The relay communication planning method proposed in the application can realize low-cost and fast far field broadband communication access.

Description

Technical Field

[0001] This invention relates to a relay communication planning method, and more particularly to a multi-fixed-wing UAV long-range chain relay communication planning method. Background Technology

[0002] In sparsely populated remote mountainous areas, grasslands, primeval forests, deserts, and vast ocean regions, the construction of high-density terrestrial high-speed communication base stations is extremely difficult due to the difficulty in amortizing costs, often resulting in ineffective coverage. When conducting scientific exploration, disaster relief, mining, border patrols, or military operations in these areas, communication with densely populated rear areas is generally only possible via satellite phones. However, satellite communication suffers from long construction cycles, high costs, low bandwidth, and very limited service content, making it difficult to meet practical needs such as remote video conferencing, high-definition image transmission, broadband network access, and real-time remote control.

[0003] Relay communication is a widely used and relatively mature technology in production and daily life. Meanwhile, various unmanned aerial vehicles (UAVs) have also developed rapidly in recent years, forming a relatively complete product portfolio. Combining relay communication technology with high-altitude, long-endurance fixed-wing UAV platforms allows for the construction of multiple mobile aerial communication base station sites. Based on communication coverage requirements and inter-platform communication distances, a chain-like relay communication network between these mobile aerial communication base station sites can be planned. This allows for the rapid and cost-effective provision of broadband access services to areas in need. Furthermore, after the communication needs are met, these aerial UAV platforms can be quickly and easily recovered and redeployed to areas with new communication needs, achieving the reuse and maximization of communication resources. However, the ability to construct a UAV chain-like relay communication link and maintain stable, high-quality communication depends heavily on planning. Therefore, it is necessary to research a practical planning method based on meeting the requirements for constructing a UAV chain-like relay communication network.

[0004] Currently, there is considerable research in China on single-UAV aerial base station services and dual-UAV platform relay communication, but research is lacking in the planning of multi-UAV platform chain relay communication. Summary of the Invention

[0005] Purpose of the invention: The technical problem to be solved by the present invention is to provide a long-range chain relay communication planning method for multi-fixed-wing UAVs, which addresses the shortcomings of the existing technology.

[0006] To address the aforementioned technical problems, this invention discloses a method for planning long-range chain relay communication for multiple fixed-wing unmanned aerial vehicles (UAVs), comprising the following steps:

[0007] Step 1: Select the model parameters of the fixed-wing UAV according to the communication coverage requirements, and select the communication terminal it is equipped with;

[0008] Step 2: Select the launch and recovery site for the fixed-wing UAV according to the communication coverage requirements, and set up a ground communication base station in a preset range near it. The base station has the capability of aerial laser communication and microwave communication.

[0009] Step 3: Based on communication coverage requirements and the influence of sunlight, plan the flight path of the fixed-wing UAV and determine the total number of UAVs;

[0010] Step 4: Perform flight control: Number the fixed-wing UAVs, launch them according to the set time sequence, and continuously control all UAVs until the relay communication mission ends;

[0011] Step 5: Conduct relay communication: Microwave and laser dual-link communication is conducted between UAVs ahead and behind on the flight path, and between UAVs at the beginning and end of the flight path and the ground communication base station; UAVs establish link relationships and hand over at preset positions; communication data streams are split and relayed through microwave and laser communication links, as well as two paths: the forward flight path and the return flight path.

[0012] Step 6: During the relay communication mission, control the flight path spacing between adjacent UAVs and adjust the communication terminals carried by the UAVs to address the impact of sunlight on laser communication.

[0013] Step 7: The relay communication task ends, and all UAVs are retrieved in sequence to complete the multi-fixed-wing UAV long-range chain relay communication.

[0014] Furthermore, the communication terminal mentioned in step 1 includes:

[0015] Two sets of airborne laser communication terminals, two microwave communication antennas, and one wireless broadband access terminal. The effective communication range of the laser communication terminals is at least 400 km, the effective communication range of the microwave communication antennas is at least 400 km, and the effective communication range of the wireless broadband access device is at least 200 km.

[0016] Furthermore, the airborne laser communication terminal described in step 1 has a retractable light-shielding tube mounted on the outside of the optical terminal.

[0017] Furthermore, the ground communication base station mentioned in step 2 is equipped with two sets of airborne laser communication terminals and two microwave communication antennas, which are used to establish communication links with fixed-wing UAVs on the forward and backward routes, respectively.

[0018] Furthermore, the specific method for planning the flight path of the fixed-wing UAV as described in step 3 is as follows:

[0019] Step 3-1: Determine the furthest point of the route coverage communication coverage requirement area;

[0020] Step 3-2: The route includes a forward route and a return route;

[0021] Step 3-3: Achieve wide-area coverage by adopting a zigzag flight path as required;

[0022] Steps 3-4: Adjust the coverage level of the communication coverage required area;

[0023] Steps 3-5: The angle between the line connecting any two points on the flight path that are 300 km apart and the sunlight shall not exceed 10 degrees for any consecutive period of time, and shall not exceed the preset duration.

[0024] Furthermore, the method for determining the total number of drones in step 3 is as follows:

[0025] The drones include mission drones, backup drones, and redundant drones. The number of mission drones is determined based on the route length and the spacing between mission drones. For every four mission drones, there is one backup drone. The backup drone accompanies the mission drones at a preset escort distance along their route. Redundant drones are set up according to a preset ratio of the sum of the number of mission drones and the number of backup drones.

[0026] Furthermore, the flight control described in step 4 is performed as follows:

[0027] Step 4-1: Number the mission drones one by one as: 1, 2, 3, ... n1, where n1 is the number of mission drones;

[0028] Step 4-2: Number each standby drone individually: n2 represents the number of backup drones;

[0029] Step 4-3: The mission drone platforms are launched sequentially, starting with drone number 1, according to their serial numbers.

[0030] Step 4-4: The backup drone platforms are launched sequentially from drone B1 according to their serial numbers;

[0031] Steps 4-5: When the distance between the i-th mission UAV and the launch and recovery site is 180 km on the forward flight path, launch the i+1 mission UAV.

[0032] Steps 4-6: When i ≥ 2 and (i-2)%4 = 0, when the distance between the i-th mission UAV and the launch and recovery site is 90 km on the forward flight path, launch the B-th mission UAV. ((i-2)％4+1) No. 1 backup drone;

[0033] Steps 4-7: When the distance between the mission UAV and the flight path to the launch and recovery site is 20km, gradually adjust its altitude to the preset mission altitude within a 10km flight distance.

[0034] Steps 4-8: When the distance between the backup drone platform and the launch and recovery site is 20km, gradually adjust its altitude to the preset mission altitude within a 10km flight distance.

[0035] Steps 4-9: After the i+1 mission drone is launched, and after it has successfully established airborne laser communication and microwave communication links with the i mission drone and the ground communication base station, adjust the flight path distance between it and the i mission drone until it is stable at 300 km.

[0036] Steps 4-10, Part B ((i-2)％4+1) After the backup drone is launched, its relative position with the mission drone is adjusted until the distance between the corresponding point on the route of the preset escort distance on its side and the mission drone is stabilized at 150 km in the forward route direction.

[0037] Step 4-11 If the mission drone or the backup drone fails to launch, or if the mission drone flies to a distance of 80km from the launch and recovery site and cannot successfully establish a link with the previous mission drone or ground communication base station, a redundant drone will be launched to take over. The redundant drone will be reassigned as the mission drone or the backup drone and will use the number of the failed drone. The drone that failed the mission will return in advance.

[0038] Furthermore, the relay communication described in step 5 is performed as follows:

[0039] Step 5-1: Each mission drone carries two airborne laser communication terminals and two microwave communication antennas, which are divided into two groups. Each group includes one airborne laser communication terminal and one microwave communication antenna, which are responsible for establishing communication links with the previous mission drone or ground communication base station and the next mission drone or ground communication base station, respectively.

[0040] Step 5-2: When the distance between the i+1 mission UAV and the launch and recovery site is within a preset range on the forward flight path, the i mission UAV and the i+1 mission UAV begin to establish a communication link. That is, the i mission UAV disconnects its communication link with the ground communication base station and establishes a communication link with the i+1 mission UAV. At the same time, the i+1 mission UAV establishes a communication link with the ground communication base station.

[0041] Step 5-3: When the distance between the i-th mission UAV and the launch and recovery site is within a preset range on the return route, the i-th mission UAV and the i+1 mission UAV begin to establish a communication link. That is, the i-th mission UAV disconnects the communication link between the i+1 mission UAV and the ground communication base station, exits the relay communication link, and the i+1 mission UAV establishes a communication link with the ground communication base station.

[0042] Step 5-4: There are two communication links, one for airborne laser communication and one for microwave communication, between every two adjacent mission drones and between drones at the beginning and end of the flight path and the ground communication base station. When both can communicate normally, the communication load is balanced and distributed.

[0043] Step 5-5: Before the communication link between the mission area and the ground communication base station is established on the return route, the information flow in the mission area is relayed to the ground communication base station one by one by the UAVs on the forward route.

[0044] Steps 5-6: After the communication link between the ground communication base station and the return route is established, the transmission is first selected according to the principle of the shortest route distance from the ground communication base station. At the same time, if the traffic in one transmission direction is detected to be close to a certain load threshold, the transmission is split to the other transmission direction.

[0045] Furthermore, the specific method for controlling the flight path spacing between adjacent UAVs as described in step 6 is as follows:

[0046] The flight speed of the mission drone at the forefront of the flight path is set to v0. Each mission drone uses the preceding mission drone as a reference to control its spacing and speed.

[0047] v = v0 + k(t(d) - 300)

[0048] Where k is the speed control coefficient, d is the flight path distance between the current mission UAV and the previous mission UAV, v is the speed of the current mission UAV, and t(d) is the distance monitoring function. When d exceeds a predetermined value, t(d) takes the value of the predetermined value.

[0049] Furthermore, the specific methods for addressing the impact of sunlight on laser communication as described in step 6 are as follows:

[0050] When the two mission drones are establishing an aerial laser communication link, the sunshades on both mission drones are retracted to 0cm, and the two laser communication terminals perform scanning, acquisition, tracking and holding.

[0051] When the CCD array inside the laser communication terminal on this mission detects stray light images other than signal light, the extension length of the light shield tube is increased until the intensity of the detected stray light returns to within the predetermined threshold, or until the extension length of the light shield tube has reached its maximum length.

[0052] Beneficial effects:

[0053] This invention eliminates the need for costly and time-consuming large-scale ground communication base stations in sparsely populated remote areas, while also solving the problems of low bandwidth and limited service content of communication satellites. This technology combines relatively mature relay communication technology with rapidly developing UAV technology, using a chain-like relay communication method to achieve interconnection between wide-area remote locations and existing high-speed ground-based optical networks. To this end, this invention, considering communication coverage requirements and the effective communication distance characteristics of laser and microwave, provides a comprehensive and targeted design covering the entire process, from UAV platform parameter selection, laser communication terminal sunlight-resistant design, launch and recovery site selection, ground communication base station establishment, mission route planning, UAV platform quantity planning, UAV platform backup and redundancy design, flight planning, communication planning, and mission process control. This achieves low-cost construction, rapid deployment, and efficient reuse of long-area broadband communication. Attached Figure Description

[0054] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0055] Figure 1 This is a schematic diagram of the structure of the airborne laser communication terminal light shielding tube of the present invention.

[0056] Figure 2 This is a schematic diagram of the overall process of the multi-fixed-wing UAV remote-domain chain relay communication of the present invention.

[0057] Figure 3 This is a schematic diagram of the planning process for the remote chain relay communication of multi-fixed-wing UAVs according to the present invention. Detailed Implementation

[0058] This invention proposes a long-range chain relay communication planning method for multi-fixed-wing UAVs, achieving rapid and low-cost long-range communication coverage. The specific technical solution is as follows: A long-range chain relay communication planning method for multi-fixed-wing UAVs, as follows... Figure 3 As shown, it includes the following steps:

[0059] Step 1: Based on the communication coverage requirements and the effective communication distance characteristics of laser and microwave, select a suitable high-altitude long-endurance fixed-wing UAV for the mission. The UAV parameters to be considered include service ceiling, speed, range, type and performance of the terminal to be carried, and special targeted designs, etc.

[0060] Step 2: Based on the communication coverage requirements, select a flat, open, unobstructed area near the communication coverage area as the launch and recovery site for the UAV platform.

[0061] Step 3: Within 10km of the launch and recovery site, select an open and unobstructed area between the launch and recovery site and the area requiring communication coverage to set up a ground communication base station, deploy two sets of airborne laser communication terminals and two microwave communication antennas. If there is an existing communication base station that meets the requirements, it should be used first.

[0062] Step 4: Plan the flight path of the mission UAV platform according to the following methods: covering the farthest point of the communication demand area, adopting a zigzag route to achieve wide-area coverage for important communication demand areas, and comprehensively considering the importance level of communication demand, cost and feasibility to determine the coverage degree of the communication demand area. Adjust the flight path in combination with the need to deal with the impact of sunlight.

[0063] Step 5: Based on the route length and the effective communication distance between platforms, determine the number of mission UAV platforms required. At the same time, considering backup escort and re-flight in case of failure to establish link during takeoff, determine the number of backup UAV platforms and the number of redundant UAV platforms required.

[0064] Step 6: Number the mission drone platform and the backup drone platform, and plan the launch sequence, launch time, key adjustment positions, and take-off and landing connection.

[0065] Step 7: The two airborne laser communication terminals and two microwave communication antennas carried on each mission UAV platform establish laser and microwave communication links with the previous mission UAV platform (or ground communication base station) and the next mission UAV platform (or ground communication base station) respectively. The communication link handover relationship during the launch phase, recovery phase and launch link establishment failure is planned, and the relay information flow direction and relay splitting are designed.

[0066] Step 8: During the mission, except for the first and last mission UAV platforms, maintain the flight path distance between adjacent mission UAV platforms at 300 km, and avoid or reduce the impact of sunlight on laser communication by controlling the extension length of the sunshade tube.

[0067] Step 9: After the drone platform returns to the launch and recovery site, it will undergo battery swapping or refueling, log download and analysis, data loading, and re-flight.

[0068] Step 10, Mission Completion Phase: The forward link information flow is disconnected, and all information flows are relayed to the ground communication base station via the return link. The UAV platforms that have completed the mission land in sequence and are either stored in a warehouse or transferred to other mission locations.

[0069] Furthermore, in step 1, the selection steps for the high-altitude long-endurance fixed-wing UAV are as follows:

[0070] Step 1-1: The service ceiling of the drone is 7500m, the maximum flight speed is 680km / h, and the range is 6000km.

[0071] Steps 1-2: Equip two airborne laser communication terminals with an effective communication range of 400km (the communication range of the airborne laser communication terminal is determined by comprehensively considering the communication performance of the laser communication terminal, the mission altitude of the UAV, the curvature of the earth, atmospheric attenuation of the light signal, and the influence of atmospheric turbulence); two microwave communication antennas with an effective communication range of 400km (the microwave communication terminal is selected reasonably based on the performance limit of the microwave communication terminal itself and the effective communication range of the laser communication terminal); and a wireless broadband access terminal with an effective communication range of 200km (determined by comprehensively considering the performance limit of the wireless broadband access equipment, the distance between the UAVs in front and behind, the mission altitude of the UAV, and the effective communication coverage requirements).

[0072] Steps 1-3: Install a retractable light shield on the outside of the laser communication terminal; the light shield has a certain retractable range with the outermost mirror surface of the optical terminal as a reference point.

[0073] Furthermore, in step 4, the steps for avoiding or mitigating the impact of sunlight on aerial laser communication are as follows:

[0074] Step 4-1: Adjust the flight path until the angle between any two points on the flight path that are 300 km apart and the sunlight is less than 10 degrees for no more than 5 minutes during the mission (when the angle is less than 10 degrees, sunlight has a significant impact on laser communication, increasing the bit error rate and even causing communication failure. This is determined by engineering experience). The flight path distance is the distance between the two points along the flight path.

[0075] Furthermore, in step 5, the steps for determining the required number of drone platforms are as follows:

[0076] Step 5-1: Determine the required number of mission drone platforms based on the total route length and the effective communication distance limitations between drone platforms.

[0077] n1 = ceil(l / 300)

[0078] Where l is the total length of the route, which must not exceed the maximum range of the UAV platform; otherwise, it is considered that the communication requirement area is too far away and the task cannot be completed by the selected UAV platform in the form of chain relay communication. 300km is the route distance between adjacent UAV platforms designed in the plan, taking into account the distance limitations of aerial laser communication and microwave communication. ceil is the round-up function.

[0079] Step 5-2: For every four mission drone platforms, prepare one backup drone platform (the number should be determined by considering mission costs and the probability of drone and communication terminal failures). The number of backup drone platforms is determined using the following formula:

[0080]

[0081] Here, % is the modulo operator.

[0082] Step 5-3: Determine the required number of redundant drone platforms using the following formula:

[0083] n3 = ceil((n1 + n2) * 0.3)

[0084] Furthermore, in step 6, the flight planning steps for the unmanned aerial vehicle platform are as follows:

[0085] Step 6-1: Number the mission UAV platform and the backup UAV platform one by one: 1, 2, 3, ... m1 and

[0086] Step 6-2: The mission drone platform and the backup drone platform are launched sequentially from drone number 1 and drone number B1, respectively, according to their serial numbers.

[0087] Step 6-3: When the distance between the i-th mission UAV platform and the launch and recovery site is 180km on the forward flight path (taking into account the distance between the preceding and following UAVs, the slower speed during launch and climb, the appropriate increase in subsequent distances, and the allowance for some time for emergency response), launch the i+1 mission UAV platform.

[0088] Step 6-4: When i ≥ 2 and (i-2)%4 = 0, on the forward flight path, when the distance between the i-th mission UAV platform and the launch and recovery site is 90 km (considering the distance between the preceding and following UAVs, the slower speed during launch and climb, the appropriate increase in subsequent distances, and the allowance for unexpected handling), launch the B-th UAV platform. ((i-2)％4+1) Backup drone platform;

[0089] Step 6-5: On the forward flight path, when the distance between the mission UAV platform or the backup UAV platform and the launch and recovery site is 20km (determined by comprehensively considering the UAV's climb capability and power consumption, as well as the ease of establishing a link and providing communication access services as soon as possible), gradually adjust its altitude to 6000m within a 10km flight distance (determined by comprehensively considering the UAV's climb capability and power consumption, as well as the ease of establishing a link and providing communication access services as soon as possible);

[0090] Step 6-6: After the i+1 mission UAV platform, the i mission UAV platform, and the ground communication base station have successfully established airborne laser communication and microwave communication links, the flight path distance between the i+1 mission UAV platform and the i mission UAV platform is gradually adjusted until it is stabilized at 300 km (taking into account the effective communication distance of the laser communication terminal, the effective communication distance of the microwave communication terminal, and the effective communication distance of the wireless broadband access equipment, and reserving a certain margin).

[0091] Steps 6-7, Part B ((i-2)％4+1) After the backup drone platform is launched, its relative position to the i-th mission drone platform is gradually adjusted until the distance between the corresponding point on the 3km route to its left and the i-th mission drone platform is stabilized at 150km (the middle position between the front and rear mission drones, in order to take over the faulty drone at any time).

[0092] Steps 6-8: If the mission drone platform or the backup drone platform cannot establish a communication link with the previous drone platform or ground communication base station during the launch phase or before flying away from the launch and recovery site by 80km (the flight path distance), a redundant drone platform will be launched to take over, using the number of the drone platform that failed the mission. The drone platform that failed the mission will return in advance.

[0093] Steps 6-9: After the UAV platform returns to the launch and recovery site, it will be refueled or have its battery swapped and then re-fly following the steps from 6-3 to 6-8. (When i=n1 after the No. 1 mission UAV platform returns, i+1 is the No. 1 mission UAV platform. The backup UAV platform is similar.)

[0094] Furthermore, in step 7, the communication planning steps for the UAV platform are as follows:

[0095] Step 7-1: Each mission UAV platform sends its location information to the ground communication base station so that subsequent mission UAV platforms can quickly establish microwave and laser communication links with it.

[0096] Step 7-2: When the distance between the i+1 mission UAV platform and the launch and recovery site is 30km on the forward flight path, the i mission UAV platform disconnects the communication link with the ground communication base station and establishes a communication link with the i+1 mission UAV platform. At the same time, the i+1 mission UAV platform establishes a communication link with the ground communication base station.

[0097] Step 7-3: When the distance between the i+1 mission UAV platform and the launch and recovery site is 80km, and the microwave and laser communication link has not been successfully established with the i mission UAV platform or the ground communication base station, the supplementary UAV platform shall establish the microwave and laser communication link with the i mission UAV platform and the ground communication base station.

[0098] Step 7-4: When the distance between the i-th mission UAV platform and the launch and recovery site is 30km on the return route, the i-th mission UAV platform disconnects the communication link with the i+1 mission UAV platform and the ground communication base station, and the i+1 mission UAV platform establishes a communication link with the ground communication base station.

[0099] Step 7-5: When both airborne laser communication and microwave communication links between adjacent UAV platforms and between UAV platforms at the beginning and end of the flight path and ground communication base stations are normal, the load is balanced between the two. When one link fails, the other link is responsible for transmitting restart and self-test commands to attempt to restore the failed link.

[0100] Steps 7-6: Before establishing a communication link with the ground communication base station on the return route, the information flow is relayed one by one through the mission UAV platform.

[0101] Step 7-7: When both the forward and return routes have communication links with the ground communication base station, the transmission direction should be selected based on the principle of the shortest route distance to the ground communication base station, while also taking into account the load balancing of the two relay directions.

[0102] Steps 7-8: At the end of the mission, after the communication link between the forward flight path and the ground communication base station is disconnected, the information flow is relayed forward one by one through the mission UAV platforms on the return flight path.

[0103] Steps 7-9: If the mission drone platform malfunctions during mission execution and cannot recover on its own, a nearby backup drone platform shall be moved to its location to take over its communication relay and communication access tasks.

[0104] Furthermore, in step 8, the task execution process control steps are as follows:

[0105] Step 8-1: The flight speed of the leading mission UAV platform along the flight path is controlled at 320 km / h. Other mission UAV platforms use the preceding mission UAV platform as a reference to control their spacing and speed.

[0106] v = 320 + k(t(d) - 300)

[0107] Where k = 1.2 is the speed control coefficient, d is the flight path distance between the current mission UAV platform and the previous mission UAV platform, and v is the speed of the current mission UAV platform.

[0108]

[0109] Step 8-2: When the laser communication terminal on the UAV platform of this mission is affected by sunlight, increase the extension length of the sunshade tube until the intensity of the sunlight effect weakens to a predetermined threshold or the sunshade tube has been extended to its maximum length.

[0110] Example:

[0111] An embodiment of the present invention will be further described below with reference to the accompanying drawings.

[0112] 1. The UAV platform selected in this method is a high-altitude long-endurance fixed-wing UAV, and its relevant parameters are as follows:

[0113] (1) Practical service ceiling: 7500m (the mission altitude in this method is 6000m);

[0114] (2) Maximum flight speed: 680 km / h;

[0115] (3) Maximum soaring time: 10h;

[0116] (4) Maximum driving range: 6000 km;

[0117] (5) The onboard communication terminals include: two sets of airborne laser communication terminals, two microwave communication antennas, and one wireless broadband access terminal. The effective communication distance of the laser communication terminal is 400 km (the communication distance of the airborne laser communication terminal is determined by comprehensively considering the communication performance of the laser communication terminal, the mission altitude of the UAV, the curvature of the earth, atmospheric attenuation of the light signal, and the influence of atmospheric turbulence). The effective communication distance of the microwave communication antenna is 400 km (the microwave communication terminal is selected based on its own performance limit and the effective communication distance of the laser communication terminal). The effective communication distance of the wireless broadband access terminal is 200 km (determined by comprehensively considering the performance limit of the wireless broadband access equipment, the distance between the UAVs in front and behind, the mission altitude of the UAV, and the effective communication coverage).

[0118] (6) Equipped with satellite positioning, laser gyroscope positioning, attitude determination and ranging systems;

[0119] (7) The drone platform supports refueling or battery swapping;

[0120] (8) Light-shielding tube: The airborne laser communication terminal adopts a targeted design, with a retractable light-shielding tube (outer diameter 17.2cm) fitted outside the optical terminal (outer diameter 15.4cm). Taking the outermost mirror surface of the optical terminal as a reference point, the retractable range of the light-shielding tube is between 0-51.6cm. The structure of the light-shielding tube is as follows: Figure 1 As shown.

[0121] 2. Select launch and recovery sites for the UAV platform based on the area requiring communication coverage. The method for selecting launch and recovery sites for the UAV platform is as follows:

[0122] (1) As close as possible to the area where communication coverage is needed;

[0123] (2) The site should have a sufficiently flat and open area for launching and recovering the human-machine platform, and there should be no mountains, building clusters or other obstructions in the direction of the communication coverage area.

[0124] (3) Within 10km of the launch and recovery site of the UAV platform, there must be conditions to set up ground communication base stations for aerial laser communication and microwave communication, and the base stations must be able to access the ground high-speed fiber optic network.

[0125] 3. Select or establish terrestrial communication base stations

[0126] (1) If there is already a ground communication base station capable of supporting aerial laser communication and microwave communication within the launch and recovery site of the UAV platform, or if it is convenient to set up such a base station, then the existing ground communication base station on site shall be used or a ground communication base station shall be set up in a suitable location on site. If the above conditions are not met, then an existing ground communication base station capable of supporting aerial laser communication and microwave communication shall be found within a 10km radius of the site, or such a base station shall be set up. The base station shall be connected to a high-speed ground fiber optic network.

[0127] (2) The ground communication base station is equipped with two sets of airborne laser communication terminals and two microwave communication antennas, which are used to establish communication links with the UAV platforms on the forward and backward routes respectively.

[0128] (3) The ground communication base station and the mission airspace should be open and unobstructed, or the ground communication base station should be erected high enough to avoid any obstructions.

[0129] 4. Plan the flight path of the mission UAV platform based on the required communication coverage and the requirements for dealing with the impact of sunlight on laser communication;

[0130] Flight routes are planned according to communication coverage requirements:

[0131] (1) The coverage area should be the farthest point of the communication demand area, which refers to the point farthest from the launch and recovery site within the communication coverage area.

[0132] (2) The coverage of the communication demand area can be achieved by using both the forward route and the return route;

[0133] (3) For certain areas with important communication needs between ground communication base stations and the farthest point of the communication coverage demand area, a zigzag route can be adopted to ensure wide-area coverage.

[0134] (4) Cover the areas with communication coverage needs as much as possible, but whether to cover them completely depends on factors such as the importance level of communication needs, cost and feasibility.

[0135] (5) Based on the above route planning, the impact of sunlight on airborne laser communication should be avoided or reduced using the following methods: The angle between the line connecting any two points 300 km apart on the route and the sunlight should not exceed 10 degrees for more than 5 minutes during the mission (e.g., ...). Figure 2 As shown in the figure, the route distance is the distance between two points along the route trajectory. This condition can be verified by using real-time sunlight angle calculation software and continuous simulation of the UAV platform position along the route. If the route does not meet this condition, the route direction can be adjusted until the condition is met.

[0136] 5. Determine the required number of drone platforms.

[0137] (1) Planning for the number of mission-specific unmanned aerial vehicle platforms:

[0138] Based on the planned total route length and communication distance limitations between UAV platforms, determine the required number of mission UAV platforms:

[0139] n1 = ceil(l / 300)

[0140] Where l is the total length of the route, which must not exceed the maximum range of the UAV platform; otherwise, it is considered that the communication requirement area is too far away and the task cannot be completed by the selected UAV platform in the form of chain relay communication. 300km is the route distance between adjacent UAV platforms designed in the plan, taking into account the distance limitations of aerial laser communication and microwave communication. ceil is the round-up function.

[0141] (2) Planning for the number of backup drone platforms:

[0142] For every four mission-oriented UAV platforms, one backup UAV platform is prepared. This backup platform flies in the middle of the four mission-oriented platforms, with its flight path parallel to the mission-oriented platforms but offset 3 km to the right (in the forward direction). It is ready to replace any malfunctioning platform among the four. The required number of backup UAV platforms is:

[0143]

[0144] Here, % is the modulo operator.

[0145] (3) Planning for the number of redundant UAV platforms:

[0146] To address the possibility of launch failure or communication link establishment failure in the event of a mission-specific UAV platform, a 30% redundancy design is implemented for the number of UAV platforms. The required number of redundant UAV platforms is:

[0147] n3 = ceil((n1 + n2) * 0.3)

[0148] The total number of drone platforms required is:

[0149] n = n1 + n2 + n3

[0150] 6. Flight Planning

[0151] (1) Number each mission UAV platform individually: 1, 2, 3, ... n1;

[0152] (2) Number each backup drone platform individually:

[0153] (3) The mission drone platforms are launched sequentially from drone number 1;

[0154] (4) The backup drone platforms will be launched sequentially from drone B1 according to their serial numbers;

[0155] (5) When the distance between the i-th mission UAV platform and the launch and recovery site is 180 km on the forward route, launch the i+1 mission UAV platform.

[0156] (6) When i≥2 and (i-2)%4=0, when the distance between the i-th mission UAV platform and the launch and recovery site is 90km on the forward flight path, the launch of mission B begins. ((i-2)％4+1) Backup drone platform;

[0157] (7) On the forward flight path, when the distance between the mission UAV platform and the flight path to the launch and recovery site is 20 km, the altitude is gradually adjusted to the mission altitude, i.e., 6000 m altitude, within a 10 km flight range.

[0158] (8) On the forward flight path, when the distance between the backup UAV platform and the flight path to the launch and recovery site is 20 km, the altitude of the UAV platform is gradually adjusted to the mission altitude, i.e., 6000 m altitude, within a 10 km flight range.

[0159] (9) After the i+1 mission UAV platform is launched, after it successfully establishes airborne laser communication and microwave communication links with the i mission UAV platform and the ground communication base station, it begins to gradually adjust the flight path distance between itself and the i mission UAV platform until it stabilizes at 300 km.

[0160] (10) B ((i-2)％4+1) After the backup drone platform is launched, its relative position to the i-th mission drone platform is gradually adjusted until the distance between the corresponding point on the 3km left of the backup drone platform and the i-th mission drone platform is stabilized at 150km in the forward flight path.

[0161] (11) If the mission UAV platform or the backup UAV platform fails to launch, or if the mission UAV platform is 80km away from the launch and recovery site and still cannot successfully establish an airborne laser communication or microwave communication link with the previous UAV platform or ground communication base station, a redundant UAV platform will be launched to take over. The redundant UAV platform will be changed to the mission UAV platform or the backup UAV platform and will use the number of the UAV platform that failed the mission. The UAV platform that failed the mission will return in advance.

[0162] (12) After the mission UAV platform No. 1 returns to the launch and recovery site, after refueling or swapping its battery, if the communication mission is not completed, No. 1 and the subsequent UAV platforms that return one after another will launch and establish links according to the rules and methods of (5)-(11). At this time, on the forward route, No. 1 establishes links with the preceding UAV platform No. n1.

[0163] 7. Communication Planning

[0164] (1) Each mission UAV platform is equipped with two airborne laser communication terminals and two microwave communication antennas, which are responsible for establishing communication links with the previous mission UAV platform (or ground communication base station) and the next mission UAV platform (or ground communication base station), respectively.

[0165] (2) Before each mission UAV platform establishes a microwave communication and airborne laser communication link with the next mission UAV platform, it sends its position, altitude, speed and body status information to the ground communication base station in real time so that the mission UAV platform launched later can quickly establish a microwave and laser communication link with it.

[0166] (3) When the distance between the i+1 mission UAV platform and the launch and recovery site on the forward flight path is 30 km, the i-th mission UAV platform and the i+1 mission UAV platform begin to establish a communication link. That is, the i-th mission UAV platform disconnects its communication link with the ground communication base station and establishes a communication link with the i+1 mission UAV platform. At the same time, the i+1 mission UAV platform establishes a communication link with the ground communication base station. In this process, a microwave communication link establishment handover is carried out first to report each other's positions and altitudes, and then an aerial laser communication link establishment handover is carried out to reduce the scanning and acquisition time and acquisition difficulty between laser communication terminals.

[0167] (4) If, during the handover of the link establishment relationship in step (3), the i+1 mission UAV platform flies to a distance of 80km from the launch and recovery site and still cannot complete the microwave and laser communication link establishment with the i mission UAV platform and the ground communication base station, then the supplementary UAV platform will establish the microwave and laser communication link with the i mission UAV platform and the ground communication base station.

[0168] (5) When the distance between the i-th mission UAV platform and the launch and recovery site is 30km on the return route, the i-th mission UAV platform and the i+1 mission UAV platform begin the link establishment handover. That is, the i-th mission UAV platform disconnects the communication link with the i+1 mission UAV platform and the ground communication base station, exits the relay communication link, and the i+1 mission UAV platform establishes a communication link with the ground communication base station. In this process, microwave link establishment handover is carried out first to report each other's positions and altitudes, and then aerial laser communication link establishment handover is carried out to reduce the acquisition time and acquisition difficulty between laser communication terminals;

[0169] (6) There are two communication links, one for airborne laser communication and one for microwave communication, between every two adjacent UAV platforms and between the UAV platforms at the beginning and end of the flight path and the ground communication base station. When both can communicate normally, the communication load is balanced and distributed. When one communication link fails, the other link is responsible for notifying the two relevant UAV platforms that a certain communication link has failed, and coordinating the two to restart or self-test and repair the equipment in an attempt to restore the communication link;

[0170] (7) Before the communication link between the mission area and the ground communication base station is established on the return route, the information flow in the mission area is relayed back to the ground communication base station one by one through the mission UAV platform.

[0171] (8) After the communication link between the ground communication base station and the return route is established, the transmission is first carried out according to the principle of the shortest route distance from the ground communication base station. At the same time, if the traffic is detected to be close to a certain load threshold in one transmission direction, the traffic is diverted to the other transmission direction.

[0172] (9) At the end of the mission, the UAV platforms are retrieved one by one. After the communication link with the ground communication base station on the forward route is disconnected, the information flow in the mission area is relayed to the ground communication base station one by one through the mission UAV platforms on the return route.

[0173] (10) When a mission UAV platform malfunctions while performing a mission and cannot recover on its own, it shall return to the nearest route in advance, and a nearby backup UAV platform shall be adjusted to its position on the route and establish microwave and air laser communication links with the mission UAV platforms in front and behind respectively.

[0174] 8. Task process control

[0175] (1) Spacing control between mission UAV platforms

[0176] After adjacent mission UAV platforms initially adjust to a flight path distance of 300 km, they need to maintain this distance. The control method is as follows:

[0177] The flight speed of the foremost mission drone platform is controlled at 320 km / h. Each mission drone platform uses the preceding mission drone platform as a reference for spacing and speed control.

[0178] v = 320 + k(t(d) - 300)

[0179] Where k = 1.2 is the speed control coefficient, d is the flight path distance between the current mission UAV platform and the previous mission UAV platform, which can be calculated by combining the position information determined by satellite positioning or high-precision laser gyroscope with the flight path information loaded on the mission UAV platform, and v is the speed of the current mission UAV platform.

[0180]

[0181] (2) Response to the impact of sunlight

[0182] 1) When establishing an aerial laser communication link between two UAV platforms, the relevant light shields on both UAV platforms are retracted to 0cm, and the two laser communication terminals perform scanning, acquisition, tracking, and holding.

[0183] 2) When the CCD array inside the laser communication terminal on the UAV platform detects stray light images other than signal light, increase the extension length of the light shield tube until the intensity of the detected stray light returns to within the predetermined threshold, or the extension length of the light shield tube has reached the maximum length of 51.6cm.

[0184] 3) If the UAV platform fails to track and maintain the airborne laser communication terminal for the current and subsequent missions, repeat the steps in 1)-2).

[0185] 9. Recycling and Refurbishment

[0186] (1) After the UAV platform is deployed, download the flight logs and communication logs for subsequent analysis and to support planning optimization;

[0187] (2) Replace the battery or fill the tank with fuel;

[0188] (3) Reload the planned route, takeoff sequence, communication link relationship and other data to enter the go-around sequence and wait for the flight to continue.

[0189] 10. End the mission

[0190] (1) No more drone platforms will be launched, and all forward link information flow will be transferred to the return link;

[0191] (2) After the UAV platforms that have taken off have completed their flight path, they shall land in sequence. Alternatively, in special circumstances, the UAV platforms that have taken off may not need to complete the remaining flight path and may return to the launch and recovery site in sequence along the nearest route.

[0192] (3) All platforms are either stored in the database or transferred to other locations to perform tasks.

[0193] In its specific implementation, this application provides a computer storage medium and a corresponding data processing unit. The computer storage medium is capable of storing a computer program, which, when executed by the data processing unit, can run the invention's content regarding a multi-fixed-wing UAV long-range chain relay communication planning method, as well as some or all of the steps in various embodiments. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0194] Those skilled in the art will clearly understand that the technical solutions in the embodiments of the present invention can be implemented using computer programs and their corresponding general-purpose hardware platforms. Based on this understanding, the technical solutions in the embodiments of the present invention, or the parts that contribute to the prior art, can be embodied in the form of computer programs, i.e., software products. These computer program software products can be stored in a storage medium and include several instructions to cause a device containing a data processing unit (which may be a personal computer, server, microcontroller, MUU, or network device, etc.) to execute the methods described in various embodiments or certain parts of the embodiments of the present invention.

[0195] This invention provides a conceptual approach and method for planning long-range chain relay communication for multiple fixed-wing unmanned aerial vehicles (UAVs). Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for planning long-range chain relay communication for multiple fixed-wing unmanned aerial vehicles (UAVs), characterized in that, Includes the following steps: Step 1: Select the model parameters of the fixed-wing UAV according to the communication coverage requirements, and select the communication terminal it is equipped with; Step 2: Select the launch and recovery site for the fixed-wing UAV according to the communication coverage requirements, and set up a ground communication base station in a preset range near it. The base station has the capability of aerial laser communication and microwave communication. Step 3: Based on communication coverage requirements and the influence of sunlight, plan the flight path of the fixed-wing UAV and determine the total number of UAVs; Step 4: Perform flight control: Number the fixed-wing UAVs, launch them according to the set time sequence, and continuously control all UAVs until the relay communication mission ends; Step 5: Conduct relay communication: Microwave and laser dual-link communication is conducted between UAVs ahead and behind on the flight path, and between UAVs at the beginning and end of the flight path and the ground communication base station; UAVs establish link relationships at preset locations; communication data streams are split and relayed through microwave and laser communication links, as well as the forward and return flight paths. Step 6: During the relay communication mission, control the flight path spacing between adjacent UAVs and adjust the communication terminals carried by the UAVs to address the impact of sunlight on laser communication; Step 7: The relay communication task ends, and all UAVs are retrieved in sequence to complete the multi-fixed-wing UAV long-range chain relay communication. The relay communication described in step 5 is performed as follows: Step 5-1: Each mission drone carries two airborne laser communication terminals and two microwave communication antennas, which are divided into two groups. Each group includes one airborne laser communication terminal and one microwave communication antenna, which are responsible for establishing communication links with the previous mission drone or ground communication base station and the next mission drone or ground communication base station, respectively. Step 5-2, when on the forward route... When the distance between the mission drone and the flight path to the launch and recovery site is within a preset range, the [missing information] The mission drone and the The first mission drone began the handover of the link-building relationship, namely the... The mission drone disconnected its communication link with the ground communication base station and communicated with the first... The first mission drone established a communication link, and at the same time, the second... The mission drone establishes a communication link with the ground communication base station; Step 5-3, when on the return route... When the distance between the mission drone and the flight path to the launch and recovery site is within a preset range, the [missing information] The mission drone and the The first mission drone began the handover of the link-building relationship, namely the... The mission drone disconnected from the first The communication link between the mission drone and the ground communication base station was terminated, and the relay communication link was disconnected. The mission drone established a communication link with the ground communication base station; Step 5-4: There are two communication links, one for airborne laser communication and one for microwave communication, between every two adjacent mission drones and between drones at the beginning and end of the flight path and the ground communication base station. When both can communicate normally, the communication load is balanced and distributed. Step 5-5: Before the communication link between the UAV and the ground communication base station is established on the return route, the information flow in the mission area is relayed to the ground communication base station one by one by the UAVs on the forward route. Steps 5-6: After the communication link between the ground communication base station and the return route is established, the transmission is first selected according to the principle of the shortest route distance from the ground communication base station. At the same time, if the traffic in one transmission direction is detected to be close to a certain load threshold, the transmission is split to the other transmission direction.

2. The multi-fixed-wing UAV long-range chain relay communication planning method according to claim 1, characterized in that, The communication terminal mentioned in step 1 includes: Two sets of airborne laser communication terminals, two microwave communication antennas, and one wireless broadband access terminal. The effective communication range of the laser communication terminals is at least 400 km, the effective communication range of the microwave communication antennas is at least 400 km, and the effective communication range of the wireless broadband access device is at least 200 km.

3. The multi-fixed-wing UAV long-range chain relay communication planning method according to claim 2, characterized in that, The airborne laser communication terminal described in step 1 has a retractable light-shielding tube mounted on the outside of the optical terminal.

4. The multi-fixed-wing UAV long-range chain relay communication planning method according to claim 3, characterized in that, The ground communication base station mentioned in step 2 is equipped with two sets of airborne laser communication terminals and two microwave communication antennas to establish communication links with fixed-wing UAVs on the forward and backward routes, respectively.

5. The multi-fixed-wing UAV long-range chain relay communication planning method according to claim 4, characterized in that, The specific method for planning the flight path of the fixed-wing UAV in step 3 is as follows: Step 3-1: Determine the furthest point of the route coverage communication coverage requirement area; Step 3-2: The route includes a forward route and a return route; Step 3-3: Achieve wide-area coverage by adopting a zigzag flight path as required; Steps 3-4: Adjust the coverage level of the communication coverage required area; Steps 3-5: The angle between the line connecting any two points on the flight path that are 300 km apart and the sunlight shall not exceed 10 degrees for any consecutive period of time, and shall not exceed the preset duration.

6. The multi-fixed-wing UAV long-range chain relay communication planning method according to claim 5, characterized in that, The method for determining the total number of drones in step 3 is as follows: The drones include mission drones, backup drones, and redundant drones. The number of mission drones is determined based on the route length and the spacing between mission drones. For every four mission drones, there is one backup drone. The backup drone accompanies the mission drones at a preset escort distance along their route. Redundant drones are set up according to a preset ratio of the sum of the number of mission drones and the number of backup drones.

7. The multi-fixed-wing UAV long-range chain relay communication planning method according to claim 6, characterized in that, The method for performing flight control as described in step 4 is as follows: Step 4-1: Number each mission drone as follows: , Number of drones for the mission; Step 4-2: Number each standby drone individually: , Number of backup drones; Step 4-3: The mission drone platforms are launched sequentially, starting with drone number 1, according to their serial numbers. Step 4-4, Backup drone platform from The aircraft began to take off in numerical order; Steps 4-5: When on the forward route, the first When the distance between the mission drone and the launch and recovery site is 180 km, the launch of the first drone will begin. Mission drone; Steps 4-6, when ,and At that time, on the forward route, the first When the distance between the mission drone and the launch and recovery site is 90 km, the launch of the first drone will begin. No. 1 backup drone; Steps 4-7: When the distance between the mission UAV and the flight path to the launch and recovery site is 20km, gradually adjust its altitude to the preset mission altitude within a 10km flight distance. Steps 4-8: When the distance between the backup drone platform and the launch and recovery site is 20km, gradually adjust its altitude to the preset mission altitude within a 10km flight distance. Steps 4-9, the After the launch of the mission drone, it was in conjunction with the first After both the UAV and ground communication base station successfully established airborne laser and microwave communication links for the mission, adjustments were made to their connection with the mission's [unclear - likely a specific mission name]. The flight path distance between the mission drones stabilized at 300 km; Steps 4-10, the After the backup drone is launched, adjust its alignment with the first... The relative positions of the mission drones are determined until, in the forward flight path, the corresponding points on the path with a preset escort distance to their sides are determined. The flight path distance between the mission drones remained stable at 150 km; Step 4-11 If the mission drone or the backup drone fails to launch, or if the mission drone flies to a distance of 80km from the launch and recovery site and cannot successfully establish a link with the previous mission drone or ground communication base station, a redundant drone will be launched to take over. The redundant drone will be reassigned as the mission drone or the backup drone and will use the number of the failed drone. The drone that failed the mission will return in advance.

8. The multi-fixed-wing UAV long-range chain relay communication planning method according to claim 7, characterized in that, The specific method for controlling the flight path spacing between adjacent UAVs as described in step 6 is as follows: The flight speed of the mission drone at the forefront of the flight path is set to... Each mission drone uses the drone from the previous mission as a reference to control its spacing and speed. ； in, For speed control coefficient, This represents the flight path distance between the current mission drone and the drone on the previous mission. The speed of the drone currently performing the mission. This is a distance monitoring function; when it detects... The value is set to the predetermined value.

9. A method for planning long-range chain relay communication for multiple fixed-wing UAVs according to claim 8, characterized in that, The specific methods for addressing the impact of sunlight on laser communication as described in step 6 are as follows: When the two mission drones are establishing an aerial laser communication link, the sunshades on both mission drones are retracted to 0cm, and the two laser communication terminals perform scanning, acquisition, tracking and holding. When the CCD array inside the laser communication terminal on this mission detects stray light images other than signal light, the extension length of the light shield tube is increased until the intensity of the detected stray light returns to within the predetermined threshold, or until the extension length of the light shield tube has reached its maximum length.

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