Unmanned aerial vehicle three-dimensional coordinate positioning method and system based on distributed MIMO nodes

Abstract

The invention provides an unmanned aerial vehicle three-dimensional coordinate positioning method and system based on distributed MIMO nodes. The method comprises the following steps: firstly, constructing a three-dimensional space layout covering an active area of an unmanned aerial vehicle, secondly, acquiring a characteristic parameter set, then, compensating a transmitted signal according to a height fall relationship, generating a directional beam group, then, converting a multipath time delay difference value and a phase deviation correlation value in the characteristic parameter set into a three-dimensional space vector component, and finally, constructing a three-dimensional space layout covering the active area of the unmanned aerial vehicle. And finally, resolving real-time three-dimensional coordinate data of the unmanned aerial vehicle in the target airspace through a spatial overlapping relationship of the three-dimensional space vector components in the three-dimensional space layout. According to the technical scheme provided by the invention, the positioning precision and the anti-interference capability in a dynamic obstacle environment are improved, centimeter-level three-dimensional positioning is realized in a GPS-free scene, the calculation complexity and the power consumption are reduced, and light-weight deployment and stable beam coverage in a complex scene are realized.

Description

Technical Field

[0001] The present application relates to the technical field of unmanned aerial vehicles, and in particular, to a method and system for three-dimensional coordinate positioning of unmanned aerial vehicles based on distributed MIMO nodes. Background Art

[0002] With the wide application of unmanned aerial vehicles in complex three-dimensional scenarios, such as indoor warehousing logistics, urban building complex inspection, and forest vegetation monitoring, etc., their positioning technology needs to meet the requirements of multi-dimensional precise perception. In an environment without GPS signal coverage, the unmanned aerial vehicle needs to obtain three-dimensional coordinate data of height, horizontal position, and depth direction in real time to avoid dynamic obstacles (such as mobile shelves, vehicles, or trees) and complete vertical space operations (such as pipeline inspection, high-altitude equipment maintenance). At the same time, the problems of multipath interference and signal attenuation in a complex electromagnetic environment (such as high-voltage power stations, metal factories) require the positioning method to have anti-interference capabilities and low computational resource consumption characteristics to ensure the stable output of centimeter-level accurate coordinates.

[0003] The current mainstream solution for the above requirements is a positioning method that combines a generative adversarial network and a pseudo fingerprint map. This method uses a generative adversarial network to perform data enhancement on sparse base station signals, constructs a high-density three-dimensional signal fingerprint library, and combines the attitude data of the unmanned aerial vehicle's inertial sensor to dynamically correct the phase offset and height drop error of the signal propagation path. In the positioning stage, the signal features collected in real time are multi-dimensionally matched with the pseudo fingerprint map, candidate coordinate points are screened, and the final three-dimensional coordinates are output through dynamic weight fusion. This solution can achieve the positioning accuracy of a preset height in a static scenario with good base station coverage.

[0004] However, this solution has significant defects in practical applications. Firstly, it highly depends on a preset dense base station network and external sensors (such as inertial units), and it is difficult to implement in the wild or underground scenarios without base station coverage, and sensor failures will cause positioning interruptions. Secondly, signal mutations or electromagnetic interference caused by dynamic obstacles will cause the pseudo fingerprint map matching to fail, resulting in coordinate jumps or cumulative errors. In addition, the collaborative deployment and data synchronization requirements of multiple types of sensors (such as Wi-Fi, lidar) greatly increase the hardware cost and system power consumption, and it is difficult to meet the application requirements of lightweight unmanned aerial vehicles. Summary of the Invention

[0005] The present application provides a method and system for three-dimensional coordinate positioning of unmanned aerial vehicles based on distributed MIMO nodes to solve the problems in the prior art, such as limited deployment due to dependence on a dense base station network and external sensors, poor positioning stability under dynamic obstacles and electromagnetic interference, and excessive hardware complexity and power consumption in multi-device collaboration.

[0006] In a first aspect, the present application provides a method for three-dimensional coordinate positioning of unmanned aerial vehicles based on distributed MIMO nodes, including: Deploy multiple MIMO node devices on at least three different altitude planes in the target airspace in an asymmetric topology to construct a three-dimensional spatial layout covering the UAV activity area; Based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional spatial layout, through the multi-node collaborative signal transmission and reception mechanism between the MIMO node devices, obtain a set of characteristic parameters related to the three-dimensional spatial distribution in the wireless signal reflected by the UAV, where the set of characteristic parameters includes the multipath delay difference value and the phase shift correlation value; According to the height difference relationship of different altitude planes in the three-dimensional spatial layout, perform phase modulation compensation on the transmitted signals of the MIMO node devices to generate a directional beam group matching the three-dimensional spatial layout; Based on the dynamic coverage range of the directional beam group in the three-dimensional spatial layout, convert the multipath delay difference value and the phase shift correlation value in the set of characteristic parameters into three-dimensional spatial vector components; Through the spatial overlap relationship of the three-dimensional spatial vector components in the three-dimensional spatial layout, calculate the real-time three-dimensional coordinate data of the UAV in the target airspace.

[0007] Optionally, based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional spatial layout, through the multi-node collaborative signal transmission and reception mechanism between the MIMO node devices, obtain a set of characteristic parameters related to the three-dimensional spatial distribution in the wireless signal reflected by the UAV, including: Set multiple MIMO node devices to alternately transmit detection signals in the asymmetric topology according to a preset time window, and synchronously receive the multipath signals reflected by the UAV; Extract the time difference sequence of the multipath signals reflected by the same detection signal through different paths to each MIMO node, and determine the multipath delay difference value by calculating the fluctuation amplitude of adjacent time differences in the time difference sequence; Based on the phase change amount between the transmission and reception of the detection signal, extract the phase offset amount of the multipath signals received by each MIMO node device, and generate a phase shift correlation value by calculating the correlation degree between the phase offset amounts of at least two MIMO node devices on the same altitude plane; Bind the multipath delay difference value and the phase shift correlation value according to the number of the signal transmission and reception node pairs to form a set of characteristic parameters containing three-dimensional spatial distribution correlation.

[0008] Optionally, according to the height difference relationship of different altitude planes in the three-dimensional spatial layout, perform phase modulation compensation on the transmitted signals of the MIMO node devices to generate a directional beam group matching the three-dimensional spatial layout, including: Calculate the phase adjustment amount corresponding to the height difference according to the vertical height difference between the elevation plane where each MIMO node device is located and the adjacent plane; Superimpose the phase adjustment amount onto the initial phase of the signal transmitted by the MIMO node device to obtain a transmitted signal with superimposed phase adjustment; Through the synchronous transmission of multiple MIMO node devices, make the transmitted signal with superimposed phase adjustment form multiple beams with different main radiation directions in three-dimensional space. At the same time, the main lobe direction of each beam is adaptively deflected according to the height difference distribution of the asymmetric topology structure to generate a directional beam group covering the UAV activity area.

[0009] Optionally, superimposing the phase adjustment amount onto the initial phase of the signal transmitted by the MIMO node device to obtain a transmitted signal with superimposed phase adjustment includes: Determine the superimposing direction of the phase adjustment amount according to the vertical height difference between the elevation plane where each MIMO node device is located and the adjacent plane. Among them, when the MIMO node device is at the elevation plane of a preset height, the superimposing direction of the phase adjustment amount is the downward compensation direction; when the MIMO node device is at a lower elevation plane, the superimposing direction of the phase adjustment amount is the upward compensation direction; Based on the superimposing direction, decompose the phase adjustment amount into orthogonal phase components corresponding to each subcarrier in the transmitted signal, and according to the frequency distribution relationship of the subcarriers, perform point-by-point superposition of the orthogonal phase components and the initial phase to obtain the superimposed phase; Perform periodic continuity verification on the superimposed phase. When the phase difference between adjacent subcarriers exceeds the preset jump threshold, insert transition phase values between adjacent subcarriers by interpolation method to generate a transmitted signal with superimposed phase adjustment.

[0010] Optionally, through the synchronous transmission of multiple MIMO node devices, making the transmitted signal with superimposed phase adjustment form multiple beams with different main radiation directions in three-dimensional space, and at the same time, the main lobe direction of each beam is adaptively deflected according to the height difference distribution of the asymmetric topology structure to generate a directional beam group covering the UAV activity area includes: Divide the MIMO node devices into multiple height-related node groups according to the height difference distribution of each elevation plane in the asymmetric topology structure, where each node group contains at least one high-elevation plane node and one low-elevation plane node; Set a synchronous transmission time window for each node group, and sequentially trigger the transmission signals of different node groups in the preset order within the time window, so that the transmission signals of the high-elevation nodes and low-elevation nodes in the same node group form a complementary phase relationship in the space propagation path; Based on the complementary phase relationship, through the superposition effect of the downward compensation direction of high-altitude nodes and the upward compensation direction of low-altitude nodes, a main lobe direction with the height difference connection line as the deflection axis is formed in three-dimensional space; According to the real-time position feedback of the UAV activity area, dynamically adjust the triggering order of the synchronous transmission time window and the node group division rule, so that the main lobe direction of each beam deflects towards the direction of the real-time position feedback, and generate a directional beam group covering the UAV activity area.

[0011] Optionally, based on the dynamic coverage range of the directional beam group in the three-dimensional space layout, convert the multipath delay difference value and phase offset correlation value in the feature parameter set into three-dimensional space vector components, including: According to the main radiation direction of each beam in the directional beam group, establish a spatial direction projection axis corresponding to each beam, and map the multipath delay difference value according to the spatial extension length of the beam coverage area as the delay vector component along the spatial direction projection axis; Based on the phase offset correlation value of the same MIMO node device pair in adjacent beam coverage areas, calculate the projection component of the phase offset amount in the main radiation direction of the beam, and generate the phase offset vector component; Pair the delay vector components and the phase offset vector components according to the beam number to generate a pairing result, and decompose and superimpose each paired component in the pairing result along the coordinate axes of the three-dimensional space layout to generate a three-dimensional space vector component set including height, horizontal position and depth direction.

[0012] Optionally, through the spatial overlapping relationship of the three-dimensional space vector components in the three-dimensional space layout, calculate the real-time three-dimensional coordinate data of the UAV in the target airspace, including: According to the direction and amplitude of the three-dimensional space vector components, delimit a corresponding spatial extension area for each vector component in the three-dimensional space layout; Extract the coordinates of the intersection points of all vector components within the spatial extension area, and by statistically analyzing the aggregation degree and the number of consecutive occurrences of the intersection points within a preset time window, screen out a set of candidate intersection points that simultaneously meet the preset aggregation threshold and continuity conditions; Based on the height, horizontal position and depth direction coordinates of each candidate intersection point in the candidate intersection point set in the three-dimensional space layout, calculate the distribution interval of the candidate intersection points in each direction respectively, and use the median of the coordinate values within the distribution interval as the basic reference value in the current direction; According to the amplitude size of the three-dimensional space vector component corresponding to each candidate intersection point and the deviation angle between the direction and the main radiation direction of the beam, dynamically adjust the contribution weight of each candidate intersection point to the basic reference value; Perform weighted fusion on the coordinate values of all candidate intersection points after adjusting the weights in the height, horizontal position, and depth directions to generate real-time three-dimensional coordinate data of the UAV in the target airspace.

[0013] In a second aspect, the present application provides a UAV three-dimensional coordinate positioning system based on distributed MIMO nodes, including: A construction module, configured to deploy multiple MIMO node devices on at least three different altitude planes in the target airspace in an asymmetric topology structure to construct a three-dimensional space layout covering the UAV activity area; An acquisition module, configured to obtain a set of characteristic parameters related to the three-dimensional space distribution in the wireless signal reflected by the UAV through a multi-node cooperative signal transceiver mechanism between the MIMO node devices based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional space layout, where the set of characteristic parameters includes a multipath delay difference value and a phase offset correlation value; A compensation module, configured to perform phase modulation compensation on the transmitted signals of the MIMO node devices according to the height difference relationship between different altitude planes in the three-dimensional space layout to generate a directional beam group matching the three-dimensional space layout; A conversion module, configured to convert the multipath delay difference value and the phase offset correlation value in the set of characteristic parameters into three-dimensional space vector components based on the dynamic coverage range of the directional beam group in the three-dimensional space layout; A solution module, configured to calculate the real-time three-dimensional coordinate data of the UAV in the target airspace through the spatial overlap relationship of the three-dimensional space vector components in the three-dimensional space layout.

[0014] In a third aspect, an embodiment of the present application provides a computing device, including a processing component and a storage component; the storage component stores one or more computer instructions; the one or more computer instructions are used to be called and executed by the processing component to implement a method for UAV three-dimensional coordinate positioning based on distributed MIMO nodes as described in the first aspect above.

[0015] In a fourth aspect, an embodiment of the present application provides a computer storage medium storing a computer program, where when the computer program is executed by a computer, it implements a method for UAV three-dimensional coordinate positioning based on distributed MIMO nodes as described in the first aspect.

[0016] In the embodiments of the present application, multiple MIMO node devices are deployed on at least three different altitude planes in an asymmetric topology structure to construct a three-dimensional spatial layout, and a multi-node collaborative transceiver mechanism is combined to extract the multipath time-delay difference value and the phase-shift correlation value, solving the problems of insufficient signal coverage and severe multipath interference in complex terrains in the traditional solutions; through the dynamic coverage of the directional beam group and the conversion of spatial vector components, the signal characteristics are directly correlated with the three-dimensional spatial distribution, avoiding the hardware limitations of relying on external sensors or dense base stations, and at the same time using the spatial overlap relationship to calculate coordinates, significantly improving the positioning accuracy and anti-interference ability in a dynamic obstacle environment, and realizing centimeter-level three-dimensional positioning in a GPS-free scenario.

[0017] Furthermore, the phase adjustment amount is dynamically calculated according to the height difference relationship and superimposed on the transmitted signal. Through the complementary phase compensation of the high / low altitude nodes in the asymmetric topology, the main lobe direction of the beam is adaptively deflected to match the terrain distribution, solving the problem of beam energy dispersion in the traditional symmetric layout; combined with the multi-node synchronous transmission mechanism, a directional beam group with a complementary phase relationship is formed in the three-dimensional space to suppress the co-frequency interference of multipath signals and enhance the effective radiation intensity of the target signal. At the same time, by dynamically adjusting the node group division and transmission timing, the calculation complexity and power consumption are reduced, realizing lightweight deployment and stable beam coverage in complex scenarios.

[0018] These aspects or other aspects of the present application will be more clearly understood in the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 The flowchart of a method for three-dimensional coordinate positioning of an unmanned aerial vehicle based on distributed MIMO nodes provided by the present application is shown; Figure 2 The structural schematic diagram of a system for three-dimensional coordinate positioning of an unmanned aerial vehicle based on distributed MIMO nodes provided by the present application is shown; Figure 3 The structural schematic diagram of a computing device provided by the present application is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to enable those skilled in the art to better understand the solution of the present application, the following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application.

[0022] In some of the processes described in the specification, claims, and above-mentioned drawings of this application, a plurality of operations appear in a specific order. However, it should be clearly understood that these operations may not be executed in the order in which they appear herein or may be executed in parallel. The serial numbers of the operations, such as 101, 102, etc., are only used to distinguish different operations, and the serial numbers themselves do not represent any order of execution. Additionally, these processes may include more or fewer operations, and these operations may be executed sequentially or in parallel. It should be noted that the descriptions such as "first" and "second" in this text are used to distinguish different messages, devices, modules, etc., do not represent a sequence, and do not limit that "first" and "second" are of different types.

[0023] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present application.

[0024] Figure 1 The following is a flowchart of a method for three-dimensional coordinate positioning of an unmanned aerial vehicle based on distributed MIMO nodes provided for an embodiment of the present application. As Figure 1 shown, the method includes: Step 101, deploy a plurality of MIMO node devices on at least three different altitude planes in the target airspace in an asymmetric topology structure to construct a three-dimensional spatial layout covering the activity area of the unmanned aerial vehicle.

[0025] In this step, the asymmetric topology structure means that a plurality of MIMO node devices are distributed in a non-uniform and non-mirror image manner in the target airspace, and are at least distributed in three different height layers (such as the ground, low-altitude platform, high-altitude device), forming a three-dimensional network with staggered space and complementary coverage.

[0026] The different altitude planes refer to the vertical height difference layers where the node devices are deployed. For example, a ground base station (altitude 0 meters), an unmanned aerial vehicle relay platform (altitude 50 meters), and a fixed node on the top of a mountain (altitude 200 meters). The diversity of the signal propagation path is enhanced through the height difference.

[0027] The three-dimensional spatial layout refers to constructing a three-dimensional signal coverage network covering the activity area of the unmanned aerial vehicle through the asymmetric distribution of multi-altitude nodes. Its coverage range expands non-uniformly in the horizontal direction and realizes multi-layer overlap in the vertical direction through the height difference.

[0028] In this embodiment, first, according to the terrain data of the target airspace and the activity range of the drone, at least three planes with different altitudes are selected as node deployment layers; secondly, MIMO node devices are installed in each layer according to asymmetric rules, and the horizontal spacing of nodes in adjacent layers is dynamically adjusted to ensure that the signal coverage range forms an overlapping area in the vertical direction; then, the altitude coordinates of the nodes are calibrated in real time through the built-in altitude sensors and positioning modules of each node, and a three-dimensional topological map including the node position, height and coverage radius is generated; finally, the continuity of the signal coverage is verified based on the topological map. If there is a blind spot, the layout is optimized by adding nodes or adjusting the existing node spacing until the full coverage requirement of the drone activity area is met.

[0029] For example, in the power inspection scenario in mountainous areas, the target airspace is the canyon area (horizontal range 1km×1km, vertical drop 300 meters). MIMO nodes are deployed at the bottom of the canyon (0 meters above sea level), the mountainside observation station (150 meters above sea level) and the mountaintop signal tower (300 meters above sea level), with 5 nodes densely deployed at the bottom of the canyon (spacing 200 meters), 2 nodes sparsely deployed on the mountainside (spacing 500 meters), and 1 node deployed on the mountaintop. Through the height difference and horizontal asymmetric distribution of the nodes, a vertical signal coverage belt from the bottom of the canyon to the top of the mountain is formed, and by adjusting the horizontal position of the mountainside node, the signal blind spot caused by the mountain occlusion is eliminated, and finally a three-dimensional layout covering the entire canyon is constructed.

[0030] Step 102, based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional spatial layout, through the multi-node collaborative signal receiving and transmitting mechanism between the MIMO node devices, obtain a set of characteristic parameters related to the three-dimensional spatial distribution in the wireless signal reflected by the drone, and the characteristic parameter set includes a multipath delay difference value and a phase offset correlation value.

[0031] In this step, the signal coverage overlap characteristic refers to the overlapping area formed in space by MIMO node signals at different altitude planes, and its coverage range partially overlaps in the vertical and horizontal directions, which is used to enhance the distinguishability of the signal reflection path.

[0032] The multi-node cooperative signal transmission and reception mechanism refers to controlling multiple nodes to transmit detection signals alternately through preset timing and synchronously receive reflected signals, avoiding signal interference while ensuring the spatial correlation of multipath signals.

[0033] The multipath delay difference value refers to the fluctuation amplitude of the propagation time difference sequence of the same detection signal reaching each node through different reflection paths, reflecting the difference in three-dimensional spatial distance between the UAV and different nodes.

[0034] The phase offset correlation value refers to the correlation between the phase changes of the signals received by at least two nodes on the same altitude plane, which is used to characterize the spatial position change of the UAV in the vertical direction.

[0035] In this embodiment, first, based on the altitude and coverage radius data of nodes in the asymmetric topology, the transmission time window of the detection signal of each node is determined, such that the ground layer nodes transmit in odd time windows, the low-altitude layer nodes transmit in even windows, and the high-altitude layer nodes transmit in alternating intervals, ensuring that the signals do not overlap in the time domain. Secondly, each node synchronously receives the multipath signals reflected by the UAV, and according to the transmission timing and node number, the time difference sequence of the same detection signal arriving at each node through different reflection paths is separated. Then, the fluctuation amplitude of adjacent time differences in the time difference sequence is calculated to generate the multipath time delay difference value. At the same time, the phase change amount of the received signal of each node is extracted, and by calculating the correlation coefficient of the phase change amounts of two nodes in the same altitude plane, the phase offset correlation value is generated. Finally, the time delay difference value and the phase offset correlation value are bound according to the transmitting node and receiving node numbers to form a set of characteristic parameters associated with the three-dimensional space distribution.

[0036] For example, based on the three-dimensional layout of the canyon (5 nodes on the ground layer, 2 nodes on the mountainside, and 1 node on the mountaintop) constructed in step 101, the multi-node collaborative transceiver mechanism is started: the ground layer nodes sequentially transmit 5 GHz detection signals in time window 1 (0 - 10 ms), the mountainside nodes transmit in window 2 (10 - 20 ms), and the mountaintop nodes transmit in window 3 (20 - 30 ms), forming an alternating transmission timing to avoid signal interference. When the UAV flies in the canyon, the mountainside nodes synchronously receive the multipath signals of the signals transmitted by the ground layer nodes reflected by the UAV and the mountain body in window 1 (for example, the signal transmitted by ground node A reaches mountainside node B after being reflected by the UAV, with a path delay of 12 ms, while the same signal reaches mountaintop node C after diffracting around the mountain body, with a path delay of 18 ms), and separate the signals of each path according to the transmitting node number and time stamp. By statistically analyzing the fluctuation amplitude of the time differences (such as the standard deviation of 0.5 ms) of the signals of the same ground node A arriving at mountainside node B and mountaintop node C within 10 consecutive windows, the time delay difference value is generated. At the same time, the phase change amounts of the received signals of nodes B and C are extracted (phase offset of B is +30°, phase offset of C is -15°), and the correlation coefficient (0.78) between the two is calculated to generate the phase offset correlation value. Finally, the time delay difference value (0.5 ms) and the phase offset correlation value (0.78) are bound according to the signal paths (A→B, A→C) to form a set of characteristic parameters, which are used as the input for subsequent three-dimensional coordinate calculation. This process makes full use of the asymmetric deployment (dense on the ground, sparse at high altitudes) and altitude difference (0 m / 150 m / 300 m) of the nodes in step 101, and through the diversity of signal reflection paths in the height overlapping area, ensures a strong correlation between the parameters and the three-dimensional space distribution, providing a reliable data basis for dynamic positioning.

[0037] Step 103: According to the height difference relationship between different altitude planes in the three-dimensional space layout, perform phase modulation compensation on the transmission signals of the MIMO node devices to generate a directional beam group matching the three-dimensional space layout.

[0038] In this step, the height difference relationship refers to the vertical height difference between nodes on different altitude planes in Step 101 (for example, the difference between the ground layer and the mountainside layer is 150 meters, and the difference between the mountainside layer and the mountaintop layer is 150 meters), which is used to quantify the spatial potential difference between nodes.

[0039] Phase modulation compensation means dynamically adjusting the phase value of the node transmission signal according to the height difference to offset the influence of the height difference on the signal propagation path, so that the beam energy is focused on the target area.

[0040] The directional beam group refers to a set of beams with controllable main radiation directions formed in the three-dimensional space by synchronously transmitting the phase-compensated signals from multiple nodes, and its coverage range matches the terrain height distribution.

[0041] In this embodiment, first, according to the altitude coordinates of each node in the three-dimensional topology map, calculate the vertical height difference between adjacent layer nodes; secondly, convert the height difference into a phase adjustment amount and determine the compensation direction; then, decompose the phase adjustment amount into orthogonal components according to the subcarrier frequency and superimpose them point by point with the initial phase of the transmission signal to generate the compensated transmission signal; subsequently, perform a phase continuity check on the superimposed signal. If the phase jump between adjacent subcarriers exceeds the threshold, insert a transition phase value to smooth the waveform; finally, synchronously transmit the compensated signal through multiple nodes, and use the superimposed effect of downward compensation by high-altitude nodes and upward compensation by low-altitude nodes to form a multi-beam group with the height difference connection line as the deflection axis in the canyon, and the main lobe direction adaptively deflects to cover the UAV activity area.

[0042] For example, based on the three-dimensional canyon layout (5 nodes on the ground layer, 2 nodes on the mountainside, and 1 node on the mountaintop) constructed in step 101 and the characteristic parameters obtained in step 102, phase modulation compensation is implemented according to the height difference relationship between nodes: the vertical height difference between ground node A (0 m) and mountainside node B (150 m) is 150 m. Node A compensates 18° of phase upward, and node B compensates 18° of phase downward; the height difference between mountainside node B and mountaintop node C (300 m) is 150 m. Node B compensates 18° of phase upward, and node C compensates 18° of phase downward. Node A decomposes the compensation amount into I / Q orthogonal components and superimposes them on the 5 GHz subcarrier to generate an upward-focused transmission signal; node B synchronously superimposes two-way compensation components and interpolates to smooth the phase jump of the subcarrier (e.g., inserts a 10° transition value for a 40° jump); node C superimposes downward compensation to generate a mountainside coverage signal. After the three nodes transmit synchronously, the upward beam of ground node A and the downward beam of mountainside node B overlap in the middle of the canyon, and the upward beam of mountainside node B and the downward beam of mountaintop node C overlap at the top, forming a main lobe direction beam group that adaptively deflects along the canyon center line (ground → mountainside → mountaintop), penetrating the mountain occlusion area and covering the UAV inspection path.

[0043] Step 104: Based on the dynamic coverage range of the directional beam group in the three-dimensional space layout, convert the multipath delay difference value and phase offset correlation value in the set of characteristic parameters into three-dimensional space vector components.

[0044] In this step, the dynamic coverage range refers to the main lobe coverage area of the directional beam group that is adjusted in real time as the UAV moves in three-dimensional space, and its range is jointly determined by the beam radiation direction and signal strength.

[0045] The three-dimensional space vector components refer to the components obtained by mapping the multipath delay difference value and phase offset correlation value to the three-dimensional coordinate axes (height, horizontal, and depth) respectively, and are used to quantify the position offset of the UAV in space.

[0046] In this embodiment, first, according to the main radiation direction of each beam in the directional beam group, a corresponding spatial direction projection axis is established for each beam; second, the multipath delay difference value is mapped as a delay vector component along the projection axis according to the spatial extension length of the beam coverage area; then, based on the phase offset correlation value of the same MIMO node device pair in adjacent beam coverage areas, the projection component of the phase offset amount in the main radiation direction of the beam is calculated to generate a phase offset vector component; finally, the delay vector component and the phase offset vector component are paired according to the beam number, and each component is decomposed and superimposed along the three-dimensional coordinate axes through the vector synthesis rule to generate a set of three-dimensional space vector components including height, horizontal position, and depth directions.

[0047] For example, the directional beam group includes the vertical beam of ground node A (the main radiation direction is along the canyon height axis), the oblique beam of hillside node B (the main direction is along the horizontal axis), and the downward beam of mountaintop node C (the main direction is along the depth axis). The multipath delay difference value (0.5 ms) between ground node A and hillside node B in step 102 is mapped to the height axis component according to the vertical beam coverage height, and the phase offset correlation value (0.78) generates the horizontal axis component according to the horizontal projection of the oblique beam; at the same time, the delay difference value (0.3 ms) between hillside node B and mountaintop node C is mapped to the depth axis component, and the phase correlation value (0.65) is projected onto the horizontal axis. The height, horizontal, and depth components are superimposed through the vector synthesis rule to generate the three-dimensional space vector of the UAV in the canyon (such as height +150 m, horizontal displacement +20 m, depth -30 m), providing input for the coordinate calculation in step 105. This process directly correlates the signal features with the spatial position through the dynamic mapping of the beam direction and characteristic parameters, eliminating the coordinate offset error caused by terrain occlusion.

[0048] Step 105, calculate the real-time three-dimensional coordinate data of the UAV in the target airspace through the spatial overlap relationship of the three-dimensional space vector components in the three-dimensional space layout.

[0049] In this step, the spatial overlap relationship means that there is partial overlap in the coverage areas of the three-dimensional space vector components in the three-dimensional layout, and the overlapping area is the candidate solution area for the UAV position.

[0050] The real-time three-dimensional coordinate data refers to the accurate coordinate values of the current position of the UAV in the height, horizontal displacement, and depth directions output through the spatial overlap calculation.

[0051] In this embodiment, first, according to the direction and amplitude of the three-dimensional space vector components, a corresponding spatial extension area is delimited for each component in the three-dimensional layout; secondly, the intersection coordinates of the spatial extension areas of all vector components are extracted; then, the aggregation degree and the number of consecutive occurrences of each intersection within a preset time window are counted, and a candidate intersection set that simultaneously meets the aggregation threshold and continuity conditions is selected; subsequently, based on the distribution intervals of the candidate intersections in the height, horizontal, and depth directions, the median of the coordinate values in each direction is taken as the basic reference value; then, according to the amplitude of the vector component corresponding to the candidate intersection and the deviation angle between the direction and the main radiation direction of the beam, the weight is dynamically adjusted; finally, the weighted candidate intersection coordinates in all directions are fused to generate the real-time three-dimensional coordinate data of the UAV.

[0052] For example, based on the three-dimensional space vector components (height +150m, horizontal +20m, depth -30m), the coverage areas of each component are delimited (height 100 - 200m, horizontal 0 - 40m, depth -50 to -10m), and the intersection point is extracted as (150m, 20m, -30m); it is statistically found that this intersection point appears 8 times within 10 seconds and continuously appears in 3 windows, meeting the threshold conditions; the distribution intervals in each direction are calculated (height 140 - 160m, horizontal 15 - 25m, depth -25 to -35m), and the median value is taken to obtain the basic reference value (150m, 20m, -30m); according to the vector component amplitudes (height 0.5, horizontal 0.3, depth 0.2) and the deviation angles (horizontal 10°, depth 5°), weights are assigned (height 0.6, horizontal 0.3, depth 0.1); after weighted fusion, the real-time coordinates (150m, 19.8m, -30.2m) are output; coordinate jumps caused by mountain reflection interference are suppressed through dynamic weights, achieving centimeter-level positioning accuracy in complex terrains.

[0053] In order to improve the accuracy of extracting the correlation between the multipath time delay difference value and the phase shift in the three-dimensional space distribution characteristics, in some embodiments, as described in step 102, based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional space layout, through the multi-node cooperative signal transmission and reception mechanism between the MIMO node devices, a set of characteristic parameters related to the three-dimensional space distribution in the wireless signals reflected by the unmanned aerial vehicle is obtained, including: Step 201, by setting multiple MIMO node devices to alternately transmit detection signals in a non-symmetric topological structure according to a preset time window, and synchronously receive the multipath signals reflected by the unmanned aerial vehicle.

[0054] In this step, alternately transmitting according to the preset time window means that multiple MIMO nodes transmit detection signals in time slots according to the pre-allocated time sequence, avoiding signal interference and ensuring that the receiving end can distinguish the reflection paths of different nodes.

[0055] The synchronous reception mechanism means that all nodes start signal capture simultaneously based on a unified clock or trigger signal during the reception phase, ensuring that the propagation time difference of the multipath signals can be accurately measured.

[0056] In this embodiment, first, according to the altitude distribution and coverage range of the nodes in the non-symmetric topology, independent transmission time windows are allocated to the nodes on different altitude planes; secondly, in the transmission phase, each node sequentially transmits detection signals with specific codes according to the allocated windows and records the transmission timestamps; in the reception phase, all nodes synchronously start the reception module after the window ends, capture the multipath signals reflected by the unmanned aerial vehicle and the environment, and separate the reflection signals of different nodes according to the coding characteristics; finally, the signals received by each node are aligned with the transmission timestamps to generate an original data set containing path propagation time, signal strength, and phase information.

[0057] Step 202: Extract the time difference sequence of the multipath signals of the same detection signal reflected to each MIMO node through different paths, and determine the multipath time delay difference value by calculating the fluctuation amplitude of adjacent time differences in the time difference sequence.

[0058] In this step, the time difference sequence refers to the set of propagation time differences of the same detection signal arriving at each node through different reflection paths, arranged in sequence according to the signal transmission order.

[0059] The fluctuation amplitude refers to the cumulative amount of absolute differences between adjacent time differences in the time difference sequence, used to quantify the stability of the reflection path.

[0060] In this embodiment, first, extract all the time differences of the reflection paths of the same detection signal from the original dataset; second, arrange the time differences in sequence according to the signal transmission order; then, calculate the fluctuation amplitude of adjacent time differences; finally, statistically analyze the fluctuation amplitudes of consecutive N windows to generate the multipath time delay difference value reflecting the path stability, and bind this value to the signal transceiver node pair.

[0061] Step 203: Based on the phase change amount of the detection signal between transmission and reception, extract the phase offset amount of each MIMO node device receiving the multipath signal, and generate a phase offset correlation value by calculating the correlation degree between the phase offset amounts of at least two MIMO node devices on the same elevation plane.

[0062] In this step, the phase change amount refers to the phase difference caused by the difference in propagation path length or environmental disturbance during the process of the detection signal from transmission to reception.

[0063] The phase offset correlation degree refers to the statistical correlation between the phase offset amounts of the signals received by at least two nodes on the same elevation plane, used to characterize the position consistency of the UAV on this plane.

[0064] In this embodiment, first, extract the phase offset amount of each node receiving the multipath signal from the received signal, that is, the phase difference between the transmitted signal and the received signal; second, calculate the covariance or correlation coefficient of the phase offset amount sequences of at least two nodes on the same elevation plane to generate the phase offset correlation value; finally, bind the correlation value to the corresponding node pair as a quantization index for the position change of the UAV in the vertical direction.

[0065] Step 204: Bind the multipath time delay difference value and the phase offset correlation value according to the number of the signal transceiver node pair to form a set of characteristic parameters including three-dimensional space distribution correlation.

[0066] In this step, the signal transceiver node pair number refers to the unique combination identifier of the transmitting node and the receiving node, used to distinguish different signal propagation paths.

[0067] The three-dimensional spatial distribution correlation means that the time delay difference value and the phase correlation value jointly reflect the spatial distribution characteristics of the UAV in the height, horizontal, and depth directions.

[0068] In this embodiment, first, for each signal transceiver node pair; second, bind the generated time delay difference value and the generated phase offset correlation value according to the number to form a parameter group including path propagation characteristics and spatial correlation; finally, integrate the parameter groups of all node pairs according to the node position relationship in the three-dimensional layout into a feature parameter set.

[0069] To solve the problem of signal energy dispersion caused by the mismatch between the beam direction and the height difference in the asymmetric terrain, in some embodiments, according to what is described in step 103, based on the height difference relationship between different altitude planes in the three-dimensional layout, perform phase modulation compensation on the transmitted signal of the MIMO node device to generate a directional beam group matching the three-dimensional layout, including: Step 301, calculate the phase adjustment amount corresponding to the height difference according to the vertical height difference between the altitude plane where each MIMO node device is located and the adjacent plane.

[0070] In this step, the phase adjustment amount refers to the phase compensation value calculated according to the vertical height difference between nodes in adjacent altitude planes, which is used to offset the signal propagation path difference caused by the height difference, and its direction is determined by the altitude of the node (compensation downward for high altitude and upward for low altitude).

[0071] In this embodiment, first, based on the altitude coordinates of each node in the three-dimensional layout, calculate the vertical height difference between nodes in adjacent planes; second, calculate the phase adjustment amount through the height difference and a preset phase adjustment coefficient; then, determine the compensation direction according to the height relationship of the plane where the node is located - downward compensation for high altitude nodes and upward compensation for low altitude nodes; finally, decompose the phase adjustment amount into mutually perpendicular phase components according to the subcarrier frequency to ensure the continuity and consistency of phase compensation for different frequency subcarriers.

[0072] Step 302, superimpose the phase adjustment amount onto the initial phase of the transmitted signal of the MIMO node device to obtain the transmitted signal with superimposed phase adjustment.

[0073] In this step, the initial phase refers to the original phase value of the transmitted signal of the MIMO node without adjustment, which is generated by the signal generator according to a preset waveform.

[0074] Superimposing phase adjustment means arithmetically superimposing the phase adjustment amount and the initial phase to form a compensated phase waveform.

[0075] In this embodiment, first, the phase adjustment amount is decomposed into orthogonal phase components corresponding to the subcarrier frequencies of the transmitted signal; second, the initial phase of each subcarrier is incrementally added point by point; then, the phase jumps between adjacent subcarriers after the addition are detected, and if they exceed a preset threshold, interpolation is used to insert transition phase values at the jump points to ensure the continuity of the signal waveform; finally, the adjusted orthogonal components are synthesized into a time-domain signal to generate a transmitted signal with superimposed phase adjustment.

[0076] Step 303: Through the synchronous transmission of multiple MIMO node devices, the transmitted signal with superimposed phase adjustment forms multiple beams with different main radiation directions in three-dimensional space. At the same time, the main lobe directions of each beam are adaptively deflected according to the height difference distribution of the asymmetric topology to generate a directional beam group covering the activity area of the UAV.

[0077] In this step, the adaptive deflection of the main radiation direction means that the radiation direction with the strongest beam energy is dynamically adjusted according to the height difference relationship of the nodes in the asymmetric topology to match the terrain features and the UAV activity path.

[0078] In this embodiment, first, according to the height difference distribution of the asymmetric topology, the nodes are divided into multiple associated groups; second, an independent synchronous transmission time window is set for each group, and the nodes within the group are triggered to synchronously transmit the phase-adjusted signal in sequence; then, through the superposition of the downward compensation signal of the high-altitude nodes and the upward compensation signal of the low-altitude nodes within the group on the spatial propagation path, a main lobe direction with the height difference connection line as the deflection axis is formed; finally, according to the real-time position feedback of the UAV, the division rule of the node group and the triggering order of the transmission window are dynamically adjusted to deflect the main lobe direction of the beam towards the target area to generate a directional beam group covering the UAV activity path.

[0079] To improve the continuity of phase adjustment superposition and signal stability, in some embodiments, according to what is described in step 302, superimposing the phase adjustment amount on the initial phase of the transmitted signal of the MIMO node device to obtain a transmitted signal with superimposed phase adjustment includes: Step 401: Determine the superimposing direction of the phase adjustment amount according to the vertical height difference between the elevation plane where each MIMO node device is located and the adjacent plane. Among them, when the MIMO node device is in the elevation plane at a preset height, the superimposing direction of the phase adjustment amount is the downward compensation direction; when the MIMO node device is in a lower elevation plane, the superimposing direction of the phase adjustment amount is the upward compensation direction.

[0080] In this step, the superimposing direction of the phase adjustment amount refers to determining the increasing or decreasing direction of the phase compensation amount according to the height relationship of the elevation planes where the nodes are located, which is used to offset the signal propagation path difference caused by the height difference.

[0081] The downward compensation direction means that when the node is at the elevation plane of the preset height, the phase adjustment amount aims to reduce the equivalent phase delay of the signal propagation path, and the compensation direction is downward.

[0082] The upward compensation direction means that when the node is at a lower elevation plane, the phase adjustment amount aims to increase the coverage ability of the signal in the high-altitude area, and the compensation direction is upward.

[0083] In this embodiment, first, obtain the elevation plane data of each node in the three-dimensional space layout; second, compare the vertical height difference between each node and its adjacent plane nodes; then, determine the phase adjustment direction according to the height relationship of the plane where the node is located - if the node is at the plane of the preset height, the superposition direction is downward compensation; if the node is at a lower plane, the superposition direction is upward compensation; finally, decompose the phase adjustment amount into the orthogonal components of the corresponding transmitted signal subcarriers to ensure the phase superposition continuity and direction consistency of different frequency subcarriers.

[0084] Step 402: Based on the superposition direction, decompose the phase adjustment amount into the orthogonal phase components of each subcarrier in the transmitted signal, and according to the frequency distribution relationship of the subcarriers, perform point-by-point superposition of the orthogonal phase components and the initial phase to obtain the superposed phase.

[0085] In this step, the orthogonal phase component refers to decomposing the phase adjustment amount into two mutually perpendicular phase components, which are used to independently adjust the phase offsets in different directions during signal modulation.

[0086] The frequency distribution relationship of the subcarriers refers to the frequency interval and arrangement rule of each subcarrier in the transmitted signal, which determines the frequency weight allocation method of the orthogonal components.

[0087] Point-by-point superposition means separately superposing the orthogonal components on the initial phase of each subcarrier to ensure the independent and continuous phase adjustment of different frequency points.

[0088] In this embodiment, first, decompose the phase adjustment amount into horizontal and vertical components according to the determined superposition direction; second, allocate the weights of the orthogonal components according to the frequency distribution of the subcarriers from low to high; then, separately superpose the horizontal and vertical components on the initial phase of each subcarrier to generate the adjusted phase value; finally, detect the phase jump amplitude between adjacent subcarriers, and if it exceeds the threshold, insert a transition phase value to smooth the signal waveform.

[0089] Step 403: Perform periodic continuity verification on the superposed phase. When the phase difference between adjacent subcarriers exceeds the preset jump threshold, insert a transition phase value between the adjacent subcarriers by interpolation to generate the transmitted signal after superposed phase adjustment.

[0090] In this step, the periodic continuity check means sequentially detecting whether the phase difference between adjacent subcarriers exceeds a preset jump threshold in the order of subcarrier frequencies. If it exceeds, it is determined as a phase mutation point.

[0091] The transition phase value refers to the intermediate phase value inserted between phase mutation points, which is used to eliminate the signal waveform distortion caused by the jump and ensure the time-domain continuity of the transmitted signal.

[0092] In this embodiment, first, scan the superimposed phase data in the order of increasing subcarrier frequencies from low to high; second, calculate the absolute value of the phase difference between adjacent subcarriers. If it exceeds the jump threshold, mark it as a mutation point; then, insert transition phase values between the mutation points by interpolation to reduce the phase difference between adjacent subcarriers within the threshold; finally, convert the phase sequence with inserted transition values into a time-domain signal waveform to generate a smooth and continuous transmitted signal.

[0093] To solve the problem of beam coverage blind areas in dynamic scenarios, in some embodiments, as described in step 303, through the synchronous transmission of multiple MIMO node devices, the transmitted signal after superimposed phase adjustment forms multiple beams with different main radiation directions in three-dimensional space. At the same time, the main lobe directions of each beam are adaptively deflected according to the height difference distribution of the asymmetric topological structure, generating a directional beam group covering the activity area of the unmanned aerial vehicle, including: Step 501, divide the MIMO node devices into multiple height-related node groups according to the height difference distribution of each elevation plane in the asymmetric topological structure, where each node group contains at least one high-elevation plane node and one low-elevation plane node.

[0094] In this step, the height-related node group refers to combining node pairs into pairs containing high / low elevation nodes according to the height difference relationship between adjacent elevation plane nodes in the asymmetric topology to achieve complementary phase compensation.

[0095] In this embodiment, first, based on the three-dimensional topological map generated in step 101, extract the height differences between adjacent elevation plane nodes; second, divide the nodes on the same vertical height difference connection line into associated groups to ensure that each group contains at least one high-elevation node and one low-elevation node; finally, assign a unique identifier to each associated group (for example, group G1 contains A - B, group G2 contains B - C), and record the elevation coordinates and coverage areas of the nodes within the group.

[0096] Step 502, set a synchronous transmission time window for each node group, and sequentially trigger the transmission signals of different node groups within the time window in a preset order, so that the transmission signals of the high-elevation nodes and low-elevation nodes within the same node group form a complementary phase relationship on the spatial propagation path.

[0097] In this step, the synchronous transmission time window refers to an independent transmission period allocated to each node group, which avoids signal interference between different groups and ensures synchronous transmission of nodes within the group.

[0098] The complementary phase relationship means that after the phase adjustment amounts of downward compensation by high-altitude nodes and upward compensation by low-altitude nodes within the group are spatially superimposed, a phase alignment effect with the same main lobe direction of the beam is formed.

[0099] In this embodiment, first, according to the coverage priority of the node groups (for example, if the UAV activity area is close to the mountainside, group G1 has a higher priority), time window 1 (0 - 10 ms) is allocated to group G1, and window 2 (10 - 20 ms) is allocated to group G2. Secondly, within window 1, the nodes in group G1 are triggered to synchronously transmit the phase-adjusted signals, so that the two signals are superimposed in the middle of the canyon to form a vertical beam. Within window 2, group G2 is triggered to synchronously transmit to form an oblique beam. Finally, according to the real-time position of the UAV, the window trigger order is dynamically adjusted (for example, when the UAV approaches the mountaintop, group G2 is triggered first), so that the main lobe direction of the beam adaptively tracks the target area.

[0100] Step 503, based on the complementary phase relationship, through the superimposing effect of the downward compensation direction of high-altitude nodes and the upward compensation direction of low-altitude nodes, a main lobe direction with the vertical height difference connection line as the deflection axis is formed in three-dimensional space.

[0101] In this step, the complementary phase relationship refers to the phase superimposing effect of the downward compensation signal of high-altitude nodes and the upward compensation signal of low-altitude nodes within the same node group on the spatial propagation path, and their interaction makes the beam energy focus in a specific direction.

[0102] The vertical height difference connection line refers to the vertical spatial connection line between high-altitude nodes and low-altitude nodes within the node group, which serves as the deflection reference axis of the main lobe direction of the beam.

[0103] In this embodiment, first, according to the node groups divided in step 501, the vertical height difference connection line within the group is extracted (A→B, with a vertical height difference of 150 meters). Secondly, through the phase adjustment rules of steps 401 and 402, the compensation signals of the nodes within the group are synchronously transmitted. Then, on the spatial propagation path, the upward compensation signal of A and the downward compensation signal of B are superimposed on the vertical height difference connection line (A→B) to form a phase-aligned main lobe direction (vertically upward). Finally, according to the real-time position of the UAV, the node group trigger order is dynamically adjusted, so that the main lobe direction deflects along different vertical height difference connection lines (such as B→C) to cover the target area.

[0104] Step 504: According to the real-time position feedback of the UAV's activity area, dynamically adjust the trigger order of the synchronous transmission time window and the node group division rule, so that the main lobe direction of each beam deflects towards the direction of the real-time position feedback, and generate a directional beam group covering the UAV's activity area.

[0105] In this step, the dynamic adjustment mechanism refers to optimizing the node group trigger order and grouping rule in real time according to the UAV position change, so that the main lobe direction of the beam deflects adaptively towards the target area.

[0106] In this embodiment, first, receive the real-time coordinates of the UAV output in step 105 and determine its covered area; secondly, if the target area is at the coverage edge of the currently activated node group (for example, group G1 covers the middle), re-divide the node group (for example, merge the mountainside node B and the mountaintop node C into a new group G2'), and give priority to triggering the transmission window of the new group; if the target area is within the coverage range of the existing group, adjust the trigger order (for example, extend the window duration of group G1); then, according to the new grouping or trigger order, synchronously transmit the compensation signal, so that the main lobe direction of the beam deflects along the new height difference connection line (such as the B→C connection line); finally, continuously monitor the UAV position change, and loop to execute the above adjustment logic to ensure that the beam group always covers the target area.

[0107] In order to improve the mapping accuracy of the time delay difference and phase offset to the three-dimensional space vector, in some embodiments, according to step 104, based on the dynamic coverage range of the directional beam group in the three-dimensional space layout, convert the multipath time delay difference value and phase offset correlation value in the feature parameter set into three-dimensional space vector components, including: Step 601: According to the main radiation direction of each beam in the directional beam group, establish a spatial direction projection axis corresponding to each beam, and map the multipath time delay difference value to a time delay vector component along the spatial direction projection axis according to the spatial extension length of the beam coverage area.

[0108] In this step, the multipath time delay difference value refers to the time difference of the same signal propagating to the receiving end through different scattering paths, reflecting the spatial diversity characteristics of the propagation path.

[0109] The spatial extension length refers to the effective coverage distance of the beam in a specific main radiation direction, which is comprehensively determined by the beam width, transmission power and environmental attenuation.

[0110] In this embodiment, first, a set of directional beams is generated through the beamforming algorithm of the MIMO node device, and the main radiation direction of each beam is determined by the phase control of the antenna array. Secondly, the multi-path delay difference value is extracted through the channel estimation algorithm. Combining with the spatial extension length of the beam coverage area, the geometric mapping model is used to convert the delay difference value into a normalized displacement amount along the projection axis. For example, the delay difference value of the vertical beam is converted into a displacement component on the height axis through geometric relations, and the horizontal beam difference value is converted into a horizontal axis component. Finally, the delay vector components of all beams are classified and integrated according to the projection axis to form a multi-dimensional delay feature set, which is used as the quantization input of the spatial position offset.

[0111] Step 602: Based on the phase offset correlation value of the same MIMO node device pair in the adjacent beam coverage area, calculate the projection component of the phase offset amount on the main radiation direction of the beam, and generate a phase offset vector component.

[0112] In this step, the phase offset correlation value refers to the phase difference of the received signals of the same MIMO node device pair in the adjacent beam coverage area, which reflects the spatial correlation of the signal propagation path.

[0113] The projection component refers to the directional quantization value obtained by decomposing the phase offset amount along the main radiation direction of the beam, which is used to evaluate the distribution of phase consistency on the spatial axis.

[0114] In this embodiment, first, the phase difference of the signals in the adjacent beam coverage area is extracted through a coherent receiver to generate a phase offset correlation value. Secondly, based on the spatial angle of the main radiation direction of the beam, the geometric projection algorithm is used to decompose the phase offset correlation value to the corresponding projection axis. For example, the phase offset value of the vertical beam is projected onto the height axis through the elevation angle, and the phase offset value of the horizontal beam is projected onto the horizontal axis through the azimuth angle. Subsequently, the projection components are normalized to eliminate the amplitude difference between the beams, and are bound to the delay vector components generated in step 601 according to the same projection axis to form a multi-dimensional space vector set that fuses delay and phase features.

[0115] Step 603: Pair the delay vector components and the phase offset vector components according to the beam number to generate a pairing result. Decompose and superimpose each paired component in the pairing result along the coordinate axes of the three-dimensional space layout to generate a set of three-dimensional space vector components including height, horizontal position, and depth directions.

[0116] In this step, the pairing result refers to a set in which the delay vector components corresponding to the same beam number are associated with the phase offset vector components one by one, ensuring the mapping consistency of the two in the spatial direction.

[0117] The vector synthesis rule refers to the principle of decomposition and superposition based on a three-dimensional coordinate system. Vector operations are performed on the paired components along the coordinate axes to generate a spatial displacement quantity that integrates multi-dimensional features.

[0118] The coordinate axes of the three-dimensional spatial layout refer to a three-dimensional orthogonal coordinate system extended from the projection axes defined in step 601, including height, horizontal position, and depth directions, and are used for the global calculation of spatial vectors.

[0119] In this embodiment, first, the time-delay vector component and the phase-offset vector component are matched by beam numbers, and fast pairing is achieved using a hash table or database indexing to ensure data association of the same beam. Secondly, according to the definition of the coordinate axes of the three-dimensional spatial layout, a vector decomposition algorithm is used to orthogonally project each paired component along the coordinate axes. For example, the paired components of the oblique beam are decomposed to the height, horizontal, and depth axes through direction cosines. Subsequently, based on the principle of linear superposition, the projection components on each axis are accumulated to generate a set of three-dimensional spatial vector components including height, horizontal position, and depth directions. Finally, normalization and weight assignment are performed on the synthesized vector set to suppress noise interference and highlight the dominant displacement direction.

[0120] To solve the problem of cumulative errors in coordinate calculation in the overlapping area of multi-source signals, in some embodiments, according to step 105, the real-time three-dimensional coordinate data of the UAV in the target airspace is calculated through the spatial overlapping relationship of the three-dimensional spatial vector components in the three-dimensional spatial layout, including: Step 701: Define a corresponding spatial extension area for each vector component in the three-dimensional spatial layout according to the direction and amplitude of the three-dimensional spatial vector components.

[0121] In this step, the spatial extension area refers to a three-dimensional spatial range defined based on the direction and amplitude of the three-dimensional spatial vector components, representing the boundary of the physical area that the vector component may affect.

[0122] The direction and amplitude refer to the directivity and intensity of the vector component and are used to define the geometric shape of the extension area.

[0123] The spatial layout matching rule refers to mapping the direction and amplitude of the vector component to the corresponding spatial area according to the geometric relationship of the three-dimensional coordinate system.

[0124] In this embodiment, first, the three-dimensional space vector components are orthogonally decomposed along the height axis (Z), the horizontal axis (X), and the depth axis (Y) through a vector decomposition algorithm, and the directions and amplitudes of each component are extracted. Secondly, a geometric model of the spatial extension region is defined according to the direction and amplitude: the vertical direction component (Z-axis) is mapped to a vertical columnar region (the height range is determined by the amplitude), and the horizontal direction components (X / Y-axis) are mapped to a fan-shaped or rectangular region (the span is determined by the amplitude). For example, the larger the amplitude of the height axis component, the longer the corresponding vertical columnar region extends along the Z-axis; the larger the amplitude of the horizontal component, the wider the coverage angle of its fan-shaped region. Finally, through a three-dimensional space index, the extension regions of all vector components are bound to the physical space coordinates to generate a spatial region mapping table.

[0125] Step 702: Extract the coordinates of the intersection points of all vector components within the spatial extension region, and screen out a set of candidate intersection points that simultaneously meet the preset aggregation threshold and continuity condition by statistically analyzing the aggregation degree and the number of consecutive occurrences of the intersection points within a preset time window.

[0126] In this step, the set of candidate intersection points refers to the set of intersection points of the spatial extension regions of different vector components in three-dimensional space, which represents the possible candidate positions of the UAV.

[0127] The aggregation degree refers to the spatial distribution density of the intersection points within a preset time window, which reflects the stability of the position solution.

[0128] The continuity condition refers to the number threshold of consecutive occurrences of the intersection points at the same position, which is used to exclude false positioning points caused by instantaneous interference.

[0129] In this embodiment, first, the coordinates of the intersection points of the spatial extension regions of all vector components are extracted through spatial geometric calculations, and a computational geometry algorithm is used to quickly identify potential intersection points in three-dimensional space. Secondly, a sliding time window statistical method is adopted to perform density clustering analysis on the intersection points within a preset time period, and high-density aggregation regions are screened out through clustering algorithms such as DBSCAN, and the number of consecutive occurrences of each clustering center point is counted. For example, if an intersection point appears in the same clustering region in three consecutive time windows, it is considered to meet the continuity condition. Finally, the intersection points that simultaneously meet the aggregation threshold and the continuity condition (such as the number of consecutive occurrences meets the standard) are included in the candidate set and output to the positioning decision module.

[0130] Step 703: Based on the height, horizontal position, and depth direction coordinates of each candidate intersection point in the three-dimensional space layout in the set of candidate intersection points, calculate the distribution intervals of the candidate intersection points in each direction respectively, and use the median of the coordinate values within the distribution interval as the basic reference value in the current direction.

[0131] In this step, the distribution range refers to the range of coordinate values of candidate intersection points in a certain direction, reflecting the possible fluctuation boundaries of the UAV position in this dimension.

[0132] The basic reference value refers to the reference position determined by statistically calculating the median of the coordinate values within the distribution range, and is used to characterize the stable position solution in this direction.

[0133] In this embodiment, first, the three-dimensional coordinates of each intersection point in the candidate intersection point set are separated in the height (Z), horizontal (X), and depth (Y) directions to respectively form coordinate data sets in each direction. Secondly, the data sets in each direction are sorted, the minimum and maximum values of their distribution ranges are calculated, and the median is extracted as the basic reference value in this direction. For example, the median of the horizontal direction coordinate data set corresponds to the most stable position of the UAV on the horizontal plane, and the median of the height direction corresponds to the reference height for vertical hovering. Finally, the basic reference values in the three directions are combined into three-dimensional reference coordinates as the initial reference points for subsequent weight adjustment.

[0134] Step 704: Dynamically adjust the contribution weights of each candidate intersection point to the basic reference value according to the magnitude of the three-dimensional space vector component corresponding to each candidate intersection point and the deviation angle between the direction and the main radiation direction of the beam.

[0135] In this step, the contribution weight refers to the influence coefficient of the candidate intersection point on the basic reference value, which is jointly determined by the magnitude of the vector component and the deviation angle.

[0136] The deviation angle refers to the angle between the direction of the vector component corresponding to the candidate intersection point and the main radiation direction of the beam, reflecting the deviation degree of the signal propagation path.

[0137] In this embodiment, first, calculate the magnitude of the vector component corresponding to each candidate intersection point and the deviation angle between its direction and the main radiation direction of the beam. Secondly, design a weight function based on the inverse relationship between the magnitude and the deviation angle: the candidate intersection point with a larger magnitude and a smaller deviation angle has a higher contribution weight.

[0138] Step 705: Perform weighted fusion on the coordinate values of all candidate intersection points after adjusting the weights in the height, horizontal position, and depth directions to generate real-time three-dimensional coordinate data of the UAV in the target airspace.

[0139] In this step, weighted fusion refers to performing a weighted average operation on the three-dimensional coordinates of different candidate intersection points according to the contribution weights to generate a comprehensive position solution with high confidence.

[0140] The real-time three-dimensional coordinate data refers to the spatial position information output after fusing the weighted results in the height, horizontal, and depth directions, characterizing the real-time dynamic position of the UAV in the target airspace.

[0141] In this embodiment, first, the adjusted candidate intersection weights in step 704 are separated in the height (Z), horizontal (X), and depth (Y) directions, and the weighted average value in each direction is calculated respectively. For example, the X coordinates of all candidate intersections in the horizontal direction are multiplied by their weights and then accumulated, and then divided by the total weight sum to obtain the X-axis coordinate after weighted fusion. Secondly, the weighted results in the three directions are normalized to ensure the physical space consistency of the coordinate values. Subsequently, the weighted coordinates in the height, horizontal, and depth directions are combined into real-time three-dimensional coordinate data and dynamically updated through a time window. Finally, the real-time coordinate data is input into the UAV navigation control system for trajectory planning, obstacle avoidance, or task execution.

[0142] Figure 2 The structure diagram of a UAV three-dimensional coordinate positioning system based on distributed MIMO nodes provided by an embodiment of the present application is as Figure 2 shown. The system includes: A construction module, configured to deploy a plurality of MIMO node devices on at least three different altitude planes in the target airspace in an asymmetric topological structure to construct a three-dimensional space layout covering the UAV activity area; An acquisition module, configured to obtain a set of characteristic parameters related to the three-dimensional space distribution in the wireless signal reflected by the UAV through a multi-node collaborative signal transceiver mechanism between the MIMO node devices based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional space layout, where the set of characteristic parameters includes a multipath delay difference value and a phase offset correlation value; A compensation module, configured to perform phase modulation compensation on the transmitted signals of the MIMO node devices according to the height difference relationship between different altitude planes in the three-dimensional space layout to generate a directional beam group matching the three-dimensional space layout; A conversion module, configured to convert the multipath delay difference value and the phase offset correlation value in the set of characteristic parameters into three-dimensional space vector components based on the dynamic coverage range of the directional beam group in the three-dimensional space layout; A solution module, configured to calculate the real-time three-dimensional coordinate data of the UAV in the target airspace through the spatial overlap relationship of the three-dimensional space vector components in the three-dimensional space layout.

[0143] Figure 2 The described UAV three-dimensional coordinate positioning system based on distributed MIMO nodes can execute Figure 1For a UAV three-dimensional coordinate positioning method based on distributed MIMO nodes described in the illustrated embodiment, its implementation principle and technical effects will not be elaborated further. For a UAV three-dimensional coordinate positioning system based on distributed MIMO nodes in the above embodiment, the specific manners in which each module and unit perform operations have been described in detail in the embodiment related to this method, and will not be elaborated herein.

[0144] In a possible design, Figure 2 A UAV three-dimensional coordinate positioning system based on distributed MIMO nodes in the illustrated embodiment can be implemented as a computing device, such as Figure 3 as shown, this computing device may include a storage component 31 and a processing component 32; The storage component 31 stores one or more computer instructions, wherein the one or more computer instructions are called and executed by the processing component 32.

[0145] The processing component 32 is used for the Figure 1 UAV three-dimensional coordinate positioning method based on distributed MIMO nodes in the above

[0146] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A three-dimensional coordinate positioning method for drones based on distributed MIMO nodes, characterized in that Including: Deploy multiple MIMO node devices on at least three different altitude planes of the target airspace in an asymmetric topology to construct a three-dimensional spatial layout covering the UAV activity area; Based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional spatial layout, through the multi-node cooperative signal transceiver mechanism between the MIMO node devices, obtain a set of characteristic parameters related to the three-dimensional spatial distribution in the wireless signal reflected by the UAV, and the set of characteristic parameters includes the multipath delay difference value and the phase offset correlation value; According to the height difference relationship between different altitude planes in the three-dimensional spatial layout, perform phase modulation compensation on the transmitted signals of the MIMO node devices to generate a directional beam group matching the three-dimensional spatial layout; Based on the dynamic coverage range of the directional beam group in the three-dimensional spatial layout, convert the multipath delay difference value and the phase offset correlation value in the set of characteristic parameters into three-dimensional spatial vector components; Through the spatial overlap relationship of the three-dimensional spatial vector components in the three-dimensional spatial layout, calculate the real-time three-dimensional coordinate data of the UAV in the target airspace.

2. The method according to claim 1, wherein Based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional spatial layout, through the multi-node cooperative signal transceiver mechanism between the MIMO node devices, obtain a set of characteristic parameters related to the three-dimensional spatial distribution in the wireless signal reflected by the UAV, including: Set multiple MIMO node devices to alternately transmit detection signals in the asymmetric topology according to a preset time window, and synchronously receive the multipath signals reflected by the UAV; Extract the time difference sequence of the multipath signals of the same detection signal reflected to each MIMO node through different paths, and determine the multipath delay difference value by calculating the fluctuation amplitude of the adjacent time differences in the time difference sequence; Based on the phase change amount between the transmission and reception of the detection signal, extract the phase offset amount of the multipath signals received by each MIMO node device, and generate a phase offset correlation value by calculating the correlation degree between the phase offset amounts of at least two MIMO node devices on the same altitude plane; Bind the multipath delay difference value and the phase offset correlation value according to the number of the signal transceiver node pair to form a set of characteristic parameters including three-dimensional spatial distribution correlation.

3. The method according to claim 1, wherein According to the height difference relationship between different altitude planes in the three-dimensional spatial layout, perform phase modulation compensation on the transmitted signals of the MIMO node devices to generate a directional beam group matching the three-dimensional spatial layout, including: Calculate the phase adjustment amount corresponding to the height difference according to the vertical height difference between the altitude plane where each MIMO node device is located and the adjacent plane; Superimpose the phase adjustment amount on the initial phase of the transmitted signal of the MIMO node device to obtain the transmitted signal after superimposing the phase adjustment; Through the synchronous transmission of multiple MIMO node devices, make the transmitted signals after superimposing the phase adjustment form multiple beams with different main radiation directions in the three-dimensional space, and at the same time, the main lobe directions of each beam are adaptively deflected according to the height difference distribution of the asymmetric topology to generate a directional beam group covering the UAV activity area.

4. The method according to claim 3, wherein Superimpose the phase adjustment amount on the initial phase of the transmission signal of the MIMO node device to obtain the transmission signal after superimposed phase adjustment, including: Determine the superimposing direction of the phase adjustment amount according to the vertical height difference between the elevation plane where each MIMO node device is located and the adjacent plane. When the MIMO node device is at the elevation plane of the preset height, the superimposing direction of the phase adjustment amount is the downward compensation direction; when the MIMO node device is below the elevation plane of the preset height, the superimposing direction of the phase adjustment amount is the upward compensation direction; Based on the superimposing direction, decompose the phase adjustment amount into the orthogonal phase components of each subcarrier in the corresponding transmission signal, and according to the frequency distribution relationship of the subcarriers, perform point-by-point superposition of the orthogonal phase components and the initial phase to obtain the superimposed phase; Perform periodic continuity verification on the superimposed phase. When the phase difference between adjacent subcarriers exceeds the preset jump threshold, insert transitional phase values between adjacent subcarriers by interpolation to generate the transmission signal after superimposed phase adjustment.

5. The method according to claim 3, wherein Through the synchronous transmission of multiple MIMO node devices, make the transmission signal after superimposed phase adjustment form multiple beams with different main radiation directions in three-dimensional space. At the same time, the main lobe directions of each beam are adaptively deflected according to the height difference distribution of the asymmetric topology structure to generate a directional beam group covering the UAV activity area, including: Divide the MIMO node devices into multiple height-related node groups according to the height difference distribution of each elevation plane in the asymmetric topology structure, where each node group includes at least one high-elevation plane node and one low-elevation plane node; Set a synchronous transmission time window for each node group, and trigger the transmission signals of different node groups in the preset order within the time window, so that the transmission signals of the high-elevation node and the low-elevation node in the same node group form a complementary phase relationship on the spatial propagation path; Based on the complementary phase relationship, through the superimposing effect of the downward compensation direction of the high-elevation node and the upward compensation direction of the low-elevation node, form the main lobe direction with the height difference connection line as the deflection axis in three-dimensional space; According to the real-time position feedback of the UAV activity area, dynamically adjust the triggering order of the synchronous transmission time window and the node group division rule, so that the main lobe directions of each beam deflect towards the direction of the real-time position feedback to generate a directional beam group covering the UAV activity area.

6. The method according to claim 1, wherein Based on the dynamic coverage range of the directional beam group in the three-dimensional space layout, convert the multipath delay difference value and the phase offset correlation value in the feature parameter set into three-dimensional space vector components, including: According to the main radiation direction of each beam in the directional beam group, establish the spatial direction projection axis corresponding to each beam, and map the multipath delay difference value to the delay vector component along the spatial direction projection axis according to the spatial extension length of the beam coverage area; Based on the phase offset correlation value of the same MIMO node device pair in the adjacent beam coverage areas, calculate the projection component of the phase offset amount in the main radiation direction of the beam to generate the phase offset vector component; Pair the time delay vector components and the phase offset vector components according to the beam numbers to generate a pairing result. Decompose and superpose each paired component in the pairing result along the coordinate axes of the three-dimensional space layout according to the vector synthesis rule to generate a set of three-dimensional space vector components including height, horizontal position, and depth direction.

7. The method according to claim 1, wherein Based on the spatial overlapping relationship of the three-dimensional space vector components in the three-dimensional space layout, calculate the real-time three-dimensional coordinate data of the UAV in the target airspace, including: According to the direction and amplitude of the three-dimensional space vector components, delimit corresponding spatial extension regions for each vector component in the three-dimensional space layout; Extract the coordinates of the intersection points of all vector components within the spatial extension regions, and screen out a set of candidate intersection points that simultaneously meet the preset aggregation threshold and continuity condition by statistically analyzing the aggregation degree and the number of consecutive occurrences of the intersection points within a preset time window; Based on the height, horizontal position, and depth direction coordinates of each candidate intersection point in the three-dimensional space layout in the candidate intersection point set, calculate the distribution intervals of the candidate intersection points in each direction respectively, and use the median value of the coordinate values within the distribution intervals as the basic reference value in the current direction; Dynamically adjust the contribution weights of each candidate intersection point to the basic reference value according to the amplitude size and the deviation angle between the direction of the three-dimensional space vector component corresponding to each candidate intersection point and the main radiation direction of the beam; Perform weighted fusion on the coordinate values of all candidate intersection points after weight adjustment in the height, horizontal position, and depth directions to generate the real-time three-dimensional coordinate data of the UAV in the target airspace.

8. A three-dimensional coordinate positioning system for unmanned aerial vehicles based on distributed MIMO nodes, characterized in that, Including: A construction module for deploying multiple MIMO node devices on at least three different altitude planes in the target airspace in an asymmetric topology structure to construct a three-dimensional space layout covering the UAV activity area; An acquisition module for obtaining a set of characteristic parameters related to the three-dimensional space distribution in the wireless signal reflected by the UAV through the multi-node cooperative signal transmission and reception mechanism between the MIMO node devices based on the signal coverage overlapping characteristics of different altitude planes in the three-dimensional space layout. The set of characteristic parameters includes multipath time delay difference values and phase offset correlation values; A compensation module for performing phase modulation compensation on the transmitted signals of the MIMO node devices according to the height difference relationship between different altitude planes in the three-dimensional space layout to generate a directional beam group matching the three-dimensional space layout; A conversion module for converting the multipath time delay difference values and phase offset correlation values in the set of characteristic parameters into three-dimensional space vector components based on the dynamic coverage range of the directional beam group in the three-dimensional space layout; A calculation module for calculating the real-time three-dimensional coordinate data of the UAV in the target airspace through the spatial overlapping relationship of the three-dimensional space vector components in the three-dimensional space layout.

9. A computing device, characterized in that, Including a processing component and a storage component; the storage component stores one or more computer instructions; the one or more computer instructions are used to be called and executed by the processing component to implement a method for three-dimensional coordinate positioning of a UAV based on distributed MIMO nodes as described in any one of claims 1 to 7.

10. A computer storage medium, characterized in that, A computer program is stored, and when the computer program is executed by a computer, it implements a method for three-dimensional coordinate positioning of an unmanned aerial vehicle based on a distributed MIMO node as described in any one of claims 1 to 7.

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