A three-dimensional coordinate positioning method and system for unmanned aerial vehicles based on distributed MIMO nodes

Abstract

The present application provides a method and system for three-dimensional coordinate positioning of drones based on distributed MIMO nodes. The present application first constructs a three-dimensional spatial layout covering the drone's activity area, then obtains a set of characteristic parameters, then compensates the transmitted signal based on the height difference relationship to generate a directional beam group, and then converts the multipath delay difference value and phase offset correlation value in the characteristic parameter set into a three-dimensional space vector component. Finally, through the spatial overlap relationship of the three-dimensional space vector components in the three-dimensional space layout, the real-time three-dimensional coordinate data of the drone in the target airspace is solved; the technical solution provided by the present application improves the positioning accuracy and anti-interference capability in a dynamic obstacle environment, realizes centimeter-level three-dimensional positioning in a GPS-free scenario, and reduces computational complexity and power consumption, achieving lightweight deployment and stable beam coverage in complex scenarios.

Description

Technical Field

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

[0002] With the widespread use of drones in complex three-dimensional scenarios, such as indoor warehousing and logistics, urban building inspections, and forest vegetation monitoring, their positioning technology must meet the needs of multi-dimensional precision perception. In environments without GPS signal coverage, drones need to obtain real-time three-dimensional coordinate data for altitude, horizontal position, and depth to avoid dynamic obstacles (such as moving shelves, vehicles, or trees) and complete vertical space operations (such as pipeline inspection and high-altitude equipment maintenance). At the same time, multipath interference and signal attenuation in complex electromagnetic environments (such as high-voltage power stations and metal factories) require positioning methods with anti-interference capabilities and low computing resource consumption to ensure stable output of centimeter-level precision coordinates.

[0003] The current mainstream solution to meet these requirements is a positioning method that integrates generative adversarial networks (GANs) with pseudo-fingerprints. This method uses a GAN to enhance sparse base station signals, constructing a high-density 3D signal fingerprint library. This library, combined with attitude data from the drone's inertial sensors, dynamically corrects for phase offset and height drop errors along the signal propagation path. During the positioning phase, multi-dimensional matching is performed between the real-time signal features and the pseudo-fingerprint, screening candidate coordinate points and outputting the final 3D coordinates through dynamic weighted fusion. This solution can achieve a preset positioning accuracy in static scenarios with good base station coverage.

[0004] However, this solution has significant drawbacks in practical applications. First, it relies heavily on a dense, pre-defined base station network and external sensors (such as inertial units), making it difficult to implement in outdoor or underground scenarios without base station coverage. Sensor failures can also lead to positioning interruptions. Second, signal mutations or electromagnetic interference caused by dynamic obstacles can cause pseudo-fingerprint matching to fail, resulting in coordinate jumps or accumulated errors. Furthermore, the coordinated deployment and data synchronization requirements of multiple sensor types (such as Wi-Fi and LiDAR) significantly increase hardware costs and system power consumption, making it difficult to meet the application requirements of lightweight drones. Summary of the Invention

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

[0006] In a first aspect, the present application provides a method for three-dimensional coordinate positioning of a UAV based on distributed MIMO nodes, comprising:

[0007] Deploy multiple MIMO node devices in an asymmetric topology on at least three different altitude planes in the target airspace to build a three-dimensional spatial layout covering the drone activity area;

[0008] Based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional spatial layout, a set of characteristic parameters related to the three-dimensional spatial distribution of the wireless signal reflected by the drone is obtained through a multi-node cooperative signal receiving and transmitting mechanism between the MIMO node devices, the characteristic parameter set including a multipath delay difference value and a phase offset correlation value;

[0009] performing phase modulation compensation on the transmission signal of the MIMO node device according to the height difference relationship between different altitude planes in the three-dimensional spatial layout to generate a directional beam group matching the three-dimensional spatial layout;

[0010] Based on the dynamic coverage of the directional beam group in the three-dimensional spatial layout, converting the multipath delay difference value and the phase offset associated value in the characteristic parameter set into a three-dimensional spatial vector component;

[0011] 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 space vector components in the three-dimensional space layout.

[0012] Optionally, based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional spatial layout, a set of characteristic parameters related to the three-dimensional spatial distribution in the wireless signal reflected by the drone is obtained through a multi-node cooperative signal receiving and transmitting mechanism between the MIMO node devices, including:

[0013] By setting multiple MIMO node devices in an asymmetric topology structure to alternately transmit detection signals according to preset time windows, and synchronously receive multipath signals reflected by drones;

[0014] Extract the time difference sequence of the multipath signals of the same detection signal reflected from 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;

[0015] Extracting the phase offset of the multipath signal received by each MIMO node device based on the phase change between the transmission and reception of the detection signal, and generating a phase offset correlation value by calculating the correlation between the phase offsets of at least two MIMO node devices on the same altitude plane;

[0016] The multipath delay difference value and the phase offset correlation value are bound according to the serial number of the signal transmitting and receiving node pair to form a characteristic parameter set including three-dimensional spatial distribution correlation.

[0017] Optionally, performing phase modulation compensation on a transmit signal of the MIMO node device according to a height difference relationship between different altitude planes in the three-dimensional spatial layout to generate a directional beam group matching the three-dimensional spatial layout includes:

[0018] Calculate the phase adjustment amount corresponding to the altitude difference between the altitude plane where each MIMO node device is located and the adjacent plane;

[0019] Adding the phase adjustment amount to the initial phase of the MIMO node device transmit signal to obtain a transmit signal after superimposing the phase adjustment;

[0020] Through the synchronous transmission of multiple MIMO node devices, the superimposed phase-adjusted transmission signal forms 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 topological structure, generating a directional beam group covering the drone activity area.

[0021] Optionally, superimposing the phase adjustment amount onto an initial phase of a transmission signal of the MIMO node device to obtain a transmission signal after superimposing the phase adjustment includes:

[0022] Determining a superposition direction of the phase adjustment amount based on a vertical height difference between an altitude plane where each MIMO node device is located and an adjacent plane, wherein when the MIMO node device is at an altitude plane at a preset height, the superposition direction of the phase adjustment amount is a downward compensation direction; when the MIMO node device is at a lower altitude plane, the superposition direction of the phase adjustment amount is an upward compensation direction;

[0023] Based on the superposition direction, decomposing the phase adjustment amount into an orthogonal phase component corresponding to each subcarrier in the transmitted signal, and superimposing the orthogonal phase component with the initial phase point by point according to the frequency distribution relationship of the subcarriers to obtain a superimposed phase;

[0024] The superimposed phase is periodically checked for continuity. When the phase difference between adjacent subcarriers exceeds a preset transition threshold, a transition phase value is inserted between adjacent subcarriers by interpolation to generate a transmitted signal after superimposed phase adjustment.

[0025] Optionally, through the synchronous transmission of multiple MIMO node devices, the superimposed phase-adjusted transmission signals are formed into 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 topological structure, thereby generating a directional beam group covering the UAV activity area, including:

[0026] According to the height difference distribution of each altitude plane in the asymmetric topology structure, the MIMO node devices are divided into multiple highly correlated node groups, where each node group contains at least one high-altitude plane node and one low-altitude plane node;

[0027] A synchronous transmission time window is set for each node group, and the transmission signals of different node groups are triggered in sequence within the time window according to a preset order, so that the transmission signals of high-altitude nodes and low-altitude nodes in the same node group form a complementary phase relationship on the spatial propagation path;

[0028] Based on the complementary phase relationship, a main lobe direction with the height difference line as the deflection axis is formed in three-dimensional space through the superposition effect of the downward compensation direction of the high-altitude node and the upward compensation direction of the low-altitude node;

[0029] According to the real-time position feedback of the drone activity area, the triggering order of the synchronous transmission time window and the node group division rules are dynamically adjusted to deflect the main lobe direction of each beam toward the direction of the real-time position feedback, thereby generating a directional beam group covering the drone activity area.

[0030] Optionally, based on the dynamic coverage of the directional beam group in the three-dimensional spatial layout, converting the multipath delay difference value and the phase offset associated value in the characteristic parameter set into a three-dimensional spatial vector component includes:

[0031] According to the main radiation direction of each beam in the directional beam group, a spatial direction projection axis corresponding to each beam is established, and the multipath delay difference value is mapped into a delay vector component along the spatial direction projection axis according to the spatial extension length of the beam coverage area;

[0032] Based on the phase offset correlation values ​​of the same MIMO node device pair within the adjacent beam coverage area, the projection component of the phase offset in the main radiation direction of the beam is calculated to generate a phase offset vector component;

[0033] The time delay vector component and the phase offset vector component are paired according to the beam number to generate a pairing result. The paired components in the pairing result are decomposed and superimposed along the coordinate axis of the three-dimensional space layout according to the vector synthesis rule to generate a three-dimensional space vector component set including height, horizontal position and depth direction.

[0034] Optionally, calculating the real-time three-dimensional coordinate data of the UAV in the target airspace by using the spatial overlap relationship of the three-dimensional space vector components in the three-dimensional space layout includes:

[0035] Delineating a corresponding spatial extension region for each vector component in the three-dimensional spatial layout according to the direction and magnitude of the three-dimensional spatial vector component;

[0036] Extracting the coordinates of the intersection points of all vector components within the spatial extension area, and screening out a set of candidate intersection points that simultaneously meet a preset aggregation threshold and continuity conditions by counting the degree of aggregation and the number of consecutive appearances of the intersection points within a preset time window;

[0037] Based on the height, horizontal position and depth coordinates of each candidate intersection point in the three-dimensional spatial layout, the distribution interval of the candidate intersection points in each direction is calculated respectively, and the median of the coordinate values ​​within the distribution interval is used as the basic reference value of the current direction;

[0038] Dynamically adjust the contribution weight of each candidate intersection point to the basic reference value based on the magnitude and direction of the three-dimensional space vector component corresponding to each candidate intersection point and the deviation angle from the main radiation direction of the beam;

[0039] The coordinate values ​​of all candidate intersection points in height, horizontal position and depth direction after weight adjustment are weighted fused to generate real-time three-dimensional coordinate data of the UAV in the target airspace.

[0040] In a second aspect, the present application provides a three-dimensional coordinate positioning system for drones based on distributed MIMO nodes, comprising:

[0041] A construction module is used to deploy multiple MIMO node devices in an asymmetric topology on at least three different altitude planes in the target airspace to build a three-dimensional spatial layout covering the drone activity area;

[0042] an acquisition module, configured to acquire, based on signal coverage overlap characteristics at different altitudes in the three-dimensional spatial layout, a set of characteristic parameters associated with the three-dimensional spatial distribution of wireless signals reflected by the drone through a multi-node cooperative signal receiving and transmitting mechanism between the MIMO node devices, the set of characteristic parameters including a multipath delay difference value and a phase offset correlation value;

[0043] a compensation module, configured to perform phase modulation compensation on a transmission signal of the MIMO node device according to a height difference relationship between different altitude planes in the three-dimensional spatial layout, and generate a directional beam group matching the three-dimensional spatial layout;

[0044] A conversion module, configured to convert the multipath delay difference value and the phase offset associated value in the characteristic parameter set into a three-dimensional space vector component based on the dynamic coverage range of the directional beam group in the three-dimensional space layout;

[0045] A solution module is used to solve 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.

[0046] In a third aspect, an embodiment of the present application provides a computing device comprising 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 three-dimensional coordinate positioning method for a drone based on distributed MIMO nodes as described in the first aspect above.

[0047] In a fourth aspect, an embodiment of the present application provides a computer storage medium storing a computer program. When the computer program is executed by a computer, it implements a three-dimensional coordinate positioning method for a drone based on distributed MIMO nodes as described in the first aspect.

[0048] The embodiment of the present application constructs a three-dimensional spatial layout by deploying multiple MIMO node devices in an asymmetric topology on at least three planes at different altitudes, and combines the multi-node cooperative transceiver mechanism to extract multipath delay difference values ​​and phase offset correlation values, thereby solving the problems of insufficient signal coverage and severe multipath interference in complex terrains in traditional solutions; through the dynamic coverage of directional beam groups and the conversion of spatial vector components, the signal characteristics are directly associated 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 overlapping relationship to solve the coordinates, significantly improving the positioning accuracy and anti-interference capability in dynamic obstacle environments, and achieving centimeter-level three-dimensional positioning in GPS-free scenarios.

[0049] Furthermore, the phase adjustment amount is dynamically calculated according to the altitude difference relationship and superimposed on the transmitted signal. Through the complementary phase compensation of 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 beam energy dispersion problem of the traditional symmetrical layout; combined with the multi-node synchronous transmission mechanism, a directional beam group with a complementary phase relationship is formed in three-dimensional space, which suppresses the co-frequency interference of multipath signals and enhances the effective radiation intensity of the target signal. At the same time, by dynamically adjusting the node group division and transmission timing, the computational complexity and power consumption are reduced, achieving lightweight deployment and stable beam coverage in complex scenarios.

[0050] These and other aspects of the present application will become more readily apparent from the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0052] Figure 1A flowchart of a method for three-dimensional coordinate positioning of a UAV based on distributed MIMO nodes provided by the present application is shown;

[0053] Figure 2 A schematic diagram of the structure of a three-dimensional coordinate positioning system for a UAV based on distributed MIMO nodes provided by the present application is shown;

[0054] Figure 3 A schematic structural diagram of a computing device provided by the present application is shown. DETAILED DESCRIPTION

[0055] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0056] In some of the processes described in the specification and claims of this application and the above-mentioned figures, multiple operations that appear in a specific order are included, but it should be clearly understood that these operations may not be executed in the order in which they appear in this document or may be executed in parallel. The serial numbers of the operations, such as 101, 102, etc., are only used to distinguish between different operations, and the serial numbers themselves do not represent any order of execution. In addition, these processes may include more or fewer operations, and these operations may be executed in sequence or in parallel. It should be noted that the descriptions of "first", "second", etc. in this document are used to distinguish different messages, devices, modules, etc., and do not represent a sequential order, nor do they limit "first" and "second" to being different types.

[0057] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0058] Figure 1 The present invention provides a flowchart of a method for three-dimensional coordinate positioning of a UAV based on distributed MIMO nodes, as shown in FIG. Figure 1 As shown, the method includes:

[0059] Step 101: deploy multiple MIMO node devices in an asymmetric topology on at least three different altitude planes in the target airspace to build a three-dimensional spatial layout covering the drone activity area.

[0060] In this step, the asymmetric topology structure refers to the distribution of multiple MIMO node devices in a non-uniform and non-mirror manner in the target airspace, and distributed in at least three different altitude layers (such as the ground, low-altitude platform, and high-altitude equipment), forming a three-dimensional network with staggered space and complementary coverage.

[0061] Different altitude planes refer to the vertical height difference layers where node devices are deployed, such as ground base stations (0 meters above sea level), drone relay platforms (50 meters above sea level), and fixed nodes on mountain tops (200 meters above sea level). The height difference enhances the diversity of signal propagation paths.

[0062] Three-dimensional spatial layout refers to the construction of a three-dimensional signal coverage network covering the drone activity area through the asymmetric distribution of nodes at multiple altitudes. Its coverage range expands non-uniformly in the horizontal direction, and multi-layer overlap is achieved in the vertical direction through height differences.

[0063] In this embodiment, first, based on the terrain data of the target airspace and the range of drone activity, 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, through the built-in altitude sensor and positioning module of each node, the altitude coordinates of the node are calibrated in real time to generate a three-dimensional topological map containing the node position, height and coverage radius; 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 spacing between existing nodes until the full coverage requirement of the drone activity area is met.

[0064] For example, in a power inspection scenario in a mountainous area, the target airspace is a canyon (1 km x 1 km horizontally, with a 300-meter vertical drop). MIMO nodes are deployed at the canyon bottom (0 meters above sea level), a mountainside observation station (150 meters above sea level), and a signal tower at the top of a mountain (300 meters above sea level). Five nodes are densely deployed at the canyon bottom (200 meters apart), two nodes are sparsely deployed at the mountainside (500 meters apart), and one node is deployed at the top of the mountain. By combining the height difference and asymmetric horizontal distribution of nodes, a vertical signal coverage band is formed from the canyon bottom to the top of the mountain. By adjusting the horizontal position of the mountainside nodes, signal blind spots caused by mountain obstruction are eliminated, ultimately creating a three-dimensional layout covering the entire canyon.

[0065] Step 102: Based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional spatial layout, a set of characteristic parameters related to the three-dimensional spatial distribution in the wireless signal reflected by the drone is obtained through the multi-node collaborative signal receiving and transmitting mechanism between the MIMO node devices. The characteristic parameter set includes a multipath delay difference value and a phase offset correlation value.

[0066] In this step, the signal coverage overlap characteristic refers to the overlapping area formed in space by MIMO node signals at different altitude planes. The coverage range partially overlaps in the vertical and horizontal directions, which is used to enhance the distinguishability of signal reflection paths.

[0067] The multi-node cooperative signal transmission and reception mechanism refers to controlling multiple nodes to alternately transmit detection signals through preset timing and synchronously receive reflected signals, avoiding signal interference while ensuring the spatial correlation of multipath signals.

[0068] 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.

[0069] 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.

[0070] In this embodiment, first, the transmission time window of the detection signal of each node is determined by the altitude and coverage radius data of the nodes in the asymmetric topology, so 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 gaps to ensure that the signals do not overlap in the time domain; secondly, each node synchronously receives the multipath signal reflected by the drone, and separates the time difference sequence of the same detection signal reaching each node through different reflection paths according to the transmission timing and node number; then, the fluctuation amplitude of adjacent time differences in the time difference sequence is calculated to generate a multipath delay difference value; at the same time, the phase change of the received signal of each node is extracted, and the phase offset correlation value is generated by calculating the correlation coefficient of the phase change of two nodes in the same altitude plane; finally, the delay difference value and the phase offset correlation value are bound according to the transmitting node and the receiving node number to form a set of characteristic parameters associated with the three-dimensional spatial distribution.

[0071] For example, based on the three-dimensional layout of the canyon constructed in step 101 (5 nodes on the ground layer, 2 nodes on the mountainside, and 1 node on the mountaintop), a multi-node cooperative transmission and reception mechanism is started: the ground layer nodes sequentially transmit 5GHz detection signals in time window 1 (0-10ms), the mountainside nodes transmit in window 2 (10-20ms), and the mountaintop nodes transmit in window 3 (20-30ms), forming an alternating transmission sequence 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 within window 1 (for example, the signal transmitted by ground node A is reflected by the UAV and reaches the mountainside node B, and the path takes 12ms, while the same signal passes through the mountain and receives the multipath signals of the signals transmitted by the ground layer nodes synchronously within window 1). After diffraction, the signal reaches node C on the top of the mountain (a path takes 18ms). Signals from each path are separated based on the transmitting node number and timestamp. A delay difference value is generated by counting the fluctuations in the time difference (e.g., standard deviation 0.5ms) between the signal from the same ground node A reaching node B on the mountainside and node C on the top of the mountain within 10 consecutive windows. The phase changes of the received signals at nodes B and C are simultaneously extracted (B has a phase shift of +30°, C has a phase shift of -15°), and the correlation coefficient (0.78) is calculated to generate a phase shift correlation value. Finally, the delay difference value (0.5ms) and the phase shift correlation value (0.78) are bound according to the signal path (A→B, A→C) to form a set of characteristic parameters, which serve as input for the subsequent three-dimensional coordinate solution. This process fully utilizes the asymmetric node deployment (dense on the ground, sparse at high altitude) and the altitude difference (0m / 150m / 300m) in step 101. By leveraging the diversity of signal reflection paths in highly overlapping areas, the parameters are strongly correlated with the three-dimensional spatial distribution, providing a reliable data foundation for dynamic positioning.

[0072] Step 103 : performing phase modulation compensation on the transmission signal of the MIMO node device according to the height difference relationship between different altitude planes in the three-dimensional spatial layout, and generating a directional beam group matching the three-dimensional spatial layout.

[0073] In this step, the height difference relationship refers to the vertical height difference between nodes at different altitudes in step 101 (e.g., the difference between the ground layer and the mountainside layer is 150 meters, and the difference between the mountainside layer and the top of the mountain is 150 meters), which is used to quantify the spatial potential difference between nodes.

[0074] Phase modulation compensation refers to dynamically adjusting the phase value of the node's transmitted signal according to the height difference to offset the impact of the height difference on the signal propagation path and focus the beam energy on the target area.

[0075] A directional beam group refers to a set of beams with controllable main radiation directions formed in three-dimensional space by synchronously transmitting phase-compensated signals from multiple nodes. Its coverage range matches the terrain height distribution.

[0076] In this embodiment, the vertical height difference between adjacent layer nodes is first calculated based on the altitude coordinates of each node in the three-dimensional topology map; secondly, the height difference is converted into a phase adjustment amount, and the compensation direction is determined; then, the phase adjustment amount is decomposed into orthogonal components according to the subcarrier frequency, and superimposed point by point with the initial phase of the transmitted signal to generate a compensated transmitted signal; then, the superimposed signal is checked for phase continuity, and if the phase jump of adjacent subcarriers exceeds a threshold, a transition phase value is inserted to smooth the waveform; finally, the compensated signal is transmitted synchronously by multiple nodes, and the superposition effect of downward compensation of high-altitude nodes and upward compensation of low-altitude nodes is utilized to form a multi-beam group in the canyon with the altitude difference line as the deflection axis, and its main lobe direction is adaptively deflected to cover the drone activity area.

[0077] For example, based on the three-dimensional canyon layout constructed in step 101 (5 nodes on the ground, 2 nodes on the mountainside, and 1 node on the mountaintop) and the characteristic parameters obtained in step 102, phase modulation compensation is implemented based on the height difference between nodes: if the vertical height difference between ground node A (0 meters) and mountainside node B (150 meters) is 150 meters, node A will compensate upward by 18°, and node B will compensate downward by 18°. If the height difference between mountainside node B and mountaintop node C (300 meters) is 150 meters, node B will compensate upward by 18°, and node C will compensate downward by 18°. Node A decomposes the compensation into orthogonal I / Q components and adds them to the 5GHz subcarrier to generate an upward-focused transmission signal. Node B simultaneously adds the bidirectional compensation components and smoothes the subcarrier phase jumps through interpolation (for example, a 40° jump is interpolated with a 10° transition value). Node C adds the downward compensation to generate the 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 is adaptively deflected along the center line of the canyon (ground → mountainside → mountaintop), penetrating the area blocked by the mountain and covering the drone inspection path.

[0078] Step 104: Based on the dynamic coverage 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 characteristic parameter set into three-dimensional spatial vector components.

[0079] 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 drone moves in three-dimensional space. Its range is determined by the beam radiation direction and signal strength.

[0080] The three-dimensional space vector component refers to the component that maps the multipath delay difference value and the phase offset correlation value to the three-dimensional coordinate axis (height, level, and depth) respectively, which is used to quantify the position offset of the UAV in space.

[0081] In this embodiment, first, a corresponding spatial direction projection axis is established for each beam based on the main radiation direction of each beam in the directional beam group; secondly, the multipath delay difference value is mapped to 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 within the adjacent beam coverage area, the projection component of the phase offset 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 the components are decomposed and superimposed along the three-dimensional coordinate axis using the vector synthesis rule to generate a three-dimensional spatial vector component set including height, horizontal position and depth direction.

[0082] For example, the directional beam group includes a vertical beam from ground node A (with its main radiation direction along the canyon's altitude axis), an oblique beam from mountainside node B (with its main direction along the horizontal axis), and a downward beam from mountaintop node C (with its main direction along the depth axis). The multipath delay difference (0.5 ms) between ground node A and mountainside node B in step 102 is mapped to an altitude component based on the vertical beam coverage height, and the phase offset correlation value (0.78) is generated as a horizontal component based on the horizontal projection of the oblique beam. Simultaneously, the delay difference (0.3 ms) between mountainside node B and mountaintop node C is mapped to a depth component, and the phase correlation value (0.65) is projected onto the horizontal axis. Using vector synthesis rules, the altitude, horizontal, and depth components are superimposed to generate a three-dimensional spatial vector for the drone in the canyon (e.g., altitude +150 m, horizontal displacement +20 m, depth -30 m), providing input for coordinate calculation in step 105. This process directly associates signal characteristics with spatial positions through dynamic mapping of beam direction and characteristic parameters, eliminating coordinate offset errors caused by terrain occlusion.

[0083] Step 105 , calculating 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.

[0084] In this step, the spatial overlapping relationship refers to the partial overlap of the coverage areas of the three-dimensional space vector components in the three-dimensional layout, and the overlapping areas are the candidate solution areas for the UAV position.

[0085] Real-time three-dimensional coordinate data refers to the precise coordinate values ​​of the drone's current position in height, horizontal displacement and depth, output through spatial overlap solution.

[0086] In this embodiment, first, according to the direction and amplitude of the three-dimensional space vector component, a corresponding spatial extension area is delineated for each component in the three-dimensional layout; secondly, the coordinates of the intersections of the spatial extension areas of all vector components are extracted; then, the degree of aggregation and the number of consecutive occurrences of each intersection within a preset time window are counted, and a set of candidate intersections that simultaneously meet the aggregation threshold and continuity conditions are screened; then, 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 and direction of the vector component corresponding to the candidate intersection and the deviation angle from the main radiation direction of the beam, the weight is dynamically adjusted; finally, all weighted candidate intersection coordinates are fused according to the direction to generate real-time three-dimensional coordinate data of the drone.

[0087] For example, based on the three-dimensional space vector components (height +150m, level +20m, depth -30m), the coverage area of ​​each component is delineated (height 100-200m, level 0-40m, depth -50 to -10m), and the intersection is extracted as (150m, 20m, -30m); statistics show that the intersection appears 8 times within 10 seconds and appears in 3 consecutive windows, which meets the threshold condition; calculate the distribution interval in each direction (height 140-160m, level 15-25m, depth -25 to The system takes the median as the basic reference value (150m, 20m, -35m). Based on the vector component amplitude (0.5 for height, 0.3 for level, 0.2 for depth) and the deviation angle (10° for level, 5° for depth), it assigns weights (0.6 for height, 0.3 for level, 0.1 for depth). After weighted fusion, it outputs the real-time coordinates (150m, 19.8m, -30.2m). Dynamic weighting is used to suppress coordinate jumps caused by mountain reflection interference, achieving centimeter-level positioning accuracy in complex terrain.

[0088] To improve the accuracy of extracting the distribution features of multipath delay difference values ​​and phase offset correlation values ​​in three-dimensional space, in some embodiments, according to step 102, based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional spatial layout, a set of characteristic parameters related to the three-dimensional spatial distribution of the wireless signal reflected by the drone is obtained through a multi-node cooperative signal transmission and reception mechanism between the MIMO node devices, including:

[0089] Step 201: multiple MIMO node devices are set to transmit detection signals alternately in a preset time window in an asymmetric topology structure, and synchronously receive multipath signals reflected by the drone.

[0090] In this step, the preset time window alternating transmission means that multiple MIMO nodes transmit detection signals in time periods according to a pre-assigned timing sequence to avoid signal interference and ensure that the receiving end can distinguish the reflection paths of different nodes.

[0091] 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 multipath signals can be accurately measured.

[0092] In this embodiment, independent transmission time windows are first allocated to nodes at different altitude planes based on the altitude distribution and coverage of nodes in the asymmetric topology. Secondly, in the transmission phase, each node sequentially transmits a specifically coded detection signal according to the allocated window and records the transmission timestamp. In the reception phase, all nodes synchronously start the receiving module after the window ends, capture the multipath signals reflected by the drone and the environment, and separate the reflected signals of different nodes based on the coding characteristics. Finally, the signals received by each node are aligned with the transmission timestamp to generate an original data set containing path propagation time, signal strength, and phase information.

[0093] Step 202: extract the time difference sequence of the multipath signals of the same detection signal reflected from 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.

[0094] In this step, the time difference sequence refers to a set of propagation time differences of the same detection signal reaching each node via different reflection paths, which is a sequence formed by arranging the signals in the order of transmission.

[0095] Fluctuation amplitude refers to the cumulative absolute difference between adjacent time difference values ​​in the time difference series, which is used to quantify the stability of the reflection path.

[0096] In this embodiment, all reflection path time differences of the same detection signal are first extracted from the original data set; secondly, the time differences are arranged into a sequence according to the order of signal transmission; then, the fluctuation amplitude of adjacent time differences is calculated; finally, the fluctuation amplitude of N consecutive windows is statistically analyzed to generate a multipath delay difference value reflecting the path stability, and this value is bound to the signal transmitting and receiving node pair.

[0097] Step 203: Based on the phase change between the transmission and reception of the detection signal, extract the phase offset of the multipath signal received by each MIMO node device, and generate a phase offset correlation value by calculating the correlation between the phase offsets of at least two MIMO node devices on the same altitude plane.

[0098] In this step, the phase change refers to the phase difference caused by the difference in propagation path length or environmental disturbance during the process from transmission to reception of the detection signal.

[0099] Phase offset correlation refers to the statistical correlation between the phase offsets of signals received by at least two nodes on the same altitude plane, which is used to characterize the position consistency of the UAV on this plane.

[0100] In this embodiment, the phase offset of the multipath signal received by each node is first extracted from the received signal, that is, the phase difference between the transmitted signal and the received signal. Secondly, for at least two nodes on the same altitude plane, the covariance or correlation coefficient of the phase offset sequence between the two nodes is calculated to generate a phase offset correlation value. Finally, the correlation value is bound to the corresponding node pair and used as a quantitative indicator of the vertical position change of the drone.

[0101] Step 204 : Bind the multipath delay difference value and the phase offset correlation value according to the serial number of the signal transmitting and receiving node pair to form a characteristic parameter set including three-dimensional spatial distribution correlation.

[0102] In this step, the signal transmitting and receiving node pair number refers to the unique combination identifier of the transmitting node and the receiving node, which is used to distinguish different signal propagation paths.

[0103] Three-dimensional spatial distribution correlation refers to the delay difference value and phase correlation value jointly reflecting the spatial distribution characteristics of the UAV in the height, horizontal and depth directions.

[0104] In this embodiment, first, each signal transmitting and receiving node pair is prepared; secondly, the generated delay difference value and the generated phase offset correlation value are bound by number to form a parameter group that includes path propagation characteristics and spatial correlation; finally, the parameter groups of all node pairs are integrated into a feature parameter set according to the node position relationship in the three-dimensional layout.

[0105] To address the signal energy dispersion problem caused by the mismatch between beam direction and altitude difference in asymmetric terrain, in some embodiments, according to step 103, phase modulation compensation is performed on the transmitted signal of the MIMO node device based on the altitude difference relationship between different altitude planes in the three-dimensional spatial layout to generate a directional beam group that matches the three-dimensional spatial layout, including:

[0106] Step 301 : Calculate a phase adjustment amount corresponding to the vertical height difference between the altitude plane where each MIMO node device is located and an adjacent plane.

[0107] In this step, the phase adjustment amount refers to the phase compensation value calculated based on the vertical height difference between adjacent altitude plane nodes. It is used to offset the signal propagation path difference caused by the altitude difference. Its direction is determined by the altitude of the node (downward compensation at high altitude and upward compensation at low altitude).

[0108] In this embodiment, the vertical height difference between adjacent plane nodes is first calculated based on the altitude coordinates of each node in the three-dimensional spatial layout. Secondly, the phase adjustment amount is calculated by combining the height difference with a preset phase adjustment coefficient. Next, the compensation direction is determined based on the plane height relationship of the nodes—high-altitude nodes are compensated downward, and low-altitude nodes are compensated upward. Finally, the phase adjustment amount is decomposed into mutually perpendicular phase components according to the subcarrier frequency to ensure the continuity and consistency of phase compensation for subcarriers of different frequencies.

[0109] Step 302: superimpose the phase adjustment amount on the initial phase of the transmission signal of the MIMO node device to obtain a transmission signal after superimposing the phase adjustment.

[0110] In this step, the initial phase refers to the original phase value of the MIMO node transmitted signal without adjustment, which is generated by the signal generator according to the preset waveform.

[0111] Superposition phase adjustment refers to the arithmetical superposition of the phase adjustment amount and the initial phase to form a compensated phase waveform.

[0112] In this embodiment, the phase adjustment amount is first decomposed into orthogonal phase components corresponding to the subcarrier frequencies of the transmitted signal. Secondly, the initial phase of each subcarrier is superimposed point by point. Next, the phase jump between adjacent subcarriers after superposition is detected. If it exceeds a preset threshold, a transition phase value is inserted at the jump point by interpolation 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.

[0113] Step 303: Through the synchronous transmission of multiple MIMO node devices, the superimposed phase-adjusted transmission signal forms 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 topological structure to generate a directional beam group covering the drone activity area.

[0114] 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 characteristics and the UAV activity path.

[0115] In this embodiment, the nodes are first divided into multiple associated groups according to the height difference distribution of the asymmetric topology; secondly, an independent synchronous transmission time window is set for each group, and the nodes in the group are triggered in sequence to synchronously transmit phase-adjusted signals; then, the downward compensation signals of the high-altitude nodes in the group and the upward compensation signals of the low-altitude nodes are superimposed on the spatial propagation path to form a main lobe direction with the height difference line as the deflection axis; finally, according to the real-time position feedback of the UAV, the node group division rules and the transmission window triggering sequence are dynamically adjusted to deflect the main lobe direction of the beam toward the target area, thereby generating a directional beam group covering the UAV's activity path.

[0116] To improve the continuity and signal stability of the phase adjustment superposition, in some embodiments, according to step 302, the phase adjustment amount is superimposed on the initial phase of the MIMO node device's transmit signal to obtain a transmit signal after superimposing the phase adjustment, including:

[0117] Step 401: Determine the superposition direction of the phase adjustment amount based on the vertical height difference between the altitude plane where each MIMO node device is located and the adjacent plane, wherein when the MIMO node device is at an altitude plane of a preset height, the superposition direction of the phase adjustment amount is a downward compensation direction; when the MIMO node device is at a lower altitude plane, the superposition direction of the phase adjustment amount is an upward compensation direction.

[0118] In this step, the superposition direction of the phase adjustment amount refers to determining the direction of increase or decrease of the phase compensation amount according to the height relationship of the node's altitude plane, which is used to offset the difference in signal propagation path caused by the altitude difference.

[0119] The downward compensation direction means that when the node is at an altitude plane of a preset height, the phase adjustment amount aims to reduce the equivalent phase delay of the signal propagation path, and the compensation direction is downward.

[0120] The upward compensation direction means that when the node is at a lower altitude, the phase adjustment amount is aimed at increasing the signal coverage capability of the high-altitude area, and the compensation direction is upward.

[0121] In this embodiment, the altitude plane data of each node in the three-dimensional spatial layout is first obtained; secondly, the vertical height difference between each node and its adjacent plane nodes is compared; then, the phase adjustment direction is determined based on the height relationship of the plane where the node is located - if the node is in a plane at a preset height, the superposition direction is downward compensation; if the node is in a lower plane, the superposition direction is upward compensation; finally, the phase adjustment amount is decomposed into orthogonal components corresponding to the transmitted signal subcarriers to ensure the phase superposition continuity and directional consistency of the subcarriers of different frequencies.

[0122] Step 402: Based on the superposition direction, decompose the phase adjustment amount into orthogonal phase components corresponding to each subcarrier in the transmitted signal, and superimpose the orthogonal phase components with the initial phase point by point according to the frequency distribution relationship of the subcarriers to obtain a superimposed phase.

[0123] 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 in signal modulation.

[0124] The frequency distribution relationship of subcarriers refers to the frequency spacing and arrangement rules of each subcarrier in the transmitted signal, which determines the frequency weight distribution method of the orthogonal components.

[0125] Point-by-point superposition means superimposing orthogonal components on the initial phase of each subcarrier to ensure that the phase adjustment at different frequency points is independent and continuous.

[0126] In this embodiment, the phase adjustment amount is first decomposed into horizontal and vertical components based on the determined superposition direction. Secondly, the weights of the orthogonal components are assigned from low to high frequency based on the frequency distribution of the subcarriers. Next, the horizontal and vertical components are superimposed on the initial phase of each subcarrier to generate an adjusted phase value. Finally, the phase jump amplitude between adjacent subcarriers is detected. If it exceeds a threshold, a transition phase value is inserted to smooth the signal waveform.

[0127] Step 403: Perform periodic continuity check on the superimposed phase. When the phase difference between adjacent subcarriers exceeds a preset transition threshold, a transition phase value is inserted between adjacent subcarriers by interpolation to generate a transmission signal after superimposed phase adjustment.

[0128] In this step, the periodic continuity check refers to detecting whether the phase difference of adjacent subcarriers exceeds a preset jump threshold in the order of subcarrier frequencies. If exceeded, it is determined to be a phase mutation point.

[0129] The transition phase value refers to the intermediate phase value inserted between phase mutation points, which is used to eliminate signal waveform distortion caused by the jump and ensure the time domain continuity of the transmitted signal.

[0130] In this embodiment, the superimposed phase data is first scanned in descending order of subcarrier frequency. Secondly, the absolute value of the phase difference between adjacent subcarriers is calculated. If it exceeds a transition threshold, it is marked as a mutation point. Next, a transition phase value is inserted between the mutation points through interpolation to reduce the phase difference between adjacent subcarriers to within the threshold. Finally, the phase sequence with the inserted transition values ​​is converted into a time-domain signal waveform to generate a smooth and continuous transmission signal.

[0131] To address the beam coverage blind spot problem in dynamic scenarios, in some embodiments, according to step 303, multiple MIMO node devices are synchronized to form multiple beams with different main radiation directions in three-dimensional space by superimposing the phase-adjusted transmission signals. At the same time, the main lobe direction of each beam is adaptively deflected according to the height difference distribution of the asymmetric topological structure, thereby generating a directional beam group covering the drone's activity area, including:

[0132] Step 501 : Divide MIMO node devices into a plurality of highly correlated node groups according to the height difference distribution of each altitude plane in the asymmetric topology structure, wherein each node group includes at least one high altitude plane node and one low altitude plane node.

[0133] In this step, the highly correlated node groups refer to grouping the nodes into pairs of high / low altitude nodes according to the height difference relationship of the nodes in the adjacent altitude planes in the asymmetric topology to achieve complementary phase compensation.

[0134] In this embodiment, first, based on the three-dimensional topological map generated in step 101, the height difference between adjacent altitude plane nodes is extracted; second, the nodes on the same vertical height difference line are divided into associated groups, ensuring that each group contains at least one high-altitude node and one low-altitude node; finally, a unique identifier is assigned to each associated group (for example, group G1 contains AB, and group G2 contains BC), and the altitude coordinates and coverage areas of the nodes in the group are recorded.

[0135] Step 502: Set a synchronous transmission time window for each node group, and trigger the transmission signals of different node groups in sequence according to a preset order within the time window, so that the transmission signals of high-altitude nodes and low-altitude nodes in the same node group form a complementary phase relationship on the spatial propagation path.

[0136] In this step, the synchronous transmission time window refers to the independent transmission period allocated to each node group to avoid mutual interference of signals from different groups while ensuring synchronous transmission of nodes within the group.

[0137] The complementary phase relationship refers to the phase alignment effect in which the main lobe direction of the beam is consistent after the phase adjustment amounts of the downward compensation of the high-altitude nodes and the upward compensation of the low-altitude nodes in the group are spatially superimposed.

[0138] In this embodiment, first, according to the coverage priority of the node group (for example, group G1 has a higher priority if the drone activity area is close to the mountainside), time window 1 (0-10ms) is allocated to group G1, and window 2 (10-20ms) is allocated to group G2. Secondly, within window 1, the nodes of group G1 are triggered to synchronously transmit the phase-adjusted signal, 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 transmit synchronously to form an oblique beam. Finally, according to the real-time position of the drone, the window triggering order is dynamically adjusted (for example, group G2 is triggered first when the drone approaches the top of the mountain), so that the main lobe direction of the beam can adaptively track the target area.

[0139] Step 503 : Based on the complementary phase relationship, a main lobe direction with the height difference line as the deflection axis is formed in three-dimensional space through the superposition effect of the downward compensation direction of the high-altitude node and the upward compensation direction of the low-altitude node.

[0140] In this step, the complementary phase relationship refers to the phase superposition effect of the downward compensation signal of the high-altitude node and the upward compensation signal of the low-altitude node in the same node group on the spatial propagation path. Their interaction causes the beam energy to be focused along a specific direction.

[0141] The height difference line refers to the vertical spatial line between the high-altitude node and the low-altitude node in the node group, which serves as the deflection reference axis of the beam main lobe direction.

[0142] In this embodiment, first, according to the node groups divided in step 501, the height difference lines of the nodes in the group are extracted (A→B, vertical height difference of 150 meters); secondly, the compensation signals of the nodes in the group are synchronously transmitted through the phase adjustment rules of steps 401 and 402; then, on the spatial propagation path, the upward compensation signal of A and the downward compensation signal of B are superimposed on the height difference line (A→B) to form a phase-aligned main lobe direction (vertically upward); finally, the node group triggering sequence is dynamically adjusted according to the real-time position of the UAV, so that the main lobe direction is deflected along different height difference lines (such as B→C) to cover the target area.

[0143] Step 504: Based on the real-time position feedback of the drone activity area, dynamically adjust the triggering sequence of the synchronous transmission time window and the node group division rules, so that the main lobe direction of each beam is deflected toward the direction of the real-time position feedback, thereby generating a directional beam group covering the drone activity area.

[0144] In this step, the dynamic adjustment mechanism refers to the real-time optimization of the node group triggering sequence and grouping rules according to the changes in the UAV position, so that the main lobe direction of the beam is adaptively deflected toward the target area.

[0145] In this embodiment, the real-time coordinates of the UAV output in step 105 are first received to determine the coverage area to which it belongs; secondly, if the target area is located at the coverage edge of the currently activated node group (such as group G1 covering the middle), the node group is re-divided (such as merging the mountainside node B and the mountaintop node C into a new group G2'), and the transmission window of the new group is triggered first; if the target area is within the coverage range of the existing group, the triggering sequence is adjusted (such as extending the window length of group G1); then, according to the new grouping or triggering sequence, the compensation signal is synchronously transmitted to deflect the main lobe direction of the beam along the new height difference line (such as the B→C line); finally, the position change of the UAV is continuously monitored, and the above adjustment logic is cyclically executed to ensure that the beam group always covers the target area.

[0146] To improve the accuracy of mapping the 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, converting the multipath delay difference value and the phase offset associated value in the characteristic parameter set into a three-dimensional space vector component includes:

[0147] Step 601: establish a spatial direction projection axis corresponding to each beam according to the main radiation direction of each beam in the directional beam group, and map the multipath delay difference value into a delay vector component along the spatial direction projection axis according to the spatial extension length of the beam coverage area.

[0148] In this step, the multipath delay difference value refers to the time difference when the same signal propagates to the receiving end through different scattering paths, reflecting the spatial diversity characteristics of the propagation path.

[0149] The spatial extension length refers to the effective coverage distance of the beam in a specific main radiation direction, which is determined by the beam width, transmission power and environmental attenuation.

[0150] In this embodiment, a directional beam group is first generated by 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 multipath delay difference value is extracted by the channel estimation algorithm. Combined with the spatial extension length of the beam coverage area, the delay difference value is converted into a normalized displacement along the projection axis using a geometric mapping model. For example, the delay difference value of the vertical beam is converted into a displacement component on the height axis through a geometric relationship, 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 multidimensional delay feature set, which serves as the quantitative input of the spatial position offset.

[0151] Step 602: Based on the phase offset correlation values ​​of the same MIMO node device pair within adjacent beam coverage areas, calculate the projection component of the phase offset in the main radiation direction of the beam to generate a phase offset vector component.

[0152] In this step, the phase offset correlation value refers to the phase difference of the signals received by the same MIMO node device pair within adjacent beam coverage areas, reflecting the spatial correlation of the signal propagation path.

[0153] The projection component refers to the directivity quantization value after decomposing the phase offset along the main radiation direction of the beam, which is used to evaluate the distribution of phase consistency on the spatial axis.

[0154] In this embodiment, a coherent receiver first extracts the phase difference between signals within adjacent beam coverage areas to generate phase offset correlation values. Secondly, a geometric projection algorithm is used to decompose the phase offset correlation values ​​onto corresponding projection axes based on the spatial angle of the main radiation direction of the beam. For example, the phase offset value of the vertical beam is projected onto the altitude axis using the elevation angle, and the phase offset value of the horizontal beam is projected onto the horizontal axis using the azimuth angle. The projected components are then normalized to eliminate amplitude differences between beams and bounded to the delay vector components generated in step 601 along the same projection axis, forming a multidimensional spatial vector set that integrates delay and phase characteristics.

[0155] In step 603, the time delay vector component and the phase offset vector component are paired according to the beam number to generate a pairing result. The paired components in the pairing result are decomposed and superimposed along the coordinate axes of the three-dimensional spatial layout using a vector synthesis rule to generate a three-dimensional space vector component set including height, horizontal position, and depth direction.

[0156] In this step, the pairing result refers to a set of one-to-one associations between the delay vector components and the phase offset vector components corresponding to the same beam number, ensuring the mapping consistency between the two in the spatial direction.

[0157] The vector synthesis rule refers to the decomposition and superposition principle based on the three-dimensional coordinate system, which performs vector operations on the paired components along the coordinate axis to generate spatial displacements that integrate multi-dimensional features.

[0158] The coordinate axes of the three-dimensional spatial layout refer to the three-dimensional orthogonal coordinate system extended from the projection axes defined in step 601 , including height, horizontal position, and depth direction, and are used for global calculation of space vectors.

[0159] In this embodiment, the delay vector components and phase offset vector components are first matched by beam number, and a hash table or database index is used to achieve rapid pairing, ensuring data association within the same beam. Next, based on the coordinate axis definition of the three-dimensional spatial layout, a vector decomposition algorithm is used to orthogonally project each paired component along the coordinate axis. For example, the paired components of an oblique beam are decomposed into height, horizontal, and depth axes using direction cosines. The projected components on each axis are then accumulated based on the principle of linear superposition to generate a three-dimensional vector component set containing height, horizontal position, and depth directions. Finally, the resulting vector set is normalized and weighted to suppress noise interference and highlight the dominant displacement direction.

[0160] In order to solve the problem of coordinate solution error accumulation in the overlapping area of ​​multiple source signals, in some embodiments, according to step 105, the real-time three-dimensional coordinate data of the UAV in the target airspace is solved based on the spatial overlap relationship of the three-dimensional space vector components in the three-dimensional space layout, including:

[0161] Step 701: Delineate a corresponding spatial extension area for each vector component in a three-dimensional spatial layout according to the direction and magnitude of the three-dimensional spatial vector component.

[0162] 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 component, representing the boundary of the physical area that the vector component may affect.

[0163] Direction and magnitude refer to the directivity and strength of the vector components and are used to define the geometry of the extended area.

[0164] The spatial layout matching rule refers to mapping the direction and magnitude of the vector components to the corresponding spatial regions according to the geometric relationship of the three-dimensional coordinate system.

[0165] In this embodiment, a vector decomposition algorithm is first used to orthogonally decompose the three-dimensional vector components along the height axis (Z), horizontal axis (X), and depth axis (Y), extracting the direction and amplitude of each component. Secondly, the geometric model of the spatial extension area is defined based on the direction and amplitude: the vertical component (Z axis) is mapped into a vertical columnar area (the height range is determined by the amplitude), and the horizontal component (X / Y axis) is mapped into a fan-shaped or rectangular area (the span is determined by the amplitude). For example, the larger the amplitude of the height axis component, the longer the corresponding vertical columnar area extends along the Z axis; the larger the amplitude of the horizontal component, the wider the coverage angle of the fan-shaped area. Finally, the extension areas of all vector components are bound to physical space coordinates through a three-dimensional spatial index to generate a spatial area mapping table.

[0166] Step 702: extract the coordinates of the intersections of all vector components in the spatial extension area, and screen out a set of candidate intersections that meet both the preset aggregation threshold and continuity conditions by counting the degree of aggregation and the number of consecutive appearances of the intersections within a preset time window.

[0167] In this step, the candidate intersection point set refers to the set of intersection points of spatial extension areas of different vector components in three-dimensional space, representing the candidate locations where the drone may exist.

[0168] The degree of aggregation refers to the spatial distribution density of intersection points within a preset time window, reflecting the stability of the position solution.

[0169] The continuity condition refers to the threshold of the number of times the intersection point appears continuously at the same position, which is used to eliminate false positioning points caused by instantaneous interference.

[0170] In this embodiment, spatial geometry calculations are first used to extract the coordinates of the intersections of the spatially extended areas of all vector components. Computational geometry algorithms are then used to rapidly identify potential intersections in three-dimensional space. Next, a sliding time window statistical method is used to perform density clustering analysis on the intersections within a preset time period. Clustering algorithms such as DBSCAN are then used to identify high-density clusters. The number of consecutive appearances of each cluster center is then counted. For example, if an intersection appears in the same cluster area within three consecutive time windows, it is considered to meet the continuity condition. Finally, intersections that meet both the clustering threshold and the continuity condition (e.g., a sufficient number of consecutive appearances) are added to the candidate set and output to the positioning decision module.

[0171] Step 703, based on the height, horizontal position and depth coordinates of each candidate intersection in the candidate intersection set in the three-dimensional space layout, calculate the distribution interval of the candidate intersection in each direction respectively, and use the median of the coordinate value in the distribution interval as the basic reference value of the current direction.

[0172] In this step, the distribution interval refers to the range of coordinate values ​​of the candidate intersection point in a certain direction, reflecting the possible fluctuation boundary of the drone position in this dimension.

[0173] The basic reference value refers to the benchmark position determined by the median of the coordinate value within the statistical distribution interval, which is used to characterize the stable position solution in that direction.

[0174] In this embodiment, the three-dimensional coordinates of each intersection point in the candidate intersection set are first separated by the height (Z), horizontal (X), and depth (Y) directions, forming coordinate datasets for each direction. Next, the datasets for each direction are sorted, the minimum and maximum values ​​within their distribution intervals are calculated, and the median is extracted as the base reference value for that direction. For example, the median of the horizontal coordinate dataset corresponds to the drone's most stable position on the horizontal plane, while the median of the height coordinate dataset corresponds to the baseline height for vertical hovering. Finally, the base reference values ​​for the three directions are combined into a three-dimensional reference coordinate, which serves as the initial reference point for subsequent weight adjustments.

[0175] Step 704 : Dynamically adjust the contribution weight of each candidate intersection point to the basic reference value according to the magnitude and direction of the three-dimensional space vector component corresponding to each candidate intersection point and the deviation angle from the main radiation direction of the beam.

[0176] In this step, the contribution weight refers to the influence coefficient of the candidate intersection point on the basic reference value, which is determined by the amplitude and direction deviation angle of the vector component.

[0177] 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 degree of deviation of the signal propagation path.

[0178] In this embodiment, the amplitude 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 are first calculated. A weighting function is then designed based on the inverse relationship between amplitude and deviation angle: candidate intersection points with larger amplitudes and smaller deviation angles receive higher contribution weights.

[0179] In step 705, the coordinate values ​​of all candidate intersection points in the height, horizontal position and depth direction after weight adjustment are weighted and fused to generate real-time three-dimensional coordinate data of the UAV in the target airspace.

[0180] In this step, weighted fusion refers to performing weighted averaging operations on the three-dimensional coordinates of different candidate intersection points according to their contribution weights to generate a comprehensive position solution with high confidence.

[0181] Real-time three-dimensional coordinate data refers to the spatial position information output after integrating the weighted results of altitude, horizontal and depth directions, representing the real-time dynamic position of the UAV in the target airspace.

[0182] In this embodiment, the candidate intersection weights adjusted in step 704 are first separated by the height (Z), horizontal (X), and depth (Y) directions, and a weighted average is calculated for each direction. For example, the X coordinates of all candidate intersections in the horizontal direction are multiplied by their weights, added together, and then divided by the sum of the weights to obtain the weighted fusion X-axis coordinate. Next, the weighted results for the three directions are normalized to ensure the physical spatial consistency of the coordinate values. The weighted coordinates for the height, horizontal, and depth directions are then combined into real-time three-dimensional coordinate data and dynamically updated within a time window. Finally, the real-time coordinate data is input into the drone navigation and control system for use in trajectory planning, obstacle avoidance, or mission execution.

[0183] Figure 2 The present invention provides a schematic diagram of a three-dimensional coordinate positioning system for a UAV based on distributed MIMO nodes. Figure 2 As shown, the system includes:

[0184] A construction module is used to deploy multiple MIMO node devices in an asymmetric topology on at least three different altitude planes in the target airspace to build a three-dimensional spatial layout covering the drone activity area;

[0185] an acquisition module, configured to acquire, based on signal coverage overlap characteristics at different altitudes in the three-dimensional spatial layout, a set of characteristic parameters associated with the three-dimensional spatial distribution of wireless signals reflected by the drone through a multi-node cooperative signal receiving and transmitting mechanism between the MIMO node devices, the set of characteristic parameters including a multipath delay difference value and a phase offset correlation value;

[0186] a compensation module, configured to perform phase modulation compensation on a transmission signal of the MIMO node device according to a height difference relationship between different altitude planes in the three-dimensional spatial layout, and generate a directional beam group matching the three-dimensional spatial layout;

[0187] A conversion module, configured to convert the multipath delay difference value and the phase offset associated value in the characteristic parameter set into a three-dimensional space vector component based on the dynamic coverage range of the directional beam group in the three-dimensional space layout;

[0188] A solution module is used to solve 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.

[0189] Figure 2 The three-dimensional coordinate positioning system of UAV based on distributed MIMO nodes can be performed Figure 1The implementation principle and technical effects of the distributed MIMO node-based three-dimensional coordinate positioning method for drones described in the illustrated embodiment will not be elaborated on here. The specific manner in which each module and unit performs operations in the distributed MIMO node-based three-dimensional coordinate positioning system for drones in the above embodiment has been described in detail in the relevant embodiments of the method and will not be elaborated on here.

[0190] In one possible design, Figure 2 The three-dimensional coordinate positioning system of a UAV based on distributed MIMO nodes of the embodiment shown can be implemented as a computing device, such as Figure 3 As shown, the computing device may include a storage component 31 and a processing component 32;

[0191] 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 .

[0192] The processing component 32 is used for the above Figure 1 The embodiment provides a three-dimensional coordinate positioning method for a UAV based on distributed MIMO nodes.

[0193] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions 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 unmanned aerial vehicles based on distributed MIMO nodes, characterized in that: include: Deploy multiple MIMO node devices in an asymmetric topology on at least three different altitude planes in the target airspace to build a three-dimensional spatial layout covering the drone activity area; Based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional spatial layout, a set of characteristic parameters related to the three-dimensional spatial distribution of the wireless signal reflected by the drone is obtained through a multi-node cooperative signal receiving and transmitting mechanism between the MIMO node devices, the characteristic parameter set including a multipath delay difference value and a phase offset correlation value; performing phase modulation compensation on the transmission signal of the MIMO node device according to the height difference relationship between different altitude planes in the three-dimensional spatial layout to generate a directional beam group matching the three-dimensional spatial layout; Based on the dynamic coverage of the directional beam group in the three-dimensional spatial layout, converting the multipath delay difference value and the phase offset associated value in the characteristic parameter set into a three-dimensional spatial vector component; 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 space vector components in the three-dimensional space layout.

2. The method according to claim 1, characterized in that Based on the signal coverage overlap characteristics of different altitude planes in the three-dimensional spatial layout, a set of characteristic parameters related to the three-dimensional spatial distribution in the wireless signal reflected by the drone is obtained through a multi-node cooperative signal receiving and transmitting mechanism between the MIMO node devices, including: By setting multiple MIMO node devices in an asymmetric topology structure to alternately transmit detection signals according to preset time windows, and synchronously receive multipath signals reflected by drones; Extract the time difference sequence of the multipath signals of the same detection signal reflected from 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; Extracting the phase offset of the multipath signal received by each MIMO node device based on the phase change between the transmission and reception of the detection signal, and generating a phase offset correlation value by calculating the correlation between the phase offsets of at least two MIMO node devices on the same altitude plane; The multipath delay difference value and the phase offset correlation value are bound according to the serial number of the signal transmitting and receiving node pair to form a characteristic parameter set including three-dimensional spatial distribution correlation.

3. The method according to claim 1, characterized in that The method further comprises performing phase modulation compensation on a transmission signal of the MIMO node device according to a height difference relationship between different altitude planes in the three-dimensional spatial layout to generate a directional beam group matching the three-dimensional spatial layout, including: Calculate the phase adjustment amount corresponding to the altitude difference between the altitude plane where each MIMO node device is located and the adjacent plane; Adding the phase adjustment amount to the initial phase of the MIMO node device transmit signal to obtain a transmit signal after superimposing the phase adjustment; Through the synchronous transmission of multiple MIMO node devices, the superimposed phase-adjusted transmission signal forms 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 topological structure, generating a directional beam group covering the drone activity area.

4. The method according to claim 3, characterized in that Adding the phase adjustment amount to the initial phase of the MIMO node device transmit signal to obtain a transmit signal after the superimposed phase adjustment, including: Determining a superposition direction of the phase adjustment amount based on a vertical height difference between an altitude plane where each MIMO node device is located and an adjacent plane, wherein when the MIMO node device is at an altitude plane at a preset height, the superposition direction of the phase adjustment amount is a downward compensation direction; and when the MIMO node device is below the altitude plane at the preset height, the superposition direction of the phase adjustment amount is an upward compensation direction; Based on the superposition direction, decomposing the phase adjustment amount into an orthogonal phase component corresponding to each subcarrier in the transmitted signal, and superimposing the orthogonal phase component with the initial phase point by point according to the frequency distribution relationship of the subcarriers to obtain a superimposed phase; The superimposed phase is periodically checked for continuity. When the phase difference between adjacent subcarriers exceeds a preset transition threshold, a transition phase value is inserted between adjacent subcarriers by interpolation to generate a transmitted signal after superimposed phase adjustment.

5. The method according to claim 3, characterized in that Through the synchronous transmission of multiple MIMO node devices, the superimposed phase-adjusted transmission signals 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 topological structure, generating a directional beam group covering the drone activity area, including: According to the height difference distribution of each altitude plane in the asymmetric topology structure, the MIMO node devices are divided into multiple highly correlated node groups, where each node group contains at least one high-altitude plane node and one low-altitude plane node; A synchronous transmission time window is set for each node group, and the transmission signals of different node groups are triggered in sequence within the time window according to a preset order, so that the transmission signals of high-altitude nodes and low-altitude nodes in the same node group form a complementary phase relationship on the spatial propagation path; Based on the complementary phase relationship, a main lobe direction with the height difference line as the deflection axis is formed in three-dimensional space through the superposition effect of the downward compensation direction of the high-altitude node and the upward compensation direction of the low-altitude node; According to the real-time position feedback of the drone activity area, the triggering order of the synchronous transmission time window and the node group division rules are dynamically adjusted to deflect the main lobe direction of each beam toward the direction of the real-time position feedback, thereby generating a directional beam group covering the drone activity area.

6. The method according to claim 1, characterized in that The method includes converting the multipath delay difference value and the phase offset associated value in the characteristic parameter set into a three-dimensional space vector component based on the dynamic coverage range of the directional beam group in the three-dimensional space layout, including: According to the main radiation direction of each beam in the directional beam group, a spatial direction projection axis corresponding to each beam is established, and the multipath delay difference value is mapped into a 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 values ​​of the same MIMO node device pair within the adjacent beam coverage area, the projection component of the phase offset in the main radiation direction of the beam is calculated to generate a phase offset vector component; The time delay vector component and the phase offset vector component are paired according to the beam number to generate a pairing result. The paired components in the pairing result are decomposed and superimposed along the coordinate axis of the three-dimensional space layout according to the vector synthesis rule to generate a three-dimensional space vector component set including height, horizontal position and depth direction.

7. The method according to claim 1, characterized in that Calculating real-time three-dimensional coordinate data of the UAV in the target airspace based on the spatial overlap relationship of the three-dimensional space vector components in the three-dimensional space layout includes: Delineating a corresponding spatial extension region for each vector component in the three-dimensional spatial layout according to the direction and magnitude of the three-dimensional spatial vector component; Extracting the coordinates of the intersection points of all vector components within the spatial extension area, and screening out a set of candidate intersection points that simultaneously meet a preset aggregation threshold and continuity conditions by counting the degree of aggregation and the number of consecutive appearances of the intersection points within a preset time window; Based on the height, horizontal position and depth coordinates of each candidate intersection point in the three-dimensional spatial layout, the distribution interval of the candidate intersection points in each direction is calculated respectively, and the median of the coordinate values ​​within the distribution interval is used as the basic reference value of the current direction; Dynamically adjust the contribution weight of each candidate intersection point to the basic reference value based on the magnitude and direction of the three-dimensional space vector component corresponding to each candidate intersection point and the deviation angle from the main radiation direction of the beam; The coordinate values ​​of all candidate intersection points in height, horizontal position and depth direction after weight adjustment are weighted fused to generate 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: include: A construction module is used to deploy multiple MIMO node devices in an asymmetric topology on at least three different altitude planes in the target airspace to build a three-dimensional spatial layout covering the drone activity area; an acquisition module, configured to acquire, based on signal coverage overlap characteristics at different altitudes in the three-dimensional spatial layout, a set of characteristic parameters associated with the three-dimensional spatial distribution of wireless signals reflected by the drone through a multi-node cooperative signal receiving and transmitting mechanism between the MIMO node devices, the set of characteristic parameters including a multipath delay difference value and a phase offset correlation value; a compensation module, configured to perform phase modulation compensation on a transmission signal of the MIMO node device according to a height difference relationship between different altitude planes in the three-dimensional spatial layout, and generate a directional beam group matching the three-dimensional spatial layout; A conversion module, configured to convert the multipath delay difference value and the phase offset associated value in the characteristic parameter set into a three-dimensional space vector component based on the dynamic coverage range of the directional beam group in the three-dimensional space layout; A solution module is used to solve 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 It includes 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 three-dimensional coordinate positioning method for a drone 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, the method for three-dimensional coordinate positioning of a drone based on distributed MIMO nodes as described in any one of claims 1 to 7 is implemented.

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