Ultra-short wave-based large-scale airborne personnel or material positioning and gathering method

Abstract

The invention discloses a personnel or material positioning and gathering method based on ultra-short wave large-scale airborne landing, and the method comprises the following steps: 1, arranging at least three beacons in a designated airborne landing region, and building a first coordinate system or a second coordinate system containing all beacons; step 2, determining position information of all beacons on the first coordinate system or the second coordinate system, and completing time synchronization of all beacons; step 3, periodically broadcasting respective position information and state information by each beacon, and air-dropping a plurality of personnel or materials in the designated airborne area as airborne nodes; and step 4, each airborne node determines its own level according to a set strategy, the airborne nodes of each level complete time synchronization with all beacons, then range finding and positioning are carried out according to a time sequence, and own position information and state information are broadcasted. According to the invention, rapid and accurate positioning and gathering of large-scale airborne personnel or materials on the ground are realized, and the action efficiency is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of positioning technology, and in particular to a method for positioning and assembling large-scale airborne personnel or materials based on ultra-short waves, which is particularly suitable for conditions of satellite denial or when the positioning function of some airborne personnel or materials fails. Background Art

[0002] Airborne operations are often accompanied by the parachuting and airdropping of a large number of personnel and supplies. Conventional airdrop missions are usually easily affected by environmental factors such as wind direction and wind speed. After the supplies and personnel are dropped in batches, the landing points are widely scattered and the posture is unstable, so the position of the airborne personnel or materials needs to be accurately located.

[0003] However, in some special cases, such as satellite denial (for some reason, the global satellite positioning system or the positioning device embedded with the global positioning function module is in an abnormal working state and cannot provide users with accurate satellite positioning information), or the positioning function of airborne personnel or materials fails, the existing products can only solve small-scale ground positioning assembly, which uses ultra-short wave radio direction finding technology, combined with the received signal strength RSSI (Received Signal Strength Indication), to preliminarily determine the target direction and distance. In specific applications, the predetermined beacon periodically transmits the predetermined signal, and the personnel hold a large and heavy directional antenna, circle around to search and determine the general direction of the target, and then gradually approach. This technology has some shortcomings. First, the directional antenna direction finding accuracy is not high enough, manual operation is complicated, and the size is large, making it inconvenient to carry. Second, the method of determining the target distance based on the received signal strength RSSI index is easily affected by the application environment, and the ranging accuracy is poor. Combined with the low direction finding accuracy, the positioning error is relatively large. Third, the positioning time of a single target is relatively long, which is difficult to apply to the positioning and assembly of large-scale airborne personnel and materials (referring to the process of using certain technical means to achieve periodic relative or absolute positioning of users, and moving to a predetermined designated position) requirements.

[0004] In view of this, the inventor provides a method for positioning and assembling large-scale airborne personnel or materials based on ultra-short waves to solve the above technical problems. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and propose a method for positioning and assembling large-scale airborne personnel or materials based on ultra-short waves. The method is based on a new idea of ​​realizing hierarchical positioning of each airborne node based on preset beacons. Airborne nodes of different levels optimize positioning anchor points in a hierarchical and time-sharing manner, adopt active ranging and positioning methods, and timely broadcast and relay their own position and status information to achieve the purpose of information sharing across the entire network.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for positioning and assembling large-scale airborne personnel or materials based on ultrashort waves, comprising the following steps:

[0008] Step 1: deploy at least 3 beacons in the designated airborne area, and establish a first coordinate system or a second coordinate system containing all beacons;

[0009] Step 2: determining the position information of all beacons in the first coordinate system or the second coordinate system, and completing the time synchronization of all beacons;

[0010] Step 3: Each of the beacons periodically broadcasts its own location information and status information, and simultaneously airdrops multiple personnel or materials in the designated airdrop area as airdrop nodes;

[0011] Step 4: Each of the airborne nodes determines its own level according to the set policy. Airborne nodes of each level complete time synchronization with all beacons, then perform ranging and positioning in a time sequence, and broadcast their own location information and status information, so that all airborne nodes can know each other's location information and status information.

[0012] Furthermore, in step 1, the process of establishing the first coordinate system is as follows:

[0013] Among at least three beacons, one beacon is designated as a main beacon, and the remaining beacons are designated as secondary beacons, and a first coordinate system including all secondary beacons is formed with the main beacon as the origin, that is, a relative positioning coordinate system;

[0014] The second coordinate system is obtained by transforming the relative positioning coordinate system, that is, the absolute positioning coordinate system.

[0015] Furthermore, in step 2, a TOA or TDOA algorithm is selected in the first coordinate system to determine the relative position information between any two of the beacons.

[0016] Further, the first coordinate system is applicable under satellite denial conditions, or under conditions where the number of airborne nodes or beacons containing satellite positioning information is less than 3;

[0017] The second coordinate system is applicable when at least three airborne nodes or beacons have satellite positioning information.

[0018] Furthermore, in step 1, the communication range formed by the at least three beacons can cover the designated airborne area, and the distance between any two beacons is greater than the ranging error.

[0019] Furthermore, in step 3, the status information includes time information and numbers of the primary beacon and the secondary beacon.

[0020] Furthermore, in step 4, the set strategy is to determine the level of each airborne node according to the number of direct connections between each airborne node and all beacons, and the level division conditions are as follows:

[0021] Level 1 airborne node, an airborne node that can directly communicate with at least 3 beacons;

[0022] Secondary airborne node, an airborne node that can communicate directly with 1 to 2 beacons;

[0023] A third-level airborne node is an airborne node that can only communicate directly with a second-level node.

[0024] Further, in step 4, the process of airborne nodes of each level performing ranging, positioning and broadcasting in time sequence includes the time slot sequence of the main beacon sending each airborne node, and the airborne nodes of each level implement ranging, positioning and information sharing in steps, and the specific steps are as follows:

[0025] Step 4.1: The first-level airborne node completes ranging and positioning within the first round of positioning sharing cycle, and shares location information and status information;

[0026] Step 4.2: In the second round of positioning sharing cycle, the second-level airborne node selects the positioning anchor point according to the positioning anchor point selection strategy, completes the ranging and positioning, and selects the located beacon and the first-level airborne node as the relay node to relay and share the location information and status information as needed. At the same time, the first-level airborne node updates the location information;

[0027] Step 4.3: In the third round of positioning sharing cycle, the third-level airborne node selects the positioning anchor point according to the positioning anchor point selection strategy, completes the ranging and positioning, and selects the first-level and second-level airborne nodes that have been located as relay nodes as needed to relay and share the location information and status information. At the same time, the first-level and second-level airborne nodes update the location information;

[0028] In the subsequent positioning sharing cycle, the ranging and positioning of airborne nodes of each level are completed in sequence according to the time slot order, and then the position information and status information are shared.

[0029] Furthermore, the ranging is accomplished by using a spread spectrum active ranging technology between each airborne node and its positioning anchor point; and the positioning is to use a TOA or TDOA algorithm to determine the relative position information of any airborne node.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1) The present invention proposes a method for positioning and assembling large-scale airborne personnel or materials based on ultra-short waves. The method pre-deploys at least three beacons as positioning anchor points, constructs a relative positioning coordinate system or an absolute positioning coordinate system with the main beacon as the origin, and classifies the airborne nodes placed on the coordinate system, and then performs ranging, positioning, and position and status information sharing on the classified airborne nodes, so that all airborne nodes can obtain each other's position information and status information. The present invention adopts ultra-short wave autonomous positioning technology to achieve rapid and accurate positioning and assembly of large-scale airborne personnel or materials on the ground, effectively improving the efficiency of operations, especially under satellite denial conditions.

[0032] 2) The present invention proposes a method for locating and assembling large-scale airborne personnel or materials based on ultra-short waves. The method adopts a relay strategy and a relay forwarding process, in which the optimization algorithm for selecting positioning anchor points and relay nodes is simple and practical, and the implementation complexity is relatively low. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the present invention.

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 It is a schematic diagram of the flow of the positioning and aggregation method of the present invention;

[0036] Figure 2 It is a schematic diagram of relative positioning of four beacons in the positioning assembly method of the present invention;

[0037] Figure 3 It is a schematic diagram of the node level ratio of the four beacons deployed at a communication distance of 2000 to 3500 meters in the positioning assembly method of the present invention;

[0038] Figure 4 It is a schematic diagram of the basic working process of airborne node communication positioning in the positioning assembly method of the present invention;

[0039] Figure 5 It is the node sharing coverage rate of the four beacon 400 nodes of the present invention at a communication distance of 3000 meters;

[0040] Figure 6 It is a schematic diagram of converting the relative coordinate system in the positioning and assembly method of the present invention into an absolute coordinate system. DETAILED DESCRIPTION

[0041] Here, exemplary embodiments will be described in detail, and the embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are only examples consistent with some aspects of the present invention described in detail in the appended claims.

[0042] Example 1

[0043] This embodiment is intended for situations where satellite denial conditions exist or where the positioning function of some airborne personnel or materials fails. Figures 1 to 5 The embodiment of the present invention provides a method for positioning and assembling large-scale airborne personnel or materials based on ultrashort waves, comprising the following steps:

[0044] Step 1: deploy at least 3 beacons in the designated airborne area and establish a first coordinate system containing all beacons;

[0045] Step 2: determining the relative position information between any two of the beacons in the first coordinate system, and completing the time synchronization between any two of the beacons;

[0046] Step 3, each beacon periodically broadcasts its own location information and status information, and at the same time airdrops multiple personnel or materials in the designated airdrop area as an airdrop node; Step 4, each airdrop node determines its own level according to the set policy, and airdrop nodes of each level complete time synchronization with all beacons, and then perform ranging and positioning in a time sequence, and broadcast their own location information and status information, so that all airdrop nodes can obtain each other's location information and status information.

[0047] It should be noted that a large number of personnel or materials airdropped into the airdrop area carry portable communication devices based on ranging and positioning, such as mobile phone terminals.

[0048] Furthermore, in step 1, the process of establishing the first coordinate system is as follows:

[0049] Among at least three beacons, one beacon is designated as a main beacon, and the remaining beacons are designated as secondary beacons. A first coordinate system including all secondary beacons is constructed with the main beacon as the origin, namely, a relative positioning coordinate system.

[0050] Solving the early deployment of beacons is a prerequisite for achieving subsequent airborne node positioning. This embodiment takes the deployment of four beacons as an example for specific explanation.

[0051] Before large-scale airdrop of personnel or materials, four personnel carrying beacons with positioning functions are airdropped first. After keeping a certain distance on the ground according to the established strategy, they begin to perform the task of mutual ranging and positioning. The positioning process is as follows: Figure 2As shown, before ranging, the main beacon No. 0 (A) sends a service message, which is equivalent to system time synchronization. The secondary beacons No. 1 to No. 3 (B, C, D) respond in turn (if there is satellite positioning information, they send their own positioning information). After several rounds, it is ensured that the beacons can communicate. Then the ranging task is performed between two beacons: 1) A first measures the distance between the two beacons B and C, and B measures the distance between the C signal. The B signal transmits the ranging information back to A. With A as the coordinate origin and AB as the X coordinate axis, the relative coordinates of C (Xc, Yc) are calculated; 2) Beacon A broadcasts the relative position of ABC signals to beacon D, and D measures the distance between ABC respectively, and then calculates its own relative position (Xd, Yd) according to the three-point ranging positioning method (TOA or TDOA), and then broadcasts and shares the result, so that the relative positions of the four beacons are all determined. The same principle can also achieve relative ranging and positioning of more beacons.

[0052] The established strategy described above is not limited here, as long as the following two conditions are met: 1) the communication range formed by the four beacons can cover the designated airborne area; 2) the distance between any two beacons is greater than the ranging error.

[0053] Furthermore, the first coordinate system is applicable to satellite denial conditions, or to conditions where the number of airborne nodes or beacons containing satellite positioning information is less than 3. In this case, only airborne nodes without Beidou positioning information need ranging and positioning processing.

[0054] In step 4, considering the ground communication distance and the range of the airdrop field, the set strategy is to determine the level of each airdrop node according to the number of direct connections between each airdrop node and all beacons. The level division conditions are as follows:

[0055] Level 1 airborne node: an airborne node that can directly communicate with at least three beacons. The level 1 airborne node can directly select the beacon as the positioning anchor point to achieve ranging and positioning;

[0056] Secondary airborne nodes are airborne nodes that can communicate directly with at least 1 beacon and at most 2 beacons. The secondary airborne nodes cannot directly rely on beacons for positioning, and need to use "communicable beacons + located primary and secondary airborne nodes" as positioning anchor points. This type of node can be divided into two cases: 1) 2 beacons + 1 primary node; 2) 1 beacon + 2 primary nodes;

[0057] The third-level airborne node can only communicate directly with the second-level node. The third-level airborne node can only select the "second-level and third-level airborne nodes that have been located" as the positioning anchor point to achieve its own ranging and positioning.

[0058] Whether the airborne node can communicate directly with the beacon depends mainly on: 1) the layout configuration of the beacon; 2) the point-to-point communication distance of the assembly waveform; 3) the ground terrain conditions of the airborne field; 4) the distribution of the airborne node landing points. The above conditions jointly determine the proportion of airborne nodes of different levels. It can be expected that in the airborne assembly application scenario, it is mainly concentrated on the first and second level airborne nodes, and the proportion of the third level airborne nodes is relatively low.

[0059] like Figure 3 As shown, it is a schematic diagram of the level ratio when 4 beacons are deployed, 400 randomly distributed nodes are in a 3km*5km airborne area, and the communication distance is 2000~3500 meters.

[0060] In this embodiment, the ranging and positioning order of airborne nodes of different levels is as follows:

[0061] In terms of positioning order, the first-level airborne node is positioned first, then the second-level airborne node, and finally the third-level airborne node. In terms of positioning accuracy (based on statistical significance), the first-level airborne node has the highest positioning accuracy, the second-level airborne node has the second highest positioning accuracy, and the third-level airborne node has the worst positioning accuracy. Positioning accuracy depends on: 1) the relative position accuracy of the positioning anchor point; 2) the layout configuration factor coefficient of the positioning anchor point; 3) the ranging accuracy between the airborne node and the positioning anchor point.

[0062] Further, in step 4, the main beacon sends relative position information, the secondary beacon forwards the relative position information in sequence, and the process of airborne nodes of each level performing ranging, positioning and broadcasting in time sequence includes the main beacon sending its corresponding time slot sequence to airborne nodes of each level, and airborne nodes of each level implement ranging, positioning and information sharing step by step. The specific steps are as follows:

[0063] Step 4.1: The first-level airborne node completes ranging and positioning within the first round of positioning sharing cycle, and shares location information and status information;

[0064] Step 4.2: In the second round of positioning sharing cycle, the second-level airborne node selects the positioning anchor point according to the positioning anchor point selection strategy, completes the ranging and positioning, and selects the located beacon and the first-level airborne node as the relay node to relay and share the location information and status information as needed. At the same time, the first-level airborne node updates the location information;

[0065] Step 4.3: In the third round of positioning sharing cycle, the third-level airborne node selects the positioning anchor point according to the positioning anchor point selection strategy, completes the ranging and positioning, and selects the first-level and second-level airborne nodes that have been located as relay nodes as needed to relay and share the location information and status information. At the same time, the first-level and second-level airborne nodes update the location information;

[0066] During subsequent positioning sharing cycles, ranging and positioning of airborne nodes at each level are sequentially completed in the order of time slots, and then position information and status information are shared.

[0067] In this embodiment, the positioning anchor point selection strategy is as follows:

[0068] For the three-anchor TOA positioning algorithm, a relatively simple and practical method is adopted: for the triangle formed by the three positioning anchor points, arrange the lengths of the three sides in ascending order (d1 < d2 < d3), calculate the ratio of the sum of the first two to the third ((d1 + d2) / d3), which theoretically ranges from (1, 2). The larger this value, the better the positioning effect. Simulation results show that as long as this value exceeds 1.1, the positioning error can be significantly reduced. In addition, it is necessary to ensure that the interval between each positioning anchor point is greater than the ranging error.

[0069] In addition, when the positioning beacon anchor point is damaged and unavailable, or there are more optimal anchor points, the already positioned target nodes can temporarily act as positioning anchor points. A simple and practical optimization algorithm is used to select appropriate positioning anchor points.

[0070] In this embodiment, the master beacon is used to be responsible for the scheduling and control of the entire process, so as to ensure the smooth operation of the assembly system composed of beacons and airborne nodes. Any one of the four beacons can serve as the master beacon, and the master beacon can be specified in advance or temporarily.

[0071] Furthermore, the ranging is completed by each airborne node and its positioning anchor point using spread spectrum active ranging technology; the positioning is to select the TOA or TDOA algorithm to determine the relative position information of any airborne node.

[0072] As Figure 4 is the flowchart of communication positioning for airborne nodes. Specifically, (1) Four beacons are pre-deployed, the beacon topology structure is initially determined, and the system time synchronization between beacons is completed; (2) After the relative position determination and time synchronization of the beacon system are completed, it enters the network positioning stage. The master beacon, as the main control node, periodically sends synchronization signals, which carry its own number and the relative position information of each beacon (if there is Beidou positioning information, it is replaced with Beidou position information), and the three slave beacons also send corresponding information in turn. The purpose of this move is to enable as many airborne nodes as possible to determine their own levels and complete the time synchronization with the beacon system within at least one complete cycle.

[0073] In this stage, all airborne nodes can complete the determination of their own levels. It should be noted that if an airborne node is an isolated node (level-three airborne node), although it cannot directly receive beacon information, it can receive the information of level-two airborne nodes and thus achieve time synchronization accordingly.

[0074] (3) After a predetermined period of time, the master beacon sends the time slot sequence of each airborne node, implementing positioning and information sharing in steps:

[0075] 1) Level 1 airborne node: During the first round of positioning sharing cycle, the level 1 airborne node completes positioning and location information sharing.

[0076] 2) Secondary airborne nodes: In the second round of positioning sharing cycle, in addition to the first-level airborne nodes completing position update and sharing within the preset time slots, the second-level airborne nodes can basically achieve positioning and sharing according to the preset time slot order with the help of necessary original positioning beacons and the located first-level airborne nodes and even the same type of located second-level airborne nodes.

[0077] After the first-level airborne node shares the positioning information, the second-level airborne node can determine which nodes can be used to achieve its own positioning and location information sharing. At this stage, the second-level airborne node can select the positioning anchor point configuration as the positioning anchor point and potential relay node during the waiting period.

[0078] The second round of positioning sharing cycle ends, and only the third-level airborne nodes and special isolated second-level airborne nodes need to be positioned.

[0079] 3) Level 3 airborne nodes: In the third round of positioning and sharing cycle, the level 1 airborne nodes and level 2 airborne nodes complete position update and sharing within the preset time slots. The level 3 airborne nodes can basically achieve positioning and sharing with the help of the located level 2 airborne nodes or even the same level 3 airborne nodes that have been located according to the preset time slot order.

[0080] After the second-level node shares the positioning information, similar to the second-level node processing, the third-level node can determine whether or which nodes to use to achieve its own positioning and location information sharing. The selection process of the relay node is also similar to the above.

[0081] After three rounds of positioning, the positioning and location information sharing of all airborne nodes can be basically guaranteed. In the end, there may be some isolated airborne nodes that cannot gather enough beacons to achieve positioning. During this period, these isolated airborne nodes can only maintain the receiving state and wait for subsequent opportunities. This is very rare in actual situations and is equivalent to a lost node.

[0082] From the above process, three positioning cycles are required to meet the positioning and location sharing requirements of all airborne nodes. The above analysis is based on the premise that there are three levels of airborne nodes. If there are only two levels of airborne nodes, only two cycles are required. Similarly, if there is only one level of airborne nodes, only one cycle is required. During these three cycles, the location information of the first-level airborne nodes is updated twice, and the location information of the second-level airborne nodes is updated once. After the three complete positioning cycles, since all airborne nodes have initial location information, subsequent location updates of airborne nodes of different levels only require one cycle.

[0083] In actual situations, in the first positioning cycle, the second-level airborne node may use the already located first-level airborne node and the communication beacon (the time slot order of the first-level airborne node is before the second-level airborne node, and it can communicate directly with the second-level airborne node) to achieve its own positioning without waiting for the time slot of the second positioning cycle. The same process is applied to the third-level airborne node.

[0084] Large-scale airborne operations generally require nodes to know each other's location and status information for task scheduling and control. Unless the communication positioning equipment configured on the airborne nodes has a long enough communication distance and all airborne nodes and beacons are within the communication range, that is, any two nodes can communicate, otherwise a relay node needs to be selected for relay forwarding.

[0085] The fully connected network formed by each airborne node and beacon in this embodiment is a distributed control network that needs to be relayed multiple times to achieve full network accessibility. Considering that the actual airborne area is distributed in a rectangular shape, in most cases, relaying twice basically satisfies the full network accessibility of node information.

[0086] The above analysis involves the selection strategy of relay nodes, and the selection of relay nodes needs to consider the coverage of relay nodes. In the stage where beacons take turns to transmit beacon positions and status information, an important task is to broadcast the relative positions of the four beacons to the entire network. All nodes within the range (union) that the four beacons can cover can obtain the beacon position and status information. As long as the beacons are reasonably laid out and can cover most of the airborne areas (including most of the first-level airborne nodes and second-level airborne nodes), each airborne node at this stage can use this to judge its own node level. Even a second-level airborne node that can only be directly connected to no more than two beacons can obtain the positions of all four beacons, and can preliminarily judge the approximate area where it is located.

[0087] In the initial positioning sharing stage, the first-level airborne node does not know the location of other airborne nodes before sharing the location, and cannot select nodes other than beacons. Therefore, it can select beacons that are far away from itself, or other first-level airborne nodes that have been located as relay nodes to cover a wider range; the relay node selection of the second-level airborne node, in addition to possible beacons, also includes the first-level airborne nodes and second-level airborne nodes that have been located; the relay node selection of the third-level airborne node, in addition to the first-level airborne node, also includes the second-level airborne nodes and third-level airborne nodes that have been located. After the initial positioning stage is completed, it enters the node update positioning stage. All airborne nodes that can receive information basically obtain the location information of beacons and other airborne nodes. The airborne node can connect to a beacon through at most one relay, and then select another beacon with the farthest distance to relay and forward once, which can basically meet the requirements of covering the airborne area.

[0088] A simple and practical relay strategy: Based on the basic position judgment of the airborne node in the airborne area (the node can make a preliminary judgment based on the beacon coordinates, its own positioning coordinates and other node coordinate data, and can also use the received signal strength RSSI indicator to assist in the judgment), if the node itself is located in the middle of the airborne field, it will give priority to both ends and relay once respectively (or the communication capability is strong enough and no relay is required); if the airborne node is located at one end, the airborne node closer to the other end will be selected to relay once, or the airborne node in the middle will be selected to continue to relay to the other end once.

[0089] Assuming that there are at most two relays, there are two relay methods: a) the node designates two relay nodes and lets them relay in turn; b) the node designates a relay node, and then the node designates subsequent relay nodes by itself, because the node itself needs to consider the relay strategy, which is equivalent to relying on the relay strategy of the relay node.

[0090] Figure 5 for Figure 3 The beacon deployment conditions shown are A (0, 1500), B (3000, 1500), C (3000, 3500) and D (0, 3500), the airdrop area is 3000*5000 meters, the airdrop node interval is at least 30 meters, the entire airdrop area is evenly and randomly distributed, the node communication distance is 3000 meters, the maximum relay is twice (using the above simple and practical relay strategy), the number of airdrop nodes is 400, and the cumulative distribution of the average shared coverage of each airdrop node to all other airdrop nodes (including beacons). Figure 5 It can be seen that the shared coverage rate of airborne nodes is as low as 96.52%, as high as 100%, and as high as 99.52% on average. Considering that the actual airborne nodes are relatively concentrated on the ground, the shared coverage rate will be further improved.

[0091] Example 2

[0092] This embodiment is for the case where at least three airborne nodes or beacons have satellite positioning information or all airborne nodes and beacons have Beidou positioning information. Figure 6 As shown, the difference between this embodiment and embodiment 1 lies in the different application scenarios and coordinate system establishment. The details are as follows:

[0093] Step 1: deploy at least 3 beacons in the designated airborne area and establish a second coordinate system containing all beacons;

[0094] Step 2: determine the absolute position information of all beacons in the second coordinate system, and complete the time synchronization of all beacons; the second coordinate system is obtained by converting the relative positioning coordinate system, that is, the absolute positioning coordinate system.

[0095] Furthermore, the second coordinate system is applicable to the case where at least three airborne nodes or beacons have satellite positioning information; or when all airborne nodes and beacons have Beidou positioning information, the entire relative positioning coordinate system can be converted into an absolute positioning coordinate system, such as Figure 6 shown.

[0096] Figure 6 The airborne nodes (D, E, F) shown in the figure have calculated their relative positions according to the relative coordinate system. When the absolute positions (D*, E*, F*) are obtained, the relative coordinate system adjustment requires a rotation of a certain angle α (∠DAD*) along the coordinate origin (A). Assume that in the relative coordinate system, the coordinates of beacon ABCD are A(0, 0), B(Xb, 0), C(Xc, Yx) and D(Xd, Yd), respectively. In the absolute coordinate system, the coordinates of beacon ABCD are A(0, 0), B(Xb*, Yb*), C(Xc*, Yx*) and D(Xd*, Yd*), respectively. The conversion relationship between the beacon coordinate values ​​is:

[0097]

[0098] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0099] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for positioning and assembling large-scale airborne personnel or materials based on ultrashort waves, characterized in that: The following steps are involved: Step 1: deploy at least 3 beacons in the designated airborne area, and establish a first coordinate system or a second coordinate system containing all beacons; Step 2: determining the position information of all beacons in the first coordinate system or the second coordinate system, and completing the time synchronization of all beacons; Step 3: Each of the beacons periodically broadcasts its own location information and status information, and simultaneously airdrops multiple personnel or materials in the designated airdrop area as airdrop nodes; Step 4: Each of the airborne nodes determines its own level according to the set policy. Airborne nodes of each level complete time synchronization with all beacons, then perform ranging and positioning in a time sequence, and broadcast their own location information and status information, so that all airborne nodes can know each other's location information and status information.

2. The method for positioning and assembling large-scale airborne personnel or materials based on ultrashort waves according to claim 1 is characterized in that: In step 1, the process of establishing the first coordinate system is as follows: Among at least three beacons, one beacon is designated as a main beacon, and the remaining beacons are designated as secondary beacons, and a first coordinate system including all secondary beacons is formed with the main beacon as the origin, that is, a relative positioning coordinate system; The second coordinate system is obtained by transforming the relative positioning coordinate system, that is, the absolute positioning coordinate system.

3. The method for positioning and assembling large-scale airborne personnel or materials based on ultrashort waves according to claim 2 is characterized in that: In step 2, the TOA or TDOA algorithm is selected in the first coordinate system to determine the relative position information between any two of the beacons.

4. The method for positioning and assembling large-scale airborne personnel or materials based on ultrashort waves according to claim 2 is characterized in that: The first coordinate system is applicable under satellite denial conditions, or under conditions where the number of airborne nodes or beacons containing satellite positioning information is less than 3; The second coordinate system is applicable when at least three airborne nodes or beacons have satellite positioning information.

5. The method for positioning and assembling large-scale airborne personnel or materials based on ultrashort waves according to claim 1, characterized in that: In step 1, the communication range formed by the at least three beacons can cover the designated airborne area, and the distance between any two beacons is greater than the ranging error.

6. The method for positioning and assembling large-scale airborne personnel or materials based on ultrashort waves according to claim 1, characterized in that: In step 3, the status information includes time information and numbers of the primary beacon and the secondary beacon.

7. The method for positioning and assembling large-scale airborne personnel or materials based on ultrashort waves according to claim 1, characterized in that: In step 4, the set strategy is to determine the level of each airborne node according to the number of direct connections between each airborne node and all beacons. The level classification conditions are as follows: Level 1 airborne node, an airborne node that can directly communicate with at least 3 beacons; Secondary airborne node, an airborne node that can communicate directly with 1 to 2 beacons; A third-level airborne node is an airborne node that can only communicate directly with a second-level node.

8. The method for positioning and assembling large-scale airborne personnel or materials based on ultrashort waves according to claim 7 is characterized in that: In step 4, the process of airborne nodes of each level performing ranging, positioning and broadcasting in time sequence includes the time slot sequence of the main beacon sending each airborne node, and airborne nodes of each level implement ranging, positioning and information sharing in steps. The specific steps are as follows: Step 4.1: The first-level airborne node completes ranging and positioning within the first round of positioning sharing cycle, and shares location information and status information; Step 4.2: In the second round of positioning sharing cycle, the second-level airborne node selects the positioning anchor point according to the positioning anchor point selection strategy, completes the ranging and positioning, and selects the located beacon and the first-level airborne node as the relay node to relay and share the location information and status information as needed. At the same time, the first-level airborne node updates the location information; Step 4.3: In the third round of positioning sharing cycle, the third-level airborne node selects the positioning anchor point according to the positioning anchor point selection strategy, completes the ranging and positioning, and selects the first-level and second-level airborne nodes that have been located as relay nodes as needed to relay and share the location information and status information. At the same time, the first-level and second-level airborne nodes update the location information; In the subsequent positioning sharing cycle, the ranging and positioning of airborne nodes of each level are completed in sequence according to the time slot order, and then the position information and status information are shared.

9. The method for positioning and assembling large-scale airborne personnel or materials based on ultrashort waves according to claim 8, characterized in that: The distance measurement is completed by using the spread spectrum active distance measurement technology between each airborne node and its positioning anchor point; the positioning is to use the TOA or TDOA algorithm to determine the relative position information of any airborne node.

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