Dynamic positioning method and system based on unmanned aerial vehicle

Abstract

The invention discloses a dynamic positioning method and system based on an unmanned aerial vehicle, and belongs to the field of wireless communication. The method comprises the following steps: estimating an angle by using the flight of the unmanned aerial vehicle, and observing a target for multiple times by using the flight of the unmanned aerial vehicle under different attitude and different position conditions so as to determine the position of the target. According to the invention, the direct path between the positioning target and the unmanned aerial vehicle is constructed by using the characteristic of free flight of the unmanned aerial vehicle. By changing the attitude and position of the unmanned aerial vehicle, multi-dimensional information related to the position of the target is obtained, and the position of the target is solved by using a geometrical relationship.

Description

Technical Field

[0001] The present invention relates to the field of wireless positioning technology, and in particular to a dynamic positioning method and system based on unmanned aerial vehicles in a multi-target scenario. Background Art

[0002] With the popularization of drone technology, people have truly felt the incomparable advantages of drones in transporting materials, geographical surveys, and fire rescue. In the future smart cities, drones with flexible configuration and low cost advantages will play an increasingly important role in traffic control, intelligent monitoring, etc.

[0003] Services based on location information are increasingly used in daily life, such as satellite navigation, automatic parking, unmanned logistics, etc. The importance of location information is becoming more and more prominent. However, high-precision positioning in complex scenarios such as urban canyons has always been difficult to solve. Various wireless positioning technologies are also emerging, including satellite navigation signal positioning, audio signal positioning, electromagnetic wave signal positioning, geomagnetic information positioning, fusion positioning, etc. At present, the positioning anchor points of most positioning methods are relatively fixed, thereby ensuring the stability of positioning, but this also limits the flexibility of positioning to a certain extent. This method cannot obtain good positioning results in blocked areas. Summary of the invention

[0004] Purpose of the invention: In order to improve the positioning accuracy and flexibility of wireless positioning in complex scenes such as urban canyons, the present invention proposes a dynamic positioning method and system based on drones. The present invention uses the characteristics of free flight of drones to construct a direct path between the positioning target and the drone. By changing the posture and position of the drone, multi-dimensional information related to the target position is obtained, and the geometric relationship is used to solve the position of the target.

[0005] Technical solution: In order to achieve the above purpose, the present invention provides a dynamic positioning method based on a drone, comprising the following steps:

[0006] Step 1: The drone flies to the sky above the working area and is in a hovering state, providing location services for K targets. The drone determines its current position based on the satellite navigation signal and the signal from the ground communication base station, which is recorded as: Position 1. And the tangent direction of the antenna array is determined based on the attitude, which is recorded as:

[0007] Step 2: The drone transmits a positioning service broadcast signal. After receiving the broadcast signal, the ground target transmits a positioning service request. After receiving the positioning service request from the target, the drone transmits an access confirmation.

[0008] Step 3: The kth user sends a positioning reference signal, and the drone uses the positioning reference signal to estimate the angle of arrival of the user's antenna array to the drone. When the drone is equipped with a planar array antenna, the angle of arrival is recorded as When the UAV is equipped with a linear array antenna, the angle of arrival is θ k,1 .

[0009] Step 4: The UAV changes its position or attitude, and the kth user sends a positioning reference signal again. The UAV uses the positioning reference signal to re-estimate the arrival angle. When the UAV is equipped with a planar array antenna, the arrival angle is recorded as When the UAV is equipped with a linear array antenna, the angle of arrival is θ k,2 .

[0010] Step 5: Repeat step 4 until the number of angle measurements reaches the preset upper limit G.

[0011] Step 6: The drone calculates the target's position based on its own coordinates, the tangent direction of the antenna array, multiple positions or attitude information, and the corresponding estimated arrival angle.

[0012] Optionally, the method for the ground base station to determine the position of the UAV is: the ground base station determines the orientation of the UAV through image recognition, and then uses a laser radar to measure the distance between the UAV and the ground base station, thereby determining the position of the UAV, and integrating it with the results of satellite positioning.

[0013] Optionally, the method for the drone to estimate the target arrival angle using the antenna array is as follows: the array antenna configured on the drone can be a fully digital structure or a digital-analog hybrid structure. When it is a fully digital structure, the angle can be estimated using estimation methods such as MUSIC and ESPRIT.

[0014] Optionally, the drone calculates the position of the target based on multiple positions / attitude information of the drone and the estimated arrival angles at different positions / attitudes by: calculating the coordinates of the drone antenna array in the global coordinate system based on the position and attitude of the drone. When the number of angle measurements reaches a preset upper limit, G antenna array coordinates and corresponding arrival angle information groups can be obtained. Based on the information of the G information groups and the geometric positioning method, the position of the target is calculated.

[0015] Optionally, K users access the UAV network using an orthogonal time division or orthogonal frequency division multi-user access strategy.

[0016] The present invention also provides a system applying the above dynamic positioning method, comprising:

[0017] Drone module: equipped with satellite positioning module, multi-antenna radio frequency unit, laser communication module and attitude sensor;

[0018] Ground base station module: equipped with computer vision unit, laser ranging unit and high-speed laser communication interface;

[0019] Ground terminal module: carries a wireless signal transmitter to establish a communication link with the drone;

[0020] The UAV module coordinates with the ground base station module to achieve precise target positioning through multiple position / attitude adjustments and angle measurements.

[0021] The present invention also provides an electronic device, comprising: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions, which, when executed by the processor, implement the steps of a dynamic positioning method based on an unmanned aerial vehicle.

[0022] The present invention also provides a computer-readable storage medium on which computer program instructions are stored. When the computer-executable instructions are executed by a processor, the steps of a dynamic positioning method based on a drone are implemented.

[0023] Beneficial effects: The present invention has the following beneficial effects:

[0024] 1) The present invention proposes a new wireless positioning method, which utilizes the flight characteristics of UAVs, expands fixed anchor points into mobile anchor points, and constructs a direct path between the target to be positioned and the UAV.

[0025] 2) In the present invention, the drone obtains multi-dimensional information related to the target position by changing its posture and position, and uses geometric relationships to solve the target position, thereby improving the positioning accuracy in complex situations such as urban canyons. The dynamic flight of the drone is used to achieve the positioning of the target by a single drone (access point), and multiple measurements are used to improve the positioning accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of the dynamic positioning method based on unmanned aerial vehicle of the present invention;

[0027] Figure 2 This is a dynamic positioning scene diagram based on a drone in the present invention. DETAILED DESCRIPTION

[0028] The present invention is further explained below in conjunction with embodiments and drawings.

[0029] Example 1

[0030] The scenario of this embodiment is as follows Figure 2 As shown in the figure, the UAV is equipped with a uniform linear array consisting of M antennas to locate ground targets in the operation area. There are K targets in the operation area, and the UAV locates K targets, each of which is equipped with L antennas.

[0031] This embodiment provides a dynamic positioning method based on a drone, which specifically includes:

[0032] The drone flies to the sky above the working area and is in a hovering state, providing location services for K targets. The K targets to be located are distinguished by orthogonal methods such as time division or frequency division. The drone determines its own position based on satellite navigation signals and signals from ground communication base stations. For the positioning targets in a specific area, the drone changes its position or posture a total of G times. For the gth time, the global coordinates of the reference point of the antenna array on the drone are And the unit vector corresponding to the tangent direction of the antenna array is recorded as

[0033] The UAV transmits a positioning service broadcast signal. After receiving the broadcast signal, the ground target transmits a positioning service request. After receiving the positioning service request from the target, the UAV transmits an access confirmation. Taking the kth user as an example, the positioning reference signal s is sent. k (n). The drone uses the positioning reference signal to estimate the angle of arrival from user k to the drone’s antenna array. When the drone is in the gth posture or position, the estimated angle of arrival of user k is denoted by θ k,g . Assume that the coordinates of the kth user are Defining vectors for:

[0034]

[0035] Then we have:

[0036]

[0037] Right now,

[0038]

[0039] Where <·,·> represents the inner product of two vectors, and ‖·‖ represents the modulus of the vector.

[0040] According to the results of G-times angle estimation, a system of equations consisting of G equations is listed, and the coordinates of the k-th user can be obtained according to the estimation

[0041] Example 2

[0042] This embodiment provides a system applying the above dynamic positioning method, including:

[0043] 1. Drone module:

[0044] Positioning module: equipped with high-precision satellite positioning (GPS+Beidou), error ≤5cm.

[0045] Sensors: Built-in gyroscope, accelerometer and magnetometer to monitor flight attitude in real time.

[0046] Communication unit: Equipped with a multi-antenna RF module, used to search for ground terminal signals and find direction.

[0047] Laser communication: Data is transmitted via laser to ground base stations at a rate of over 1Gbps.

[0048] 2. Ground base station module:

[0049] Visual positioning: Use a camera to identify the drone's position, combined with laser ranging (accuracy ±1cm).

[0050] Control center: Analyzes data and sends instructions to the drone (such as adjusting the flight path).

[0051] 3. Ground terminal module:

[0052] Device to be located: carries a wireless signal transmitter (such as a Wi-Fi or UWB tag) for drone detection.

[0053] Example 3

[0054] This embodiment provides an electronic device, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions, which, when executed by the processor, implement the steps of a dynamic positioning method based on a drone.

[0055] Processor: High-performance multi-core chip (such as ARM Cortex-A72) to support fast computing.

[0056] Memory: Large-capacity hard disk stores maps, sensor data and positioning algorithms.

[0057] Communication interface: supports Wi-Fi, 4G / 5G, used to connect drones and base stations.

[0058] Example 4

[0059] This embodiment provides a computer-readable storage medium having computer program instructions stored thereon. When the computer-executable instructions are executed by a processor, the steps of a dynamic positioning method based on a drone are implemented.

[0060] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0061] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "N" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0062] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0063] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A dynamic positioning method based on drone, characterized in that: The following steps are involved: Step 1: The drone flies to the sky above the working area and is in a hovering state to provide location services for ground users; the drone determines its current position based on satellite navigation signals and signals from ground communication base stations, and determines the tangent direction of the antenna array based on its attitude; Step 2: The drone transmits a positioning service broadcast signal. After receiving the broadcast signal, the ground user transmits a positioning service request. After receiving the user's positioning service request, the drone transmits an access confirmation. Step 3: The ground user sends a positioning reference signal, and the UAV uses the positioning reference signal to estimate the arrival angle of the ground user to the UAV's antenna array; Step 4: The UAV changes its position or attitude, and the ground user sends a positioning reference signal again. The UAV uses the positioning reference signal to re-estimate the arrival angle; Step 5: Repeat step 4 until the number of angle measurements reaches the preset upper limit G; Step 6: The drone calculates the target's position based on its own coordinates, the tangent direction of the antenna array, multiple positions or attitude information, and the corresponding estimated arrival angle.

2. A method for dynamic positioning based on a drone as claimed in claim 1, characterized in that: In step 1, the method by which the UAV determines its current position based on the satellite navigation signal and the signal from the ground communication base station is as follows: the ground base station determines the orientation of the UAV through image recognition, and then uses a laser radar to measure the distance between the UAV and the ground base station, thereby determining the position of the UAV and integrating it with the result of satellite positioning.

3. A method for dynamic positioning based on a drone as claimed in claim 1, characterized in that: In step 3, the method for the drone to estimate the target arrival angle using the antenna array is: the array antenna configured on the drone is a fully digital structure or a digital-analog hybrid structure; when it is a fully digital structure, the MUSIC or ESPRIT estimation method is used to estimate the angle.

4. A method for dynamic positioning based on a drone as claimed in claim 1, characterized in that: In step six, the UAV calculates the position of the target based on multiple positions / attitude information of itself and the estimated arrival angles at different positions / attitudes. The method is as follows: according to the position and attitude of the UAV, the coordinates of the UAV antenna array in the global coordinate system are calculated; according to the number of angle measurements reaching the preset upper limit, G antenna array coordinates and corresponding arrival angle information groups are obtained; according to the information of the G information groups and the geometric positioning method, the position of the target is calculated.

5. A dynamic positioning method based on an unmanned aerial vehicle as claimed in claim 1, characterized in that: Ground users access the UAV network using orthogonal time division or orthogonal frequency division multi-user access strategies.

6. A system using the dynamic positioning method according to any one of claims 1 to 5, characterized in that: include: Drone module: equipped with satellite positioning module, multi-antenna radio frequency unit, laser communication module and attitude sensor; Ground base station module: equipped with computer vision unit, laser ranging unit and high-speed laser communication interface; Ground terminal module: carries a wireless signal transmitter to establish a communication link with the drone; The UAV module coordinates with the ground base station module to achieve precise target positioning through multiple position / attitude adjustments and angle measurements.

7. An electronic device comprising: Memory and processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the method described in any one of claims 1 to 5 are implemented.

8. A computer-readable storage medium having computer program instructions stored thereon, wherein the computer-executable instructions, when executed by a processor, implement the steps of the method according to any one of claims 1 to 5.

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