UAV target positioning method, system, electronic device and computer storage medium

Abstract

The present invention discloses a method, system, electronic device, and computer storage medium for unmanned aerial vehicle (UAV) target positioning, relating to the field of UAV positioning. The method comprises obtaining two UAV pitch angles and azimuth angles relative to a target, and the UAV's local coordinate system; determining intermediate variables based on the pitch angles, azimuth angles, and the UAV's local coordinate system; confirming an estimated azimuth error based on the intermediate variables; and determining the target's local coordinates based on the estimated azimuth error. The method can effectively reduce positioning errors caused by using magnetic heading as the source of UAV heading data, based on target capture by a UAV's onboard vision pod.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicle (UAV) positioning, and in particular to a UAV target positioning method, system, electronic equipment and computer storage medium. Background Art

[0002] Target positioning is one of the basic functions of drone reconnaissance. At present, drone target positioning mainly relies on the gimbal pod. Based on target identification or manual selection, the gimbal optical axis is pointed at the target to obtain the elevation angle and heading deviation angle of the drone relative to the target. At the same time, the target is illuminated by laser to obtain the distance between the drone and the target, and then the target position is calculated, which is generally expressed in latitude, longitude and elevation.

[0003] Although the above drone positioning method can accurately obtain the target position, it requires the drone to be equipped with a gimbal pod with a laser, which is expensive and heavy. As a low-cost positioning method for ground or sea targets, the altitude difference between the target and the drone can be replaced by the drone's flight altitude. Therefore, the latitude and longitude of the target can still be calculated without using laser ranging and only using a vision pod.

[0004] However, for targets in urban or mountainous environments, their elevation often differs from the drone's flight starting point, making accurate positioning difficult with a single existing drone or observation point. This requires dual drones or a single drone with multiple locations for observation and positioning. Furthermore, since three-dimensional positioning is required, the angular measurement accuracy of the gimbal pod directly affects target positioning accuracy. Once locked onto a target, the gimbal pod typically provides the target's pitch and azimuth angles. The pitch angle is typically obtained using an inertial measurement element and offers high accuracy, while the azimuth angle is typically output by an encoder and offers high accuracy. However, deriving the target heading angle from the azimuth angle requires consideration of the drone's heading accuracy and installation errors. This is especially true for low-cost applications, where using magnetic heading, or magnetic heading after compensating for declination, as true north often results in low target heading accuracy, leading to significant deviations in target positioning accuracy. Summary of the Invention

[0005] The purpose of the present invention is to provide a method, system, electronic device and computer storage medium for unmanned aerial vehicle (UAV) target positioning, which can effectively reduce the positioning error caused by using magnetic heading as the source of UAV heading data on the basis of capturing the target by the UAV's onboard vision pod.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A method for positioning a target of an unmanned aerial vehicle, comprising:

[0008] Obtain the pitch angle, azimuth angle and local coordinate system of the drone to the target twice;

[0009] Determining an intermediate variable based on the pitch angle, the azimuth angle, and a local coordinate system of the UAV;

[0010] confirming an estimated value of the bearing error based on the intermediate variable;

[0011] The local coordinates of the target are determined based on the position error estimate.

[0012] Optionally, the two pitch angles of the drone to the target are pitch angles of the same drone to the target at different positions or pitch angles of two different drones to the target.

[0013] Optionally, confirming the estimated value of the orientation error according to the intermediate variable specifically includes:

[0014] Determine a first orientation error estimate value and a second orientation error estimate value according to the intermediate variable;

[0015] The one with the smaller absolute value between the first azimuth error estimate value and the second azimuth error estimate value is selected as the azimuth error estimate value.

[0016] The present invention also provides a UAV target positioning system, comprising:

[0017] The acquisition module is used to obtain the pitch angle, azimuth angle of the drone to the target and the local coordinate system of the drone twice;

[0018] an intermediate variable determination module, configured to determine an intermediate variable based on the pitch angle, the azimuth angle, and the local coordinate system of the UAV;

[0019] an azimuth error estimation value determination module, configured to determine an azimuth error estimation value based on the intermediate variable;

[0020] The target local coordinate determination module is used to determine the target local coordinates according to the azimuth error estimation value.

[0021] Optionally, the two pitch angles of the drone to the target are pitch angles of the same drone to the target at different positions or pitch angles of two different drones to the target.

[0022] Optionally, the azimuth error estimation value determination module specifically includes:

[0023] A first orientation error estimate value and a second orientation error estimate value determining unit, configured to determine a first orientation error estimate value and a second orientation error estimate value according to the intermediate variable;

[0024] A selection unit is configured to select the one with the smaller absolute value between the first azimuth error estimate value and the second azimuth error estimate value as the azimuth error estimate value.

[0025] The present invention further provides an electronic device, comprising:

[0026] one or more processors;

[0027] a storage device having one or more programs stored thereon;

[0028] When the one or more programs are executed by the one or more processors, the one or more processors are enabled to implement the above-described method.

[0029] A computer storage medium stores a computer program, wherein the computer program implements the method described above when executed by a processor.

[0030] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0031] The present invention obtains the pitch angle, azimuth angle and local coordinate system of the drone of two times relative to the target; determines intermediate variables based on the pitch angle, azimuth angle and local coordinate system of the drone; confirms an azimuth error estimate based on the intermediate variables; and determines the local coordinates of the target based on the azimuth error estimate, thereby effectively reducing the positioning error caused by using magnetic heading as the source of drone heading data on the basis of the drone's onboard vision pod capturing the target. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 is a schematic diagram of the target pitch angle;

[0034] Figure 2 is a schematic diagram of the target azimuth;

[0035] Figure 3 This is a flow chart of the UAV target positioning method provided by the present invention. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] The purpose of the present invention is to provide a method, system, electronic device and computer storage medium for unmanned aerial vehicle (UAV) target positioning, which can effectively reduce the positioning error caused by using magnetic heading as the source of UAV heading data on the basis of capturing the target by the UAV's onboard vision pod.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] When the vision pod is locked on a target, the optical axis points to the target and the target pitch angle θ can be output, such as Figure 1 As shown, the pitch angle θ of the target below the drone is negative, where G represents the vertical downward direction; the target azimuth angle ψ, as shown Figure 2 As shown in the figure, the azimuth angle ψ is based on the north direction N and ranges from 0 to 360 degrees clockwise. Figure 3 As shown, the present invention provides a UAV target positioning method, which is applied to a UAV equipped with a vision pod, comprising:

[0040] Step 101: Obtain the pitch angle, azimuth angle and local coordinate system of the drone to the target twice. The two pitch angles of the drone to the target are the pitch angles of the same drone to the target at different positions or the pitch angles of two different drones to the target.

[0041] In the case of two drones, the vision pods of drones at different positions and orientations lock onto the target respectively. When locking onto the target, the vision pod can output the pitch angle and the azimuth angle of the target relative to the body (vision pod function). The azimuth angle of the target relative to the body plus the heading angle of the drone itself can be used to obtain the target azimuth. Obtain the pitch angle θ1 and azimuth ψ1 of drone 1 when the gimbal locks onto the target, as well as the coordinates (m) of drone 1 in the local coordinate system (northeast celestial coordinate system, with a certain point in the mission area, such as the take-off point of drone 1, as the origin) of drone 1. x ,m y ,m z ); obtain the pitch angle θ2, azimuth angle ψ2 of UAV 2 to the target, and the local coordinate system coordinates of UAV 2 (n x ,n y ,n z ).

[0042] For a single UAV, after the onboard vision pod locks onto the target at a certain position, the pitch angle θ1 and azimuth angle ψ1 of the UAV to the target are obtained, as well as the coordinates (m x ,m y ,m z); The aircraft flies to another position by changing its horizontal position and flight altitude, so that the pitch angle and azimuth angle of the vision pod to the target are changed, and the pitch angle θ2 and azimuth angle ψ2 of the new position to the target are obtained, as well as the coordinates of the drone's local coordinate system (n x ,n y ,n z ).

[0043] When selecting the positions of two machines or selecting the positions of a single machine twice, it is required that θ1≠θ2, ψ1≠ψ2.

[0044] Step 102: Determine an intermediate variable based on the pitch angle, the azimuth angle, and the local coordinate system of the UAV.

[0045] According to the physical quantities obtained in step 101, the following variables are obtained, including A1, B1, C1, D1, A2, B2, C2, D2, E, F, a, b, and c. These variables are only intermediate replacement variables to facilitate the implementation of step 103, and the variables have no physical meaning.

[0046] A1=-tanθ2cosψ1+tanθ1cosψ2

[0047] B1=tanθ2cosψ1m z -tanθ1cosψ2n z

[0048] C1=-tanθ2sinψ1+tanθ1sinψ2

[0049] D1=tanθ2sinψ1m z -tanθ1sinψ2n z -tanθ1tanθ2(m x -n x )

[0050] A2=tanθ2sinψ1-tanθ1sinψ2

[0051] B2=-tanθ2sinψ1m z +tanθ1sinψ2n z

[0052] C2=-tanθ2cosψ1+tanθ1cosψ2

[0053] D2=tanθ2cosψ1m z -tanθ1cosψ2n z -tanθ1tanθ2(m y -n y )

[0054]

[0055]

[0056] a=A1E

[0057] b=A1F+B1+C1E

[0058] c=C1F+D1

[0059] Step 103: Confirming the azimuth error estimate based on the intermediate variable. Step 103 specifically includes: determining a first azimuth error estimate and a second azimuth error estimate based on the intermediate variable; and selecting the smaller absolute value of the first azimuth error estimate and the second azimuth error estimate as the azimuth error estimate.

[0060] According to the intermediate variables, the estimated value of the orientation error δ is obtained.

[0061]

[0062] If |δ1|<|δ2|, δ=δ1, otherwise δ=δ2. δ1 is the original estimated value of the orientation error 1, and δ2 is the original estimated value of the orientation error 2.

[0063] Step 104: Determine the local coordinates of the target according to the estimated value of the orientation error.

[0064] According to the estimated value of the orientation error, the local coordinates (x, y, h) of the target are obtained as follows:

[0065] h=Eδ+F

[0066] x=m x -(m z -h)sin(ψ1+x) / tanθ1

[0067] y=m y -(m z -h)cos(ψ1+x) / tanθ1

[0068] The longitude and latitude of the target point can be further calculated from the coordinates of the local coordinate system and the longitude and latitude of the origin of the local coordinate system.

[0069] Application examples:

[0070] Taking dual-aircraft collaborative positioning as an example, the local coordinates of UAV 1 are (0, 120, 45), and the local coordinates of UAV 2 are (0, -87, 30). After the onboard vision pod locks on the target, the pitch angle and heading angle of UAV 1 to the target are (-9.21, 130.69), and the pitch angle and heading angle of UAV 2 to the target are (-6.64, 67.32). According to this method, the local coordinates of the target can be obtained as (161.25, -23.59, 10), where the actual position of the target is set to (160, -25, 10).

[0071] The present invention also provides a UAV target positioning system, comprising:

[0072] The acquisition module is used to obtain the pitch angle, azimuth angle and local coordinate system of the drone to the target twice.

[0073] An intermediate variable determination module is used to determine an intermediate variable based on the pitch angle, the azimuth angle and the local coordinate system of the UAV.

[0074] The azimuth error estimation value determination module is used to confirm the azimuth error estimation value according to the intermediate variable.

[0075] The target local coordinate determination module is used to determine the target local coordinates according to the azimuth error estimation value.

[0076] As an optional implementation manner, the two pitch angles of the drone to the target are the pitch angles of the same drone to the target at different positions or the pitch angles of two different drones to the target.

[0077] As an optional implementation manner, the azimuth error estimation value determination module specifically includes:

[0078] A first orientation error estimation value and a second orientation error estimation value determining unit is configured to determine a first orientation error estimation value and a second orientation error estimation value according to the intermediate variable.

[0079] A selection unit is configured to select the one with the smaller absolute value between the first azimuth error estimate value and the second azimuth error estimate value as the azimuth error estimate value.

[0080] The present invention further provides an electronic device, comprising:

[0081] One or more processors.

[0082] A storage device having one or more programs stored thereon.

[0083] When the one or more programs are executed by the one or more processors, the one or more processors are enabled to implement the above-described method.

[0084] The present invention also provides a computer storage medium having a computer program stored thereon, wherein the computer program implements the method described above when executed by a processor.

[0085] Low-cost drone applications typically use magnetic heading, or simply magnetic heading after magnetic declination compensation, as the drone's heading. This often results in a constant heading error. In this case, the target azimuth angle obtained after the onboard gimbal locks onto the target will also have a constant error. Target positioning is achieved using two-point positions and two sets of pitch and azimuth angles. Existing techniques typically use direct solution or least squares methods, which can result in large errors when there is a constant azimuth error. This invention addresses the situation where a constant deviation in the drone's heading causes a deviation in the target azimuth angle. By first estimating the deviation angle, the target position is then estimated based on the compensated deviation angle, effectively improving target positioning accuracy.

[0086] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0087] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method for positioning a target of an unmanned aerial vehicle, characterized in that: include: Obtain the pitch angle, azimuth angle and local coordinate system of the drone to the target twice; The two pitch angles of the drone to the target are the pitch angles of the same drone to the target at different positions or the pitch angles of two different drones to the target; Determining an intermediate variable based on the pitch angle, the azimuth angle, and a local coordinate system of the UAV; confirming an estimated value of the bearing error based on the intermediate variable; determining the local coordinates of the target based on the estimated position error; According to the obtained physical quantities, the following variables are obtained, including A1, B1, C1, D1, A2, B2, C2, D2, E, F, a, b, c. These variables are only intermediate replacement variables; A1=-tanθ2cosψ1+tanθ1cosψ2 B1=tanθ2cosψ1m z -tanθ1cosψ2n z C1=-tanθ2sinψ1+tanθ1sinψ2 D1=tanθ2sinψ1m z -tanθ1sinψ2n z -tanθ1tanθ2(m x -n x ) A2=tanθ2sinψ1-tanθ1sinψ2 B2=-tanθ2sinψ1m z +tanθ1sinψ2n z C2=-tanθ2cosψ1+tanθ1cosψ2 D2=tanθ2cosψ1m z -tanθ1cosψ2n z -tanθ1tanθ2(m y -n y ) a=A1E b=A1F+B1+C1E c=C1F+D1 Among them, θ1 is the pitch angle of the UAV to the target, ψ1 is the azimuth angle of the UAV to the target; θ2 is the pitch angle of the new position to the target, ψ2 is the azimuth angle of the new position to the target; (m x ,m y ,m z ) is the coordinate of the local coordinate system of the UAV; (n x ,n y ,n z ) is the coordinate of the new position of the drone in the local coordinate system; Confirming the azimuth error estimate value according to the intermediate variable specifically includes: determining a first azimuth error estimate value and a second azimuth error estimate value according to the intermediate variable; selecting the azimuth error estimate value having a smaller absolute value between the first azimuth error estimate value and the second azimuth error estimate value as the azimuth error estimate value; According to the intermediate variables, the estimated value of the azimuth error δ is obtained; If |δ1|<|δ2|, δ=δ1, otherwise δ=δ2; δ1 is the original estimated value of the orientation error 1, and δ2 is the original estimated value of the orientation error 2; According to the estimated value of the orientation error, the local coordinates (x, y, h) of the target are obtained as follows: h=Eδ+F x=m x -(m z -h)sin(ψ1+x) / tanθ1 y=m y -(m z -h)cos(ψ1+x) / tanθ1 The longitude and latitude of the target point can be further calculated from the coordinates of the local coordinate system and the longitude and latitude of the origin of the local coordinate system.

2. A UAV target positioning system, characterized in that: The UAV target positioning system applies the UAV target positioning method according to claim 1, and the system comprises: The acquisition module is used to obtain the pitch angle, azimuth angle of the drone to the target and the local coordinate system of the drone twice; an intermediate variable determination module, configured to determine an intermediate variable based on the pitch angle, the azimuth angle, and the local coordinate system of the UAV; an azimuth error estimation value determination module, configured to determine an azimuth error estimation value based on the intermediate variable; The target local coordinate determination module is used to determine the target local coordinates according to the azimuth error estimation value.

3. The UAV target positioning system according to claim 2, characterized in that: The two pitch angles of the drone to the target are the pitch angles of the same drone to the target at different positions or the pitch angles of two different drones to the target.

4. The UAV target positioning system according to claim 2, characterized in that: The azimuth error estimation value determination module specifically includes: A first orientation error estimate value and a second orientation error estimate value determining unit, configured to determine a first orientation error estimate value and a second orientation error estimate value according to the intermediate variable; A selection unit is configured to select the one with the smaller absolute value between the first azimuth error estimate value and the second azimuth error estimate value as the azimuth error estimate value.

5. An electronic device, characterized in that: include: one or more processors; a storage device having one or more programs stored thereon; When the one or more programs are executed by the one or more processors, the one or more processors are caused to implement the method according to claim 1 .

6. A computer storage medium, characterized in that A computer program is stored thereon, wherein when the computer program is executed by a processor, the method according to claim 1 is implemented.

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