High-precision target positioning method based on IMU inside the optoelectronic turret of unmanned aerial vehicle

Abstract

The present invention relates to the technical field of ground target positioning by unmanned aerial vehicles, and in particular to a high-precision target positioning method based on an IMU inside an unmanned aerial vehicle photoelectric turret. The method comprises: a ground calibration stage: the installation deviations between the azimuth frame and the pitch frame between the IMU inside the unmanned aerial vehicle photoelectric turret and the photoelectric load are calibrated respectively; an aerial calibration stage: the photoelectric load flies with the unmanned aerial vehicle, the photoelectric load is locked to azimuth zero and pitch zero, and the deviations between the photoelectric load and the unmanned aerial vehicle in the three directions of roll, pitch and yaw are measured respectively; when the photoelectric turret locates the target to be measured, the photoelectric turret corrects the deviation angles in pitch, roll and yaw directions between the photoelectric turret coordinate system and the carrier coordinate system in real time, and calculates the target position after correcting the miss amount deviation in real time. The method has the advantages of small amount of calculation, and can perform high-precision positioning of people and ships in distress when running on the unmanned aerial vehicle onboard computer, thereby improving the efficiency of commanding rescue work.

Description

Technical Field

[0001] The present invention relates to the technical field of ground target positioning by unmanned aerial vehicles, and in particular to a high-precision target positioning method based on an IMU inside an optoelectronic turret carried by an unmanned aerial vehicle. Background Art

[0002] UAVs usually need to continuously track and monitor targets, observe target status, and continuously locate targets. Therefore, a shock absorber needs to be installed between the optoelectronic turret and the UAV to isolate the vibration of the aircraft engine and prevent the vibration of the UAV engine from being transmitted to the optoelectronic turret, causing blurred imaging of the optoelectronic turret.

[0003] Due to the existence of the shock absorber, the UAV and the optoelectronic turret are not rigidly connected, that is, the heading, pitch, and roll angles of the UAV are directly superimposed on the target positioning equation of the optoelectronic turret through matrix transformation, resulting in low target positioning accuracy.

[0004] When performing search and rescue missions for people in distress in the wild, or for people in distress or ships in distress on the sea, there are usually no obvious landmark buildings to serve as positioning reference points. Obtaining the precise coordinates of people in distress or ships in distress is crucial for the command center to direct the rescue work.

[0005] Therefore, when there is no rigid connection between the UAV and the optoelectronic turret, a method is needed to perform high-precision positioning of the target by relying on the inertial measurement unit inside the optoelectronic turret. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a high-precision target positioning method based on the IMU inside the optoelectronic turret onboard an unmanned aerial vehicle.

[0007] The present invention provides a high-precision target positioning method based on an IMU inside an optoelectronic turret onboard an unmanned aerial vehicle, which specifically comprises the following steps:

[0008] S1. Ground calibration stage: Calibrate the installation deviations between the azimuth frame and the pitch frame between the IMU and the optoelectronic payload inside the optoelectronic turret on the UAV respectively;

[0009] S2. Air calibration stage: The optoelectronic payload flies with the UAV, locks the optoelectronic payload to zero azimuth and zero pitch, and measures the deviations between the optoelectronic payload and the UAV in the three directions of roll, pitch and yaw;

[0010] S3. When the optoelectronic turret locates the target to be measured, the optoelectronic turret corrects the deviation angles in pitch, roll and yaw between the optoelectronic turret coordinate system and the carrier coordinate system in real time, and calculates the target position after correcting the miss deviation in real time.

[0011] Preferably, step S1 specifically includes the following sub-steps:

[0012] S101. First, lock the optoelectronic payload to zero azimuth and zero elevation;

[0013] S102. Control the servo system of the photoelectric load to rotate the azimuth axis of the photoelectric load at a constant speed V, and record the IMU angular velocity value V_IMU;

[0014] S103. According to the difference between V_IMU and V, calculate the installation deviation between the IMU installation plane and the photoelectric payload azimuth axis plane; the formula is as follows:

[0015] ;

[0016] Where: i represents the azimuth angle value of the optoelectronic payload; j represents the pitch angle value of the optoelectronic payload; V_IMU represents the IMU angular velocity value; V represents the azimuth angular velocity of the optoelectronic payload;

[0017] S104. After solving all deviations, a two-dimensional array X is obtained.

[0018] Preferably, in step S1, the azimuth angle value and the pitch angle value of the photoelectric load are recorded once every 0.1 degree rotation, that is, i=0, 0.1, 0.2, ... 359.9, j=0, 0.1, 0.2, ... 90;

[0019] Step S103 specifically includes: when the azimuth angle value of the photoelectric load is i and the pitch angle is j, according to the deviation value between the azimuth velocity V_IMU measured by the IMU and the azimuth velocity V of the photoelectric load given by the servo, the installation deviation between the IMU installation plane and the azimuth axis plane of the photoelectric load is calculated to be ;

[0020] The two-dimensional array X is represented as:

[0021] .

[0022] Preferably, step S2 specifically includes:

[0023] When the drone enters a straight line, the IMU inside the optoelectronic turret is used to record the azimuth, pitch and roll angles of the starting point of the route. , as well as longitude, latitude, and altitude ; Use the IMU in the optoelectronic turret to record the azimuth, pitch and roll angles of the route endpoint , as well as longitude, latitude, and altitude ;

[0024] Record the azimuth, pitch and roll angles of the starting point of the UAV inertial navigation route , as well as longitude, latitude, and altitude ; Record the azimuth, pitch and roll angles of the end point of the UAV inertial navigation route , as well as longitude, latitude, and altitude ;

[0025] In three-dimensional space, and The connection line is line1, and The connecting line is line2, calculate the angle between line1 and line2 in space: the angle between line1 and line2 in the pitch direction is , that is, the angle between the optoelectronic turret IMU and the UAV inertial navigation in the pitch direction; the angle between line1 and line2 in the roll direction is , that is, the angle between the optoelectronic turret IMU and the UAV inertial navigation in the rolling direction; the angle between line1 and line2 in the yaw direction is , that is, the angle between the optoelectronic turret IMU and the UAV inertial navigation in the yaw direction.

[0026] Preferably, in step S3, the pitch direction deviation angle between the photoelectric turret coordinate system and the carrier coordinate system is t The expression is:

[0027] ;

[0028] Deviation angle in the roll direction between the optoelectronic turret coordinate system and the carrier coordinate system p The expression is:

[0029] ;

[0030] The yaw direction deviation angle between the photoelectric turret coordinate system and the carrier coordinate system f The expression is:

[0031] ;

[0032] In the formula, E It is the angle between the optoelectronic turret IMU and the UAV inertial navigation in the pitch direction. F It is the angle between the optoelectronic turret IMU and the UAV inertial navigation in the rolling direction. G It is the angle between the optoelectronic turret IMU and the UAV inertial navigation in the yaw direction. C is the azimuth angle of the photoelectric turret encoder, B is the pitch angle of the photoelectric turret encoder, X C,B is the deviation value after table lookup in the two-dimensional array X.

[0033] Preferably, the coordinates of the target in WGS-84 geodetic coordinate system C , represents the target longitude, represents the target latitude, Represents the target height; the expressions are as follows:

[0034] ;

[0035] ;

[0036] ;

[0037] In the above formula, a represents the major radius of the ellipsoid, b represents the minor radius of the ellipsoid, e represents the first eccentricity, E represents the second eccentricity, r represents the distance of the target point relative to the reference point on the horizontal plane, U represents the elevation angle of the target point, and n is the radius of curvature of the target's umbo ring; the calculation formulas are as follows:

[0038] ;

[0039] ;

[0040] ;

[0041] ;

[0042] .

[0043] Preferably, the coordinates of the target in the geocentric rectangular coordinate system G are as follows:

[0044] ;

[0045] In the formula, x b , y b and z b The coordinates are x b , y b and z b The three-axis position of the target in the optoelectronic turret coordinate system B; M1~M10 are defined as follows:

[0046] ;

[0047] ;

[0048] ;

[0049] ;

[0050] ;

[0051] ;

[0052] ;

[0053] ;

[0054] ;

[0055] ;

[0056] In the above formula, N represents the radius of curvature of the aircraft's yaw circle, L represents the aircraft's latitude, A represents the aircraft's longitude, H represents the aircraft's altitude, T represents the aircraft's pitch angle, P represents the aircraft's roll angle, and F represents the aircraft's yaw angle. t Indicates the deviation angle in the pitch direction between the optoelectronic turret coordinate system and the carrier coordinate system. p Indicates the roll deviation angle between the optoelectronic turret coordinate system and the carrier coordinate system. f Indicates the yaw direction deviation angle between the optoelectronic turret coordinate system and the carrier coordinate system;

[0057] The expression of the curvature radius N of the airplane's camber circle is: ; In the formula, a represents the major radius of the ellipsoid, e represents the first eccentricity, .

[0058] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0059] A high-precision target positioning method based on the IMU inside the airborne optoelectronic turret is provided. Specifically, a method is provided to calibrate the installation deviation between the azimuth frame and the pitch frame between the ground IMU and the optoelectronic payload, calibrate the deviation between the optoelectronic payload and the UAV in roll, pitch, and yaw in the air, and the optoelectronic turret real-time corrects the deviation angle of the pitch, roll, and yaw directions between the optoelectronic turret coordinate system and the carrier coordinate system. After real-time correction of the miss amount deviation, a method is used to calculate the target position. This method has a small amount of calculation and runs on the UAV's onboard computer. It can perform high-precision positioning of people and ships in distress, effectively improving the efficiency of the command center in commanding rescue work. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 The present invention provides a flowchart of a high-precision target positioning method based on an IMU inside an optoelectronic turret onboard an unmanned aerial vehicle. DETAILED DESCRIPTION

[0061] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are represented by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0062] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0063] The present invention provides a high-precision target positioning method based on the IMU inside the photoelectric turret onboard an unmanned aerial vehicle (UAV) Figure 1 ), specifically including the following steps:

[0064] S1. Ground calibration stage: Calibrate the installation deviations between the azimuth frame and the pitch frame between the IMU and the optoelectronic payload inside the optoelectronic turret on the UAV respectively;

[0065] Specifically, the angle between the horizontal axis of the IMU and the horizontal axis of the optoelectronic load is measured, a number of calibration points are collected, and curve fitting is performed, and the fitting curve is stored in the onboard computer; the angle between the vertical axis of the IMU and the vertical axis of the optoelectronic load is calibrated in the same way;

[0066] The calibration methods include:

[0067] S101. First, lock the optoelectronic payload to zero azimuth and zero elevation;

[0068] S102. Control the servo system of the photoelectric load to rotate the azimuth axis of the photoelectric load at a constant speed V, and record the IMU angular velocity value V_IMU every 0.1 degrees;

[0069] S103. According to the difference between V_IMU and V, calculate the installation deviation between the IMU installation plane and the photoelectric payload azimuth axis plane; the formula is as follows:

[0070] ;

[0071] Where: i represents the azimuth angle value of the optoelectronic payload, i=0, 0.1, 0.2, ... 359.9; j represents the pitch angle value of the optoelectronic payload, j=0, 0.1, 0.2, ... 90; V_IMU represents the IMU angular velocity value; V represents the azimuth angular velocity of the optoelectronic payload;

[0072] When the azimuth angle value of the photoelectric load is i and the pitch angle is j, according to the deviation between the azimuth velocity V_IMU measured by the IMU and the azimuth velocity V of the photoelectric load given by the servo, the installation deviation between the IMU installation plane and the azimuth axis plane of the photoelectric load is calculated as follows: ;

[0073] S104. After solving all deviations, a two-dimensional array X is obtained:

[0074] .

[0075] S2. Air calibration stage: The optoelectronic payload flies with the UAV, locks the optoelectronic payload to zero azimuth and zero pitch, and measures the deviations between the optoelectronic payload and the UAV in the three directions of roll, pitch and yaw;

[0076] Specifically, the drone’s flight path is a straight line;

[0077] The specific method of air calibration is as follows:

[0078] When the drone enters a straight line, the IMU inside the optoelectronic turret is used to record the azimuth, pitch and roll angles of the starting point of the route. , as well as longitude, latitude, and altitude ; Use the IMU in the optoelectronic turret to record the azimuth, pitch and roll angles of the route endpoint , as well as longitude, latitude, and altitude ;

[0079] Record the azimuth, pitch and roll angles of the starting point of the UAV inertial navigation route , as well as longitude, latitude, and altitude ; Record the azimuth, pitch and roll angles of the end point of the UAV inertial navigation route , as well as longitude, latitude, and altitude .

[0080] In three-dimensional space, and The connection line is line1, and The connecting line is line2, and the angle between line1 and line2 in space is calculated:

[0081] The angle between line1 and line2 in the pitch direction is , that is, the angle between the optoelectronic turret IMU and the UAV inertial navigation in the pitch direction;

[0082] The angle between line1 and line2 in the rolling direction is , that is, the angle between the optoelectronic turret IMU and the UAV inertial navigation in the rolling direction;

[0083] The angle between line1 and line2 in the yaw direction is , that is, the angle between the optoelectronic turret IMU and the UAV inertial navigation in the yaw direction.

[0084] S3. When the optoelectronic turret locates the target to be measured, the optoelectronic turret corrects the deviation angles in pitch, roll and yaw between the optoelectronic turret coordinate system and the carrier coordinate system in real time, and calculates the target position after correcting the miss deviation in real time.

[0085] Specifically, the pitch deviation angle between the optoelectronic turret coordinate system and the carrier coordinate system t The expression is:

[0086] ;

[0087] Deviation angle in the roll direction between the optoelectronic turret coordinate system and the carrier coordinate system p The expression is:

[0088] ;

[0089] The yaw direction deviation angle between the photoelectric turret coordinate system and the carrier coordinate system f The expression is:

[0090] ;

[0091] In the formula, E It is the angle between the optoelectronic turret IMU and the UAV inertial navigation in the pitch direction. F It is the angle between the optoelectronic turret IMU and the UAV inertial navigation in the rolling direction. G It is the angle between the optoelectronic turret IMU and the UAV inertial navigation in the yaw direction. C is the azimuth angle of the photoelectric turret encoder, B is the pitch angle of the photoelectric turret encoder, X C,B is the deviation value after table lookup in the two-dimensional array X;

[0092] The position of the target in the photoelectric turret coordinate system is ( C,B,R ), C is the azimuth angle of the photoelectric turret encoder, B is the pitch angle of the photoelectric turret encoder, R It is the laser distance measurement value.

[0093] The coordinates of the target in WGS-84 geodetic coordinate system C , represents the target longitude, represents the target latitude, Represents the target height; the expressions are as follows:

[0094] ;

[0095] ;

[0096] ;

[0097] In the above formula, a represents the major radius of the ellipsoid, b represents the minor radius of the ellipsoid, e represents the first eccentricity, E represents the second eccentricity, r represents the distance of the target point relative to the reference point on the horizontal plane, U represents the elevation angle of the target point, and n is the radius of curvature of the target's umbo ring; the calculation formulas are as follows:

[0098] ;

[0099] ;

[0100] ;

[0101] ;

[0102] .

[0103] In a specific embodiment, the major radius a of the ellipsoid is 6378137.0 m; the minor radius b of the ellipsoid is 6356752.0 m.

[0104] The coordinates of the target in the geocentric rectangular coordinate system G are shown as follows:

[0105] ;

[0106] In the formula, x b , y b and z b The coordinates are x b , y b and z b The three-axis position of the target in the optoelectronic turret coordinate system B; M1~M10 are defined as follows:

[0107] ;

[0108] ;

[0109] ;

[0110] ;

[0111] ;

[0112] ;

[0113] ;

[0114] ;

[0115] ;

[0116] ;

[0117] In the above formula, N represents the radius of curvature of the aircraft's yaw circle, L represents the aircraft's latitude, A represents the aircraft's longitude, H represents the aircraft's altitude, T represents the aircraft's pitch angle, P represents the aircraft's roll angle, and F represents the aircraft's yaw angle. t Indicates the deviation angle in the pitch direction between the optoelectronic turret coordinate system and the carrier coordinate system. p Indicates the roll deviation angle between the optoelectronic turret coordinate system and the carrier coordinate system. f Indicates the yaw direction deviation angle between the optoelectronic turret coordinate system and the carrier coordinate system;

[0118] The expression of the curvature radius N of the airplane's camber circle is: .

[0119] The coordinates of the target in the optoelectronic turret coordinate system B are expressed as:

[0120] ;

[0121] In the formula, λ2 represents, For vector The simplified form of Where G is the projection center point of the camera, and T is the corresponding point of the target on the imaging plane; The expression is as follows:

[0122] ;

[0123] In the formula, The photoelectric turret coordinate system In the three-dimensional space, the basis vectors, u represents the horizontal coordinate of the pixel coordinates of the corresponding point T of the target in the imaging plane, u0 represents the horizontal coordinate of the center point F of the imaging plane, v represents the vertical coordinate of the pixel coordinates of the corresponding point T of the target in the imaging plane, and v0 represents the vertical coordinate of the center point F of the imaging plane; the pixel coordinates of the center point F of the imaging plane are , the pixel coordinates of the corresponding point T of the target on the imaging plane are .

[0124] Specifically, in the target positioning model considering the miss distance, the projection center point of the camera is G, the target on the ground is P, the center point of the imaging plane is F, and points G, F, and P are on a straight line. GF is the focal length of the visible light camera. f; The target on the ground is point Q, the corresponding point of the target on the imaging plane is T, the projection point directly below the camera is K, the intersection of GK and the imaging plane is J, and the following vectors are defined: , , ;

[0125] express and The angle of and , The relationship is shown in the following formula; express and The angle of and , The relationship is shown in the following formula:

[0126] ;

[0127] ;

[0128] The photoelectric turret coordinate system In three-dimensional space, basis vectors, vectors and vector In the photoelectric turret coordinate system The coordinates are as follows:

[0129] ;

[0130] ;

[0131] in, Indicates the focal length of the visible light camera (in units of ), the pixel coordinates of point F are , the pixel coordinates of point T are .

[0132] is the basis vector of the carrier geographic coordinate system S in three-dimensional space. In the carrier geographic coordinate system S, The Z axis of the aircraft's geographic coordinate system S The same direction, The coordinates in the aircraft geographic coordinate system S are as follows:

[0133] ;

[0134] The coordinates in the photoelectric turret coordinate system B are as follows:

[0135] ;

[0136] in, , , , , , is defined as follows:

[0137] ;

[0138] ;

[0139] ;

[0140] ;

[0141] ;

[0142] .

[0143] is the Z axis of the aircraft's geographic coordinate system S With the Z axis of the photoelectric turret coordinate system B The angle between.

[0144]

[0145] Right now

[0146] therefore ;

[0147] Right now ;

[0148] Will Substituting the value of into the above formula, the coordinates of the target in the photoelectric turret coordinate system B are obtained as follows:

[0149] ;

[0150] Substituting the result into the coordinates of the target in the WGS-84 geodetic coordinate system C can be obtained.

[0151] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0152] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-precision target positioning method based on the IMU inside the optoelectronic turret onboard an unmanned aerial vehicle, characterized in that: The specific steps include: S1. Ground calibration stage: Calibrate the installation deviations between the azimuth frame and the pitch frame between the IMU and the optoelectronic payload inside the optoelectronic turret on the drone. Specifically, it includes the following sub-steps: S101. First, lock the optoelectronic payload to zero azimuth and zero elevation; S102. Control the servo system of the optoelectronic load to rotate the azimuth axis of the optoelectronic load at a constant speed V, and record the IMU angular velocity value V_IMU; S103. According to the difference between V_IMU and V, calculate the installation deviation between the IMU installation plane and the photoelectric payload azimuth axis plane; the formula is as follows: ； Where: i represents the azimuth angle value of the optoelectronic payload; j represents the pitch angle value of the optoelectronic payload; V_IMU represents the IMU angular velocity value; V represents the azimuth angular velocity of the optoelectronic payload; The azimuth angle value and elevation angle value of the photoelectric payload are recorded every 0.1 degree rotation, i.e., i=0, 0.1, 0.2, ... 359.9, j=0, 0.1, 0.2, ... 90; When the azimuth angle value of the photoelectric load is i and the pitch angle is j, according to the deviation between the azimuth velocity V_IMU measured by the IMU and the azimuth velocity V of the photoelectric load given by the servo, the installation deviation between the IMU installation plane and the azimuth axis plane of the photoelectric load is calculated as follows: ; The two-dimensional array X is represented as: ； S104. After solving all deviations, a two-dimensional array X is obtained; S2. Air calibration stage: The optoelectronic payload flies with the UAV, locks the optoelectronic payload to zero azimuth and zero pitch, and measures the deviations between the optoelectronic payload and the UAV in the three directions of roll, pitch and yaw; S3. When the optoelectronic turret locates the target to be measured, the optoelectronic turret corrects the deviation angles in pitch, roll and yaw between the optoelectronic turret coordinate system and the carrier coordinate system in real time, and calculates the target position after correcting the miss deviation in real time.

2. The high-precision target positioning method based on the IMU inside the optoelectronic turret onboard an unmanned aerial vehicle according to claim 1 is characterized in that: The step S2 specifically includes: When the drone enters a straight line, the IMU inside the optoelectronic turret is used to record the azimuth, pitch and roll angles of the starting point of the route. , as well as longitude, latitude, and altitude ; Use the IMU in the optoelectronic turret to record the azimuth, pitch and roll angles of the route endpoint , as well as longitude, latitude, and altitude ; Record the azimuth, pitch and roll angles of the starting point of the UAV inertial navigation route , as well as longitude, latitude, and altitude ; Record the azimuth, pitch and roll angles of the end point of the UAV inertial navigation route , as well as longitude, latitude, and altitude ; In three-dimensional space, and The connection line is line1, and The connecting line is line2, calculate the angle between line1 and line2 in space: the angle between line1 and line2 in the pitch direction is , that is, the angle between the optoelectronic turret IMU and the UAV inertial navigation in the pitch direction; the angle between line1 and line2 in the roll direction is , that is, the angle between the optoelectronic turret IMU and the UAV inertial navigation in the rolling direction; the angle between line1 and line2 in the yaw direction is , that is, the angle between the optoelectronic turret IMU and the UAV inertial navigation in the yaw direction.

3. The high-precision target positioning method based on the internal IMU of the optoelectronic turret onboard an unmanned aerial vehicle according to claim 2, characterized in that: In step S3, the pitch deviation angle between the photoelectric turret coordinate system and the carrier coordinate system is t The expression is: ； Deviation angle in the roll direction between the optoelectronic turret coordinate system and the carrier coordinate system p The expression is: ； The yaw direction deviation angle between the photoelectric turret coordinate system and the carrier coordinate system f The expression is: ； In the formula, E It is the angle between the optoelectronic turret IMU and the UAV inertial navigation in the pitch direction. F It is the angle between the optoelectronic turret IMU and the UAV inertial navigation in the rolling direction. G It is the angle between the optoelectronic turret IMU and the UAV inertial navigation in the yaw direction. C is the azimuth angle of the photoelectric turret encoder, B is the pitch angle of the photoelectric turret encoder, X C,B is the deviation value after table lookup in the two-dimensional array X.

4. The high-precision target positioning method based on the internal IMU of the optoelectronic turret onboard an unmanned aerial vehicle according to claim 3 is characterized in that: The coordinates of the target in WGS-84 geodetic coordinate system C , represents the target longitude, represents the target latitude, Represents the target height; the expressions are as follows: ； ； ； In the above formula, a represents the major radius of the ellipsoid, b represents the minor radius of the ellipsoid, e represents the first eccentricity, E represents the second eccentricity, r represents the distance of the target point relative to the reference point on the horizontal plane, U represents the elevation angle of the target point, and n is the radius of curvature of the target's umbo ring; the calculation formulas are as follows: ； ； ； ； 。 5. The high-precision target positioning method based on the internal IMU of the optoelectronic turret onboard an unmanned aerial vehicle according to claim 4, characterized in that: The coordinates of the target in the geocentric rectangular coordinate system G are shown as follows: ； In the formula, x b , y b and z b The coordinates are x b , y b and z b The three-axis position of the target in the optoelectronic turret coordinate system B; M1~M10 are defined as follows: ； ； ； ； ； ； ； ； ； ； In the above formula, N represents the radius of curvature of the aircraft's yaw circle, L represents the aircraft's latitude, A represents the aircraft's longitude, H represents the aircraft's altitude, T represents the aircraft's pitch angle, P represents the aircraft's roll angle, and F represents the aircraft's yaw angle. t Indicates the deviation angle in the pitch direction between the optoelectronic turret coordinate system and the carrier coordinate system. p Indicates the roll deviation angle between the optoelectronic turret coordinate system and the carrier coordinate system. f Indicates the yaw direction deviation angle between the optoelectronic turret coordinate system and the carrier coordinate system; The expression of the curvature radius N of the airplane's camber circle is: ; In the formula, a represents the major radius of the ellipsoid, e represents the first eccentricity, .

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