Target tracking method based on distributed radar guide photoelectricity of vehicle-mounted platform

Abstract

The invention discloses a vehicle-mounted platform-based distributed radar-guided photoelectric target tracking method. The method comprises the following steps of: 1, converting a WGS-84 coordinate of a vehicle-mounted photoelectric device and a target detected by a radar into an ECEF coordinate; step 2, calculating a displacement vector of the detection target and the vehicle-mounted photoelectric equipment based on the ECEF coordinate, and converting the displacement vector to an ENU coordinate system of a vehicle-mounted local system; 3, measuring the attitude of the vehicle-mounted photoelectric equipment according to inertial navigation equipment, and converting the relative displacement of the detection target and the vehicle-mounted photoelectric equipment into an EOC photoelectric coordinate system; step 4, calculating vehicle-mounted photoelectric equipment guiding information required by photoelectric guiding according to the relative displacement of the detection target and the vehicle-mounted photoelectric equipment under the EOC coordinate system; and step 5, calculating vehicle-mounted photoelectric equipment control information according to the vehicle-mounted photoelectric equipment guide information, and completing target locking and tracking.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photoelectric guidance, and in particular to a distributed radar-guided photoelectric target tracking method based on a vehicle-mounted platform. BACKGROUND

[0002] In the field of "low, slow and small" target detection, radar combined with photoelectricity has become an important detection combination means. The combination of radar and photoelectric system can improve the target detection and tracking capability. The advantages of radar in long-range and all-weather detection and the high-resolution imaging capability of photoelectric system are utilized to realize accurate detection, identification and tracking of targets, especially in complex environments (such as ground clutter, bird interference, etc.), which can significantly improve the perception ability of "low, slow and small" targets. The combination of radar and photoelectricity can enhance the system autonomy and reaction speed. Radar provides the initial positioning and speed information of the target, guides the photoelectric system to quickly lock the target, shortens the reaction time, improves the system autonomy and detection efficiency, and is suitable for dynamic "low, slow and small" target detection environment. Radar and photoelectricity data fusion can complement each other. Radar has accurate distance and speed measurement, but the angle resolution is low. The photoelectric system has a small field of view and high accuracy in pitch and azimuth, and has a clear target picture. The fusion of the two can make up for the shortcomings of a single sensor, provide more comprehensive target information, and support stable monitoring and target identification of "low, slow and small" targets. In the "low, slow and small" target detection system, due to the limited detection range of the sensor and the use habits of "low, slow and small" targets, mobile vehicle-mounted platforms are widely used. The vehicle-mounted photoelectric system deployed on the moving platform combined with radar guidance can perform reconnaissance, monitoring and target indication tasks while moving, and adapt to the high mobility requirements of "low, slow and small" target detection. Therefore, radar-guided vehicle-mounted photoelectricity has important use value and wide application prospect.

[0003] Currently, radar-guided photoelectricity at home and abroad is mainly divided into fixed systems and vehicle-mounted platforms. In the fixed system, the radar and the photoelectricity are calibrated separately, and the guidance is relatively simple and will not be described here. In the case of vehicle-mounted radar-guided photoelectric system, the vehicle body has a leveling system that can ensure that there is no system error in the pitch and roll directions of the radar and photoelectric platform. In this case, only the installation error of the radar and the photoelectricity needs to be considered, but this case limits the system to be used only in the parked state, which limits the mobility of the system to some extent. The vehicle-mounted radar and photoelectricity can be coaxially designed, and the installation error can be ignored in this case, but it is difficult to complete the guidance of other distributed radars to the photoelectricity on the vehicle. Finally, a stabilizing platform can be installed on the vehicle-mounted radar and photoelectric equipment, so that the system error caused by the pitch and roll can be ignored, but this will increase the additional hardware cost. SUMMARY

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide a distributed radar-guided photoelectric target tracking method based on a vehicle platform, which addresses the shortcomings of the existing technology.

[0005] To address the aforementioned technical problems, this invention discloses a distributed radar-guided optoelectronic technology based on a vehicle-mounted platform. This technology incorporates the WGS84 (World Geodetic System 1984) geodetic coordinate system, the ECEF (Earth-Centered Earth-Fixed) geocentric fixed coordinate system, the ENU (East-North-Up) vehicle-mounted local navigation coordinate system, and the EOC (Electronic-Optical-Coordinate) optoelectronic coordinate system. Through coordinate system transformation and optoelectronic attitude information, EO guidance information is calculated to achieve target locking and tracking.

[0006] A distributed radar-guided electro-optical target tracking method based on a vehicle-mounted platform includes the following steps:

[0007] Step 1: Convert the targets detected by the vehicle-mounted optoelectronic equipment and radar from WGS-84 (Geodetic Coordinate System) coordinates to ECEF (Earth-Centered, Earth-Fixed) coordinates;

[0008] Step 2: Calculate the displacement vectors of the detection target and the vehicle-mounted optoelectronic equipment based on the ECEF coordinate system, and transform the displacement vectors to the ENU (East-North-Up) coordinate system of the vehicle's local system;

[0009] Step 3: Based on the attitude measurement of the vehicle-mounted optoelectronic equipment by the inertial navigation equipment, transform the relative displacement between the detection target and the vehicle-mounted optoelectronic equipment into the EOC (Electronic-Optical-Coordinate) optoelectronic coordinate system;

[0010] Step 4: Calculate the guidance information of the vehicle-mounted optoelectronic equipment required for optoelectronic guidance based on the relative displacement between the detected target and the vehicle-mounted optoelectronic equipment in the EOC coordinate system.

[0011] Step 5: Calculate the control information of the vehicle-mounted optoelectronic equipment based on the guidance information of the vehicle-mounted optoelectronic equipment to complete the target locking and tracking.

[0012] Step 1 is as follows:

[0013] The location information of the vehicle-mounted optoelectronic device is obtained through an inertial navigation system.

[0014] The WGS84 coordinate information of the vehicle-mounted optoelectronic device is obtained by GPS positioning, including longitude γ. v ,latitude Height h v ;

[0015] The target location information is obtained by radar or other sensors and is denoted as longitude γ. t ,latitude Height h t ;

[0016] The ECEF geocentric fixed coordinate system is a Cartesian coordinate system with its origin at the Earth's center of mass. The X-axis points to the intersection of the prime meridian and the equator, the Z-axis points to the conventional Earth pole, and the Y-axis forms a right-handed system with the X and Z axes. Converting WGS84 coordinates into linear ECEF coordinates is the basis for subsequent spatial vector calculations.

[0017] The conversion formula from WGS84 coordinates to ECEF coordinates is as follows:

[0018]

[0019] Where N is the radius of curvature of the geoid, R is the semi-major axis of the Earth (constant), e is the first eccentricity of the Earth (constant), and γ is the longitude of the target or photoelectric object. is the target or photoelectric latitude, h is the height of the target or vehicle-mounted photoelectric equipment, and X, Y, and Z are the coordinate axes of the ECEF geocentric fixed coordinate system.

[0020] Step 2 is as follows:

[0021] The local navigation coordinate system / station center coordinate system uses the ENU coordinate system, with the origin located at the vehicle's center of mass. The E-axis points due east, the N-axis points due north, and the U-axis is perpendicular to the local horizontal plane and pointing upwards (opposite to the direction of gravity). This coordinate system is coplanar with the vehicle platform and describes the relative positional relationships near the vehicle, facilitating subsequent calculations of relative positions in the EOC coordinate system. The vehicle's WGS84 coordinates are also used. Perform a transformation from ECEF coordinates to ENU coordinates, using the transformation matrix R. ECEF2ENU for:

[0022]

[0023] The displacement vectors of the detection target and the vehicle-mounted optoelectronic equipment in the ECEF coordinate system are (Pos t_ECEF -Pos v_ECEF ), that is, the target's coordinates Pos in the ECEF coordinate system. t_ECEF Subtract the coordinates Pos of the vehicle-mounted optoelectronic equipment in the ECEF coordinate system v_ECEF To obtain the vector distance between the two, use R ECEF2ENU The displacement vector calculation in the ENU coordinate system is as follows:

[0024] Pos ENU=R ECEF2ENU ×(Pos t_ECEF -Pos v_ECEF ).

[0025] The EOC coordinate system mentioned in step 3 is specifically as follows:

[0026] The EOC coordinate system is an improvement on the ENU coordinate system, and it takes into account the installation errors of photoelectric devices, making it more conducive to calculating guidance information.

[0027] Define the EOC coordinate system: the origin is located at the reference point of the vehicle-mounted optoelectronic equipment, i.e., the optoelectronic zero position. The X-axis points to the right side of the vehicle, the Y-axis points to the front of the vehicle, and the Z-axis is perpendicular to the vehicle and upwards. This serves as the coordinate system directly sensed by the optoelectronic system. The final target pointing angle is represented in this coordinate system. After the vehicle-mounted optoelectronic equipment is installed, the optoelectronic zero position is calibrated according to the installation status. For example, first, the position information of the vehicle-mounted optoelectronic equipment is obtained from the inertial navigation system. Then, a drone target is launched at a distance of 1 kilometer, at an altitude of 200 meters, and locked by the optoelectronic equipment. The relative azimuth and pitch of the target and the optoelectronic equipment can be calculated theoretically. When locked, the actual azimuth and pitch of the optoelectronic equipment can be obtained. By comparing the theoretical and actual values, the deviation between the optoelectronic installation status and the theoretical zero position is calculated. This process is called calibrating the optoelectronic zero position.

[0028] Step 3 describes the ENU to EOC coordinate system transformation, which involves coordinate system rotation but not translation or scaling. The ENU coordinate system rotation involves three axes: yaw, pitch, and roll, defined as follows:

[0029] Heading angle Defined as degree a, defined as a counterclockwise rotation around the vehicle's top-view center axis, i.e., the Z-axis;

[0030] Pitch angle (θ): defined as b degrees, which is defined as a counterclockwise rotation around the vehicle's side-view lateral axis, i.e., the X-axis;

[0031] Roll angle (Roll, γ): defined as c degrees, which is defined as a counterclockwise rotation around the vehicle's frontal longitudinal axis, i.e., the Y-axis;

[0032] The attitude of the optoelectronic system is described by the heading angle (Yaw), pitch angle (Pitch), and roll angle (Roll): The attitude angles (Heading / Yaw, Pitch, Roll) of the onboard optoelectronic equipment describe the orientation of the optoelectronic coordinate system relative to the local navigation coordinate system (ENU).

[0033] Step 3 specifically involves:

[0034] Transform from ENU coordinate system to EOC coordinate system: Construct the rotation matrix R based on the attitude angles (Heading / Yaw, Pitch, Roll). ENU2EO ;

[0035] R ENU2EO =R y(c) ×R x(b) ×R z(a)

[0036] Among them, R z(a) R represents the basic rotation matrix for rotating about the Z-axis by 'a' degrees. x(b) R represents the basic rotation matrix for rotating about the X-axis by b degrees. y(c) The basic rotation matrix representing a rotation of c degrees around the Y-axis:

[0037]

[0038] The selection of the positive directions and rotation order of rotation angles a, b, and c is consistent with the definition of attitude angles of inertial navigation equipment.

[0039] The rotation order is crucial to the result. Since rotations of different axes influence each other, the rotation of a later axis will affect the rotation of an earlier axis. Considering that the azimuth angle of a photoelectric sensor is generally in the range of (-π, π], which is relatively large, while the pitch and roll angles are not significantly affected by the vehicle's dimensions, and the roll angle deflection should generally be minimal, this order aims to minimize the mutual influence between the rotating axes.

[0040] The coordinate transformation sequence is defined as Z→X→Y, or Yaw→Pitch→Roll. This means first rotating around the U-axis at the yaw angle 'a', then around the intermediate X-axis at the pitch angle 'b', and finally around the final Y-axis at the roll angle 'c'. The relative displacement Pos between the transformed target and the vehicle-mounted optoelectronic equipment is then calculated. EOC for:

[0041] Pos EOC =R ENU2EO ×Pos ENU

[0042] The relative displacement Pos EOC Represented as Pos EOC =[X EO Y EO Z EO ] T , where X EO It represents its displacement in the X-axis direction, Y EO It represents its displacement in the Y-axis direction, Z EO This indicates its displacement in the Z-axis direction.

[0043] Step 4 is as follows:

[0044] Based on the target's displacement relative to the photoelectric system in the EOC photoelectric coordinate system, Pos EOC =[XEO Y EO Z EO ] T Based on the coordinate data, the system calculates the guidance information required by the vehicle-mounted optoelectronic equipment, including azimuth, pitch, and distance information.

[0045] Az EO =tan -1 (X EO ,Y EO )

[0046]

[0047] Azimuth Az EO (Azimuth): The angle relative to the Y-axis of the photoelectric zero position, usually measured in the XY plane of the vehicle-mounted photoelectric equipment, pointing towards the X-axis (right side) as positive. EO =tan -1 (X EO ,Y EO The function can handle all quadrants, and the result range is (-π, π].

[0048] Pitch angle El EO (Elevation): The angle of elevation relative to the XY plane of the vehicle body (positive upwards), with a result range of -π / 2 to π / 2.

[0049] Range information: Range information is used to adjust the focal length and focus value of the photoelectric sensor. Based on the initial calibration information of the photoelectric sensor, the range information ensures that the target is clearly imaged in the video.

[0050] The vehicle-mounted optoelectronic equipment control information mentioned in step 5 includes optoelectronic azimuth angle, pitch angle, lens focal length, and focus value.

[0051] The focal length and focus value of the lens of the vehicle-mounted optoelectronic equipment are determined by the distance between the vehicle-mounted optoelectronic equipment and the target.

[0052] Step 5 specifically includes: This step is mainly completed through theoretical calculations combined with photoelectric calibration.

[0053] Step 5-1: Based on the imaging principle theory of photoelectric, calculate and convert the control information of the photoelectric device into the focal length and sharpness value of the photoelectric device to obtain the focal length required by the lens for clear imaging at different distances of the vehicle-mounted photoelectric device.

[0054] Step 5-2: Compare the lens focal lengths corresponding to targets at different distances during photoelectric calibration, correct the relationship between theoretically calculated distance and lens focal length, and obtain the lens focal length values ​​at different distances by actually flying a UAV target from near to far (200m to 3km) and comparing them with the theoretical calculations.

[0055] Step 5-3: Compare the lens focus values ​​(which affect sharpness) with the different weather visibility and temperature conditions during photoelectric calibration, or manually adjust the focus value of the photoelectric equipment to achieve a clear image and complete target locking.

[0056] Beneficial effects:

[0057] This method is adaptable to photoelectric guidance on most vehicle-mounted platforms, solving the problem of distributed radar-guided photoelectric systems in situations where there is no leveling system or stabilization equipment. This technology has significant practical value and broad application prospects in the development of detection systems for "low, slow, and small" targets and mobile equipment. Compared to traditional radar-guided photoelectric systems that require coaxial operation of the radar and photoelectric components, and vehicle-mounted radar systems that require leveling systems or stabilization equipment, this technology significantly reduces implementation costs and operational complexity. Furthermore, this technology can also be used for photoelectric guidance in distributed radar systems, which helps improve product competitiveness. Attached Figure Description

[0058] Figure 1 This is a diagram of the algorithm structure of the present invention.

[0059] Figure 2 The relationship between the WGS84 coordinate system and the ECEF coordinate system.

[0060] Figure 3 The relationship between the WGS84 / ECEF and ENU coordinate systems.

[0061] Figure 4 This is a schematic diagram of the target tracking results. Detailed Implementation

[0062] Based on the actual situation, it is necessary to develop a low-cost, distributed radar information-supporting vehicle-mounted optoelectronic system guidance technology that supports movement, in order to reduce the requirements of optoelectronic equipment on the vehicle platform, improve the system's detection capabilities through radar-optoelectronic coordination, increase the system's mobility, and expand the system's application scenarios and value.

[0063] In most vehicle-mounted radar-optical systems, radar-guided optoelectronic systems primarily rely on onboard leveling systems, stabilization systems, or coaxial designs between the radar and optoelectronic components. However, each of these designs has its limitations. Onboard leveling systems restrict the system to use only when the vehicle is parked, stabilization systems increase hardware costs, and coaxial designs between the radar and optoelectronic components struggle to guide vehicle-mounted optoelectronic systems from other distributed radar systems. This invention proposes a distributed radar-guided optoelectronic technology based on an onboard platform, which can effectively improve the success rate of radar-guided vehicle-mounted optoelectronic systems without adding new hardware structures.

[0064] In this embodiment, taking a radar-guided vehicle-mounted optoelectronic capture scenario of a drone as an example, the vehicle's attitude is (91.6°, 0.23°, -1.48°), where the vehicle's yaw angle is 91.6 degrees, the pitch angle is 0.23 degrees, the roll angle is -1.48 degrees, and the radar measurement accuracy is 0.5°.

[0065] A distributed radar-guided electro-optical target tracking method based on a vehicle-mounted platform includes the following steps:

[0066] Step 1: Convert the targets detected by the vehicle-mounted optoelectronic equipment and radar from WGS-84 (Geodetic Coordinate System) coordinates to ECEF (Earth-Centered, Earth-Fixed) coordinates;

[0067] Step 2: Calculate the displacement vectors of the detection target and the vehicle-mounted optoelectronic equipment based on the ECEF coordinate system, and transform the displacement vectors to the ENU (East-North-Up) coordinate system of the vehicle's local system;

[0068] Step 3: Based on the attitude measurement of the vehicle-mounted optoelectronic equipment by the inertial navigation equipment, transform the relative displacement between the detection target and the vehicle-mounted optoelectronic equipment into the EOC (Electronic-Optical-Coordinate) optoelectronic coordinate system;

[0069] Step 4: Calculate the guidance information of the vehicle-mounted optoelectronic equipment required for optoelectronic guidance based on the relative displacement between the detected target and the vehicle-mounted optoelectronic equipment in the EOC coordinate system.

[0070] Step 5: Calculate the control information of the vehicle-mounted optoelectronic equipment based on the guidance information of the vehicle-mounted optoelectronic equipment to complete the target locking and tracking.

[0071] Step 1 is as follows:

[0072] The location information of the vehicle-mounted optoelectronic device is obtained through an inertial navigation system.

[0073] The WGS84 coordinate information of the vehicle-mounted optoelectronic device is obtained by GPS positioning, including longitude γ. v ,latitude Height h v ;

[0074] The target location information is obtained by radar or other sensors and is denoted as longitude γ. t ,latitude Height h t ;

[0075] The ECEF geocentric fixed coordinate system is a Cartesian coordinate system with its origin at the Earth's center of mass. The X-axis points to the intersection of the prime meridian and the equator, the Z-axis points to the conventional Earth pole, and the Y-axis forms a right-handed system with the X and Z axes. Converting WGS84 coordinates into linear ECEF coordinates is the basis for subsequent spatial vector calculations.

[0076] The conversion formula from WGS84 coordinates to ECEF coordinates is as follows:

[0077]

[0078]

[0079] Where N is the radius of curvature of the geoid, R is the semi-major axis of the Earth (constant), e is the first eccentricity of the Earth (constant), and γ is the longitude of the target or photoelectric object. is the target or photoelectric latitude, h is the height of the target or vehicle-mounted photoelectric equipment, and X, Y, and Z are the coordinate axes of the ECEF geocentric fixed coordinate system.

[0080] Step 2 is as follows:

[0081] The local navigation coordinate system / station center coordinate system uses the ENU coordinate system, with the origin located at the vehicle's center of mass. The E-axis points due east, the N-axis points due north, and the U-axis is perpendicular to the local horizontal plane and pointing upwards (opposite to the direction of gravity). This coordinate system is coplanar with the vehicle platform and describes the relative positional relationships near the vehicle, facilitating subsequent calculations of relative positions in the EOC coordinate system. The vehicle's WGS84 coordinates are also used. Perform a transformation from ECEF to ENU, with the transformation matrix R. ECEF2ENU for:

[0082]

[0083] The displacement vectors of the detection target and the vehicle-mounted optoelectronic equipment in the ECEF coordinate system are (Pos t_ECEF -Pos v_ECEF ), that is, the target's coordinates Pos in the ECEF coordinate system. t_ECEF Subtract the coordinates Pos of the vehicle-mounted optoelectronic equipment in the ECEF coordinate system v_ECEF To obtain the vector distance between the two, use R ECEF2ENU The displacement vector calculation in the ENU coordinate system is as follows:

[0084] Pos ENU =R ECEF2ENU ×(Pos t_ECEF -Pos v_ECEF ).

[0085] In this embodiment, the displacement of the detection target relative to the vehicle-mounted optoelectronic equipment in the ENU coordinate system is (-270.95, 2651.68, 205.44), which means that the X coordinate is -270.95 meters, the Y coordinate is 2651.68 meters, and the Z coordinate is 205.44 meters.

[0086] The EOC coordinate system mentioned in step 3 is specifically as follows:

[0087] The EOC coordinate system is an improvement upon the ENU coordinate system, and it takes into account the installation errors of photoelectric components.

[0088] It is more conducive to calculating guidance information.

[0089] Define the EOC coordinate system: the origin is located at the reference point of the vehicle-mounted optoelectronic equipment, i.e., the optoelectronic zero position. The X-axis points to the right side of the vehicle, the Y-axis points to the front of the vehicle, and the Z-axis is perpendicular to the vehicle and upwards. This serves as the coordinate system directly sensed by the optoelectronic system. The final target pointing angle is represented in this coordinate system. After the vehicle-mounted optoelectronic equipment is installed, the optoelectronic zero position is calibrated according to the installation status. First, the position information of the optoelectronic equipment is obtained according to the inertial navigation equipment. Then, the UAV target is launched 1 km due north at an altitude of 200 meters and locked by the optoelectronic system. The relative azimuth and pitch (0°, 9.74°) between the target and the optoelectronic equipment are calculated theoretically. When locked, the actual azimuth and pitch (0.13°, 9.15°) of the optoelectronic equipment are obtained. By comparing the theoretical and actual values, the deviation between the optoelectronic installation status and the theoretical zero position (-0.13°, 0.59°) is calculated. This process is called calibrating the optoelectronic zero position.

[0090] Step 3 describes the ENU to EOC coordinate system transformation, which mainly involves coordinate system rotation and does not involve translation or scaling. The ENU coordinate system rotation involves three axes of rotation: yaw, pitch, and roll, defined as follows:

[0091] Heading angle Defined as degree a, defined as a counterclockwise rotation around the vehicle's top-view center axis, i.e., the Z-axis;

[0092] Pitch angle (θ): defined as b degrees, which is defined as a counterclockwise rotation around the vehicle's side-view lateral axis, i.e., the X-axis;

[0093] Roll angle (Roll, γ): defined as c degrees, which is defined as a counterclockwise rotation around the vehicle's frontal longitudinal axis, i.e., the Y-axis;

[0094] The attitude of the optoelectronic system is described by the heading angle (Yaw), pitch angle (Pitch), and roll angle (Roll): The attitude angles (Heading / Yaw, Pitch, Roll) of the onboard optoelectronic equipment describe the orientation of the optoelectronic coordinate system relative to the local navigation coordinate system (ENU).

[0095] Step 3 specifically involves:

[0096] Transform from ENU coordinate system to EOC coordinate system: Construct the rotation matrix R based on the attitude angles (Heading / Yaw, Pitch, Roll). ENU2EO ;

[0097] R ENU2EO =R y(c) ×R x(b) ×R z(a)

[0098] Among them, R z(a) R represents the basic rotation matrix for rotating about the Z-axis by 'a' degrees. x(b) R represents the basic rotation matrix for rotating about the X-axis by b degrees. y(c) The basic rotation matrix representing a rotation of c degrees around the Y-axis:

[0099]

[0100] The positive directions and rotation order of the rotation angles a, b, and c are selected in accordance with the definition of the attitude angles of the inertial navigation device. In this embodiment, according to the vehicle attitude data, the rotation angle is 91.6°, the pitch angle is 0.23°, and the roll angle is -1.48°.

[0101] The coordinate transformation sequence is Z→X→Y, i.e., Yaw→Pitch→Roll. First, rotate around the U-axis at the yaw angle 'a', then around the intermediate X-axis at the pitch angle 'b', and finally around the final Y-axis at the roll angle 'c'. The resulting relative displacement Pos between the target and the vehicle-mounted optoelectronic equipment is... EOC for:

[0102] Pos EOC =R ENU2EO ×Pos ENU

[0103] The relative displacement Pos EOC Represented as Pos EOC =[X EO Y EO Z EO ] T , where X EO It represents its displacement in the X-axis direction, Y EO It represents its displacement in the Y-axis direction, Z EO This indicates its displacement in the Z-axis direction.

[0104] In this embodiment, based on the attitude (91.6°, 0.23°, -1.48°) of the vehicle-mounted optoelectronic equipment measured by the inertial navigation system, the relative displacement between the detection target and the vehicle-mounted optoelectronic equipment is transformed to the EOC optoelectronic coordinate system, and Pos is calculated. EOCThe coordinates are (-2647.47, -345.73, 135.72), which means the X coordinate is -2647.47 meters, the Y coordinate is -345.73 meters, and the Z coordinate is 135.72 meters.

[0105] Step 4 is as follows:

[0106] Based on the target's displacement relative to the photoelectric system in the EOC photoelectric coordinate system, Pos EOC =[X EO Y EO Z EO ] T Based on the coordinate measuring machine (CMM) data, the required guidance information for the vehicle-mounted optoelectronic equipment is calculated, including azimuth, pitch, and distance information.

[0107] Az EO =tan -1 (X EO ,Y EO )

[0108]

[0109] Azimuth Az EO (Azimuth): The angle relative to the Y-axis of the photoelectric zero position, usually measured in the XY plane of the vehicle-mounted photoelectric equipment, pointing towards the X-axis (right side) as positive. EO =tan -1 (X EO ,Y EO The function can handle all quadrants, and the result range is (-π, π].

[0110] Pitch angle El EO (Elevation): The angle of elevation relative to the XY plane of the vehicle body (positive upwards), with a result range of -π / 2 to π / 2.

[0111] Distance Information (Range): Distance information is used to adjust the focal length and focus value of the optoelectronic device. Based on the initial calibration information of the optoelectronic device, the distance information ensures that the target is clearly imaged in the video (in this embodiment, the calibration information of the optoelectronic device is as follows: target distance less than 300m, focal length is 1180, focus value is 2607; target distance 300-800m, focal length is 600, focus value is 2607; target distance 800m-1200m, focal length is 450, focus value is 2607; target distance greater than 1200m, focal length is 346, focus value is 2607).

[0112] In this embodiment, the calculated photoelectric guidance parameters are (262.56°, 2.91°, 2673.4), where the azimuth angle is 262.56°, the elevation angle is 2.91°, and the distance information is 2673.4 meters.

[0113] The vehicle-mounted optoelectronic equipment control information mentioned in step 5 includes optoelectronic azimuth angle, pitch angle, lens focal length, and focus value.

[0114] The focal length and focus value of the lens of the vehicle-mounted optoelectronic device are determined by the distance between the vehicle-mounted optoelectronic device and the target (in this embodiment, the optoelectronic calibration information is as follows: target distance less than 300m, focal length is 1180, focus value is 3452; target distance 300-800m, focal length is 600, focus value is 3452; target distance 800m-1200m, focal length is 450, focus value is 3452; target distance greater than 1200m, focal length is 346, focus value is 3452).

[0115] Step 5 specifically includes: This step is mainly completed through theoretical calculations combined with photoelectric calibration.

[0116] Step 5-1: Based on the imaging principle theory of photoelectric, calculate the control information of the photoelectric device into the focal length and sharpness value of the photoelectric device (the calculated value can be verified by the drone at the same time) to obtain the focal length required by the lens for clear imaging at different distances of the vehicle-mounted photoelectric device.

[0117] Step 5-2: Compare the lens focal lengths corresponding to different distance targets during photoelectric calibration, and correct the relationship between the theoretically calculated distance and the lens focal length. In this embodiment, the distance is 2673.4 meters, and the corresponding focal length is 346.

[0118] Step 5-3: Compare the lens focus value (which affects sharpness) with the different weather visibility and temperature during photoelectric calibration, or manually adjust the focus value of the photoelectric equipment to make the image clear and achieve target tracking. In this embodiment, the focus value is 3452.

[0119] Thus, the photoelectric control parameters (focal length 346, focus value 3452) correspond to a field of view of 0.69° and a focus value of 3452. Based on the latitude and longitude information detected by radar and the vehicle attitude information (91.6°, 0.23°, -1.48°), the photoelectric guidance parameters are calculated to be (262.56°, 2.91°, 2673.4). Combined with the photoelectric calibration information, the focal length is obtained as 346 and the focus value is 3452. The final photoelectric guidance information is an azimuth angle of 262.56°, a pitch angle of 2.91°, a focal length of 346, and a focus value of 3452.

[0120] The tracking results of this embodiment are as follows: Figure 4 As shown.

[0121] This invention provides a concept and method for a distributed radar-guided photoelectric target tracking method based on a vehicle-mounted platform. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A distributed radar-guided photoelectric target tracking method based on a vehicle-mounted platform, characterized in that, The steps include the following: Step 1: Convert the targets detected by the vehicle-mounted optoelectronic equipment and radar from WGS-84 coordinates to ECEF coordinates; Step 2: Calculate the displacement vectors of the detection target and the vehicle-mounted optoelectronic equipment based on the ECEF coordinate system, and then convert the displacement vectors to the ENU coordinate system of the vehicle-mounted local system. Step 3: Based on the attitude of the vehicle-mounted optoelectronic equipment measured by the inertial navigation system, transform the relative displacement between the detection target and the vehicle-mounted optoelectronic equipment into the EOC optoelectronic coordinate system; Step 4: Calculate the guidance information of the vehicle-mounted optoelectronic equipment required for optoelectronic guidance based on the relative displacement between the detected target and the vehicle-mounted optoelectronic equipment in the EOC coordinate system. Step 5: Calculate the control information of the vehicle-mounted optoelectronic equipment based on the guidance information of the vehicle-mounted optoelectronic equipment to complete the target locking and tracking.

2. The distributed radar-guided photoelectric target tracking method based on a vehicle-mounted platform according to claim 1, characterized in that, Step 1 is as follows: The location information of the vehicle-mounted optoelectronic device is obtained through an inertial navigation system. The WGS84 coordinate information of the vehicle-mounted optoelectronic device is obtained by GPS positioning, including longitude γ. v ,latitude Height h v ; The target location information is obtained by radar or other sensors and is denoted as longitude γ. t ,latitude Height h t ; The conversion formula from WGS84 coordinates to ECEF coordinates is as follows: Where N is the radius of curvature of the geoid, R is the Earth's semi-major axis, e is the Earth's first eccentricity, and γ is the target or photoelectric longitude. is the target or photoelectric latitude, h is the height of the target or vehicle-mounted photoelectric equipment, and X, Y, and Z are the coordinate axes of the ECEF geocentric fixed coordinate system.

3. The distributed radar-guided photoelectric target tracking method based on a vehicle-mounted platform according to claim 1, characterized in that, Step 2 is as follows: The local navigation coordinate system uses the ENU coordinate system, with the origin located at the vehicle's center of mass. The E-axis points due east, the N-axis points due north, and the U-axis is perpendicular to the local horizontal plane and pointing upwards. This coordinate system is coplanar with the vehicle platform and describes the relative positional relationships in the vicinity of the vehicle, utilizing the vehicle's WGS84 coordinates. Perform a transformation from ECEF coordinates to ENU coordinates, using the transformation matrix R. ECEF2ENU for: The displacement vectors of the detection target and the vehicle-mounted optoelectronic equipment in the ECEF coordinate system are (Pos t_ECEF -Pos v_ECEF 0, which is the target's coordinate Pos in the ECEF coordinate system. t_ECEF Subtract the coordinates Pos of the vehicle-mounted optoelectronic equipment in the ECEF coordinate system v_ECEF To obtain the vector distance between the two, use R ECEF2ENU The displacement vector calculation in the ENU coordinate system is as follows: Pos ENU =R ECEF2ENU ×(Pos t_ECEF -Pos v_ECEF )。 4. The distributed radar-guided photoelectric target tracking method based on a vehicle-mounted platform according to claim 1, characterized in that, The EOC coordinate system mentioned in step 3 is specifically as follows: Define the EOC coordinate system: the origin is located at the reference point of the vehicle-mounted optoelectronic equipment, i.e., the optoelectronic zero position. The X-axis points to the right side of the vehicle, the Y-axis points to the front of the vehicle, and the Z-axis is perpendicular to the vehicle and upwards. This serves as the coordinate system for direct sensing by the optoelectronic system. The final target pointing angle is represented in this coordinate system. After the vehicle-mounted optoelectronic equipment is installed, the optoelectronic zero position is calibrated according to the installation status.

5. The distributed radar-guided photoelectric target tracking method based on a vehicle-mounted platform according to claim 1, characterized in that, Step 3 describes the ENU to EOC coordinate system transformation, which involves coordinate system rotation but not translation or scaling. The ENU coordinate system rotation involves three axes: yaw, pitch, and roll, defined as follows: Heading angle: defined as 'a' degrees, which is defined as a counterclockwise rotation around the vehicle's top-view center axis, i.e., the Z-axis; Pitch angle: defined as b degrees, which is defined as a counterclockwise rotation around the vehicle's side-view horizontal axis, i.e., the X-axis; Roll angle: defined as c degrees, which is defined as a counterclockwise rotation around the vehicle's frontal longitudinal axis, i.e., the Y-axis; The attitude of the optoelectronic system is described by the yaw, pitch, and roll angles: the attitude angles of the onboard optoelectronic equipment describe the orientation of the optoelectronic coordinate system relative to the local navigation coordinate system.

6. The distributed radar-guided photoelectric target tracking method based on a vehicle-mounted platform according to claim 5, characterized in that, Step 3 specifically involves: Transformation from ENU coordinate system to EOC coordinate system: Constructing the rotation matrix R based on the attitude angles ENU2EO ; R ENU2EO =R y(c) ×R x(b) ×R z(a) Among them, R z(a) R represents the basic rotation matrix for rotating about the Z-axis by 'a' degrees. x(b) R represents the basic rotation matrix for rotating about the X-axis by b degrees. y(c) The basic rotation matrix representing a rotation of c degrees around the Y-axis: The selection of the positive directions and rotation order of rotation angles a, b, and c is consistent with the definition of attitude angles of inertial navigation equipment. The coordinate transformation sequence is defined as Z→X→Y, or Yaw→Pitch→Roll. This means first rotating around the U-axis at the yaw angle 'a', then around the intermediate X-axis at the pitch angle 'b', and finally around the final Y-axis at the roll angle 'c'. The relative displacement Pos between the transformed target and the vehicle-mounted optoelectronic equipment is then calculated. EOC for: Pos EOC =R ENU2EO ×Pos ENU The relative displacement Pos EOC Represented as Pos EOC =[X EO Y EO Z EO ] T , where X EO It represents its displacement in the X-axis direction, Y EO It represents its displacement in the Y-axis direction, Z EO This indicates its displacement in the Z-axis direction.

7. A distributed radar-guided photoelectric target tracking method based on a vehicle-mounted platform according to claim 6, characterized in that, Step 4 specifically involves: Based on the target's displacement relative to the photoelectric system in the EOC photoelectric coordinate system, Pos EOC =[X EO Y EO Z EO ] T Based on the coordinate data, the system calculates the guidance information required by the vehicle-mounted optoelectronic equipment, including azimuth, pitch, and distance information. The EO =teaching -1 (X EO ,Y EO ) Azimuth Az EO The rotation angle relative to the photoelectric zero position Y-axis is usually measured in the XY plane of the vehicle-mounted photoelectric equipment, with the direction pointing towards the X-axis being positive. Az EO =tan -1 (X EO ,Y EO The function can handle all quadrants, and the result range is (-π, π]. Pitch angle El EO The angle of elevation relative to the XY plane of the vehicle body has a range of (-π / 2, π / 2]; Distance information: Distance information is used to adjust the focal length and focus value of the photoelectric sensor. Based on the initial calibration information of the photoelectric sensor, the distance information ensures that the target is clearly imaged in the video.

8. The distributed radar-guided photoelectric target tracking method based on a vehicle-mounted platform according to claim 1, characterized in that, The vehicle-mounted optoelectronic equipment control information mentioned in step 5 includes optoelectronic azimuth angle, pitch angle, lens focal length, and focus value.

9. A distributed radar-guided photoelectric target tracking method based on a vehicle-mounted platform according to claim 8, characterized in that, in, The focal length and focusing value of the lens of the vehicle-mounted optoelectronic equipment are determined by the distance between the vehicle-mounted optoelectronic equipment and the target.

10. A distributed radar-guided photoelectric target tracking method based on a vehicle-mounted platform according to claim 9, characterized in that, Step 5 specifically includes: Step 5-1: Based on the imaging principle theory of photoelectric, calculate and convert the control information of the photoelectric device into the focal length and sharpness value of the photoelectric device to obtain the focal length required by the lens for clear imaging at different distances of the vehicle-mounted photoelectric device. Step 5-2: Compare the lens focal lengths corresponding to targets at different distances during photoelectric calibration, and correct the relationship between the theoretically calculated distance and the lens focal length. This is done by flying a drone target from near to far and recording the lens focal length values ​​at different distances, and comparing them with the theoretical calculations. Step 5-3: Compare the lens focus values ​​corresponding to different weather visibility and temperature during photoelectric calibration, or manually adjust the focus value of the photoelectric equipment to make the image clear and complete target locking.

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