Electro-optical pod-based method for correcting IMU installation misalignment angle in geographic tracking mode

Abstract

The present application relates to the technical field of electro-optical control. The present application provides an electro-optical pod-based method for correcting an IMU installation misalignment angle in a geographic tracking mode. In embodiments of the present disclosure, online calibration is performed by continuously correcting a target geographic tracking result by means of image-derived line-of-sight angle calculation, thereby enabling an electro-optical pod to achieve more accurate target positioning and geographic tracking during a calibration flight; moreover, storing the calibrated installation misalignment angle ensures target positioning and geographic tracking effects in subsequent flights, thereby significantly improving the execution efficiency of flight missions.

Description

A method for correcting IMU installation deviation angle based on geo-tracking mode of photoelectric pod Technical Field

[0001] This disclosure relates to the field of optoelectronic control technology, and in particular to a method for correcting IMU installation deviation angles based on optoelectronic pod geographic tracking mode. Background Technology

[0002] The electro-optical pod is a multispectral airborne electro-optical detection system integrating infrared, visible light, and laser technologies, serving as a primary electro-optical reconnaissance device for aircraft platforms. The key component for high-precision positioning and geographic tracking within the electro-optical pod is the positioning and orientation system (POS), composed of an inertial measurement unit (IMU) and a navigation calculation (PCS) board. An external GPS provides GNSS signals to the POS, which then outputs combined navigation information to the electro-optical pod controller, enabling the pod to locate the target and obtain its geographic location. Simultaneously, combining this with the target's geographic location information, the electro-optical pod controller calculates the required rotational deviation angle, driving the pod's aiming line to quickly point towards the target, completing the staring tracking.

[0003] During actual assembly, installation errors between the IMU and the electro-optical pod's line of sight can cause the frame to be non-orthogonal, affecting target positioning and geographic tracking accuracy. Therefore, to obtain higher accuracy in target positioning and geographic tracking, it is necessary to calibrate the installation errors between the IMU and the electro-optical pod's line of sight.

[0004] Traditional installation error calibration methods require multiple flights or fixed routes, which have specific requirements on time and route, compressing the effective execution time of the mission. This invention performs online calibration by continuously correcting the target geographic tracking results through image-based line-of-sight angle calculation. This not only makes the target positioning and geographic tracking of the electro-optical pod more accurate during the current flight, but also ensures the target positioning and geographic tracking effect of subsequent flights by storing the calibrated installation deviation angle, significantly improving the execution efficiency of flight missions.

[0005] Therefore, it is necessary to improve one or more of the problems existing in the above-mentioned related technical solutions.

[0006] It should be noted that this section is intended to provide background or context for the technical solutions of this disclosure as set forth in the claims. The description herein does not constitute an admission that it is prior art simply because it is included in this section. Summary of the Invention

[0007] The purpose of this disclosure is to provide a method for correcting the installation deviation angle of an IMU based on a geographic tracking mode of an optoelectronic pod, thereby overcoming, to at least some extent, one or more problems caused by the limitations and defects of related technologies.

[0008] According to an embodiment of this disclosure, a method for correcting IMU installation deviation angle based on a photoelectric pod geographic tracking mode is provided, the method comprising:

[0009] The target's true geographical location is obtained, enabling the photoelectric pod to perform geographic tracking on the target;

[0010] Adjust the photoelectric sensor to a wide field of view, perform coarse adjustment on the photoelectric pod, align the aiming line of the photoelectric pod with the target, and calculate in real time the coarse adjustment angle corresponding to the aiming line in the current field of view; wherein, the coarse adjustment angle includes azimuth coarse adjustment angle and pitch coarse adjustment angle;

[0011] The coarse adjustment angle is written into the geographic tracking function as the initial IMU installation deviation angle;

[0012] Adjust the photoelectric sensor to a small field of view, fine-tune the photoelectric pod, and press the aiming line of the photoelectric pod onto the target, and calculate in real time the fine adjustment angle corresponding to the aiming line in the current field of view; wherein, the fine adjustment angle includes azimuth fine adjustment angle and pitch fine adjustment angle;

[0013] The fine-tuning angle is written into the geographic tracking function as the final IMU installation deviation angle and saved to the storage chip.

[0014] Furthermore, the step of obtaining the target's true geographical location and enabling the photoelectric pod to perform geographic tracking of the target includes:

[0015] The predetermined geographical location of the target is bound together to obtain the target's location coordinates;

[0016] The target's position coordinates are converted to an optoelectronic geographic coordinate system, and combined with the attitude information of the optoelectronic pod, the target spatial pointing angle of the optoelectronic pod's rotation is obtained; wherein, the target spatial pointing angle of the optoelectronic pod's rotation includes the pointing azimuth angle and the pointing pitch angle;

[0017] The photoelectric pod is directed toward the target based on the target spatial pointing angle of its rotation.

[0018] Further, the step of converting the target's position coordinates to an optoelectronic geographic coordinate system and combining it with the attitude information of the optoelectronic pod to obtain the target spatial pointing angle of the optoelectronic pod's rotation includes:

[0019] The coordinates of the optoelectronic pod and the target are transformed from geodetic coordinates to optoelectronic geographic coordinates; wherein,

[0020] The coordinates of the photoelectric pod in the geographic coordinate system are: The target has coordinates in the geographic coordinate system as follows: The positional difference between the target and the photoelectric pod is:

[0021] The coordinates of the target in the photoelectric coordinate system are, i.e., Among them, M a,g This is the matrix for converting geographic coordinates to photoelectric coordinates.

[0022] Based on the target's coordinates in the photoelectric coordinate system, the target spatial pointing azimuth angle of the rotating photoelectric pod is obtained. and pitch angle

[0023] Further, the steps of adjusting the photoelectric sensor to a large field of view, coarsely adjusting the photoelectric pod, aligning the aiming line of the photoelectric pod with the target, and calculating the coarse adjustment angle corresponding to the aiming line in the current field of view in real time include:

[0024] Adjust the photoelectric sensor to the large field of view, divide the image into groups of 10 pixels, and move the aiming line toward the target under the geographic tracking position until it presses against the target;

[0025] The coarse azimuth movement pixel, coarse pitch movement pixel, and photoelectric sensor parameters of the aiming line movement are obtained, and the coarse azimuth adjustment angle and the coarse pitch adjustment angle are calculated.

[0026] Furthermore, the expression for the coarse azimuth adjustment angle is: Δfw1 = px fw1 (2arctan(h / (2f)))

[0027] The expression for the coarse pitch adjustment angle is: Δfy1 = px fy1 (2arctan(v / (2f)))

[0028] Among them, px fw1 To move the coarse azimuth of the aiming line by pixels, px fy1 To move the aiming line coarsely in pitch by pixels, h = px sz *1920 represents the horizontal dimension, v = px sz *1080 represents the horizontal dimension, in pixels (px) sz Let f be the size of the photoelectric sensor, and f be the focal length of the photoelectric sensor.

[0029] Further, the steps of adjusting the photoelectric sensor to a small field of view, fine-tuning the photoelectric pod, aligning the aiming line of the photoelectric pod with the target, and calculating in real time the fine-tuning angles of azimuth and pitch corresponding to the aiming line in the current field of view include:

[0030] Reduce the field of view of the photoelectric sensor, adjust the photoelectric sensor to the small field of view, and move the aiming line toward the target in the geographic tracking position until the aiming line coincides with the center of the target;

[0031] The fine-tuning azimuth movement pixels, fine-tuning pitch movement pixels, and photoelectric sensor parameters of the aiming line movement are obtained, and the fine-tuning azimuth adjustment angle and the fine-tuning pitch adjustment angle are calculated.

[0032] Furthermore, the expression for the fine adjustment angle of the azimuth is: Δfw2 = px fw2 (2arctan(h / (2f)))

[0033] The expression for the coarse pitch adjustment angle is: Δfy2=px fy2 (2arctan(v / (2f)))

[0034] Among them, px fw2 To fine-tune the azimuth of the aiming line, move the pixel (px). fy2 To fine-tune the elevation of the aiming line, move the target line by pixels, h = px sz *1920 represents the horizontal dimension, v = px sz *1080 represents the horizontal dimension, in pixels (px) sz Let f be the size of the photoelectric sensor, and f be the focal length of the photoelectric sensor.

[0035] The technical solutions provided by the embodiments of this disclosure may include the following beneficial effects:

[0036] In the embodiments of this disclosure, the IMU installation deviation angle correction method based on the above-described geo-tracking mode of the electro-optical pod involves the following steps: First, before takeoff, the ground checks that the zero-point pointing of the electro-optical pod's line of sight is basically consistent with the pointing of the aircraft nose. After the aircraft takes off and enters the flight path, the electro-optical pod performs geo-tracking based on the target position. The electro-optical pod calculates the rotation azimuth and rotation pitch angles in real time based on the relative positions of the aircraft and the target, achieving staring tracking of the target. The electro-optical pod sensor is adjusted to a suitable field of view where the target appears in the image. The image is divided into groups of 10 pixels. Under the geo-tracking position, the aiming line is moved towards the target until it is pressed against the target, completing the coarse calibration of the IMU installation deviation angle. The electro-optical pod sensor is adjusted to the minimum field of view to further correct the geo-tracking position. When the center of the aiming line is moved to coincide with the center of the target, the moved field of view angle is written as the IMU installation deviation angle into the electro-optical pod's storage chip, completing the precise calibration of the IMU installation deviation angle. On the other hand, online calibration by continuously correcting the target geographic tracking results through image conversion of the line-of-sight angle not only makes the target positioning and geographic tracking of the electro-optical pod more accurate during the calibration flights, but also ensures the target positioning and geographic tracking effect of subsequent flights by storing the calibrated installation deviation angle, thus greatly improving the execution efficiency of flight missions. Attached Figure Description

[0037] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0038] Figure 1 illustrates the steps of an IMU installation deviation angle correction method based on a photoelectric pod geographic tracking mode in an exemplary embodiment of the present disclosure.

[0039] Figure 2 shows a detailed flowchart of the IMU installation deviation angle correction method based on the optoelectronic pod geographic tracking mode in an exemplary embodiment of this disclosure;

[0040] Figure 3 illustrates the principle of controlling the optoelectronic pod using the IMU installation deviation angle correction method based on the optoelectronic pod geographic tracking mode in an exemplary embodiment of this disclosure. Detailed Implementation

[0041] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0042] Furthermore, the accompanying drawings are merely illustrative diagrams of embodiments of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0043] This example embodiment provides a method for correcting IMU installation deviation angles under a geo-tracking mode based on an optoelectronic pod. Referring to Figure 1, this method for correcting IMU installation deviation angles under a geo-tracking mode based on an optoelectronic pod may include steps S101 to S105.

[0044] Step S101: Obtain the target's true geographical location, and enable the photoelectric pod to perform geographic tracking on the target;

[0045] Step S102: Adjust the photoelectric sensor to a large field of view, perform coarse adjustment on the photoelectric pod, press the aiming line of the photoelectric pod into the target, and calculate the coarse adjustment angle corresponding to the aiming line in the current field of view in real time;

[0046] Step S103: Write the coarse adjustment angle as the initial IMU installation deviation angle into the geographic tracking function; wherein, the coarse adjustment angle includes the azimuth coarse adjustment angle and the pitch coarse adjustment angle;

[0047] Step S104: Adjust the photoelectric sensor to a small field of view, fine-tune the photoelectric pod, press the aiming line of the photoelectric pod into the target, and calculate the fine adjustment angle corresponding to the aiming line in the current field of view in real time; wherein, the fine adjustment angle includes azimuth fine adjustment angle and pitch fine adjustment angle;

[0048] Step S105: Write the fine-tuning angle as the final IMU installation deviation angle into the geographic tracking function and save it to the storage chip.

[0049] The above-described method for correcting IMU installation deviation angles based on the geo-tracking mode of the electro-optical pod involves several steps. First, before takeoff, ground checks ensure the zero-point orientation of the electro-optical pod's line of sight is roughly consistent with the nose direction. After takeoff and entering the flight path, the electro-optical pod performs geo-tracking based on the pre-set target position. The pod calculates the rotation azimuth and pitch angles in real-time based on the relative positions of the aircraft and the target, achieving staring tracking of the target. The pod's sensor is adjusted to a suitable field of view where the target appears in the frame. The frame is divided into groups of 10 pixels, and the aiming line is moved towards the target at the geo-tracking position until it overlaps with the target, completing the coarse calibration of the IMU installation deviation angle. The pod's sensor is then adjusted to the minimum field of view to further correct the geo-tracking position. When the center of the aiming line is moved to coincide with the target center, the shifted field of view angle is written into the pod's storage chip as the IMU installation deviation angle, completing the precise calibration of the IMU installation deviation angle. On the other hand, online calibration by continuously correcting the target geographic tracking results through image conversion of the line-of-sight angle not only makes the target positioning and geographic tracking of the electro-optical pod more accurate during the calibration flights, but also ensures the target positioning and geographic tracking effect of subsequent flights by storing the calibrated installation deviation angle, thus greatly improving the execution efficiency of flight missions.

[0050] The steps of the IMU installation deviation angle correction method based on the optoelectronic pod geographic tracking mode in this example embodiment will now be described in more detail with reference to Figures 1 to 3.

[0051] In step S101, after the aircraft takes off, it hovers and flies. The electro-optical pod receives the PPS signal sent by the aircraft's GPS and sends it to the internal inertial navigation component. It waits for the inertial navigation data to output attitude information and converges the data through aircraft maneuvers.

[0052] Binding reservation target T1 geographical location P T (lon T lat T H T The geographic tracking of target T1 requires the following input data for the entire solution process:

[0053] a) Internal inertial navigation information for electro-optical systems: Aircraft ellipsoidal height H B , yaw angle of the electro-optical pod Pitch angle θ of the electro-optical pod, roll angle γ of the electro-optical pod, longitude λ of the carrier aircraft, latitude φ of the carrier aircraft;

[0054] b) Target's true location: Longitude (lon) T latitude T Height H T ;

[0055] The output data is: the rotation angle of the optical pod's line of sight: azimuth angle and pitch angle.

[0056] First, transform the coordinates of the photoelectric sensor and the target point from geodetic coordinates to the photoelectric geographic coordinate system. Let the coordinates in the photoelectric geographic coordinate system be... The coordinates in the target geographic coordinate system are The positional difference between the target and the photoelectric field is:

[0057] The coordinates of the target in the photoelectric coordinate system are... Where M a,g This is the matrix for converting geographic coordinates to photoelectric coordinates.

[0058] Therefore, the target spatial pointing angle for geographic tracking rotation is obtained: the azimuth angle is... Pitch angle

[0059] In steps S102 and S103, the sensor is adjusted to a suitable field of view to detect the target T1, the aiming line is coarsely adjusted towards the target direction to make the aiming line hit the target, and the azimuth adjustment angle Δfw1 and pitch adjustment angle Δfy1 corresponding to the movement of the aiming line in the current field of view are calculated in real time, and the initial IMU installation deviation angle in the photoelectric pod positioning algorithm is updated in real time.

[0060] The formula for calculating the field of view angle for each field of view is: fw_fov=(2arctan(sensor size / (2*focal length)))

[0061] Then adjust the orientation angle:

[0062] Pitch adjustment angle:

[0063] In steps S104 and S105, the sensor is adjusted to the minimum field of view, the aiming line is finely adjusted so that the center of the aiming line coincides with the center of the target, and the azimuth adjustment angle Δfw2 and pitch adjustment angle Δfy2 corresponding to the amount of aiming line movement in the current field of view are calculated in real time, and the final IMU installation deviation angle in the photoelectric pod positioning algorithm is updated in real time.

[0064] Furthermore, the final IMU installation deviation angle is written into the optoelectronic pod storage chip.

[0065] In one specific embodiment, the optoelectronic pod is mounted on an aircraft.

[0066] The electro-optical pod includes optical sensors, a POS (Positioning Target), a controller, and a memory. The optical sensors enable target imaging; the POS measures the pod's heading, pitch, and roll angles, as well as its position in the Earth coordinate system. The controller performs target search and tracking, target localization, and geographic tracking algorithm calculations; the memory stores the calibrated IMU installation deviation angles.

[0067] In one embodiment, as shown in Figure 2, is a flowchart of the IMU installation deviation angle correction method based on the geographical tracking mode of the photoelectric pod.

[0068] Before takeoff, ground checks ensured that the zero-point alignment of the electro-optical pod's line of sight was basically consistent with the aircraft's nose direction. After takeoff and entering the flight path, the electro-optical pod performed geo-tracking based on the pre-set target position. The pod calculated the rotation azimuth and pitch angles in real time based on the relative positions of the aircraft and the target, achieving staring tracking of the target. The pod's sensors were adjusted to a suitable field of view where the target appeared in the frame. The frame was divided into groups of 10 pixels, and the aiming line was moved towards the target at the geo-tracking position until it was aligned with the target, completing the coarse calibration of the IMU installation deviation angle. The pod's sensors were then adjusted to the minimum field of view to further correct the geo-tracking position. When the center of the aiming line was moved to coincide with the target's center, the moved field of view angle was written as the IMU installation deviation angle into the pod's storage chip, completing the precise calibration of the IMU installation deviation angle.

[0069] Figure 3 shows the schematic diagram of the IMU installation deviation angle correction method for controlling the photoelectric pod based on the geographical tracking mode of the photoelectric pod.

[0070] In one specific embodiment, the input is: local inertial navigation information: longitude: 122.1576959°, latitude: 37.93841°; altitude: 2000m, heading: 10.89°; pitch: -9.10°; roll: 0.23°;

[0071] Target location: Longitude: 122.155234°, Latitude: 37.93091°; Altitude: 100m.

[0072] The angles required for the photoelectric pod to perform geographic tracking are: azimuth: -178.45°, pitch: -74.98°.

[0073] At this point, the crosshairs of the electro-optical pod cannot completely lock onto the target after rotation. Assuming a pixel deviation of 20 in a 1920×1080 pixel image with a horizontal field of view of 1.87° and a pitch field of view of 1.5°, then, based on geographic tracking, adjust the horizontal angle by 0.019° and the pitch angle by 0.028°. At this point, the crosshairs in the center of the electro-optical pod's image will completely lock onto the target.

[0074] The above-described method for correcting IMU installation deviation angles based on the geo-tracking mode of the electro-optical pod involves several steps. First, before takeoff, ground checks ensure the zero-point orientation of the electro-optical pod's line of sight is roughly consistent with the nose direction. After takeoff and entering the flight path, the electro-optical pod performs geo-tracking based on the pre-set target position. The pod calculates the rotation azimuth and pitch angles in real-time based on the relative positions of the aircraft and the target, achieving staring tracking of the target. The pod's sensor is adjusted to a suitable field of view where the target appears in the frame. The frame is divided into groups of 10 pixels, and the aiming line is moved towards the target at the geo-tracking position until it overlaps with the target, completing the coarse calibration of the IMU installation deviation angle. The pod's sensor is then adjusted to the minimum field of view to further correct the geo-tracking position. When the center of the aiming line is moved to coincide with the target center, the shifted field of view angle is written into the pod's storage chip as the IMU installation deviation angle, completing the precise calibration of the IMU installation deviation angle. On the other hand, online calibration by continuously correcting the target geographic tracking results through image conversion of the line-of-sight angle not only makes the target positioning and geographic tracking of the electro-optical pod more accurate during the calibration flights, but also ensures the target positioning and geographic tracking effect of subsequent flights by storing the calibrated installation deviation angle, thus greatly improving the execution efficiency of flight missions.

[0075] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" in the above description indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.

[0076] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0077] In the embodiments of this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0078] In embodiments of this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0079] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0080] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. An IMU installation bias angle correction method based on an optical-electric pod geographic tracking mode, characterized in that, The method includes: The target's true geographical location is obtained, enabling the photoelectric pod to perform geographic tracking on the target; Adjust the photoelectric sensor to a wide field of view, perform coarse adjustment on the photoelectric pod, align the aiming line of the photoelectric pod with the target, and calculate in real time the coarse adjustment angle corresponding to the aiming line in the current field of view; wherein, the coarse adjustment angle includes azimuth coarse adjustment angle and pitch coarse adjustment angle; The coarse adjustment angle is written into the geographic tracking function as the initial IMU installation deviation angle; Adjust the photoelectric sensor to a small field of view, fine-tune the photoelectric pod, and press the aiming line of the photoelectric pod onto the target, and calculate in real time the fine adjustment angle corresponding to the aiming line in the current field of view; wherein, the fine adjustment angle includes azimuth fine adjustment angle and pitch fine adjustment angle; The fine-tuning angle is written into the geographic tracking function as the final IMU installation deviation angle and saved to the storage chip.

2. The IMU installation bias angle correction method based on the optical-electric pod geographic tracking mode according to claim 1, characterized in that, The step of obtaining the target's true geographical location and enabling the photoelectric pod to perform geographic tracking of the target includes: The predetermined geographical location of the target is bound together to obtain the target's location coordinates; The target's position coordinates are converted to an optoelectronic geographic coordinate system, and combined with the attitude information of the optoelectronic pod, the target spatial pointing angle of the optoelectronic pod's rotation is obtained; wherein, the target spatial pointing angle of the optoelectronic pod's rotation includes the pointing azimuth angle and the pointing pitch angle; The photoelectric pod is directed toward the target based on the target spatial pointing angle of its rotation.

3. The IMU installation bias angle correction method based on the optical-electric pod geographic tracking mode according to claim 2, characterized in that, The step of converting the target's position coordinates to an optoelectronic geographic coordinate system and combining this with the attitude information of the optoelectronic pod to obtain the target spatial pointing angle of the optoelectronic pod's rotation includes: The coordinates of the optoelectronic pod and the target are transformed from geodetic coordinates to optoelectronic geographic coordinates; wherein, The optoelectronic pod has coordinates in a geographical coordinate system The target is at coordinates in a geographical coordinate system The position difference of the target relative to the optoelectronic pod is then: The coordinate of the target in the photoelectric coordinate system is wherein M a,g is a matrix for converting a geographic coordinate system to an optical coordinate system; According to the coordinates of the target under the optoelectronic coordinate system, a target space pointing azimuth angle of rotation of the optoelectronic pod is obtained and pointing to the pitch angle 4. The IMU installation bias angle correction method in the optical-electric pod geographic tracking mode according to claim 1, characterized in that, The steps of adjusting the photoelectric sensor to a wide field of view, coarsely adjusting the photoelectric pod, aligning the aiming line of the photoelectric pod with the target, and calculating the coarse adjustment angle corresponding to the aiming line in the current field of view in real time include: Adjust the photoelectric sensor to the large field of view, divide the image into groups of 10 pixels, and move the aiming line toward the target under the geographic tracking position until it presses against the target; The coarse azimuth movement pixel, coarse pitch movement pixel, and photoelectric sensor parameters of the aiming line movement are obtained, and the coarse azimuth adjustment angle and the coarse pitch adjustment angle are calculated.

5. The IMU installation bias angle correction method in the optical-electric pod geographic tracking mode according to claim 4, characterized in that, The expression of the azimuth coarse adjustment angle is: Δfw1=px fw1 (2arctan(h / (2f))) The expression for the pitch coarse adjustment angle is: Δfy1 = px fy1 (2arctan(v / (2f))) where px fw1 is the first azimuthal direction movement pixel of the boresight, px fy1 is the first elevation direction movement pixel of the boresight, h = px sz * 1920 is the horizontal dimension, v = px sz * 1080 is the horizontal dimension, px sz is the size of the photosensor, and f is the focal length of the photosensor.

6. The IMU installation bias angle correction method in the optical-electric pod geographic tracking mode according to claim 1, characterized in that, The steps of adjusting the photoelectric sensor to a small field of view, fine-tuning the photoelectric pod, aligning the aiming line of the photoelectric pod with the target, and calculating the fine-tuning angle corresponding to the aiming line in the current field of view in real time include: Reduce the field of view of the photoelectric sensor, adjust the photoelectric sensor to the small field of view, and move the aiming line toward the target in the geographic tracking position until the aiming line coincides with the center of the target; Fine adjustment azimuth angle and fine adjustment pitch angle are calculated by using the fine adjustment azimuth moving pixel and the fine adjustment pitch moving pixel of the line-of-sight movement and combining with the photoelectric pod sensor parameters.

7. The IMU installation bias angle correction method in the optical-electric pod geographic tracking mode according to claim 6, characterized in that, The expression of the fine orientation angle is: Δfw2=px fw2 (2arctan(h / (2f))) The expression of the pitch coarse adjustment angle is: Δfy2 = px fy2 (2arctan(v / (2f))) where px fw2 is the fine adjustment azimuth direction moving pixel of the boresight, px fy2 is the fine adjustment elevation direction moving pixel of the boresight, h = px sz * 1920 is the horizontal dimension, v = px sz * 1080 is the horizontal dimension, px sz is the size of the photoelectric sensor, and f is the focal length of the photoelectric sensor.

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