A method and system for on-site calibration of multi-optical-axis consistency of an optoelectronic tracking and sighting device

Abstract

This invention discloses a method and system for on-site calibration of multi-optical axis consistency of an optoelectronic tracking device. The method utilizes an optical axis calibration component integrating a target simulation and measurement unit, an inertial measurement unit, and a comprehensive information processor. At close range, it sequentially establishes optical path connections with the laser, visible light, and infrared optical axes of the optoelectronic tracking device under test, while simultaneously acquiring the absolute attitude information of the inertial measurement unit and the relative centroid deviation of each optical axis. Through data fusion, the pointing direction of each optical axis in global space is accurately calculated. Finally, using the visible light optical axis as a reference, the parallelism error of the infrared and laser optical axes is calculated through projection, completing the consistency calibration. This invention overcomes the dependence of traditional methods on laboratory environments, achieving rapid and high-precision calibration of multi-optical axis consistency of optoelectronic tracking devices under outdoor field conditions.

Description

Technical Field

[0001] This invention belongs to the field of photoelectric measurement and calibration technology, specifically relating to a method and system for on-site calibration of the consistency of multiple optical axes of a photoelectric tracking sight under outdoor conditions. Background Technology

[0002] Electro-optical tracking devices are crucial in modern detection and tracking systems, and their measurement data is a key source of target information. However, electro-optical tracking devices are susceptible to deviations in multiple optical axes due to factors such as environmental temperature variations and random vibrations, leading to spatial pointing offsets of each optical axis, reducing measurement accuracy, and posing a significant challenge to high-precision electro-optical tracking tasks.

[0003] Currently, photoelectric tracking and aiming instrument calibration technology is widely used in aerospace, industrial inspection, and other fields with extremely high measurement accuracy requirements. Traditional optical axis consistency testing methods are mainly based on indoor environments, including projection target plate method, collimator method, pentaprism method, laser optical axis meter method, and beam splitting projection method. However, due to the need for on-site calibration, the working environment conditions are far inferior to those in laboratories, and the above-mentioned traditional calibration methods cannot meet the requirements. Strong environmental adaptability, compact calibration equipment, and fast calibration speed are required, making multi-optical load optical axis consistency calibration a major research direction in various countries. Therefore, the field of photoelectric tracking and aiming instrument calibration urgently needs an efficient and accurate multi-optical axis consistency calibration method that is suitable for on-site conditions. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a field calibration method for multi-optical axis consistency of photoelectric tracking sights, so as to achieve high-precision measurement and pointing under field conditions.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for on-site calibration of multi-optical axis consistency of an optoelectronic tracking sight includes the following steps: The optical axis calibration component is installed on the support frame at a set distance from the photoelectric tracking device under test; Adjust the support frame so that the target simulation and measurement unit of the optical axis calibration component receives the laser ranging signal from the photoelectric tracking sight, and simultaneously records the attitude information output by the inertial measurement unit and the laser centroid deviation calculated by the target simulation and measurement unit. Adjust the support frame so that the broadband light source emitted by the target simulation and measurement unit is incident on the vicinity of the visible light detection center and the infrared detection center of the photoelectric tracking and aiming instrument, and simultaneously record the attitude information, visible light centroid deviation and infrared centroid deviation at this time. Using the visible light optical axis as the reference optical axis, the infrared optical axis and the laser ranging optical axis are projected onto the reference optical axis respectively, and the measurement error of the consistency of the optical axes of the multi-light load is calculated.

[0006] Furthermore, the optical axis calibration component includes: The target simulation and measurement unit is used to provide a broadband light source, receive laser signals, and calculate the centroid deviation. An inertial measurement unit is used to output the attitude information of the optical axis calibration component in real time; The integrated information processor is used to synchronously acquire and process laser centroid deviation, inertial measurement unit attitude information, visible light centroid deviation, and infrared centroid deviation.

[0007] Furthermore, the support frame can adjust the optical axis orientation of the optical axis calibration component in the vertical direction to ensure that it can transmit and receive visible light, infrared, and laser signals from the photoelectric tracking device.

[0008] Furthermore, the spatial orientation of the laser ranging optical axis is calculated through the following steps: The horizontal and pitch deviation angles of the laser spot centroid, as well as the attitude angles of the inertial measurement unit, are continuously acquired. Calculate the arithmetic mean of the deviation angle and the attitude angle; Based on the average value, and combined with the attitude information of the inertial measurement unit, the azimuth and pitch angles of the laser ranging optical axis in space are calculated.

[0009] Furthermore, the spatial orientation of the visible light optical axis and the infrared optical axis is calculated through the following steps: Continuously acquire visible light or infrared centroid deviation and attitude angle of inertial measurement unit; Calculate the arithmetic mean of the deviation and the attitude angle; Based on the average value, and combined with the attitude information of the inertial measurement unit, the azimuth and pitch angles of the visible light or infrared optical axis in space are calculated.

[0010] Furthermore, the calculation of the optical axis parallelism measurement error of the multi-optical load includes: The infrared optical axis and the laser ranging optical axis are projected onto the visible light reference optical axis, respectively. Calculate the deviation angles of each optical axis from the reference optical axis in the azimuth and elevation directions; The multi-axis parallelism error is calculated based on the deviation angle.

[0011] A calibration system for implementing the above method, characterized in that it comprises: The optical axis calibration component integrates a target simulation and measurement unit, an inertial measurement unit, and a comprehensive information processor; An adjustable support frame is used to support and adjust the spatial position and orientation of the optical axis calibration component; The photoelectric tracking device under test has visible light, infrared and laser ranging functions, and is used to receive light sources and emit laser signals.

[0012] Beneficial effects: 1. This invention, through an optical axis calibration component that integrates a target simulation and measurement unit and an inertial measurement unit (IMU), eliminates the dependence on fixed laboratory infrastructure and enables direct calibration at the site where equipment such as aircraft and automobiles are parked (at a close distance of about 0.5 meters), effectively overcoming the adverse effects of outdoor factors such as temperature difference and vibration on calibration accuracy.

[0013] 2. The core of the method of this invention lies in the synchronous recording of the attitude information of the inertial measurement unit and the centroid deviation of each optical path. By integrating the relative deviation angle of the optical axis with the absolute attitude information in space through the integrated information processor, the pointing of each optical axis in global space is accurately obtained. This improves the calibration from simple relative alignment to absolute spatial pointing calibration, fundamentally improving the accuracy and reliability of multi-optical axis consistency calibration.

[0014] 3. This invention proposes using the visible light optical axis as the reference optical axis, and projecting the spatial orientation of the infrared optical axis and the laser ranging optical axis onto this reference for calculation. This method provides a stable and clear reference for multi-axis systems, enabling the parallelism error between optical axes to be objectively quantified and evaluated. It ensures the consistency and comparability of results from different batches of calibrations and different devices, laying a reliable foundation for the system's accurate tracking and aiming.

[0015] 4. Compared to traditional calibration methods that require multiple steps and adjustments, this invention uses an integrated calibration component and adjustable support frame to sequentially complete measurements of the three optical axes: laser, visible light, and infrared. The highly integrated process simplifies operation steps, shortens calibration time, and lowers the technical requirements for operators, making it particularly suitable for quickly completing calibration tasks in field conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the calibration method of the present invention; Among them, 1-Optical axis calibration component; 2-Target simulation and measurement unit; 3-Inertial measurement unit; 4-Support frame; 5-Electro-optical tracking and aiming device; 6-Visible light window; 7-Infrared window; 8-Laser ranging window; 9-Aircraft base. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1 As shown, this invention discloses a method for on-site calibration of multi-optical axis consistency of an optoelectronic tracking sight. The apparatus involved includes: an optical axis calibration component, a support frame, and the optoelectronic tracking sight to be tested; wherein, The optical axis calibration component includes a target simulation and measurement unit, an inertial measurement unit, and a comprehensive information processor. The target simulation and measurement unit provides a broad-spectrum light source covering visible and infrared light, and is capable of acquiring laser ranging spectrum and calculating centroid deviation. The inertial measurement unit provides real-time attitude information of the optical axis calibration component. The comprehensive information processor can simultaneously acquire laser centroid deviation, attitude information of the inertial measurement unit, and visible and infrared centroid deviations in the electro-optical tracking device under test.

[0019] The support frame carries the photoelectric calibration component and can adjust the optical axis of the photoelectric calibration component in the vertical direction to ensure that its optical axis can transmit and receive visible light, infrared and laser signals from the photoelectric tracking device under test.

[0020] The photoelectric tracking device under test carries visible light, infrared and laser spectra. When the detection is in a static state, it can receive a broadband light source sent by the target simulation and measurement unit of the photoelectric calibration component, and provide the visible light and infrared centroid deviation to the integrated information processor of the optical axis calibration component; at the same time, it can emit laser signals to the target simulation and measurement unit of the photoelectric calibration component.

[0021] Preferably, by adjusting the spatial position of the support frame, the target simulation and measurement unit of the optical axis calibration component is aligned with the laser ranging window. The pose of the support frame is finely adjusted to ensure that the laser ranging spot is near the center of the focal plane and the pose of the support frame remains unchanged. The azimuth and pitch angles of the laser optical axis relative to the optical axis calibration component are calculated. Then, combined with the attitude information of the inertial measurement unit at this moment, the direction of the laser optical axis in space is calculated, and the spatial direction measurement of the laser ranging optical axis of the photoelectric tracking sight is completed.

[0022] The spatial orientation calculation of the laser ranging optical axis is specifically as follows: When the optical axis calibration component is powered on, the inertial measurement unit is powered on and enters the self-calibration mode, and the optical axis calibration component remains stationary. After the inertial measurement unit has completed calibration, the optical axis calibration component begins self-calibration. By adjusting the spatial position of the support frame, the target simulation and measurement unit of the optical axis calibration component are aligned with the laser ranging window. The pose of the support frame is finely adjusted to ensure that the laser ranging spot is near the center of the focal plane and the pose of the support frame remains unchanged. The azimuth and pitch angles of the laser optical axis relative to the optical axis calibration component are calculated. Then, combined with the attitude information of the inertial measurement unit at this moment, the direction of the laser optical axis in space is calculated, and the measurement of the laser ranging optical axis of the photoelectric tracking sight is completed. The laser ranging spot is located near the center of the focal plane, and the horizontal and pitch deviation angles of the spot's centroid are simultaneously and continuously acquired. Inertial measurement unit attitude angle Record separately and , and ... and (Units are degrees (°)). The centroid deviation angle of the light spot is calculated using the arithmetic mean method. and inertial measurement unit attitude angle Finally, the idle direction of the light spot centroid is calculated. According to measurement data and ,calculate , and Please fill in Table 1.

[0023] Table 1. Measurement values ​​of optical axis parallelism under multiple loads

[0024] (1) In the formula, —Arithmetic mean of the horizontal deviation angle of the centroid of the laser ranging spot, (°); —Arithmetic mean of the elevation deviation angle of the centroid of the laser ranging spot, (°); —Measure the horizontal deviation angle of the centroid of the light spot, (°); —Measure the reading of the pitch deviation angle of the centroid of the light spot, (°); —Corresponding optical axis to the calibration Indicates the calibration of the laser rangefinder optical axis; —Corresponding measurement series, .

[0025] (2) In the formula, —Arithmetic mean of the reference azimuth angle of the inertial measurement unit, (°); —Arithmetic mean of the reference pitch angles of the inertial measurement unit, (°); —Arithmetic mean of the reference tilt angle of the inertial measurement unit, (°); —Measure the azimuth reading of the inertial measurement unit, (°); —Measure the pitch angle reading of the inertial measurement unit, (°); —Measure the tilt angle reading of the inertial measurement unit, (°); —Corresponding optical axis to the calibration Indicates the calibration of the laser rangefinder optical axis; —Corresponding measurement series, .

[0026] Given that the optical axis of the target simulation and measurement unit is consistent with the tilt optical axis of the inertial measurement unit, and disregarding the influence of tilt angle on the optical axis direction, the spatial direction of the laser ranging optical axis is: (3) —The azimuth angle of the laser ranging optical axis in space, (°); —The pitch angle of the laser ranging optical axis in space, (°); —The tilt angle of the laser ranging optical axis in space, (°); —Corresponding optical axis to the calibration Indicates the calibration of the laser rangefinder optical axis; —Corresponding measurement series, .

[0027] Preferably, the spatial position of the support frame is adjusted so that the target simulation and measurement unit of the optical axis calibration component is aligned with the visible light / infrared window. The pose of the support frame is finely adjusted to ensure that the visible light / infrared camera of the photoelectric tracking device can acquire the visible light target emitted by the target simulation and measurement unit. Then, combined with the attitude information of the inertial measurement unit at this moment, the direction of the visible light / infrared optical axis in space is calculated, and the spatial direction measurement of the visible light / infrared optical axis of the photoelectric tracking device is completed respectively.

[0028] The spatial orientation calculation of the visible and infrared optical axes is as follows: Adjust the spatial position of the support frame so that the target simulation and measurement unit of the optical axis calibration component is aligned with the visible light window. Finely adjust the posture of the support frame to ensure that the visible light camera of the photoelectric tracking device can collect the visible light target emitted by the target simulation and measurement unit. Then, combine the attitude information of the inertial measurement unit at this moment to calculate the direction of the visible light optical axis in space and complete the measurement of the visible light optical axis of the photoelectric tracking device. The centroid deviation of the visible light target emitted by the target simulation and measurement unit at the visible light camera of the electro-optical tracking and aiming device. Simultaneously, the attitude angles of the inertial measurement unit are collected. Record separately and , and ... and (Units are degrees (°)). The visible light centroid deviation was calculated using the arithmetic mean method. and inertial measurement unit attitude angle Finally, the spatial orientation of the visible light centroid deviation is calculated. According to measurement data and ,calculate , and And fill in Table 1. Among them, Indicates calibration of the visible light optical axis; The optical axis calibration of infrared cameras is the same as that of visible light cameras, among which... This indicates the calibration of the infrared optical axis.

[0029] Preferably, the visible light optical axis is used as the reference optical axis, and the infrared optical axis and the laser ranging optical axis are projected onto the reference optical axis respectively, and the parallelism measurement error of the multi-light load optical axis is calculated and calibrated.

[0030] Solving the spatial vector of optical axis parallelism for multi-optical loads.

[0031] Using the visible light optical axis as the reference optical axis, project the infrared optical axis and the laser ranging optical axis onto the reference optical axis respectively, calculate the calibration error of the multi-light load optical axis parallelism measurement, and fill it into Table 2. The optical axis parallelism is decomposed into two optical axes: azimuth and elevation. (4) In the formula, — The azimuth error between the optical axis and the visible light optical axis in spatial orientation, (°); — The pitch axis error between the optical axis and the visible light optical axis in spatial orientation, (°); —Corresponding optical axis to the calibration Indicates the calibration of the infrared optical axis. This indicates the optical axis for calibrating laser ranging.

[0032] Calculation of optical axis parallelism measurement error for multi-optical loads: (5) In the formula, — Measurement error of optical axis parallelism of multi-optical load, (°).

[0033] The measurement error of the optical axis parallelism of the multi-optical load Fill in Table 2.

[0034] Table 2 Calibration of Multi-Load Optical Axis Parallelism Measurement Error

[0035] Example First, the aircraft / vehicle carrying the electro-optical tracking device is parked. After the optical axis calibration component completes its power-on test, it is mounted on the support frame, approximately 0.5m away from the electro-optical tracking device under test. Second, the electro-optical tracking device and the optical axis calibration component are powered on. The support frame is adjusted so that the target simulation and measurement unit of the optical axis calibration component receives the laser signal emitted by the laser rangefinder of the electro-optical tracking device, and simultaneously records the attitude information output by the inertial measurement unit of the optical axis calibration component and the centroid deviation calculated by the target simulation and measurement unit. Then, the support frame is adjusted so that the broadband light source emitted by the target simulation and measurement unit of the optical axis calibration component is incident on the visible light and infrared detection centers of the electro-optical tracking device, respectively, and the attitude information, visible light, and infrared centroid deviation are recorded simultaneously. Finally, using the visible light optical axis as the reference optical axis, the infrared optical axis and the laser rangefinder optical axis are projected onto the reference optical axis, respectively, and the multi-light load optical axis consistency measurement error calibration is calculated.

[0036] This embodiment provides a method for on-site calibration of multi-optical axis consistency of an optoelectronic tracking sight, which can be achieved through an angle calibration component. A schematic diagram of the method is shown below. Figure 1 As shown, the specific steps of this method are as follows: S1. Adjust the geometric position of the support frame to ensure that the target simulation and measurement unit of the optical axis calibration assembly accurately receives the laser signal emitted by the photoelectric tracking device. During this process, the attitude data of the inertial measurement unit and the centroid deviation calculated by the target simulation and measurement unit are simultaneously acquired. These data allow for the precise determination of the spatial pointing characteristics of the laser ranging optical axis.

[0037] S2, similarly adjust the support frame so that the target simulation and measurement unit emits a broadband light source, illuminating the center positions of the visible light and infrared detectors of the electro-optical tracking device, respectively. Simultaneously record the attitude information and the visible light and infrared centroid deviations of the electro-optical tracking device. Using this data, the spatial pointing characteristics of the visible light and infrared optical axes can be accurately determined.

[0038] S3. Select the visible light optical axis as the reference, and project the laser ranging optical axis and the infrared optical axis onto this reference axis respectively. By comparing the spatial pointing deviations of each optical axis, the optical axis consistency measurement error of the multi-optical load is calculated. These error data will be used for subsequent system calibration to ensure that the output accuracy of all optical axes is consistent in different operating modes.

[0039] Specifically, as shown in Table 1, in this embodiment, S1 is implemented as follows: S11, during the on-site calibration of the multi-light load consistency of the photoelectric tracking and aiming device, the spatial position and attitude of the support frame are first adjusted to ensure that the target simulation and measurement unit of the optical axis calibration component is precisely aligned with the laser ranging window. Based on this, the position and attitude of the support frame are finely adjusted to ensure that the laser ranging spot stably appears near the center of the focal plane while maintaining the attitude of the support frame. Subsequently, based on the attitude information of the support frame at this time, the azimuth and pitch angles of the laser optical axis relative to the optical axis calibration component are calculated. In step S12, combining the attitude data acquired by the inertial measurement unit (IMU) at this moment, a spatial transformation is performed between the target simulation and the local coordinate system of the measurement unit, thereby accurately calculating the direction of the laser ranging optical axis in global space. By integrating the attitude information provided by the IMU, spatial positioning and measurement of the laser ranging optical axis of the electro-optical tracking sight are achieved. S13. After the laser ranging spot stabilizes near the center of the focal plane, the horizontal and pitch deviation angles of the spot centroid and the attitude angles of the IMU are simultaneously and continuously acquired. To improve measurement accuracy and reduce noise interference, the arithmetic mean method is used to process these parameters, calculate the mean deviation angle of the spot centroid and the mean attitude angle of the IMU, and further calculate the spatial orientation of the spot centroid based on the results. Finally, the relevant data are compiled and filled into Table 1.

[0040] S14. Based on the premise that the optical axis of the target simulation and measurement unit is consistent with the tilt optical axis of the inertial measurement unit (IMU), the influence of the tilt angle on the spatial pointing of the laser ranging optical axis can be ignored in this calibration process, and the specific pointing of the laser ranging optical axis in space can be calculated.

[0041] As shown in Table 1, in this embodiment, S2 is implemented as follows: S21, by adjusting the spatial position and attitude of the support frame, the target simulation and measurement unit of the optical axis calibration component is precisely aligned with the visible light / infrared window. Based on this, the position and attitude of the support frame are finely adjusted to ensure that the visible light / infrared camera of the photoelectric tracking sight can stably acquire the visible light target emitted by the target simulation and measurement unit. S22, combining the attitude data acquired by the inertial measurement unit (IMU) at the current moment, performs a spatial transformation between the target simulation and the local coordinate system of the measurement unit, thereby accurately calculating the direction of the visible / infrared optical axis in global space. By integrating the attitude information provided by the IMU, the spatial positioning and measurement of the visible / infrared optical axis of the electro-optical tracking device are completed.

[0042] S23. During the process of the target simulation and measurement unit emitting a visible light / infrared target, the centroid deviation of the visible light / infrared camera of the electro-optical tracking sight and the attitude angle data of the inertial measurement unit are simultaneously acquired. To improve measurement accuracy and reduce noise interference, the arithmetic mean method is used to process these parameters, calculating the mean value of the visible light / infrared centroid deviation and the mean value of the IMU attitude angle. The results are then used to further calculate the spatial pointing of the visible light / infrared centroid deviation. Finally, the relevant data are compiled and entered into Table 1.

[0043] As shown in Table 2, in this embodiment, S3 is implemented as follows: S31 uses the visible light optical axis as a reference, projecting the infrared optical axis and the laser ranging optical axis onto this reference optical axis. This enables the analysis of the relative positional relationships between different optical axes. S32, the parallelism error between the optical axes of the multi-optical load is decomposed into components in the azimuth and elevation directions, and the measurement error in each direction is calculated separately. Finally, these error data are compiled and filled into Table 2.

[0044] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for on-site calibration of multi-optical axis consistency of an optoelectronic tracking sight, characterized in that, Includes the following steps: The optical axis calibration component is installed on the support frame at a set distance from the photoelectric tracking device under test; Adjust the support frame so that the target simulation and measurement unit of the optical axis calibration component receives the laser ranging signal from the photoelectric tracking sight, and simultaneously records the attitude information output by the inertial measurement unit and the laser centroid deviation calculated by the target simulation and measurement unit. Adjust the support frame so that the broadband light source emitted by the target simulation and measurement unit is incident on the vicinity of the visible light detection center and the infrared detection center of the photoelectric tracking and aiming instrument, and simultaneously record the attitude information, visible light centroid deviation and infrared centroid deviation at this time. Using the visible light optical axis as the reference optical axis, the infrared optical axis and the laser ranging optical axis are projected onto the reference optical axis respectively, and the measurement error of the consistency of the optical axes of the multi-light load is calculated.

2. The method according to claim 1, characterized in that, The optical axis calibration component includes: The target simulation and measurement unit is used to provide a broadband light source, receive laser signals, and calculate the centroid deviation. An inertial measurement unit is used to output the attitude information of the optical axis calibration component in real time; The integrated information processor is used to synchronously acquire and process laser centroid deviation, inertial measurement unit attitude information, visible light centroid deviation, and infrared centroid deviation.

3. The method according to claim 2, characterized in that, The support frame can adjust the optical axis orientation of the optical axis calibration component in the vertical direction to ensure that it can transmit and receive visible light, infrared and laser signals from the photoelectric tracking device.

4. The method according to claim 2, characterized in that, The spatial orientation of the laser ranging optical axis is calculated through the following steps: The horizontal and pitch deviation angles of the laser spot centroid, as well as the attitude angles of the inertial measurement unit, are continuously acquired. Calculate the arithmetic mean of the deviation angle and the attitude angle; Based on the average value, and combined with the attitude information of the inertial measurement unit, the azimuth and pitch angles of the laser ranging optical axis in space are calculated.

5. The method according to claim 2, characterized in that, The spatial orientation of the visible light optical axis and the infrared optical axis is calculated through the following steps: Continuously acquire visible light or infrared centroid deviation and attitude angle of inertial measurement unit; Calculate the arithmetic mean of the deviation and the attitude angle; Based on the average value, and combined with the attitude information of the inertial measurement unit, the azimuth and pitch angles of the visible light or infrared optical axis in space are calculated.

6. The method according to any one of claims 1-5, characterized in that, The calculation of the optical axis parallelism measurement error of the multi-optical load includes: The infrared optical axis and the laser ranging optical axis are projected onto the visible light reference optical axis, respectively. Calculate the deviation angles of each optical axis from the reference optical axis in the azimuth and elevation directions; The multi-axis parallelism error is calculated based on the deviation angle.

7. A calibration system for implementing the method of claim 1, characterized in that, include: The optical axis calibration component integrates a target simulation and measurement unit, an inertial measurement unit, and a comprehensive information processor; An adjustable support frame is used to support and adjust the spatial position and orientation of the optical axis calibration component; The photoelectric tracking device under test has visible light, infrared and laser ranging functions, and is used to receive light sources and emit laser signals.

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