Unmanned aerial vehicle photoelectric load laser optical axis flight calibration system and method

Abstract

The invention relates to the technical field of airborne photoelectric load application, and particularly discloses an unmanned aerial vehicle photoelectric load laser optical axis flight calibration system and method, and the system comprises a photoelectric load which is carried on an unmanned aerial vehicle; the target is used for enabling the laser emitted by the photoelectric load to form a light spot; the light spot acquisition and transmission module comprises a near-infrared light source, a light spot detector and wireless transmission equipment A and B and is used for performing light spot acquisition and remote transmission; the unmanned aerial vehicle ground command and control station comprises a network switch and a load operation seat, and the load operation seat is provided with calibration software; and the calibration software is used for receiving the load image sent by the photoelectric load, displaying the remotely transmitted light spot as a light spot image, calculating the offset of the light spot on the target, and uploading and programming the offset to the photoelectric load. The light spot detector with a single function is organically combined with the ground base station, real-time communication between the unmanned aerial vehicle and the light spot detector can be achieved, and the real-time performance and accuracy of axis calibration are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of airborne optoelectronic load applications, and in particular to a flight calibration system and method for a laser optical axis of an optoelectronic load of an unmanned aerial vehicle. Background Art

[0002] Nowadays, the missiles mounted on large and medium-sized reconnaissance and strike drones mostly use laser semi-active guidance, so this requires that the optoelectronic payload mounted on the drone has not only visible light and infrared display functions, but also laser ranging and laser irradiation functions. After the optoelectronic payload finds, tracks and locks the target, the laser irradiation function of the optoelectronic payload is used to continuously illuminate the target to guide the missile to hit the target.

[0003] Generally, the detection band of the visible light sensor of the optoelectronic load is the visible light band (working wavelength range 0.4μm-0.7μm), and the detection band of the infrared sensor is the medium-wave infrared band (working wavelength range 3μm-5μm), while the general laser working wavelength is 1.064μm. Therefore, the payload operator of the UAV cannot see the actual position of the light spot in the visible light or infrared image of the optoelectronic load of the ground command and control station of the UAV. In actual applications, the position of the light spot in the image is generally marked with specific markings (generally cross markings) to indicate the actual position of the laser spot, and to assist the operator in laser aiming at the target to be hit. The general optoelectronic load will calibrate the laser position when leaving the factory. Detection under specific field of view.

[0004] Therefore, the calibration of the laser optical axis position in the optoelectronic payload is one of the key factors for the missile's hit accuracy. However, due to assembly errors, the optical axis of the new optoelectronic payload needs to be calibrated before performing a strike mission. At the same time, due to the influence of vibration and impact during transportation or flight, and creep of connecting components caused by temperature changes, the optical axis also needs to be calibrated during use.

[0005] During the calibration process, additional special equipment is required to detect the light spot in order to determine the actual position of the light spot and the deviation from the tracking center.

[0006] In the visible light and infrared images of the optoelectronic payload, the center of the cross mark is the optical axis of the infrared and visible light. At the same time, the center of the cross mark also represents the position of the laser irradiation. If the center of the cross mark in the image is inconsistent with the optical axis of the laser irradiation, it will affect the missile's hit accuracy.

[0007] It can be seen that the consistency of the optical axis of the visible light sensor, infrared sensor and laser is one of the key factors for the missile's hit accuracy. However, due to assembly errors, the optical axis of the new optoelectronic payload needs to be calibrated before performing the strike mission. At the same time, due to the influence of vibration and impact during transportation or flight, and creep of connecting components caused by temperature changes, the optical axis also needs to be calibrated during use.

[0008] Generally speaking, the detection band of the visible light sensor of the optoelectronic payload is the visible light band (wavelength range 0.4μm-0.7μm), and the detection band of the infrared sensor is the medium-wave infrared band (wavelength range 3μm-5μm). The general laser operating wavelength is 1.064μm. Therefore, the payload operator cannot see the actual position of the light spot in the optoelectronic payload image of the ground control station. Additional special equipment is needed for light spot detection to determine the actual position of the light spot and the deviation from the tracking center.

[0009] The commonly used spot calibration process is to set up a square cross center target in the open space outside the ground control station in advance, and set the spot detector in front of the target. The UAV flies close to the target at a distance of 10km. When it is 8km away from the target, the load operator tracks the center of the target and emits a laser. The spot detector operator can see the actual position of the spot in the spot detector computer, and tell the position deviation to the load operator through the intercom. The load operator calculates or looks up the table based on the deviation value, the distance between the UAV and the target and other parameters to obtain the change that needs to be adjusted. However, the operation process of this method is relatively cumbersome, and the laser spot deviation mainly depends on the operator to interpret, and the calculation and lookup process may also introduce human errors.

[0010] Based on this technical background, the present invention studies a flight calibration system and method for the laser optical axis of an optoelectronic payload of an unmanned aerial vehicle. Summary of the invention

[0011] In view of the shortcomings of the prior art, the present invention provides a system and method for flight calibration of the laser optical axis of an optoelectronic payload of an unmanned aerial vehicle. The system organically combines a single-function spot detector with a ground base station, thereby improving the intelligence and speed of the equipment. At the same time, the spot detector and the ground base station are connected via a network, thereby enabling real-time communication between the unmanned aerial vehicle and the spot detector, which not only improves the real-time and accuracy of the calibration, but also significantly improves the efficiency of the optical axis correction operation and reduces the calibration flight time.

[0012] In order to achieve the above-mentioned object, the first aspect of the present invention provides a UAV optoelectronic load laser optical axis flight calibration system, comprising:

[0013] Optoelectronic payload, carried on the UAV;

[0014] A target, used to form a light spot from the laser emitted by the photoelectric payload;

[0015] A light spot acquisition and transmission module, including a near-infrared light source, a light spot detector, a wireless transmission device A, and a wireless transmission device B, is used for performing the light spot acquisition and remote transmission;

[0016] The UAV ground command and control station includes a network switch and a payload operation seat, wherein the payload operation seat is provided with a computer, and the computer has built-in calibration software;

[0017] The calibration software is used to receive the load image sent by the optoelectronic payload, display the remotely transmitted light spot as a light spot image, calculate the offset of the light spot on the target, and upload and burn the offset to the optoelectronic payload.

[0018] A second aspect of the present invention provides a method for calibrating the laser optical axis of an unmanned aerial vehicle optoelectronic load in the above system, comprising:

[0019] The optoelectronic payload carried on the UAV is used to irradiate the laser onto the target to form a light spot;

[0020] Detecting the position of the light spot on the target by a light spot detector and forming a light spot image;

[0021] Remotely transmitting the light spot image to a computer at a ground command and control station of the UAV;

[0022] The offset of the light spot on the target is calculated by the calibration software of the computer through image recognition;

[0023] The offset is uploaded and burned into the photoelectric load to calibrate the actual position of the light spot.

[0024] The beneficial effects of the present invention include:

[0025] (1) The UAV optoelectronic payload laser optical axis flight calibration system proposed in the present invention organically combines a single-function spot detector with a ground base station, thereby improving the intelligence and speed of the equipment. At the same time, the spot detector and the ground base station are connected via a network, which enables real-time communication between the UAV and the spot detector. This not only improves the real-time and accuracy of the calibration, but also significantly improves the efficiency of the optical axis correction operation and reduces the calibration flight time.

[0026] (2) The UAV optoelectronic payload laser optical axis flight calibration method proposed in the present invention can automatically determine the pixel offset, avoid the error caused by manual reading, and improve the accuracy of axis calibration. At the same time, it does not require a special day and night light spot detector operator, which reduces the required personnel, improves efficiency, and saves costs.

[0027] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

[0029] Figure 1 This is a schematic diagram of the UAV optoelectronic payload laser optical axis flight calibration system proposed by the present invention.

[0030] Figure 2 This is a schematic diagram of the calibration process of the UAV optoelectronic payload laser optical axis flight calibration system proposed by the present invention.

[0031] Figure 3 This is a schematic diagram of the light spot image in the calibration software of the UAV optoelectronic payload laser optical axis flight calibration system proposed by the present invention.

[0032] Figure 4 This is a schematic diagram of the light spot offset in the calibration software of the UAV optoelectronic payload laser optical axis flight calibration system proposed by the present invention.

[0033] Figure 5 This is a schematic diagram of the operating interface in the calibration software of the UAV optoelectronic payload laser optical axis flight calibration system proposed by the present invention.

[0034] Description of reference numerals:

[0035] 1-target, 2-near-infrared light source, 3-day and night light spot detector, 4-wireless transmission equipment A, 5-wireless transmission equipment B, 6-network switch, 7-payload operation seat, 8-calibration software, 9-UAV, 10-photoelectric payload, 11-data link, 12-payload image, 13-laser, 14-light spot image. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0037] The present invention provides a UAV optoelectronic load laser optical axis flight calibration system, such as Figure 1 As shown, including:

[0038] An optoelectronic payload 10 is carried on the UAV 9;

[0039] The target 1 is used to form a light spot of the laser 13 emitted by the photoelectric load 10;

[0040] The light spot acquisition and transmission module includes a near-infrared light source 2, a light spot detector 3, a wireless transmission device A4, and a wireless transmission device B5, and is used for light spot acquisition and remote transmission;

[0041] The UAV ground command and control station includes a network switch 6 and a payload operation seat 7. The payload operation seat 7 is provided with a computer, and the computer has built-in calibration software 8;

[0042] The calibration software 8 is used to receive the load image 12 sent by the optoelectronic payload 10 , display the remotely transmitted light spot as a light spot image 14 , and calculate the offset of the light spot on the target 1 , and upload and burn the offset to the optoelectronic payload 10 .

[0043] In the present invention, a single-function light spot detector is organically combined with a ground base station, which improves the intelligence and speed of the equipment. At the same time, the light spot detector is connected to the ground base station through a network, which can realize real-time communication between the UAV and the light spot detector, which not only improves the real-time and accuracy of the axis calibration, but also significantly improves the efficiency of the optical axis calibration operation and reduces the calibration flight time.

[0044] According to the present invention, the UAV ground command and control station forms a bidirectional data link 11 with the optoelectronic payload 10;

[0045] The calibration software 8 receives the load image 12 sent by the photoelectric load 10 and uploads and burns the offset into the photoelectric load 10 through a bidirectional data link 11 .

[0046] According to the present invention, the target surface of the target 1 is arranged obliquely in an open area;

[0047] The emitting end of the near-infrared light source 2 and the receiving end of the light spot detector 3 are both arranged opposite to the target surface;

[0048] The wireless transmission device A4 is close to the light spot detector 3 and is in communication connection with it;

[0049] The wireless transmission device B5 is close to the UAV ground command and control station and is in communication connection with it;

[0050] Wireless transmission device A and wireless transmission device B are connected to communicate with each other.

[0051] According to the present invention, the network switch 6 transmits signals with the wireless transmission device B and the load operation seat 7 respectively via Ethernet.

[0052] Preferably, the light spot detector 3 operates in the near-infrared band, and is used to detect and display the laser light spot with a wavelength of 1064 nm.

[0053] According to the present invention, the working band of the near-infrared light source 2 coincides with the detection band of the light spot detector 3;

[0054] The near-infrared light source 2 is turned on when used at night to provide auxiliary lighting, so that the light spot detector 3 can detect the light spot and the target 1 at night.

[0055] The present invention also provides a method for flight calibration of laser optical axis of optoelectronic load of unmanned aerial vehicle in the above system, comprising:

[0056] The laser 13 is irradiated onto the target 1 to form a light spot by using the photoelectric payload 10 carried on the drone 9;

[0057] The position of the light spot on the target 1 is detected by the light spot detector 3 and a light spot image 14 is formed;

[0058] Remotely transmitting the spot image 14 to a computer at a ground command and control station of the UAV;

[0059] The offset of the light spot on the target 1 is calculated by the calibration software 8 of the computer through image recognition;

[0060] The offset is uploaded and burned into the photoelectric load 10 to calibrate the actual position of the light spot.

[0061] According to the present invention, the offset of the light spot on the target 1 calculated by the calibration software 8 of the computer through image recognition includes:

[0062] Taking the center of the target 1 as the origin of the coordinate system, the relationship between the pixel coordinates in the spot image 14 and the three-dimensional coordinates of the actual target spot center is obtained;

[0063] Based on the relationship, the three-dimensional coordinates of the actual target spot are converted into the two-dimensional coordinates of the spot on the target plane, and a two-dimensional equation group is obtained;

[0064] Select four feature points on the target 1 and the spot image 14 and the spot center coordinates of the spot image 14 respectively, and bring them into the two-dimensional equation group to obtain the actual spot offset distance;

[0065] Based on the actual spot offset distance, the offset is calculated according to the principle of optical axis calibration.

[0066] According to the present invention, the relationship between the three-dimensional coordinates is:

[0067]

[0068] Among them, (x, y) is the pixel coordinate, (X, Y, Z) is the actual target spot center coordinate, and a11-a33 is the transformation matrix coefficient;

[0069] The expression of the two-dimensional equation system is:

[0070]

[0071] Wherein, X'=X / Z, Y'=Y / Z, a33=1, (X', Y') is the actual spot offset distance;

[0072] Based on the actual spot offset distance, the formula used to calculate the offset according to the principle of optical axis calibration is:

[0073]

[0074] Among them, n is the number of pixels that need to be adjusted, that is, the offset, which is obtained by calculating the x-direction and y-direction respectively and then rounding; D is the distance between the target and the photoelectric load; h is the spot offset distance, that is, the corresponding value of h in the x-direction is X′, and the corresponding value of h in the y-direction is Y′; P is the size of a single pixel of the photoelectric load sensor; f is the focal length value of the photoelectric load sensor.

[0075] Preferably, the spot offset distance is obtained in the calibration software by an image processing method, and the unit is m;

[0076] The distance between the target and the photoelectric payload is obtained by the laser ranging value of the photoelectric payload, and the unit is m;

[0077] The size of a single pixel of the photoelectric load sensor is preset in the calibration software;

[0078] The focal length value of the photoelectric load sensor is pre-configured in the calibration software or obtained from the real-time telemetry information of the photoelectric load;

[0079] The sensor type is obtained from the telemetry data of the electro-optical payload.

[0080] In the present invention, the pixel offset can be automatically judged, thus avoiding the error caused by manual reading and improving the accuracy of axis calibration. At the same time, no special day and night light spot detector operator is required, thus reducing the required personnel, improving efficiency and saving costs.

[0081] The present invention will be described in more detail below by way of examples.

[0082] Embodiment 1:

[0083] like Figure 1 As shown, this embodiment proposes a UAV optoelectronic payload laser optical axis flight calibration system and method, the system includes a target 1, a near-infrared light source 2, a day and night light spot detector 3, a wireless transmission device A4, a wireless transmission device B5, a network switch 6, and a calibration software 8 arranged at a payload operation seat 7 in a UAV ground command and control station;

[0084] The method of this embodiment requires three coordinate systems, all of which take the center of the target as the origin of the coordinate system, the actual coordinates of the target as the three-dimensional coordinate system T1, the two-dimensional coordinate system T2 of the image of the spot detector, and the target plane coordinate system T3;

[0085] First, the target 1 and the day-night light spot detector 3 are set up, and then the day-night light spot detector 3 is connected to the payload operation seat 7 in the UAV ground command and control station through the wireless transmission device A4, the wireless transmission device B5, and the network switch 6 by network connection;

[0086] Open the calibration software 8 of the load operation seat 7, adjust the parameters of the day and night light spot detector 3, and at the same time, automatically calibrate and correct the target and light spot image in the day and night light spot detector 3;

[0087] like Figure 2 As shown, after the UAV 9 carrying the optoelectronic payload takes off, the optoelectronic payload 10 on the UAV 9 transmits the payload image 12 to the ground station through the data link 11 to find the position of the target 1. The UAV 9 flies close to the target 1 at a distance of 10 km. When the distance from the target 2 is 8 km, the optoelectronic payload 10 tracks the center of the target 1 and emits a laser 13.

[0088] like Figure 3 As shown, the day-night spot detector 3 detects the spot image 14 and displays it in the calibration software 8, but the spot image 14 collected by the day-night spot detector 3 is the result of perspective after the target 1 passes through the imaging system of the day-night spot detector 3. The coordinate points picked up directly are not the actual coordinates on the target 1. The coordinates in the image must be converted to the coordinates of the actual target through perspective coordinate transformation;

[0089] Taking T2 as the coordinate system and the target center as the origin of the coordinate system, the coordinates of the spot in the spot image of the spot detector are (x, y); taking T1 as the coordinate system and the target center as the origin of the coordinate system, the corresponding three-dimensional coordinates of the actual target spot are (X, Y, Z). Therefore, the coordinates of the spot in the spot image (x, y) and the three-dimensional coordinates of the actual target spot (X, Y, Z) have the following relationship:

[0090]

[0091] Take T3 as the coordinate system, the target center as the origin of the coordinate system, and set the coordinates of the light spot on the target plane to (X′, Y′, Z′). Since the light spot on the target plane is a two-dimensional image, it is necessary to convert the actual target light spot three-dimensional coordinates (X, Y, Z) into two-dimensional coordinates on the target plane; the light spot on the target plane is a two-dimensional image, so Z′=1, and divide the actual target light spot three-dimensional coordinates by Z′, and the coordinates are reduced from three dimensions to two dimensions, and the following equation can be obtained:

[0092]

[0093] Generally, we let a 33 =1, expand the above formula to get the coordinates of a target plane point:

[0094]

[0095] There are 8 unknowns in the two equations. If we want to solve the unknowns, we need to list 8 sets of equations, that is, select four known corresponding points on the target and the target image, and select the coordinates of the four corner points of the target as references, such as Figure 3 As shown; the transformation matrix can be solved by substituting the coordinate values ​​of the four points into the equation; the coordinate unit of the target image is pixel, and the coordinate unit of the target is meter;

[0096] like Figure 4 As shown in the figure, the position of the light spot on the target plane and its real offset can be obtained through image perspective transformation and its transformation matrix, which can be directly calculated based on the principle of optical axis calibration:

[0097]

[0098] h is the spot deviation. The spot deviation has two values ​​in the x-axis direction and the y-axis direction, namely Δx and Δy, which are obtained through the calibration software and the unit is m;

[0099] D: The distance between the target and the carrier, obtained by laser ranging using the optoelectronic payload on the UAV, in meters;

[0100] n: The number of pixels to be adjusted, calculated for the x direction and y direction respectively and then rounded;

[0101] P: The size of a single pixel, which needs to be preset in the software;

[0102] f: current focal length. Axis calibration is usually performed at the minimum field of view and can be obtained through telemetry information from the optoelectronic payload.

[0103] The day and night spot detector 3 is connected to the ground local area network through a network connection. The calibration software is arranged on the computer of the load operation seat 7. The calibration software consists of the day and night spot detector 3 video display area, the day and night spot detector 3 parameter setting area, the spot image operation area, the target calibration correction area, and the correction parameter calculation area. Figure 5 As shown; different areas of the calibration software have corresponding functions, as follows:

[0104] Day and night light spot detector 3 video display area: real-time display of day and night light spot detector 3 video;

[0105] Day and night light spot detector 3 parameter setting area: you can remotely control the day and night light spot detector 3, set the day and night light spot detector 3's integration time, frame rate, brightness, contrast and other parameters; you can also take screenshots and save videos;

[0106] Spot image operation area: This area is used to display screenshots during target calibration and optical axis calibration, and can extract pixel coordinates from the screenshots;

[0107] Target calibration correction area: before calibration, after the target and the day and night spot detector 3 are arranged, perform target calibration; that is, input the actual length and width of the target, then click capture to capture a target image, select the upper left, upper right, lower left, and lower right corner points of the target in the image operation area, and finally click the "Target Correction" button to complete the calibration;

[0108] Axis calibration parameter calculation area: When the UAV equipped with the optoelectronic payload enters the axis calibration route, the optoelectronic payload stably tracks the target center and emits laser light. The operator can clearly see the spot position in the video of the day and night spot detector 3;

[0109] The operator clicks the "Capture" button, and the software issues two instructions. One instruction is a telemetry instruction to the photoelectric payload. After receiving the instruction, the photoelectric payload returns several frames of information, which includes the optical axis pixel coordinates of the current sensor. The software reads and displays the current sensor type (Sensor: TV / IR), focal length (Focallength), laser distance value (distance) and optical axis pixel coordinates (Current Coord) in the photoelectric telemetry information; on the other hand, the software automatically captures several frames (configurable, 64 frames by default) of images after this moment, and the first frame of the captured image is displayed in the spot image operation area. The operator can use shortcut keys to view the captured images frame by frame until an image with a spot is found;

[0110] Then click the "Spot location" button and select the center of the spot on the image. The software automatically calculates the offset distance (distance offset) of the spot on the target, the corresponding pixel offset (Pixeloffset) and the new coordinate to be adjusted based on the information.

[0111] Then, the new coordinate value is uploaded and burned into the photoelectric load through "active", "upload" and "confirm" to complete the calibration work. The entire calibration process can be completed independently by the photoelectric load operator without the need for a dedicated day and night spot detector 3 operator.

[0112] Embodiment 2:

[0113] This embodiment provides a UAV optoelectronic payload laser optical axis flight calibration system, such as Figure 1-2 As shown, including:

[0114] An optoelectronic payload 10 is carried on the UAV 9;

[0115] The target 1 is used to form a light spot of the laser 13 emitted by the photoelectric load 10;

[0116] The light spot acquisition and transmission module includes a near-infrared light source 2, a light spot detector 3, a wireless transmission device A4, and a wireless transmission device B5, and is used for light spot acquisition and remote transmission;

[0117] The UAV ground command and control station includes a network switch 6 and a payload operation seat 7. The payload operation seat 7 is provided with a computer, and the computer has built-in calibration software 8;

[0118] The calibration software 8 is used to receive the load image 12 sent by the photoelectric load 10, display the remotely transmitted light spot as a light spot image 14, and calculate the offset of the light spot on the target 1, and upload and burn the offset to the photoelectric load 10;

[0119] In this embodiment, the UAV ground command and control station forms a bidirectional data link 11 with the optoelectronic payload 10;

[0120] The calibration software 8 receives the load image 12 sent by the photoelectric load 10 and uploads and burns the offset to the photoelectric load 10 through a two-way data link 11;

[0121] In this embodiment, the target surface of the target 1 is arranged obliquely in an open area;

[0122] The emitting end of the near-infrared light source 2 and the receiving end of the light spot detector 3 are both arranged opposite to the target surface;

[0123] The wireless transmission device A4 is close to the light spot detector 3 and is in communication connection with it;

[0124] The wireless transmission device B5 is close to the UAV ground command and control station and is in communication connection with it;

[0125] The wireless transmission device A and the wireless transmission device B are connected to communicate with each other;

[0126] In this embodiment, the network switch 6 transmits signals to the wireless transmission device B and the load operation seat 7 respectively through Ethernet;

[0127] In this embodiment, the spot detector 3 works in the near-infrared band and is used to detect and display the laser spot with a wavelength of 1064nm;

[0128] In this embodiment, the working band of the near-infrared light source 2 coincides with the detection band of the light spot detector 3;

[0129] The near-infrared light source 2 is turned on when used at night to provide auxiliary lighting, so that the light spot detector 3 can detect the light spot and the target 1 at night.

[0130] The present invention provides a method for flight calibration of a laser optical axis of an unmanned aerial vehicle optoelectronic load, comprising:

[0131] The laser 13 is irradiated onto the target 1 to form a light spot by using the photoelectric payload 10 carried on the drone 9;

[0132] The position of the light spot on the target 1 is detected by the light spot detector 3 and a light spot image 14 is formed;

[0133] Remotely transmitting the spot image 14 to a computer at a ground command and control station of the UAV;

[0134] The offset of the light spot on the target 1 is calculated by the calibration software 8 of the computer through image recognition;

[0135] The offset is uploaded and burned into the photoelectric load 10 to calibrate the actual position of the light spot;

[0136] In this embodiment, the offset of the light spot on the target 1 calculated by the calibration software 8 of the computer through image recognition includes:

[0137] Taking the center of the target 1 as the origin of the coordinate system, the relationship between the pixel coordinates in the spot image 14 and the three-dimensional coordinates of the actual target spot center is obtained;

[0138] Based on the relationship, the three-dimensional coordinates of the actual target spot are converted into the two-dimensional coordinates of the spot on the target plane, and a two-dimensional equation group is obtained;

[0139] Select four feature points on the target 1 and the spot image 14 and the spot center coordinates of the spot image 14 respectively, and bring them into the two-dimensional equation group to obtain the actual spot offset distance;

[0140] Based on the actual spot offset distance, the offset is calculated according to the principle of optical axis calibration;

[0141] In this embodiment, the relationship between the three-dimensional coordinates is:

[0142]

[0143] Among them, (x, y) is the pixel coordinate, (X, Y, Z) is the actual target spot center coordinate, and a11-a33 is the transformation matrix coefficient;

[0144] The expression of the two-dimensional equation system is:

[0145]

[0146] Wherein, X'=X / Z, Y'=Y / Z, a33=1, (X', Y') is the actual spot offset distance;

[0147] Based on the actual spot offset distance, the formula used to calculate the offset according to the principle of optical axis calibration is:

[0148]

[0149] Among them, n is the number of pixels that need to be adjusted, that is, the offset, which is obtained by calculating the x direction and y direction respectively and then rounding; D is the distance between the target and the photoelectric load; h is the spot offset distance, that is, the corresponding value of h in the x direction is X', and the corresponding value of h in the y direction is Y'; P is the size of a single pixel of the photoelectric load sensor; f is the focal length value of the photoelectric load sensor;

[0150] In this embodiment, the spot offset distance is obtained in the calibration software by an image processing method, and the unit is m;

[0151] The distance between the target and the photoelectric payload is obtained by the laser ranging value of the photoelectric payload, and the unit is m;

[0152] The size of a single pixel of the photoelectric load sensor is preset in the calibration software;

[0153] The focal length value of the photoelectric load sensor is pre-configured in the calibration software or obtained from the real-time telemetry information of the photoelectric load;

[0154] The sensor type is obtained from the telemetry data of the electro-optical payload.

[0155] The UAV optoelectronic payload laser optical axis flight calibration system proposed in the embodiment of the present invention organically combines a single-function spot detector with a ground base station, thereby improving the intelligence and speed of the equipment. At the same time, the spot detector and the ground base station are connected via a network, thereby enabling real-time communication between the UAV and the spot detector, which not only improves the real-time and accuracy of the axis calibration, but also significantly improves the efficiency of the optical axis correction operation and reduces the correction flight time.

[0156] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A UAV optoelectronic payload laser optical axis flight calibration system, characterized in that: include: An optoelectronic payload (10) is mounted on the UAV (9); A target (1) for forming a light spot from the laser light (13) emitted by the photoelectric load (10); A light spot acquisition and transmission module, comprising a near-infrared light source (2), a light spot detector (3), a wireless transmission device A (4), and a wireless transmission device B (5), for performing the light spot acquisition and remote transmission; A ground command and control station for an unmanned aerial vehicle, comprising a network switch (6) and a payload operation seat (7), wherein the payload operation seat (7) is provided with a computer, and the computer has built-in calibration software (8); The calibration software (8) is used to receive the load image (12) sent by the photoelectric load (10), display the remotely transmitted light spot as a light spot image (14), and calculate the offset of the light spot on the target (1), and upload and burn the offset to the photoelectric load (10).

2. The system according to claim 1, characterized in that The UAV ground command and control station forms a bidirectional data link (11) with the optoelectronic payload (10); The calibration software (8) receives the load image (12) sent by the photoelectric load (10) and uploads and burns the offset into the photoelectric load (10) through the bidirectional data link (11).

3. The system according to claim 1, characterized in that The target surface of the target (1) is arranged obliquely in an open area; The emitting end of the near-infrared light source (2) and the receiving end of the light spot detector (3) are both arranged opposite to the target surface; The wireless transmission device A (4) is close to the light spot detector (3) and is in communication connection with it; The wireless transmission device B (5) is close to the UAV ground command and control station and is in communication connection with it; The wireless transmission device (A) and the wireless transmission device (B) are connected to communicate with each other.

4. The system according to claim 3, characterized in that The network switch (6) performs signal transmission with the wireless transmission device (B) and the load operation seat (7) respectively via Ethernet.

5. The system according to claim 1, characterized in that The light spot detector (3) operates in the near-infrared band and is used to detect and display the laser light spot with a wavelength of 1064 nm.

6. The system according to claim 1, characterized in that The working band of the near-infrared light source (2) overlaps with the detection band of the light spot detector (3); The near-infrared light source (2) is turned on when used at night to provide auxiliary lighting, so as to enable the light spot detector (3) to detect the light spot and the target (1) at night.

7. A method for calibrating the laser optical axis of an unmanned aerial vehicle optoelectronic payload in flight, characterized in that: include: Using a photoelectric load (10) mounted on a drone (9) to irradiate a laser (13) onto a target (1) to form a light spot; The position of the light spot on the target (1) is detected by a light spot detector (3) and a light spot image (14) is formed; Remotely transmitting the light spot image (14) to a computer at a ground command and control station of the UAV; The offset of the light spot on the target (1) is calculated by image recognition using the calibration software (8) of the computer; The offset is uploaded and burned into the photoelectric load (10) to calibrate the actual position of the light spot.

8. The method according to claim 7, characterized in that The offset of the light spot on the target (1) calculated by the calibration software (8) of the computer through image recognition includes: Taking the center of the target (1) as the origin of the coordinate system, a relationship between the pixel coordinates in the spot image (14) and the three-dimensional coordinates of the center of the actual target spot is obtained; Based on the relationship, the three-dimensional coordinates of the actual target light spot are converted into two-dimensional coordinates of the light spot on the target plane to obtain a two-dimensional equation group; Select four feature points on the target (1) and the spot image (14) and the spot center coordinates of the spot image (14) respectively, and substitute them into the two-dimensional equation group to obtain the actual spot offset distance; Based on the actual light spot offset distance, the offset is calculated according to the principle of optical axis calibration.

9. The method according to claim 8, characterized in that The relationship between the three-dimensional coordinates is: Among them, (x, y) is the pixel coordinate, (X, Y, Z) is the actual target spot center coordinate, and a11-a33 is the transformation matrix coefficient; The expression of the two-dimensional equation system is: Wherein, X'=X / Z, Y'=Y / Z, a33=1, (X', Y') is the actual spot offset distance; Based on the actual spot offset distance, the formula used to calculate the offset according to the principle of optical axis calibration is: Among them, n is the number of pixels that need to be adjusted, that is, the offset, which is obtained by calculating the x-direction and y-direction respectively and then rounding; D is the distance between the target and the photoelectric load; h is the spot offset distance, that is, the corresponding value of h in the x-direction is X', and the corresponding value of h in the y-direction is Y'; P is the size of a single pixel of the photoelectric load sensor; f is the focal length value of the photoelectric load sensor.

10. The method according to claim 9, characterized in that The light spot offset distance is obtained in the calibration software by image processing method, and the unit is m; The distance between the target and the photoelectric load is obtained by the laser ranging value of the photoelectric load, and the unit is m; The size of a single pixel of the photoelectric load sensor is preset in the calibration software; The focal length value of the photoelectric load sensor is pre-configured in the calibration software, or obtained from the real-time telemetry information of the photoelectric load; The sensor type is obtained from the telemetry data of the optoelectronic payload.

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