CN111044994A - Optical axis calibration device and method for airborne laser range finder of airplane - Google Patents

Abstract

The invention discloses an optical axis calibration device for an airborne laser range finder of an airplane, which comprises a target correcting instrument host and a main control unit; the target calibration instrument host comprises an optical system, an image processing unit and an inertia measuring instrument which are arranged in the shell; the direction of the navigation axis of the inertial measurement instrument is consistent with the direction of the optical axis of the optical system; and the main control unit calculates and obtains the attitude angle parameter of the optical axis of the laser range finder according to the angle data of the inertial measuring instrument and the axial deviation angle data of the image processing unit. The invention realizes the calibration of the optical axis of the laser range finder by combining the optical system and the inertial measurement instrument, has high calibration precision and convenient and quick use, is suitable for the use of airplanes (helicopters) under the conditions of maintenance and assembly, and can also be used in shipborne, hangar, strong wind or narrow and disordered working spaces.

Description

Optical axis calibration device and method for airborne laser range finder of airplane

Technical Field

The invention belongs to the technical field of weaponry, and relates to an optical axis calibration device and method for an airborne laser range finder of an airplane.

Background

Armed aircraft (helicopters) can carry various weapons such as missiles, rockets, aeroguns, bombs and the like, and carry out aerial striking on enemy targets, and the striking effect depends on the precision of a weapon system. However, in practical use, due to the influence of factors such as temperature, impact, vibration and fatigue deformation, the aiming accuracy of the weapon system changes, so that the boresight instrument needs to be adopted to calibrate the axial direction of the weapon system of the airplane (helicopter), which is called boresight for short.

The boresight is a general term for all calibration and adjustment operations for coordinating and conforming optical, electrical and mechanical axes of each device of the weapon system with a reference coordinate axis or maintaining a certain spatial position relationship, and is an important work frequently and directly related to the hit rate of airborne weapons and the task efficiency of the whole weapon system. The existing target calibration method is to adopt the original methods of jacking an airplane, aligning, erecting a target or drawing a target picture and readjusting to calibrate the weapon system, and the target calibration method is time-consuming and labor-consuming, low in efficiency and precision, and the structure of target calibration equipment is complex, so that the target calibration work efficiency, the weapon hit rate and the movement speed of a large machine group are severely limited.

Disclosure of Invention

The invention aims to provide an optical axis calibration device and method for an aircraft-mounted laser range finder, which can quickly, accurately and automatically calibrate the axial deviation of the laser range finder, is suitable for target calibration of an aircraft (helicopter) parked on the land, is more suitable for small-space dynamic target calibration under a ship-borne condition, and has the characteristics of strong universality, high intelligent degree and obvious efficiency.

The technical scheme of the invention is as follows:

the optical axis calibration device for the airborne laser range finder of the airplane comprises a boresight instrument host and a main control unit; the target calibration instrument host comprises an optical system, an image processing unit and an inertia measuring instrument which are arranged in the shell; the direction of the navigation axis of the inertial measurement instrument is consistent with the direction of the optical axis of the optical system;

the optical system comprises a focusing lens group and an image sensor arranged at the focus of the focusing lens group, laser emitted by the laser range finder is attenuated and then focused and imaged on the image sensor to form an image point, and the image processing unit is used for processing data of an image of the image sensor to obtain an axial deviation angle; and the main control unit calculates and obtains the attitude angle parameter of the laser range finder optical axis according to the angle data of the inertial measurement instrument and the axial deviation angle data of the image processing unit.

In the optical axis calibration device for the airborne laser range finder of the aircraft, the inertia measurement unit is an optical fiber strapdown inertial navigation system.

In the optical axis calibration device for the aircraft airborne laser range finder, the focusing lens group comprises the secondary mirror and the primary mirror which are coaxially arranged, and the secondary mirror and the primary mirror are both of hollow structures.

In the optical axis calibration device for the aircraft airborne laser range finder, the light attenuation sheet is arranged in front of the secondary mirror.

In the optical axis calibration device for the aircraft airborne laser range finder, the light absorption sheet is additionally arranged between the light attenuation sheet and the secondary mirror, and the caliber of the light absorption sheet is larger than the size of the central through hole of the secondary mirror and smaller than the size of the secondary mirror.

In the optical axis calibration device for the aircraft airborne laser range finder, the image sensor is a CCD sensor.

The optical axis calibration method for the laser range finder on the airplane comprises the following steps:

【1】 Taking the calibrated airborne inertial navigation data of the airplane as a reference, and constructing to obtain a virtual digital geometric longitudinal axis of the airplane;

【2】 The laser emitted by the laser range finder is focused and imaged on the image sensor after being attenuated, and the image processing unit performs data processing on the image of the image sensor to obtain an axial deviation angle; the main control unit calculates an axial attitude angle parameter of the optical axis of the laser range finder according to the axial deviation angle and an angle parameter obtained by measurement of the inertia measuring instrument;

【3】 Comparing the axial attitude angle parameter of the laser range finder with the attitude angle parameter of the virtual digital geometric longitudinal axis to obtain an axial deflection angle parameter of the optical axis of the laser range finder;

【4】 And determining whether mechanical shaft calibration is needed or not according to the shaft deflection angle parameter value.

In the optical axis calibration method for the laser range finder on the aircraft, the axial attitude angle parameter is represented as Ω (α + θ x, β + θ z, γ);

wherein thetax = Lx/f, thetaz = Lz/f respectively represent the axial deviation angles of the incident laser axis in the X-axis and Z-axis directions, f is the focal length of the imaging lens unit in the camera, Lx and Lz are coordinate values of the focused image point on the X-axis and the Z-axis of the camera image sensor, and (α, gamma) is an angle parameter obtained by the measurement of the inertial measurement instrument.

The invention has the following beneficial technical effects:

1. the invention realizes the axial calibration of the laser range finder of the armed aircraft by combining the optical system and the inertial measurement instrument, utilizes the optical technical means in the comprehensive target-correcting instrument and adopts the inertial measurement technology to obtain the space postures of the reference axis of the aircraft (helicopter) and the optical axis of the laser range finder in real time, and can automatically measure the axial deviation of the optical axis of the laser range finder at the current moment through the interpretation and operation of a computer. The target calibration method has high calibration precision, is convenient and quick to use, overcomes interpretation errors existing in traditional subjective measurement, increases the automation degree of target calibration, is suitable for being used by airplanes (helicopters) under the conditions of maintenance and assembly, and can be used in shipborne, hangar, strong wind or narrow and disordered working spaces.

2. The device can measure the space attitude of the airplane (helicopter) in real time, position and orient the space attitude, finish the self-boresighting of the airplane (helicopter), is particularly suitable for boresighting operation under the parking state of a carrier-based aircraft, can realize the regular overhaul of equipment such as an optoelectronic pod aiming device of the airplane (helicopter), a laser range finder, a photoelectric radar and the like, the overhaul before shooting training, the specific overhaul of a weapon system before operation and the like, and liberates operating personnel from a complicated and tedious boresighting process.

3. In the measuring and calculating process of the axial error of the weapon system, the invention adopts a comparison and difference compensation method, and effectively solves the problem that the target calibration precision is seriously influenced because the initial alignment precision of the airborne inertial navigation is low. In the whole target calibration process, only the self-carried high-precision inertial navigation on the target calibration instrument has drift errors, the inertial navigation drift is small in the target calibration process controlled within 1 hour, the system adopts CCD image display and computer operation, and the whole process is directly checked through a sensor, so that errors caused by human eye interpretation are avoided, and the precision of the target calibration system is greatly improved.

4. The invention can instantly calculate the axial error of a weapon system (a laser range finder, a photoelectric pod aiming device, a photoelectric radar and the like) to be calibrated, has small equipment volume, light weight and hand-held operation, adopts modular design, has good maintainability and interchangeability and is easy to expand to all armed airplanes (helicopters).

Drawings

FIG. 1 is a schematic diagram of the principle of the composition of the main unit of the comprehensive boresight instrument;

FIG. 2 is a schematic diagram of the optical system of the integrated boresight instrument of the present invention;

FIG. 3 illustrates the principle of the present invention in which the mirror induces angular deflection;

FIG. 4 is a schematic diagram illustrating the principle of the deviation of image caused by oblique incident light according to the present invention;

FIG. 5 is a schematic diagram of spatial attitude parameter measurement realized by the combination of an optical system and inertial navigation in the boresight instrument according to the present invention;

FIG. 6 is a schematic view of a reference plane mirror according to the present invention

FIG. 7 is a schematic diagram of the comprehensive boresight instrument of the present invention for multi-class axial calibration;

FIG. 8 is a schematic diagram of the operation of the comprehensive boresight instrument boresight;

FIG. 9 is a schematic diagram of the integrated boresight used for axial calibration of a laser rangefinder according to the present invention;

FIG. 10 is a schematic diagram of the integrated boresight for calibrating a weapon camera according to the present invention;

FIG. 11 is a flow chart of the integrated boresight alignment instrument for the axial alignment of an aircraft according to the present invention.

The reference numbers are as follows:

1-an optical system; 2-an image processing unit; 3-a display screen; 4-an inertial measurement unit; 5-a machine shell; 6-a lens barrel; 10-optical axis; 11-a secondary mirror; 12-a primary mirror; 13-a first cemented semi-reflecting prism; 14-second cemented semi-reflecting prism; 15-an image sensor; 16-a diaphragm; 17-tungsten filament lamp; 18-visible laser; 20-a main control unit; 21-image point; 22-a focusing lens group; 23-ideal mirror surface; 24-actual mirror surface; 50-laser rangefinder; 51-a light attenuation sheet; 52-light absorbing sheet; 60-aircraft longitudinal axis; 61-a reference plane mirror; 62-fixing the round handle; 63-positioning the reed; 64-a reference mirror; 65-outer circular surface; 70-camera lens.

Detailed Description

As shown in fig. 1 to 5, the comprehensive boresight system is composed of a comprehensive boresight instrument host, a main control unit 20, a reference plane mirror 61 and its tooling, a weapon system adapter, a tripod and a connecting cable.

In fig. 2, the integrated boresight instrument host comprises an optical system 1, an image processing unit 2, a display screen 3 and an inertial measurement unit 4 which are arranged inside a casing 5; wherein the direction of the flight axis of the inertial measurement unit is consistent with the direction of the optical axis of the optical system 1.

The optical system 1 comprises a secondary mirror 11, a primary mirror 12, a first cemented semi-reflecting prism 13, a second cemented semi-reflecting prism 14 and an image sensor 15 which are coaxially arranged in sequence along the direction of an optical axis 10, wherein the secondary mirror 11 and the primary mirror 12 are both of hollow structures, and a focusing lens group is formed in a spatial position; a tungsten lamp 17 and a visible light laser 18 are respectively arranged on the reflection light paths of the first gluing semi-reflecting prism 13 and the second gluing semi-reflecting prism 14, a cross-shaped diaphragm 16 is arranged between the tungsten lamp 17 and the first gluing semi-reflecting prism 13, the visible light laser 18 is a green laser with cross-shaped output light spots, the light spots are cross-shaped, and the divergence angle is not more than 0.2 mrad. The tungsten lamp 17 has an emission spectrum of 0.47-5 μm, and is compatible with visible light, near infrared and intermediate infrared. The optical system is arranged in a lens barrel 6, and the outlet end of the lens barrel 6 is a first reference surface 7 which is perpendicular to an optical axis 10 with high precision. The image sensor 15 adopts the CCD to carry out digital processing on the obtained image, so that the interpretation error of the traditional subjective measurement is overcome, the target calibration precision is improved, and the target calibration time is shortened.

When the device is used, the green cross laser 18 emits collimated cross laser, the collimated cross laser is reflected by the second gluing semi-reflecting prism 14 and then is directly transmitted to a target to be detected through the central light through hole of the secondary mirror 11, and the axis of the weapon rack can be calibrated by using the light path. Meanwhile, a tungsten lamp 17 can be used for emitting light, the light passes through a cross diaphragm 16 and then enters a first gluing semi-reflecting prism 13, and the light is reflected into a clamping system consisting of a secondary mirror 11 and a primary mirror 12, so that the light is collimated and output to a target to be detected; the tungsten lamp 17 can image on the visible light sensor and the infrared sensor, and the visible light/infrared sensor is calibrated by using the light path. In system debugging, laser emitted by a visible light laser 18 and light emitted by a combination of a tungsten filament lamp 17 and a diaphragm 16 have higher coaxiality, so that the optical system is an auto-collimation system, can be suitable for correcting optical axes of an infrared camera and a visible light camera by an external field, and can also receive laser incident into the auto-collimator to correct the optical axis of the laser.

The inertial measurement unit 4 adopts a commercially available optical fiber strapdown inertial navigation system, is based on the principle of an optical fiber gyroscope, has small volume and light weight, is convenient for handheld measurement, and is mainly used for measuring the attitude angle of the host machine of the comprehensive target calibration instrument in real time, wherein the optical fiber strapdown inertial navigation component consists of a high-precision triaxial optical fiber gyroscope and an accelerometer, is arranged on a base shell of the host machine of the comprehensive target calibration instrument, and is axially parallel to the collimating optical measurement component. The optical fiber strapdown inertial navigation calculates data information such as course angle, pitch angle, roll angle and the like of the carrier in real time at a high speed by measuring the rotation angle rate and acceleration information of the carrier.

The image processing unit 2 processes and calculates imaging video data of the emitted light beam and the reflected light beam, a display screen 3 is installed on a host of the comprehensive boresight instrument, the display screen is mainly used for inputting control instructions and displaying measurement results, an 8-inch liquid crystal display screen is selected, the display screen has a touch screen function, and is used for selecting data input and data input of a boresight mode, boresight time, machine types, machine numbers and the like after starting up, and meanwhile, measurement errors, imaging positions and boresight measurement results of two inertial navigations can be displayed.

The main control unit 20 is composed of an industrial personal computer and a power supply module, is an operation control center of the system, and performs operation and image processing by receiving attitude data of airborne inertial navigation, attitude data of a comprehensive target correcting instrument host and space imaging data of a CCD (charge coupled device), and finally calculates the axial deflection angle of the weapon system.

When the target is calibrated, a reference plane mirror needs to be installed on the carrier, and the direction of the normal line of the reference plane mirror is consistent with the direction of an axis to be calibrated of the airplane (helicopter). Thus, the reference plane mirror provides a reference plane perpendicular to the reference axis of the airplane (helicopter) for the system, and the reference plane mirror is mainly used for completing the initial alignment of the main machine of the comprehensive target calibration instrument.

In fig. 3, light emitted from the boresight instrument along the optical axis 10 is reflected by the reference plane mirror and then enters the inside of the boresight instrument. Ideally, the ideal mirror 23 of the reference plane mirror is perpendicular to the optical axis 10, but due to assembly and long-term use, there is a deviation angle θ between the actual mirror 24 and the ideal mirror 23, which is also why the aircraft needs to be calibrated frequently. According to the principle of light reflection, the angle between the light reflected by the actual mirror surface 24 and the optical axis becomes 2 θ.

In fig. 4, when the reflected light enters the focusing lens set 22 of the boresight at an included angle of 2 θ (paraxial conditions), and forms an image at a position spaced from the image sensor 15 by a distance L, the focal length of the focusing lens set 22 is f, so that there is a certain distance

L=2fθ

Conversely, the deviation angle θ can also be calculated from L and f.

As shown in FIG. 5, the direction and angle of the boresight is defined with reference to the attitude of the airborne navigation. The direction of the optical axis 10 is consistent with the direction of the course axis (Y axis) of the boresight inertial measurement unit 4, the light reflected from the reference plane mirror passes through the focusing lens group 22 and is imaged on the image point 21 of the image sensor 15, and the x axis and the z axis represent the pixel coordinate axes of the image sensor 15. As can be seen from the principle of fig. 3 and 4, by acquiring the coordinates Lx and Lz of the image point 21 on the X-axis and Z-axis of the image sensor and the focal length f of the focusing lens group 22, the deviation angle of the reference plane mirror can be known, so as to calculate the axial deviation angles θ X and θ Z of the calibrated axis in the X-axis and Z-axis directions, and have

θx=Lx/2f

θz=Lz/2f

The direction of the optical axis 10 is consistent with the direction of the heading axis (Y axis) of the inertial measurement unit 4 of the target calibration instrument, so that the calculation can be converted into the attitude angle of the calibrated axis by adding the angle parameter of the inertial measurement unit 4 and the axial deviation angle of the optical system, wherein α represents the heading angle, β represents the pitch angle, and γ represents the roll angle, assuming that the true attitude angle of the calibrated axis is Ω (α 2, β 2, γ 2), while the angle parameter obtained by the inertial measurement system on the calibration instrument is (α 1, β 1, γ 1), and the axial deviation angle on the calibration instrument is (θ x, θ z), then Ω (α 1+ θ x, β 1+ θ z, γ 1) can be obtained by simple coordinate transformation (α 2, β 2, γ 2), and the angle between the reflected light ray of the reference plane mirror and the optical axis in the actual measurement is not too large, so as long as to ensure that the imaging point 21 can meet the measurement requirement in the effective pixel range of the image sensor 15, and realize the axial calibration.

As shown in fig. 6 and 7, the reference plane mirror 8 is connected with the weapon and the sensor through various tools and adapters, and has a precise assembly relation with the airplane (helicopter), so that the normal of the mirror surface of the reference plane mirror can accurately reflect the azimuth and the pitch angle of the weapon/sensor to be calibrated. Generally, when an airplane (helicopter) leaves a factory, tools such as an airplane longitudinal axis 60 (reference axis) and a weapon system launching axis are equipped on the airplane, so that only the reference plane mirror 8 needs to be fixedly installed on the tool on the axis to be calibrated, the mirror surface is perpendicular to the calibrated axis, and the normal line of the mirror surface can accurately reflect the course angle and the pitch angle of the airplane body. The structural schematic diagram of the reference plane mirror 61 is shown in fig. 6, and includes a reference mirror surface 64, a fixed round handle 62 and a positioning reed 63, the fixed round handle 62 is inserted into a tool round hole of an airplane longitudinal axis or a weapon system launching shaft, the surface of the fixed round handle 62 is an outer round surface processed with high precision, and the outer round surface 65 of the fixed round handle 62 is tightly attached to the inner round surface of the tool round hole under the elastic action of the positioning reed 63, so as to ensure that the fixed round handle 62 is coaxial with the axis of the tool, further ensure that the normal of the reference mirror surface 64 is coaxial with the axis of a shaft to be checked, and ensure the installation precision; the reference mirror 64 is a functional part of this component and is used to reflect the light emitted from the target calibration instrument back into the target calibration instrument and image it on the CCD to complete the optical measurement.

When the imaging device is applied, light emitted by a light source tungsten lamp 17 and a visible light laser 18 in the optical system 1 passes through an objective lens (namely the secondary mirror 11 and the primary mirror 12) or directly passes through a through hole in the secondary mirror 11 to form a beam of parallel light which irradiates on a reference plane mirror 61, if the reference plane mirror 61 is perpendicular to the optical axis of the objective lens, reflected light returns along the original path, and after passing through the objective lens, an imaging point falls on the focus of the objective lens, namely the central position of an image sensor CCD (charge coupled device), and the position is determined as the zero position of the imaging point; if the reference plane mirror 61 is not perpendicular to the optical axis of the objective lens, the axial deviation angle can be calculated according to the principle of fig. 5, and once the deviation angle exceeds the allowable range, the measured axis needs to be mechanically adjusted.

Tripod (optional): and the comprehensive target calibration instrument host is supported, and the stable erection of the equipment is ensured.

Connecting cables: the device comprises a communication cable and a power supply cable which are used for transmitting image video and connecting equipment power supply.

The comprehensive target calibration instrument can realize the following axial calibration: (1) calibrating the optical axis of an airplane crankshaft and a photoelectric pod aiming device; (2) the calibration function of weapon axes of various weapon hangers (missile, rocket projectile, aerogun and the like); (3) a head-up display aiming axis calibration function; (4) and the calibration function of the installation error of the photoelectric radar.

As is known, the target calibration situation of an airplane (helicopter) when the airplane is parked on land is relatively simple, and under the shipboard situation, the body posture of the airplane (helicopter) can be changed in real time due to the movement of a ship body, the target calibration site is narrow and small, the marine climate environment is severe, and meanwhile, the body can swing under the influence of sea waves, incline due to elastic deformation of tires, shake due to the influence of a damping device of an undercarriage, and the like, so that a lot of difficulties are added to the target calibration work of the shipboard aircraft. In order to effectively solve the problems, an inertial measurement technology is adopted in the comprehensive boresight calibrating instrument to acquire the space postures of a reference shaft of an airplane (helicopter) and a boresight weapon system shaft in real time, the space position relation between the boresight calibrating instrument and the airplane and boresight equipment is acquired instantly by using an optical technical means, and the axial deviation of the weapon system at the current moment can be automatically measured through computer interpretation and operation, so that the axis directions related to weapons are adjusted to be consistent with the longitudinal axis of the airplane or a specified angle.

The technical key of the comprehensive boresight instrument is how to quickly acquire the longitudinal axis direction of the airplane. The system makes the mirror surface perpendicular to the reference axis of the body by installing the reference plane mirror 61 at a designated position of the body and a tool, namely, the direction of the normal line of the mirror surface represents the direction of the reference axis of the body. This provides the basis for the fast establishment of the coordinate system of the body. The attitude angle of each measured point is measured by the same method, and the error of each measured point is obtained by calculation. When the device is used, the comprehensive target calibration instrument main machine aims at a reference plane mirror 61 arranged on the longitudinal axis of the airplane to emit a beam of parallel light, the parallel light is reflected by a mirror surface and then is turned back into the target calibration instrument main machine, an image is formed on a CCD (charge coupled device) of a focal plane, and the space attitude of the longitudinal axis of the airplane, namely a fuselage reference axis, can be measured according to the principle. Comparing the measurement result of the comprehensive target calibration instrument with the attitude angle data of the airborne inertial navigation, detecting the difference value of the measurement data of the two inertial navigations, storing the difference value and compensating the measurement data of the airborne inertial navigation; and taking the compensated space attitude of the longitudinal axis of the airplane as a zero reference for system calibration, and establishing a space three-dimensional coordinate system of the airplane body by taking the space attitude as the reference.

In the space coordinate system, all axes of the weapon system are calibrated, and the attitude data of the axes of the weapon system is measured by using a collimating optical imaging and image interpretation mode, so that the axial deviation of the weapon system is finally obtained, and the adjustment of the space position of the weapon system is guided. The axial errors of all weapon systems are adjusted to be consistent (preferably 0 error), so that the axes of all calibrated weapon systems are ensured to be in a parallel state (or a specified angle) with the longitudinal axis of the airplane, namely the reference axis of the fuselage, and the consistency target calibration of the weapon systems is realized. If the calibrated axial error exceeds the error range of the system distribution, the mechanical structure of the weapon system needs to be calibrated, so that the axial error is limited within the allowable range of the system. The operator carries out the school target mode selection and operation instruction input through display screen 3, and image processing unit 2 exports the school target result and shows on display screen 3, and display screen 3 includes upper screen and side position screen, shows different contents respectively according to the convenience of field operation.

As shown in fig. 8-10, the following is a process for calibrating a weapon for a model drone. In fig. 8, the calibration process includes the aircraft longitudinal axis, the weapon system axis, the optical system aiming axis, which in turn includes the laser rangefinder, the visible light camera, the near infrared camera, and the head-up display, wherein the weapon system axis and the optical system aiming axis are parallel. The practice of boresight is essentially to adjust the weapon system axis, the optical sighting axis and other axes to be parallel to or at a specified angle with respect to the longitudinal axis of the aircraft (fuselage reference axis) or to measure the angular deviation between the weapon system axis, the optical sighting axis and other axes and the longitudinal axis of the aircraft. The method comprises the following steps:

aircraft longitudinal axis: the reference plane mirror 61 is installed on a longitudinal axis interface of the airplane through the tool, and the normal line of the reference plane mirror 61 is parallel to the longitudinal axis of the airplane, so that the normal line of the reference plane mirror 61 can represent the longitudinal axis of the airplane. As shown in fig. 6, the visible laser 18 emits a parallel light beam, and the parallel light beam is reflected back when encountering a reference plane mirror 61 mounted on the body, enters the boresight main body again, and is imaged on the CCD. Through the calculation of the position of the imaging point, the included angle delta between the axis of the light collimation measuring instrument and the normal of the plane reflector can be calculated, so that the space attitude parameter of the longitudinal axis of the airplane is obtained, and the specific working principle is shown in fig. 6.

Weapon system shaft: an independent reference plane mirror 61 is installed on an interface of a longitudinal axis of each weapon through a tool, the normal line of the reference plane mirror 61 is consistent with the launching axis of the weapon, so that the normal line of the reference plane mirror 61 represents the launching axis of each weapon, a specific calibration method is consistent with the method of the longitudinal axis of the airplane, and a specific working principle is that the same target correcting method is adopted for weapons of other platforms such as missiles, rocket bullets, machine guns and bomb hangers as shown in fig. 6, and the purpose is to adjust the axial directions of the plane mirrors and the longitudinal axis of the airplane to be parallel to each other.

Aiming axis of optical system: the optical sighting axis in turn includes a laser rangefinder, a visible light camera, a near infrared camera, and a heads-up display.

The laser range finder can emit a laser beam, the direction of the laser beam is the direction of the aiming axis, and the direction of the laser beam can be measured by using an optical system of the comprehensive target correcting instrument. As shown in fig. 9, the boresight measurement method is similar to the previous one, except that the light source is not emitted by the light collimation measurement instrument, but is a laser emitted by an onboard laser rangefinder. The laser emitted by the laser range finder is strong, and in order to protect the optical system from being burnt out by the laser, a light attenuation sheet 51 is added in front of the secondary mirror 11 before measurement, so that the laser energy entering the system can not burn out the optical system; if necessary, the light absorption sheet 52 is additionally arranged between the light attenuation sheet 51 and the secondary mirror 1, and the caliber of the light absorption sheet 52 is larger than the size of the central through hole of the secondary mirror 11 and smaller than the size of the secondary mirror, so that the light entering the secondary mirror after passing through the attenuation sheet 51 can not influence the measurement, otherwise, the light can directly pass through the central through hole of the secondary mirror to carry out secondary imaging on ccd, especially, the distortion of an imaging light spot is generated during oblique incidence, and the judgment of the position of the image point 21 is influenced.

Visible camera and infrared camera optical axes: both the visible light camera and the infrared camera are imaging devices including an optical lens and a CCD, and can output a video signal. As shown in fig. 10, the optical system of the integrated boresight instrument is aligned with the lens of the camera during calibration, the camera images the parallel light emitted by the boresight instrument and images the parallel light on the CCD of the camera, and the image is connected to the boresight instrument through the video interface on the photoelectric pod, and referring to the principle of fig. 3 and 4, the boresight instrument can resolve the parallel light to obtain the included angle between the boresight instrument and the optical axis of the camera, and further obtain the angle deviation between the optical axis of the camera and the longitudinal axis of the airplane.

Head-up display axis: and (3) installing an adapter tool on the leading-out shaft of the head-up display, and calibrating according to the shaft calibrating method which is the same as that of the weapon system shaft, so as to finally obtain the shaft deflection angle of the head-up display. And other aerogun and rocket launcher adopt specific adapter tools for measurement after adapter.

It should be noted that, for optical axis calibration of the laser range finder, the visible light camera and the infrared camera, except that the reference plane mirror 61 is not required to be installed, the direction of the incident laser is the direction of the optical axis, that is, the incident angle in fig. 4 is θ instead of 2 θ, and then the calibrated axial attitude angle parameter is represented as Ω (α + θ X, β + θ Z, γ), where θ X = Lx/f, θ Z = Lz/f represents the axial deviation angle of the incident laser axis in the X-axis and Z-axis directions, respectively, f is the focal length of the imaging lens unit in the camera, and Lx and Lz are coordinate values of the focused image point on the X-axis and Z-axis of the camera image sensor, and α, γ) are angle parameters obtained by measurement of the inertial measurement instrument.

As shown in fig. 11 and 8, the work flow of the integrated boresight instrument is as follows:

1) detection of airborne inertial navigation measurement error

Installing a reference plane mirror 61 on the longitudinal axis of the airplane, emitting parallel light to the reference plane mirror 61 by the comprehensive boresight instrument, acquiring position coordinates of image points by an image sensor, and obtaining an axial attitude angle of the longitudinal axis of the airplane by combining angle data of an inertial measurement instrument, wherein the axial attitude angle is marked as an airplane-carrying attitude 1; and comparing the measured axial attitude angle (recorded as an airborne attitude 2) of a fuselage reference axis (an aircraft longitudinal axis) obtained by measuring airborne inertial navigation installed on the aircraft with the measured axial attitude angle, wherein the difference value of the two axial attitude angles is the measurement error of the airborne inertial navigation, and the main control unit records and stores the value for carrying out system compensation when calculating the axial error. The main reason is that the invention is a calibration device, so that an inertial measurement instrument with higher precision than airborne inertial navigation is adopted, and the error of airborne inertial navigation data can be calibrated, corrected and compensated.

2) Establishing a virtual digital geometric longitudinal axis of an aircraft (helicopter)

And constructing a virtual digital geometric longitudinal axis of the airplane by taking the corrected airborne inertial navigation data or the actually measured axial attitude angle data of the longitudinal axis of the airplane as a reference, wherein the digital geometric longitudinal axis is parallel to the actual longitudinal axis of the airplane or forms a certain included angle with the actual longitudinal axis of the airplane according to different airplane conditions, and is usually parallel.

And then entering the selection of the boresight mode to calibrate a plurality of axial directions on the airplane.

3) Alignment of weapon system and weapon hanger shafts

Installing a reference plane mirror 61 on a weapon system shaft, emitting parallel light by the boresight instrument, reflecting the parallel light into the boresight instrument through the reference plane mirror 61, acquiring position coordinates of image points by an image sensor, resolving by combining angle data of an inertia measuring instrument to obtain attitude angles of the weapon system shaft and a weapon hanger shaft, comparing the attitude angles with the attitude angles of the airplane digital geometric longitudinal axis obtained in the front to obtain axial deviations of the weapon system shaft and the weapon hanger shaft, and performing mechanical boresight if the deviations are larger than an allowable range.

4) Laser rangefinder optical axis calibration

The laser range finder emits laser, the laser passes through the light attenuation sheet 51 and the light absorption sheet 52 and then enters the interior of the boresight corrector, the image sensor acquires position coordinates of image points, the attitude angle of the optical axis of the laser range finder is obtained by combining angle data of the inertial measurement instrument in a resolving mode, the attitude angle is compared with the attitude angle of the airplane digital geometric longitudinal axis, the axial deviation of the optical axis of the laser range finder is obtained, and if the deviation is larger than an allowable range, mechanical boresight correction is carried out.

5) Optical axis calibration for visible/infrared camera

The integrated target calibrating instrument host sequentially emits visible and infrared parallel light to a visible light/infrared camera lens, an image sensor in the visible light/infrared camera acquires position coordinates of an image point, an attitude angle of the axis of the visible light/infrared camera is obtained by combining angle data of an inertia measuring instrument through calculation, the attitude angle is compared with the attitude angle of the airplane digital geometric longitudinal axis obtained in the front, axial deviation of the axis of the visible light/infrared camera is obtained, and if the deviation is larger than an allowable range, mechanical axis calibration is carried out.

6) Head-up display axis alignment

The head-up display is taken down, the adapter and the reference plane mirror 61 and the tool thereof are installed at the position of the head-up display, the boresight instrument emits parallel light, the parallel light is reflected to the inside of the boresight instrument through the reference plane mirror 61, the image sensor measures the position coordinates of an image point, the attitude angle of the head-up display is obtained through calculation by combining the angle data of the inertia measuring instrument, the attitude angle is compared with the attitude angle of the airplane digital geometric longitudinal axis obtained in the front, the axial deviation of the head-up display is obtained, and if the deviation is larger than the allowable range, mechanical boresi.

The comprehensive target calibration instrument can calibrate the relevant axes of the weapon system shaft, the weapon hanger shaft, the laser range finder, the visible light/infrared camera, the head-up display and other airplanes on the basis of calibrating the airborne inertial navigation, only the inertial navigation of the comprehensive target calibration instrument has drift errors in the whole target calibration process, the inertial navigation drift is small in the target calibration process controlled within 1 hour, the system adopts CCD image display and computer operation, the whole process is directly checked through the sensor, errors caused by human eye interpretation are avoided, and the precision of the target calibration system is greatly improved.

Claims (8)

1. A optical axis calibrating device for aircraft machine carries laser rangefinder which characterized in that: comprises a boresight instrument host and a main control unit (20); the target calibration instrument host comprises an optical system (1) arranged in a shell (5), an image processing unit (2) and an inertia measuring instrument (4); the direction of the flight direction axis of the inertial measurement instrument (4) is consistent with the direction of the optical axis of the optical system (1);

the optical system (1) comprises a focusing lens group and an image sensor (15) arranged at the focus of the focusing lens group, laser emitted by a laser range finder is attenuated and then focused and imaged on the image sensor (15) to form an image point (21), and an image processing unit (2) performs data processing on an image of the image sensor (15) to obtain an axial deviation angle; the main control unit (20) calculates and obtains an attitude angle parameter of the laser range finder optical axis according to the angle data of the inertial measurement unit (4) and the axial deviation angle data of the image processing unit (2).

2. The optical axis calibration device for an aircraft-mounted laser range finder according to claim 1, characterized in that: the inertia measurement unit (4) is an optical fiber strapdown type inertia navigation system.

3. The optical axis calibration device for an aircraft-mounted laser range finder according to claim 1, characterized in that: the focusing lens group comprises a secondary mirror (11) and a primary mirror (12) which are coaxially arranged, and the secondary mirror (11) and the primary mirror (12) are both of a hollow structure.

4. The optical axis calibration device for an aircraft-mounted laser range finder according to claim 1, characterized in that: the secondary mirror (11) is provided with a light attenuation sheet (51) in front.

5. The optical axis calibration device for an aircraft-mounted laser range finder according to claim 4, wherein: a light absorption sheet (52) is additionally arranged between the light attenuation sheet (51) and the secondary mirror (1), and the caliber of the light absorption sheet (52) is larger than the size of a central through hole of the secondary mirror (11) and smaller than the size of the secondary mirror (11).

6. The optical axis calibration device for an aircraft-mounted laser range finder according to claim 1, characterized in that: the image sensor (15) is a CCD sensor.

7. Method for calibration by means of an optical axis calibration device for a laser rangefinder on board an aircraft according to any of claims 1 to 6, characterized in that it comprises the following steps:

【1】 Taking the calibrated airborne inertial navigation data of the airplane as a reference, and constructing to obtain a virtual digital geometric longitudinal axis of the airplane;

【2】 The laser emitted by the laser range finder is focused and imaged on the image sensor after being attenuated, and the image processing unit performs data processing on the image of the image sensor to obtain an axial deviation angle; the main control unit calculates an axial attitude angle parameter of the optical axis of the laser range finder according to the axial deviation angle and an angle parameter obtained by measurement of the inertia measuring instrument;

【3】 Comparing the axial attitude angle parameter of the laser range finder with the attitude angle parameter of the virtual digital geometric longitudinal axis to obtain an axial deflection angle parameter of the optical axis of the laser range finder;

【4】 And determining whether mechanical shaft calibration is needed or not according to the shaft deflection angle parameter value.

8. The optical axis calibration method for an aircraft-borne laser rangefinder as claimed in claim 7, wherein the axial attitude angle parameter is represented by Ω (α + θ x, β + θ z, γ);

wherein thetax = Lx/f, thetaz = Lz/f respectively represent the axial deviation angles of the incident laser axis in the X-axis and Z-axis directions, f is the focal length of the imaging lens unit in the camera, Lx and Lz are coordinate values of the focused image point on the X-axis and the Z-axis of the camera image sensor, and (α, gamma) is an angle parameter obtained by the measurement of the inertial measurement instrument.

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