CN101526420B - A device for simulating a small-angle moving laser target - Google Patents

Abstract

The invention discloses a device for simulating a small-angle moving laser target, which comprises: an optical part and an electric control part. The optical part is composed of laser, energy adjustment device, beam expander and prism. The electric control part is an electric control rotary table device and its controller and angle output device. The beam emitted by the laser is adjusted by the energy adjustment device and enters the beam expander. The outgoing light is deflected by the central prism of the electronically controlled rotary table, and then enters the photoelectric tracking system under test. Angle rotation simulates a moving target. The invention has the advantages of compact structure, simple installation and adjustment, low cost, and easy calculation of the simulated target orientation, and can be applied to indoor testing of small-angle photoelectric tracking systems such as aerospace and military affairs.

Description

A device for simulating a small-angle moving laser target

technical field

The invention relates to a photoelectric instrument testing technology, in particular to a device for simulating a small-angle moving laser target, which is used for performance testing of an indoor small-angle photoelectric tracking system.

Background technique

In the field of photoelectric tracking technology, the testing and performance evaluation of photoelectric tracking system is an important part of its development. In the indoor test of the photoelectric tracking system, a certain device is often used to simulate the movement of the target in space, and the photoelectric system under test is turned on to complete the tracking, and the tracking results are recorded to analyze and evaluate the tracking performance of the photoelectric tracking system. Whether the motion characteristics and optical characteristics of the simulated target are realistic or not has become the difficulty of the test system.

The existing target simulation methods mainly include a rotating target device for indoor testing of the photoelectric tracking theodolite performance, which is realized by using a collimator and a rotating arm structure. The basic structure diagram is shown in Figure 1. Generally speaking, it includes a collimator 1 , a drive motor 4 , a rotating arm 3 , a reflector 2 , a bracket 5 and other components. The collimated light emitted by the collimator 1 enters the system under test through the reflector 2 . The driving motor 4 drives the collimator 1 on the cantilever 3 and the reflector device 2 to rotate together, so that the parallel light forms a light cone incident and simulates the movement of the target. The length of the cantilever and the inclination angle of the mirror determine the angle variation range of the simulated target. The half-cone angle of the rotating target is generally above 15 degrees. In addition, the cantilever length is fixed, and the small half-cone angle will cause the test device to occupy a large space, which is not suitable for testing the performance of the small-angle photoelectric tracking system. Moreover, since the optical components in this structure are all positioned on the cantilever and rotate together, it is difficult to develop and the cost is high.

Contents of the invention

The purpose of the present invention is to provide a target simulation device for performance testing of an indoor small-angle photoelectric tracking system, which solves the problems of difficulty in development and high cost of the current device.

The target simulation device of the present invention includes two parts of optics and electric control as described in Fig. 2 .

The optical part is composed of a laser 6 , an energy adjustment device 7 , a beam expander 8 and a prism 10 .

The electric control part is an electric control rotary table 9 with a controller and an angle output device.

Said laser 6 selects the laser with the same wavelength band as the tracked laser target.

Said energy adjustment device 7 is fixed on the output port of laser 6, and the energy adjustment device 7 adopts an optical attenuation sheet for adjusting the output laser energy.

Said beam expander 8 is fixed behind the energy adjustment device 7, and its optical axis is placed on the same straight line as the center of the laser beam, so as to reduce the divergence angle of the laser beam and expand the width of the laser beam in a certain proportion.

Said electronically controlled rotary table 9 is a hollow rotary table formed by a motor 9-1 and a reduction mechanism, and its rotation axis is placed on the same line as the optical axis of the laser beam expander. The electronically controlled rotary table is equipped with a controller and an angle output device.

Said prism 10 is a circular prism with a certain apex angle, which is fixed on the rotation center of the electric control rotary table 9 and rotates together with the electric control rotary table 9 .

The operating principle of the device of the present invention is as follows:

The light beam emitted by the laser 6 is adjusted by the energy adjustment device 7 and enters the beam expander 8, and the outgoing light is deflected by the central prism 10 of the electronically controlled rotating table 9, and then exits into the photoelectric tracking system under test.

When the apex angle of the prism 10 is θ, the angle α of the incident parallel light deflection can be expressed by formula (1):

α = arcsin(nsinθ)-θ(1)

Where n is the refractive index of the prism material.

The equivalent schematic diagram of the imaging system of the photoelectric tracking system under test is shown in Figure 5, including the optical system and the detector system, the focal length of the system is f, and the pixel size of the detector is d. Considering the one-dimensional situation, as shown in the figure, the parallel light incident optical system at an angle α with the principal optical axis, ideally the center of the image point should be located at the nth pixel upward, and n is expressed by formula (2).

$\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; the\; tan</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Define the three-dimensional coordinate system xyz, the laser emission direction is the z-axis direction, the y-axis is perpendicular to the plane where the components are placed upward, and the x-axis and the above two axes constitute the right-hand rule.

In the initial state, the inclination direction of the apex angle of the prism coincides with the y-axis. The angle of counterclockwise rotation of the electronically controlled rotary table is Ω, and the angle of deflection of parallel light by the prism is α, then the calculation can be obtained that the center of the image point is at the position of the detector under ideal conditions, and the pixel number is expressed by formula (3) (4).

${\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; the\; tan</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&Omega;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; the\; tan</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; arcsin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&Omega;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; the\; tan</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&Omega;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; the\; tan</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; arcsin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&Omega;</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

It can be seen that the relationship between the center position of the imaging spot of the tracked system at a certain moment and the rotation angle of the electronically controlled rotary table, the vertex angle of the prism, the focal length of the system under test and the pixel size. For a fixed system under test, f and d are constant, select a prism with a certain vertex angle α, and control the change trajectory of the rotation angle Ω of the electronically controlled rotary table to calculate the trajectory of the imaging center of the simulated target.

If the rotational angular velocity of the electronically controlled turntable is ω, the angular velocity of the target is expressed by formula (5) for the tested photoelectric tracking system, and the decomposition speed in the y direction and x direction is expressed by formula (6) and formula (7) respectively :

ω′=sin(α)*ω=sin(arcsin(nsinθ)-θ)*ω (5)

ω _y '=sin(α)*ω*sinΩ=sin(arcsin(nsinθ)-θ)*ω*sinΩ(6)

ω _x ′=sin(α)*ω*cosΩ=sin(arcsin(nsinθ)-θ)*ω*cosΩ(7)

The specific steps that the laser target simulation device of the present invention uses are as follows:

1. Fix the relative position of the laser 6, the energy adjustment device 7, the beam expander 8, and the electric control rotary table 9 including the prism 10, so that the optical axes or rotation axes of each component are on the same straight line, and the fixing method can be screwed with a bracket or glued.

2. Optical path adjustment: Turn on the laser 6, set the stationary electronically controlled rotary table 9 to the zero position, and the outgoing light deflected by the prism 10 enters the tracked system for imaging, observe the center position of the imaging spot of the tracked system, and compare the spots according to the geometric position relationship of the imaging system The angle of incident light corresponding to the central position and the angle of deflected light by the prism are used to adjust the light path. The system adjustment is completed when the imaging geometric relationship is established.

3. Turn on the laser, control the operation of the electronically controlled rotary table 9 at a certain speed, and the light emitted by the prism 10 enters the entrance pupil of the tracking system under test, and the motion characteristics of the simulated moving target can be obtained according to the geometric relationship of the imaging system. Turn on the tracking system under test to track the simulated target, record the tracking results of the tracking system and the rotation angle of the electronically controlled rotary table to evaluate the tracking performance of the system under test.

The present invention has following beneficial effect:

1. The laser target simulator of the present invention is simple in structure, low in cost and compact. For the test of the small-angle photoelectric tracking system, the cost of realizing the present invention is greatly reduced compared with the traditional cantilever type rotating target device.

2. The target simulation device of the present invention is suitable for testing small-field-of-view photoelectric tracking systems for different purposes.

Description of drawings

Fig. 1 Schematic diagram of traditional cantilever rotating target device.

Fig. 2 is a schematic diagram of a target simulation device of the present invention.

Fig. 3 is a schematic diagram of the installation of the prism and the electric control rotary table of the present invention.

Fig. 4 is a schematic diagram of the prism of the present invention.

Figure 5 is a schematic diagram of the imaging geometry.

Detailed ways

The specific embodiment of the present invention is described in further detail below in conjunction with accompanying drawing:

The laser target simulation device of the present invention is shown in Figure 2, the optical axis of the laser 6, the energy adjustment device 7, the beam expander 8, the prism 10 and the rotation axis of the electric control rotary table 9 are on the same straight line.

The structure of the electric control rotary table 9 is shown in Fig. 3, and is composed of a motor 9-1, a table body fixing part 9-2 and a table body rotating part 9-3. The rotating shaft of motor 9-1 constitutes the transmission relationship with the table body rotating part 9-3 through the transmission mechanism installed inside the table body fixed part 9-2. The interior of the table body rotating part 9-3 is hollow and has a certain space for installing the prism. The electronically controlled rotary table angle output device can output the relative angle of the rotating part 9-3 of the table body relative to the fixed part 9-2 of the table body. The prism 10 is a circular prism with a fixed apex angle, as shown in FIG. 4 , and the inclination direction of the apex angle of the prism is defined as the direction of point A in the figure. The prism 5 is fixed in the central circular hole of the rotating part 9-3 of the electric control rotating table body, and can rotate around the optical axis together with the rotating part 9-3.

The light beam emitted by the laser 6 is adjusted by the energy adjustment device 7 and enters the beam expander 8, and the outgoing light is transmitted through the central prism 10 of the electronically controlled rotating table 9 and enters the photoelectric tracking system under test. The energy adjustment device 7 mainly adjusts the output light power of the laser 6, and the energy adjustment device 7 with different attenuation multiples can be selected to obtain the laser power required by the simulation system, and at the same time avoid blinding the detector due to excessive laser power. Select the attenuation film magnification according to actual needs. The beam expander 8 is mainly used to reduce the divergence angle of the laser beam. When the divergence angle of the laser output from the laser is Δ, and the beam expansion factor of the beam expander is m, the divergence angle of the laser output from the beam expander is Δ/m, and the further reduction of the divergence angle makes the output light closer to parallel light. A commercial common beam expander or lens magnifying device can be used.

The electric control rotary table motor is controlled by a motor controller. According to the precision and speed requirements, the closed-loop control of the servo motor and angle sensor can be used, and the open-loop control of the stepping motor can also be used.

When the electric control turntable stops rotating, since the angle of the prism is fixed, the outgoing beam will deviate from the vertex angle of the prism by a certain angle. When the electronically controlled rotary table rotates, the vertex angle of the prism changes accordingly, so that the outgoing parallel light can be rotated and scanned according to the light cone output rotation according to the electronically controlled rotary table rotation. From the perspective of the photoelectric tracking system under test, the rotating parallel light represents a moving target. By controlling the motion characteristics of the parallel light, different simulated target motion characteristics can be obtained.

In summary, the device of the present invention has the characteristics of simple and compact structure, easy adjustment of optical path, flexible use, low cost, and strong practicability.

Claims (2)

1. A device for simulating a small-angle moving laser target, comprising: an optical part and an electric control part, characterized in that: The optical part is composed of a laser (6), an energy adjustment device (7), a beam expander (8) and a prism (10); The electric control part is an electric control rotary table (9) with a motor controller and an angle output device; Said laser (6) selects the same laser as the tracked laser target band; Said energy regulating device (7) is fixed on the exit port of the laser (6), and is used for regulating the outgoing laser energy; Said beam expander (8) is fixed behind the energy adjustment device (7), and its optical axis is placed on the same line as the center of the laser beam; Said electronically controlled rotary table (9) is a centrally hollow rotary table composed of a motor and a reduction mechanism, and its rotation axis is placed on the same line as the optical axis of the laser beam expander. The electronically controlled rotary table (9) is controlled by the motor (9-1 ), the table body fixed part (9-2) and the table body rotating part (9-3), and the electric control rotating table angle output device outputs the table body rotating part (9-3) relative to the table body fixed part (9-2 ) relative angle; Said prism (10) is a circular prism with a certain vertex angle, which is fixed on the rotation center of the electric control rotary table (9) and rotates therewith; The beam emitted by the laser (6) is regulated by the energy adjustment device (7) and enters the beam expander (8), and the outgoing light is deflected by the central prism (10) of the electronically controlled rotating table (9), and then enters the photoelectric tracking system under test. 2. A device for simulating a small-angle moving laser target according to claim 1, characterized in that: said energy adjustment device (7) is an optical attenuation sheet.

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