Optoelectronic system with multi-target ranging capability and method for multi-target ranging

Abstract

This invention relates to an optoelectronic system and method for multi-target ranging, comprising an infrared optical system and a laser ranging system. A radome, scanning mirror, correction mirror group, infrared laser beam splitter, infrared converging mirror group, and infrared cooled detector enable imaging search and tracking of infrared targets. A laser emission and reception beam splitter, a first laser emission rapid scanning mechanism, a laser emission antenna, a laser, a laser receiving antenna, a second laser emission rapid scanning mechanism, and a laser receiving detector enable laser ranging. When tracking multiple targets, it ensures stable tracking of the primary target while simultaneously performing laser ranging on other targets within the field of view. For stable tracking of the primary target, which remains centered in the field of view, when other secondary targets are also present within the field of view, ranging of the other targets is achieved through a rapid scanning and steering mechanism within the laser rangefinder.

Description

Technical Field

[0001] This invention belongs to the field of optoelectronic product design and relates to an optoelectronic system and method with multi-target ranging capability. It is mainly used for multi-target tracking, ensuring stable tracking of the primary target while simultaneously performing laser ranging on other targets within the field of view. It mainly includes an infrared optical system, a laser ranging system, and a laser rapid steering mechanism. Background Technology

[0002] Optoelectronic detection equipment is mainly used for searching and tracking enemy aircraft at long distances during air combat. In free air combat, fighter jets typically engage in multi-aircraft formations against each other. Enemy formations may be manned fighter formations, manned aircraft with multiple unmanned wingmen, or unmanned aerial vehicle (UAV) formations. Our pilots can identify the primary targets of interest through optical or radar signatures. For example, in a mixed formation of manned and unmanned aircraft, the optoelectronic detection equipment primarily tracks the manned aircraft while simultaneously tracking other targets within the staring field of view using image and video technology.

[0003] Photoelectric detection equipment typically tracks targets using a scanning mechanism, constantly imaging the target at the center of the detector. In multi-target tracking, the primary target is at the center of the detector, while other targets are scattered around it. Traditional laser ranging requires rotating the scanning mechanism to align each target individually before laser ranging; however, when ranging secondary targets, the primary target may be lost after maneuvering. Summary of the Invention

[0004] Technical problems to be solved

[0005] To avoid the shortcomings of existing technologies, this invention proposes an optoelectronic system and a method for multi-target ranging. By setting a fast scanning mechanism in the laser emission and reception optical paths, it is possible to measure the distance of other secondary targets within the field of view while the main target is being stably tracked.

[0006] Technical solution

[0007] An optoelectronic system with multi-target ranging capability is characterized by comprising a radome 1, a scanning mirror 2, a correction mirror group 3, an infrared laser beam splitter 4, an infrared converging mirror group 5, an infrared cooled detector 6, a laser emission and receiving beam splitter 7, a first laser emission rapid scanning mechanism 8, a laser emission antenna 9, a laser 10, a laser receiving antenna 11, a second laser emission rapid scanning mechanism 12, and a laser receiving detector 13; wherein the incident infrared light path of the radome 1 is sequentially provided with the scanning mirror 2, the correction mirror group 3, the projection light path of the infrared laser beam splitter 4, the infrared converging mirror group 5, and the infrared cooled detector 6, constituting an infrared target imaging search and tracking system; the laser light path emitted by the laser 10 is sequentially provided with the laser emission antenna 9, the first laser emission rapid scanning mechanism 8, the laser emission receiving beam splitter 7, the laser receiving antenna 11, the second laser emission rapid scanning mechanism 12, and the laser receiving detector 13 to realize the laser ranging function; wherein the optical path between the laser emission and receiving beam splitter 7 and the infrared laser beam splitter 4 provides a pathway between the laser emission and reflection signals and the radome 1.

[0008] The infrared laser beam splitter 4 is coated with a beam splitting film, which transmits infrared energy of 3-5μm and reflects laser energy of 1.064μm.

[0009] The laser emission and reception beam splitter 7 adopts a zoned coating method, with a laser reflection film coated in the central area to form the laser emission aperture, and a laser transmission film coated in the edge area to form the laser reception aperture, thereby realizing the splitting of laser emission and laser reception.

[0010] The infrared laser beam splitter 4 uses zinc sulfide material, or sapphire or single-crystal silicon material.

[0011] The infrared laser beam splitter 4 has a beam splitting film deposited on its upper surface to achieve the function of transmitting mid-wave infrared and reflecting laser.

[0012] The correction lens assembly uses two lenses to cancel out the aberrations introduced by the fairing 1, and the materials are zinc sulfide and calcium fluoride.

[0013] The first laser emission rapid scanning mechanism 8 and the second laser emission rapid scanning mechanism 12 adopt a fast-reflecting mirror or a liquid crystal phased array module.

[0014] The parameters of the correction lens group are as follows:

[0015] Serial Number surface radius of curvature Thickness / Spacing Material Correction mirror 1 Front surface -158.5 8 Zinc sulfide Back surface -150.11 10 Correction mirror 2 Front surface 174.16 5 Calcium fluoride Back surface 149.47

[0016] The fairing 1 is a spherical cap with concentric inner and outer surfaces, and the parameters are as follows:

[0017] radius of curvature thickness Front surface 105mm 5mm Back surface 100mm sapphire

[0018] A method for multi-target ranging using the aforementioned photoelectric system with multi-target ranging capability, characterized in that while the main target is being stably tracked, ranging is performed on other secondary targets within the field of view. The method steps are as follows:

[0019] Step 1: The scanning mirror 2 rotates around the axis of the spherical fairing 1 to perform azimuth and elevation scans; when a specific infrared main target is detected in the air, the scanning mirror 2 rotates in azimuth and elevation directions to scan the target. After the aberrations introduced are canceled by the correction mirror group 3, the infrared laser beam splitter 4 transmits the image to the infrared converging mirror group 5 to converge the main target onto the focal plane of the infrared cooled detector 6.

[0020] The scanning mirror 2 is used to track the main target, and continuous and stable tracking is achieved through the scanning mirror 2.

[0021] Step 2: The energy of laser 10 is refracted into infrared laser beam splitter 4 after passing through laser transmitting antenna 9, first fast scanning mechanism 8, and laser transmitting and receiving beam splitter 7. After being refracted by infrared laser beam splitter 4, it passes through correction mirror group 3, scanning reflector 2, and rectifier 1 before being emitted and illuminating the main target to form a reflected laser beam. This reflected laser beam passes through rectifier 1 to infrared laser beam splitter 4 and is reflected into laser transmitting and receiving beam splitter 7. The transmitted laser passes through laser receiving antenna 11. Laser receiving antenna 11 compresses and focuses the laser beam scattered back from the target, and finally focuses it to the focal plane of laser receiving detector 13 through second fast scanning mechanism 12. Laser receiving detector 13 performs laser ranging.

[0022] The first laser emission rapid scanning mechanism 8 and the second laser emission rapid scanning mechanism 12 lock onto the main target with lasers.

[0023] Step 3: When tracking the main target, if there are other secondary targets in the field of view, the other targets are ranged by laser while tracking the main target; the angle that the two laser-emitting rapid scanning mechanisms need to rotate is calculated based on the angle of the secondary targets relative to the main target.

[0024] The first laser emission rapid scanning mechanism 8 is activated to perform two-dimensional adjustment of the laser emission optical path optical axis to achieve laser emission scanning motion independent of the scanning mirror (2) and to scan the field of view of this system; when the scan locks onto a secondary target, it measures the distance to other secondary targets in the field of view;

[0025] The second laser emission rapid scanning mechanism 12 has corresponding angular movements with the first laser emission rapid scanning mechanism 8.

[0026] Beneficial effects

[0027] This invention proposes an optoelectronic system and method for multi-target ranging, comprising an infrared optical system and a laser ranging system. The system utilizes a radome, scanning mirror, correction mirror group, infrared laser beam splitter, infrared converging mirror group, and infrared cooled detector to achieve infrared target imaging, search, and tracking. The laser ranging function is achieved by a laser emission and reception beam splitter, a first laser emission rapid scanning mechanism, a laser emission antenna, a laser, a laser receiving antenna, a second laser emission rapid scanning mechanism, and a laser receiving detector. When used for multi-target tracking, it ensures stable tracking of the primary target while simultaneously performing laser ranging on other targets within the field of view. For stable tracking of the primary target, which remains centered in the field of view, and when other secondary targets are also present within the field of view, ranging of the other targets is achieved through a rapid scanning and steering mechanism within the laser rangefinder.

[0028] The advantages of this invention are:

[0029] 1. While ensuring tracking of the primary target, range measurement is performed on other secondary targets within the field of view;

[0030] 2. The correction lens group eliminates the aberrations of the rectifier, ensuring that all subsequent optical paths are aberration-free parallel light incident and emitted. It can be modularly designed and assembled. Attached Figure Description

[0031] Figure 1 This is an optical configuration diagram of an example of the present invention;

[0032] Figure 2 This is an example of multi-target tracking and target tracing in this invention;

[0033] Figure 3 This is a schematic diagram of the front-end optical system of an example of the present invention;

[0034] Figure 4 This is a schematic diagram of a laser beam splitter according to an example of the present invention;

[0035] 1-Fairing, 2-Scanning mirror, 3-Correction mirror group, 4-Infrared laser beam splitter, 5-Infrared converging mirror group, 6-Infrared cooled detector, 7-Laser emission and receiving beam splitter, 8-First laser emission rapid scanning mechanism, 9-Laser emission antenna, 10-Laser, 11-Laser receiving antenna, 12-Second laser emission rapid scanning mechanism, 13-Laser receiving detector. Detailed Implementation

[0036] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0037] The optoelectronic system has multi-target ranging capability, and the infrared system has a field of view of 2°×1.6°.

[0038] The system includes a fairing 1, a scanning mirror 2, a correction mirror group 3, an infrared laser beam splitter 4, an infrared converging mirror group 5, an infrared cooled detector 6, a laser emission and reception beam splitter 7, a first laser emission rapid scanning mechanism 8, a laser emission antenna 9, a laser 10, a laser receiving antenna 11, a second laser emission rapid scanning mechanism 12, and a laser receiving detector 13. The fairing 1, scanning mirror 2, correction mirror group 3, infrared laser beam splitter 4, infrared converging mirror group 5, and infrared cooled detector 6 enable imaging, searching, and tracking of infrared targets. The radome 1 is equipped with an infrared beam path consisting of a scanning reflector 2, a correction mirror group 3, a projection beam path of an infrared laser beam splitter 4, an infrared converging mirror group 5, and an infrared cooled detector 6, forming an infrared target imaging search and tracking system. The laser beam path emitted by the laser 10 is equipped with a laser emitting antenna 9, a first laser emitting rapid scanning mechanism 8, a laser emitting receiving beam splitter 7, a laser receiving antenna 11, a second laser emitting rapid scanning mechanism 12, and a laser receiving detector 13, realizing the laser ranging function. The optical path between the laser emitting receiving beam splitter 7 and the infrared laser beam splitter 4 provides a pathway between the laser emitting and reflecting signals and the radome 1.

[0039] Compared to similar optoelectronic radars or optoelectronic turrets currently available, the main feature is that a first laser emission rapid scanning mechanism 8 and a second laser emission rapid scanning mechanism 12 are respectively set in the laser emission optical path and the laser receiving optical path. This mechanism can be a fast-reflecting mirror or a liquid crystal phased array module. This rapid scanning mechanism can ensure that when the scanning mirror is stably tracking the main target, the laser optical path can independently scan and illuminate other targets.

[0040] A correction mirror group is set behind the fairing 1 and the scanning mirror 2 to correct the optical aberrations introduced by the fairing. The infrared and laser systems at the rear can be designed and assembled in a modular manner.

[0041] The correction lens group 3 consists of two lenses, which can cancel the aberrations introduced by the rectifier 1 and ensure that the subsequent infrared and laser light paths are uniform and aberration-free parallel light in and out.

[0042] The fairing 1 is a spherical cap with concentric inner and outer surfaces. The scanning mirror 2 performs azimuth and elevation scans around the axis of the sphere to achieve airspace search and tracking. When a specific infrared target is detected in the air, the scanning mirror rotates in the azimuth and elevation directions to image the target onto the center of the infrared cooled detector 6, ensuring that the target's position remains unchanged during the tracking process.

[0043] like Figure 1 As shown, the front fairing 1 is made of sapphire material. The parameters are:

[0044] radius of curvature thickness Front surface 105mm 5mm Back surface 100mm sapphire

[0045] The scanning mirror 2 is made of aluminum alloy with a mirror surface size of 80mm × 160mm. The material of the scanning mirror is not limited to aluminum alloy; titanium alloy, silicon carbide, and other materials can also be used.

[0046] Correction lens group 3 parameters:

[0047] Serial Number surface radius of curvature Thickness / Spacing Material Correction mirror 1 Front surface -158.5 8 Zinc sulfide Back surface -150.11 10 Correction mirror 2 Front surface 174.16 5 Calcium fluoride Back surface 149.47

[0048] A first laser emission rapid scanning mechanism 8 is set in the laser emission optical path. This mechanism can scan the laser emission optical path within a certain angle range when the scanning reflector 2 is fixed.

[0049] A second laser emission rapid scanning mechanism 12 is provided in the laser receiving optical path. This mechanism can cooperate with the first laser emission rapid scanning mechanism 8 to perform corresponding scanning when the scanning reflector 2 is fixed.

[0050] The infrared laser beam splitter 4 uses zinc sulfide, but sapphire, single-crystal silicon, or other materials can also be used. A beam-splitting film is deposited on its upper surface to achieve the function of transmitting mid-wave infrared light and reflecting laser light. The infrared laser beam splitter 4 primarily achieves the separation of mid-wave infrared light and laser light through surface coating. The transmitted infrared band energy is 3-5μm, and the reflected laser energy is 1.064μm. The laser transmitting and receiving beam splitter 7 adopts a zoned coating method, with the central Φ20mm area reflecting laser light and the remaining areas transmitting laser light.

[0051] The infrared optical system has a wavelength of 3-5μm, and the fairing 1 is made of sapphire material; the correction lens group uses two lenses made of zinc sulfide and calcium fluoride.

[0052] The infrared converging lens group 5 adopts a secondary imaging configuration; it converges the incident infrared light and images it at the focal plane of the infrared cooled detector 6. The infrared detector can select parameters such as array size and F-number as needed.

[0053] The infrared cooled detector 6 uses a 320×256 area array with 25μm pixels.

[0054] The laser beam splitter 7 uses K9 glass and employs a zoned coating, such as... Figure 4 As shown. The central area is coated with a reflective film to reflect the laser emission path; this is the laser emission aperture, with an effective aperture of 25mm. The outer area is coated with a laser antireflective film, which is the laser receiving aperture, with an effective aperture of 80mm, allowing the laser receiving path to transmit.

[0055] The first laser emission rapid scanning mechanism 8 uses a two-dimensional fast-reflecting mirror to perform two-dimensional adjustment of the laser emission optical axis. The fast-reflecting mirror scans at angles > ±1° in both azimuth and elevation directions. This mechanism can also use a liquid crystal phased array module to achieve rapid scanning of the laser optical axis. This enables laser emission to be independent of the scanning mirror (2). This scanning mechanism can also use a liquid crystal phased array module to achieve two-dimensional adjustment of the laser emission optical axis.

[0056] The laser transmitting antenna 9 has a beam expansion ratio of 4. The beam expansion ratio can be adjusted according to the required evacuation angle and is not limited to 4. It expands the laser beam emitted from laser 10 to narrow the evacuation angle and improve the laser beam quality. The antenna narrowing ratio can be adjusted as needed.

[0057] The laser receiving antenna 11 has a focal diameter of 3mm. It compresses and converges the laser beam scattered back from the target, and finally converges it to the focal plane of the laser receiving detector 13. The fast scanning mechanism 212 uses a two-dimensional fast mirror to adjust the optical axis of the laser receiving optical path in two dimensions, so as to achieve a scanning angle that matches the optical axis of the laser emitting optical path.

[0058] Laser 10 generates 1.064 multi-pulse laser with a laser energy of 100 mJ.

[0059] The second laser emission rapid scanning mechanism 12 is a rapid reflecting mirror, which scans at angles > ±2° in both azimuth and elevation directions. This mechanism can also utilize a liquid crystal phased array module to achieve rapid scanning of the laser optical axis.

[0060] The method for multi-target ranging using the aforementioned photoelectric system with multi-target ranging capability, while stably tracking the main target, involves ranging other secondary targets within the field of view. The steps are as follows:

[0061] Step 1: Scan mirror 2 performs azimuth and elevation scans around the axis of the spherical shape of fairing 1; when a specific infrared primary target in the air is detected, Figure 2 As shown; the scanning mirror 2 rotates in azimuth and pitch directions to scan the target. After the aberrations introduced are canceled by the correction mirror group 3, the laser beam splitter 4 transmits the laser to the infrared converging mirror group 5 to converge and image the main target onto the focal plane of the infrared cooled detector 6.

[0062] The scanning mirror 2 is used to track the main target, and continuous and stable tracking is achieved through the scanning mirror 2.

[0063] Step 2: The energy of laser 10 is refracted into infrared laser beam splitter 4 after passing through laser transmitting antenna 9, first fast scanning mechanism 8, and laser transmitting and receiving beam splitter 7. After being refracted by infrared laser beam splitter 4, it passes through correction mirror group 3, scanning reflector 2, and rectifier 1 before being emitted and illuminating the main target to form a reflected laser beam. This reflected laser beam passes through rectifier 1 to infrared laser beam splitter 4 and is reflected into laser transmitting and receiving beam splitter 7. The transmitted laser passes through laser receiving antenna 11. Laser receiving antenna 11 compresses and focuses the laser beam scattered back from the target, and finally focuses it to the focal plane of laser receiving detector 13 through second fast scanning mechanism 12. Laser receiving detector 13 performs laser ranging.

[0064] The first laser emission rapid scanning mechanism 8 and the second laser emission rapid scanning mechanism 12 lock onto the main target with lasers.

[0065] Step 3: When tracking the primary target, if there are other secondary targets within the field of view, Figure 2 As shown in the diagram; while tracking the main target, ranging of other targets is achieved using lasers; the angles that the two laser-emitting rapid scanning mechanisms need to rotate are calculated based on the angles of the secondary targets relative to the main target;

[0066] The first laser emission rapid scanning mechanism 8 is activated to perform two-dimensional adjustment of the laser emission optical path optical axis to achieve laser emission scanning motion independent of the scanning mirror (2) and to scan the field of view of this system; when the scan locks onto a secondary target, it measures the distance to other secondary targets in the field of view;

[0067] The second laser emission rapid scanning mechanism 12 has corresponding angular movements with the first laser emission rapid scanning mechanism 8.

[0068] The parts of this invention not described in detail are well-known in the field.

Claims

1. A photoelectric system with multi-target ranging capability, characterized in that... The system includes a fairing (1), a scanning mirror (2), a correction mirror group (3), an infrared laser beam splitter (4), an infrared converging mirror group (5), an infrared cooled detector (6), a laser emission and reception beam splitter (7), a first laser emission rapid scanning mechanism (8), a laser emission antenna (9), a laser (10), a laser receiving antenna (11), a second laser emission rapid scanning mechanism (12), and a laser receiving detector (13). The fairing (1) contains the incident infrared light path, which is sequentially provided with the projection light paths of the scanning mirror (2), the correction mirror group (3), and the infrared laser beam splitter (4). The infrared converging lens group (5) and the infrared cooling detector (6) constitute an infrared target imaging search and tracking system; the laser light path emitted by the laser (10) is provided with a laser emitting antenna (9), a first laser emitting fast scanning mechanism (8), a laser emitting receiving beam splitter (7), a laser receiving antenna (11), a second laser emitting fast scanning mechanism (12) and a laser receiving detector (13) to realize the laser ranging function; among them, the optical path between the laser emitting receiving beam splitter (7) and the infrared laser beam splitter (4) provides a path between the laser emitting and reflecting signals and the fairing (1).

2. The photoelectric system with multi-target ranging capability according to claim 1, characterized in that... The infrared laser beam splitter (4) is coated with a beam splitting film, which transmits infrared energy of 3-5 μm and reflects laser energy of 1.064 μm.

3. The photoelectric system with multi-target ranging capability according to claim 1, characterized in that... The laser emission and reception beam splitter (7) adopts a partitioned coating method, with a laser reflection film coated in the central area to form the laser emission aperture, and a laser transmission film coated in the edge area to form the laser reception aperture, thereby realizing the splitting of laser emission and laser reception.

4. The photoelectric system with multi-target ranging capability according to claim 1, characterized in that... The infrared laser beam splitter (4) is made of zinc sulfide, or sapphire or single-crystal silicon.

5. The photoelectric system with multi-target ranging capability according to claim 1 or 4, characterized in that... The upper surface of the infrared laser beam splitter (4) is coated with a beam splitting film to achieve the function of transmitting mid-wave infrared and reflecting laser.

6. The photoelectric system with multi-target ranging capability according to claim 1, characterized in that... The correction lens group uses two lenses to cancel the aberrations introduced by the fairing (1), and the materials are zinc sulfide and calcium fluoride.

7. The photoelectric system with multi-target ranging capability according to claim 1, characterized in that... The first laser emission rapid scanning mechanism (8) and the second laser emission rapid scanning mechanism (12) adopt a fast-reflecting mirror or a liquid crystal phased array module.

8. A method for multi-target ranging using the photoelectric system with multi-target ranging capability as described in any one of claims 1 to 7, characterized in that... When the main target is being stably tracked, the range of other secondary targets within the field of view is measured. The steps are as follows: Step 1: The scanning mirror (2) scans the azimuth and elevation of the sphere around the fairing (1) along its axis. When a specific infrared main target is detected in the air, the scanning mirror (2) rotates in the azimuth and elevation directions to scan the target. After the aberrations introduced are canceled by the correction mirror group (3), the laser beam splitter (4) transmits the laser beam to the infrared converging mirror group (5) to converge the main target onto the focal plane of the infrared cooled detector (6). The scanning mirror (2) tracks the main target and achieves continuous and stable tracking. Step 2: The energy of the laser (10) is refracted into the infrared laser beam splitter (4) after passing through the laser transmitting antenna (9), the first laser transmitting fast scanning mechanism (8), and the laser transmitting receiving beam splitter (7). After being refracted by the infrared laser beam splitter (4), it passes through the correction mirror group (3), the scanning reflector (2), and the rectifier (1) and then shines on the main target to form a reflected laser beam. The reflected laser beam passes through the rectifier (1) to the infrared laser beam splitter (4) and is reflected into the laser transmitting receiving beam splitter (7). The transmitted laser passes through the laser receiving antenna (11). The laser receiving antenna (11) compresses and converges the laser beam that is scattered back from the target. Finally, it is converged to the focal plane of the laser receiving detector (13) through the second laser transmitting fast scanning mechanism (12). The laser receiving detector (13) performs laser ranging. The first laser emission rapid scanning mechanism (8) and the second laser emission rapid scanning mechanism (12) lock onto the main target with lasers; Step 3: When tracking the main target, if there are other secondary targets in the field of view, the other targets are ranged by laser while tracking the main target; the angle that the two laser-emitting rapid scanning mechanisms need to rotate is calculated based on the angle of the secondary targets relative to the main target. The first laser emission rapid scanning mechanism (8) is activated to make two-dimensional adjustments to the optical axis of the laser emission optical path so as to realize the scanning motion of the laser emission independent of the scanning mirror (2) and to scan the field of view of this system; when the scan locks on the secondary target, the distance of other secondary targets in the field of view is measured. The second laser emission rapid scanning mechanism (12) has corresponding angular motion to the first laser emission rapid scanning mechanism (8).

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