Airborne infrared early warning system and method for tracking and ranging

Abstract

An airborne infrared early warning system and method for tracking and ranging relate to the field of infrared early warning technology. To address the issues of large size and low tracking accuracy in existing tracking systems, the system comprises: a primary mirror, a secondary mirror, a wavelength splitter, a first converging lens group, a single-photon detector, a first reflector, a first relay lens group, a first fast reflector, a second converging lens group, a cold stop, a medium-wave infrared refrigerated detector, a first laser, a first collimating lens, a second reflector, a second fast reflector, a second laser, a second collimating lens, an energy splitter, a third reflector, a fourth reflector, a fifth reflector, a third converging lens group, and a CCD imaging sensor. The infrared early warning system is compact, lightweight, has high pointing accuracy, and is quick to respond, thereby improving tracking accuracy. The system can maintain the coaxiality of the infrared tracking branch and the ranging transmission branch in real time, thereby forming an infrared early warning system suitable for airborne platforms for real-time tracking and ranging of infrared targets.

Description

Technical Field

[0001] The present invention relates to the field of infrared early warning technology, and in particular to an airborne infrared early warning system and method for tracking and ranging. Background Art

[0002] The airborne infrared early warning system is a long-range detection system based on the infrared search and tracking system. It operates in the infrared band of optical frequency and has the advantages of strong anti-electronic interference ability, good concealment, not susceptible to anti-radiation missile attacks, sensitive to the target's thermal radiation, and strong ability to detect stealth targets. Based on the above, research on the infrared early warning system is imperative. On the basis of tracking infrared targets, it is proposed to integrate the infrared tracking system with laser ranging to achieve target search, tracking and accurate measurement of flight trajectory.

[0003] Chinese patent publication number "CN 216083102 U," titled "A Scanning Laser Rangefinder and Laser Ranging System," proposes that a scanning laser rangefinder can achieve omnidirectional scanning motion using two motors. This structure enables tracking and ranging of moving ships. The system achieves tracking by fixing the first and second motors so that the laser rangefinder swings in two mutually perpendicular planes. However, the system utilizes dual perpendicular servo turntables for omnidirectional scanning, resulting in a large size and low tracking accuracy. Summary of the Invention

[0004] To address the issues of bulky tracking systems and low tracking accuracy in existing technologies, the present invention provides an airborne infrared early warning system and method for tracking and ranging. This system simultaneously tracks infrared targets and accurately measures their flight trajectories, while meeting the requirements of small size, light weight, and high pointing accuracy. It is suitable for transport by light aircraft or floating platforms, thus reducing costs.

[0005] The technical solutions adopted by the present invention to solve the technical problems are as follows:

[0006] The airborne infrared early warning system for tracking and ranging of the present invention comprises: a primary mirror, a secondary mirror, a wavelength spectrometer, a first converging lens group, a single-photon detector, a first reflector, a first relay lens group, a first fast reflector, a second converging lens group, a cold stop, a medium-wave infrared refrigeration detector, a first laser, a first collimating lens, a second reflector, a second fast reflector, a second laser, a second collimating lens, an energy spectrometer, a third reflector, a fourth reflector, a fifth reflector, a third converging lens group, and a CCD imaging sensor;

[0007] The external light beam is reflected by the primary mirror and the secondary mirror in sequence. After that, part of the light is transmitted through the wavelength splitter and enters the infrared tracking branch; while the other part of the light is reflected by the wavelength splitter and enters the ranging receiving branch.

[0008] In the infrared tracking branch, the light beam is reflected by the first reflector, transmitted by the relay lens group, reflected by the first fast reflector, transmitted by the second converging lens group, and then enters the medium-wave infrared refrigerated detector through the cold aperture. In the ranging receiving branch, the light beam is converged by the first converging lens group and enters the single-photon detector.

[0009] In the ranging transmission branch, the laser light emitted by the fiber laser 1 is sequentially collimated and transmitted by the collimating lens 1, reflected by the reflecting mirror 2, and reflected by the fast reflecting mirror 2 before being emitted in parallel.

[0010] In the closed-loop monitoring branch, the laser light emitted by the second fiber laser is transmitted through the second collimating lens. Part of the laser light is reflected by the energy beam splitter, the first fast reflector, the fourth reflector, and the third convergent lens group before entering the CCD imaging sensor. The other part of the laser light is transmitted through the energy beam splitter, the third reflector, the second fast reflector, the fifth reflector, and the third convergent lens group before entering the CCD imaging sensor.

[0011] Furthermore, the primary mirror and the secondary mirror form a reduced beam antenna system with a receiving aperture of 350 mm, which reduces the beam aperture after reception; the surfaces of the primary mirror and the secondary mirror are both concave parabolic reflectors.

[0012] Furthermore, the primary mirror 1 and the secondary mirror 2 are placed in parallel; the wavelength splitter 3, the converging lens group 1 4 and the single-photon detector 5 are on the same optical axis; the reflector 1 6, the relay lens group 7, the fast reflector 1 8, the converging lens group 2 9, the cold aperture 10 and the medium-wave infrared refrigerated detector 11 are on the same optical axis; the fiber laser 1 12, the collimating lens 1 13, the reflector 2 14 and the fast reflector 2 15 are on the same optical axis.

[0013] Furthermore, the emission wavelength of the laser 1 is 1064 nm, and the emission wavelength of the laser 2 is 808 nm.

[0014] Furthermore, the pixel size of the medium-wave infrared detector is 30 μm, and the pixel size of the single-photon detector is 0.4 mm.

[0015] Furthermore, the wavelength splitter has a working angle of 45°, which is used to reflect lasers with a wavelength of 1064nm and transmit lasers with a wavelength of 8-12μm; the working angles of the reflector 1 and the reflector 2 are 45°; the working angle of the fast reflector 1 is 45°, which is used for precise infrared light tracking with a tracking accuracy of 20μrad; the working angle of the fast reflector 2 is 45°, which is a follow-up fast reflector of the fast reflector 1, and is used to adjust the coaxiality of the ranging emission branch and the infrared tracking branch, with a tracking accuracy of 20μrad.

[0016] Furthermore, the energy splitter has a splitting ratio of 50:50.

[0017] The airborne infrared early warning system based on tracking and ranging of the present invention comprises the following steps:

[0018] Step 1: After obtaining the approximate direction of the infrared target, guide the infrared tracking branch to scan within the beam pointing range to capture the infrared target;

[0019] Step 2: The captured infrared target light is incident on a beam reduction antenna system consisting of a primary mirror and a secondary mirror for beam reduction. The infrared light is reflected by the primary mirror to the secondary mirror. The reduced infrared target light is then reflected by the secondary mirror, transmitted by the wavelength splitter, reflected by reflector 1, and transmitted by the relay lens group to the fast reflector 1. The fast reflector 1 is adjusted so that the infrared target light is reflected to the converging lens group 2. The convergent lens group 2 then transmits the infrared target light to the cold aperture, and then transmits the infrared target light to the medium-wave infrared refrigerated detector through the cold aperture, thereby continuously tracking the infrared target.

[0020] Step 3: After capturing the infrared target, the fiber laser 2 emits a closed-loop monitoring light of 808nm, which is transmitted through the collimating lens 2. A portion of the light is reflected by the energy beam splitter, the fast reflector 1, the reflector 4, and the converging lens group 3 before entering the CCD imaging sensor to obtain the angular position of the fast reflector 1 at this time.

[0021] Step 4: The fiber laser 1 emits a ranging light with a wavelength of 1064 nm, which is transmitted through the collimating lens group 1 and reflected by the reflector 2 to the fast reflector 2;

[0022] Adjust the second fast reflector to make it consistent with the angle of the first fast reflector, so that the ranging emission branch and the infrared tracking branch are coaxial. The ranging laser is reflected by the second fast reflector and then emitted. Finally, the ranging laser is irradiated onto the infrared target.

[0023] Step 5, the fiber laser 2 emits a closed-loop monitoring light of 808 nm, which is transmitted through the collimating lens group 2, and the other part of the light is transmitted through the energy beam splitter, reflected by the third reflector, reflected by the second fast reflector, reflected by the fifth reflector, and transmitted by the third convergent lens group before entering the CCD imaging sensor. By observing the imaging coordinate positions of the two fiber lasers on the CCD imaging sensor (23), it is monitored whether the vibration angles of the second fast reflector and the first fast reflector are consistent, that is, whether the infrared receiving branch and the ranging transmitting branch are coaxial;

[0024] Step 6: The ranging laser described in step 4 is reflected by the infrared target to the beam reduction antenna system composed of a primary mirror and a secondary mirror for beam reduction. The ranging laser is reflected by the primary mirror to the secondary mirror. The beam reduced is reflected by the secondary mirror, the wavelength splitter, and the converging lens group 1 to the single photon detector, thereby measuring the infrared target distance at this time.

[0025] The beneficial effects of the present invention are:

[0026] The present invention adopts a system design that combines infrared target tracking and target ranging. The overall structure of the system is complete. When an infrared target is received, the system starts working to track the infrared target. At this time, the ranging laser emits laser to illuminate the infrared target. Then, based on the reflected ranging laser, the system's ranging single-photon detector measures the distance to the infrared target at this time, and the overall system coordination is reasonable. In the infrared tracking branch, the fast reflector and the medium-wave infrared refrigerated detector are in a conjugate relationship, respectively serving as the primary exit pupil and the secondary exit pupil of the infrared tracking branch. Compared with the traditional infrared tracking system, this system can control the light aperture so that the infrared target can enter the medium-wave infrared refrigerated detector completely.

[0027] In the present invention, the coarse tracking platform accuracy of the infrared tracking branch is 80μrad, and the fast reflection mirror accuracy is 20μrad. In order to maintain the synchronization of infrared target tracking and ranging, a follow-up fast reflection mirror is introduced in the ranging transmission branch. This fast reflection mirror will vibrate synchronously with the fast reflection mirror in the infrared tracking branch to keep the infrared tracking branch and the ranging transmission branch coaxial, so as to achieve stable irradiation of the 100μrd transmission light beam onto the target. Compared with the traditional transceiver common aperture system, this system can eliminate the mutual interference between the received and transmitted lasers, and through the vibration of the fast reflection mirror, it can accurately capture the infrared target in real time, and the follow-up fast reflection mirror can simultaneously cooperate to achieve real-time irradiation of the ranging laser on the target, thereby performing real-time distance measurement on it.

[0028] In actual environments, the PSD output instructions of the fast reflection mirror will produce errors as the external temperature changes, resulting in the inability of the infrared tracking branch and the fast reflection mirrors of the ranging transmission branch to be synchronized. Therefore, in the present invention, a closed-loop monitoring branch is introduced to address the error problem of the system. The monitoring laser in this branch is emitted into the fast reflection mirrors of the two branches through the energy splitter and the reflector, and then reflected by the reflector and enters the CCD imaging sensor. The real-time vibration direction of the two fast reflection mirrors can be monitored in a closed loop, eliminating the error problem between the infrared tracking branch and the ranging transmission branch, and maintaining the accuracy of ranging.

[0029] The system of the present invention can track infrared targets in real time and measure distance by emitting a ranging laser to illuminate the infrared target. The fast reflector of the ranging transmission branch follows the infrared tracking branch according to instructions obtained from closed-loop monitoring, adjusting the angle in real time to keep the tracking and ranging branches coaxial, thus establishing a complete system link. This infrared early warning system has the advantages of small size, light weight, high pointing accuracy, and rapid response. It solves the size and weight issues of traditional laser tracking and ranging systems and improves target tracking accuracy. The system can maintain the coaxiality of the infrared tracking branch and the ranging transmission branch in real time, forming an infrared early warning system suitable for airborne platforms, which can track and measure the distance of infrared targets in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a schematic structural diagram of the airborne infrared early warning system for tracking and ranging of the present invention.

[0031] Figure 1 Among them, 1-primary mirror, 2-secondary mirror, 3-wavelength spectrometer, 4-converging lens group 1, 5-single-photon detector, 6-reflector 1, 7-relay lens group, 8-fast reflector 1, 9-converging lens group 2, 10-cold stop, 11-medium-wave infrared cooling detector, 12-fiber laser 1, 13-collimating lens 1, 14-reflector 2, 15-fast reflector 2, 16-fiber laser 2, 17-collimating lens 2, 18-energy spectrometer, 19-reflector 3, 20-reflector 4, 21-reflector 5, 22-converging lens group 3, 23-CCD imaging sensor. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is described clearly and completely below with reference to the accompanying drawings.

[0033] like Figure 1As shown, the airborne infrared early warning system based on tracking and ranging of the present invention mainly includes: a primary mirror 1, a secondary mirror 2, a wavelength spectrometer 3, a converging lens group 1 4, a single photon detector 5, a reflector 1 6, a relay lens group 7, a fast reflector 1 8, a converging lens group 2 9, a cold aperture 10, a medium-wave infrared refrigerated detector 11, a fiber laser 1 12, a collimating lens 1 13, a reflector 2 14, a fast reflector 2 15, a fiber laser 2 16, a collimating lens 2 17, an energy spectrometer 18, a reflector 3 19, a reflector 4 20, a reflector 5 21, a converging lens group 3 22 and a CCD imaging sensor 23.

[0034] In this embodiment, the antenna system is composed of a primary mirror 1 and a secondary mirror 2 placed in parallel, which reduces the beam aperture during reception. The surfaces of the primary mirror 1 and the secondary mirror 2 are both concave parabolic reflectors.

[0035] In this embodiment, the wavelength splitter 3 has a working angle of 45°, which is used to reflect laser light with a wavelength of 1064 nm and transmit laser light with a wavelength of 8-12 μm; the working angles of the reflector 1 6 and the reflector 2 14 are both 45°; the working angle of the fast reflector 1 8 is 45°; and the working angle of the fast reflector 2 15 is 45°.

[0036] In this embodiment, the fast reflector 1 8 is used for the infrared tracking branch, and is used for precise tracking of infrared target light; the fast reflector 2 15 is used for the ranging emission branch, and serves as a follow-up fast reflector of the fast reflector 1 8 to adjust the coaxiality of the ranging laser emission branch and the infrared tracking branch.

[0037] In this embodiment, the wavelength splitter 3 reflects the laser light with a wavelength of 1064 nm and transmits the laser light with a wavelength of 8-12 μm;

[0038] In this embodiment, the wavelength splitter 3, the converging lens group 4, and the single photon detector 5 together form a distance measurement receiving branch.

[0039] In this embodiment, the energy beam splitter 3, the reflector 1 6, the relay lens group 7, the fast reflector 1 8, the converging lens group 2 9, the cold aperture 10, and the medium-wave infrared refrigerated detector 11 together form an infrared tracking branch.

[0040] In this embodiment, the laser 1 12 , the collimating lens 1 13 , the reflector 2 14 , and the fast reflector 2 15 together constitute a distance measurement transmission branch.

[0041] In this embodiment, laser 2 16, collimating lens 2 17, energy beam splitter 18, fast reflector 1 8, reflector 3 19, fast reflector 2 15, reflector 4 20, reflector 5 21, converging lens group 3 22, and CCD imaging sensor 23 together constitute a closed-loop monitoring branch.

[0042] In this embodiment, the wavelength splitter 3, the converging lens group 1 4 and the single-photon detector 5 are placed on the same optical axis; the reflector 1 6, the relay lens group 7, the fast reflector 1 8, the converging lens group 2 9, the cold aperture 10 and the medium-wave infrared refrigerated detector 11 are placed on the same optical axis; the laser 12, the converging lens 13, the reflector 2 14 and the fast reflector 2 15 are placed on the same optical axis.

[0043] In this embodiment, the wavelength of the laser emitted by the laser 12 is 1064 nm; the wavelength of the laser emitted by the laser 2 16 is 808 nm.

[0044] In this embodiment, the splitting ratio of the energy splitter 18 is 50:50; the energy splitter 18 reflects 50% of the closed-loop monitoring laser to the fast reflection mirror 1 8, and the splitter 13 transmits 50% of the closed-loop monitoring laser to the reflection mirror 3 18, and then reflects to the fast reflection mirror 2 15.

[0045] In the tracking and ranging-based airborne infrared early warning system of the present invention, an external light beam is sequentially reflected by the primary mirror 1 and the secondary mirror 2, after which a portion of the light is transmitted through the wavelength splitter 3 and enters the infrared tracking branch; while the other portion of the light is reflected by the wavelength splitter 3 and enters the ranging receiving branch;

[0046] In the infrared tracking branch, the light beam is reflected by the reflector 1 6 , transmitted by the relay lens group 7 , reflected by the fast reflector 1 8 , transmitted by the converging lens group 2 9 , and then passes through the cold aperture 10 into the medium-wave infrared refrigerated detector 11 .

[0047] In the ranging receiving branch, the light beam is converged by the converging lens group 4 and then enters the single photon detector 5;

[0048] In the ranging transmission branch, the laser light from the fiber laser 12 is sequentially transmitted through the collimating lens 13, reflected by the reflecting mirror 14, and then reflected by the fast reflecting mirror 15 before being emitted.

[0049] In the closed-loop monitoring branch, after the fiber laser 2 16 is transmitted through the collimating lens 2 17, part of the laser light is reflected by the energy beam splitter 18, the fast reflector 1 8, the reflector 4 20, and the converging lens group 3 22 before entering the CCD imaging sensor 23; the other part of the laser light is transmitted through the energy beam splitter 18, the reflector 3 19, the fast reflector 2 15, the reflector 5 21, and the converging lens group 3 22 before entering the CCD imaging sensor 23.

[0050] The airborne infrared early warning system for tracking and ranging of the present invention mainly comprises the following steps:

[0051] Step 1: After obtaining the approximate direction of the infrared target, guide the infrared tracking branch to scan within the beam pointing range to capture the infrared target;

[0052] Step 2: The captured infrared target light is transmitted to the beam reduction antenna system composed of primary mirror 1 and secondary mirror 2 for beam reduction. The infrared light is reflected by primary mirror 1 to secondary mirror 2. The beam reduced infrared target light is reflected by secondary mirror 2, transmitted by wavelength splitter 3, reflected by reflector 1 6, and transmitted by relay lens group 7 to fast reflector 1 8.

[0053] Adjust the fast reflector 1 8 so that the infrared target light is reflected to the converging lens group 2 9, and then transmitted by the converging lens group 2 9 to the cold aperture 10, and then transmitted through the cold aperture 10 to the medium-wave infrared refrigerated detector 11, thereby continuously tracking the infrared target;

[0054] Step 3: After capturing the infrared target, the fiber laser 2 16 emits 808nm closed-loop monitoring light. After being transmitted through the collimating lens 2 17, a portion of the light is reflected by the energy beam splitter 18, the fast reflector 1 8, the reflector 4 20, and the converging lens group 3 22 before entering the CCD imaging sensor 23 to obtain the angular position of the fast reflector 1 at this time.

[0055] Step 4: The optical fiber laser 12 emits a ranging light with a wavelength of 1064 nm, which is transmitted through the collimating lens 13 and reflected by the reflecting mirror 2 14 to the fast reflecting mirror 2 15;

[0056] Adjust the quick reflector 2 15 to make it consistent with the angle of the quick reflector 1 8, so that the ranging emission branch and the infrared tracking branch are coaxial. At this time, the ranging emission light is reflected by the quick reflector 2 15 and then emitted to illuminate the infrared target.

[0057] Step 5: Fiber laser 2 16 emits 808nm closed-loop monitoring light, which is transmitted through collimating lens 2 17. Another portion of the light is transmitted through energy beam splitter 18, reflected by reflector 3 19, reflected by fast reflector 2 15, reflected by reflector 5 21, and transmitted through converging lens group 3 22 before entering CCD imaging sensor 23. By observing the imaging coordinate positions of the two fiber lasers on CCD imaging sensor 23, it is monitored whether the angles of fast reflector 2 15 and fast reflector 1 8 are consistent, that is, whether the infrared receiving branch and the ranging transmitting branch are coaxial.

[0058] Step 6. The ranging laser described in step 4 is reflected by the infrared target to the beam-contracting antenna system composed of the primary mirror 1 and the secondary mirror 2. The ranging laser is reflected by the primary mirror 1 to the secondary mirror 2. The beam-contracted ranging laser is reflected by the secondary mirror 2, the wavelength splitter 3, and the converging lens group 4 to the single-photon detector 5, thereby measuring the infrared target distance at this time. At this point, the infrared tracking branch, the ranging transmitting branch, and the ranging receiving branch work coaxially, and the closed-loop monitoring branch monitors in real time, thereby achieving the purpose of real-time tracking and ranging of the infrared target.

[0059] The implementation scheme described above can be further optimized, and the implementation scheme is only a description of the preferred embodiment of the present invention. Without departing from the design concept and scheme of the present invention, various changes and improvements made to the technical scheme of the present invention by professional and technical personnel in this field shall fall within the scope of protection of the present invention.

Claims

1. An airborne infrared early warning system for tracking and ranging, characterized by: The system comprises: a primary mirror (1), a secondary mirror (2), a wavelength spectrometer (3), a converging lens group 1 (4), a single photon detector (5), a reflector 1 (6), a relay lens group (7), a fast reflector 1 (8), a converging lens group 2 (9), a cold aperture (10), a medium-wave infrared cooling detector (11), a fiber laser 1 (12), a collimating lens 1 (13), a reflector 2 (14), a fast reflector 2 (15), a fiber laser 2 (16), a collimating lens 2 (17), an energy spectrometer (18), a reflector 3 (19), a reflector 4 (20), a reflector 5 (21), a converging lens group 3 (22) and a CCD imaging sensor (23); The external light beam is reflected by the primary mirror (1) and the secondary mirror (2) in sequence, and a portion of the light is transmitted through the wavelength splitter (3) and enters the infrared tracking branch; while the other portion of the light is reflected by the wavelength splitter (3) and enters the ranging receiving branch; In the infrared tracking branch, the light beam is reflected by the reflector 1 (6), transmitted by the relay lens group (7), reflected by the fast reflector 1 (8), transmitted by the converging lens group 2 (9), and then enters the medium-wave infrared cooling detector (11) through the cold aperture (10); in the ranging receiving branch, the light beam is converged by the converging lens group 1 (4) and then enters the single-photon detector (5); In the distance measurement transmission branch, the laser light emitted by the fiber laser 1 (12) is sequentially collimated and transmitted by the collimating lens 1 (13), reflected by the reflecting mirror 2 (14), and reflected by the fast reflecting mirror 2 (15), and then emitted in parallel; In the closed-loop monitoring branch, the laser light emitted by the fiber laser 2 (16) is transmitted through the collimating lens 2 (17), a portion of the laser light is reflected by the energy beam splitter (18), reflected by the fast reflector 1 (8), reflected by the reflector 4 (20), transmitted by the converging lens group 3 (22), and then enters the CCD imaging sensor (23); the other portion of the laser light is transmitted through the energy beam splitter (18), reflected by the reflector 3 (19), reflected by the fast reflector 2 (15), reflected by the reflector 5 (21), transmitted by the converging lens group 3 (22), and then enters the CCD imaging sensor (23); The primary mirror (1) and the secondary mirror (2) are placed in parallel; the wavelength splitter (3), the converging lens group 1 (4) and the single-photon detector (5) are on the same optical axis; the reflector 1 (6), the relay lens group (7), the fast reflector 1 (8), the converging lens group 2 (9), the cold stop (10) and the medium-wave infrared cooling detector (11) are on the same optical axis; the fiber laser 1 (12), the collimating lens 1 (13), the reflector 2 (14) and the fast reflector 2 (15) are on the same optical axis; The wavelength splitter (3) has a working angle of 45° and is used to reflect laser light with a wavelength of 1064 nm and transmit laser light with a wavelength of 8-12 μm; the reflector 1 (6) and the reflector 2 (14) have a working angle of 45°; the fast reflector 1 (8) has a working angle of 45° and is used for precise infrared light tracking with a tracking accuracy of 20 μrad; the fast reflector 2 (15) has a working angle of 45° and is a follow-up fast reflector of the fast reflector 1, and is used to adjust the coaxiality of the ranging emission branch and the infrared tracking branch, with a tracking accuracy of 20 μrad.

2. The airborne infrared early warning system for tracking and ranging according to claim 1, characterized in that: The primary mirror (1) and the secondary mirror (2) form a reduced beam antenna system with a receiving aperture of 350 mm, which reduces the beam aperture after reception; the surfaces of the primary mirror (1) and the secondary mirror (2) are both concave parabolic reflecting surfaces.

3. The airborne infrared early warning system for tracking and ranging according to claim 1, characterized in that: The emission wavelength of the fiber laser 1 (12) is 1064 nm, and the emission wavelength of the fiber laser 2 (16) is 808 nm.

4. The airborne infrared early warning system for tracking and ranging according to claim 1, characterized in that: The pixel size of the medium-wave infrared cooling detector (11) is 30 μm, and the pixel size of the single-photon detector (5) is 0.4 mm.

5. The airborne infrared early warning system for tracking and ranging according to claim 1, characterized in that: The energy splitter (18) has a splitting ratio of 50:

50.

6. An airborne infrared early warning method for tracking and ranging implemented based on the airborne infrared early warning system for tracking and ranging according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: Step 1: guide the infrared tracking branch to scan within the beam pointing range to capture the infrared target; Step 2: The captured infrared target light is incident on the beam reduction antenna system composed of the primary mirror (1) and the secondary mirror (2) for beam reduction. The infrared light is reflected by the primary mirror (1) to the secondary mirror (2). The infrared target light after beam reduction is reflected by the secondary mirror (2), transmitted by the wavelength splitter (3), reflected by the reflector 1 (6), and transmitted by the relay lens group (7) to the fast reflector 1 (8). Adjust the fast reflector 1 (8) to reflect the infrared target light to the converging lens group 2 (9), and then transmit the infrared target light to the cold stop (10) through the converging lens group 2 (9), and then transmit the infrared target light to the medium-wave infrared cooling detector (11) through the cold stop (10), thereby continuously tracking the infrared target; Step 3: After capturing the infrared target, the fiber laser 2 (16) emits a closed-loop monitoring light of 808 nm. After being transmitted through the collimating lens 2 (17), a portion of the light is reflected by the energy beam splitter (18), reflected by the fast reflector 1 (8), reflected by the reflector 4 (20), and transmitted through the converging lens group 3 (22) before entering the CCD imaging sensor (23) to obtain the angular position of the fast reflector 1 (8) at this time. Step 4: The optical fiber laser 1 (12) emits a ranging light with a wavelength of 1064 nm, which is transmitted through the collimating lens 1 (13) and reflected by the reflector 2 (14) to the fast reflector 2 (15); Adjust the second quick reflector (15) so that its angle is consistent with that of the first quick reflector (8), so that the ranging emission branch and the infrared tracking branch are coaxial. At this time, the ranging laser is reflected by the second quick reflector (15) and then emitted, and the ranging laser is irradiated onto the infrared target; Step 5: The fiber laser 2 (16) emits a closed-loop monitoring light of 808 nm, which is transmitted through the collimating lens 2 (17). Another part of the light is transmitted through the energy beam splitter (18), reflected by the reflector 3 (19), reflected by the fast reflector 2 (15), reflected by the reflector 5 (21), and transmitted by the converging lens group 3 (22) before entering the CCD imaging sensor (23). By observing the imaging coordinate positions of the two fiber lasers on the CCD imaging sensor (23), it is monitored whether the vibration angles of the fast reflector 2 (15) and the fast reflector 1 (8) are consistent, that is, whether the infrared receiving branch and the ranging transmitting branch are coaxial. Step 6: The ranging laser light described in step 4 is reflected by the infrared target to the beam reduction antenna system composed of the primary mirror (1) and the secondary mirror (2). The ranging laser light is reflected by the primary mirror (1) to the secondary mirror (2). The beam-reduced ranging laser light is reflected by the secondary mirror (2), reflected by the wavelength splitter (3), and transmitted by the converging lens group (4) to the single-photon detector (5), thereby measuring the infrared target distance at this time.

Images