An optical seeker

Abstract

The application provides an optical guiding head, comprising a fairing, a wide-angle optical system comprising part of the fairing, a transmission lens group designed in a transmission mode, a first detector, in the direction of light propagation, the optical components are sequentially arranged in the order of light propagation, a long-focus optical system comprising part of the fairing, an aberration correction lens, a coaxial Cassegrain form lens group, a residual aberration correction lens group and a second detector, a hole is formed in the aberration correction lens of the long-focus optical system, and the wide-angle optical system is nested between the long-focus optical system and the fairing. The guiding head provided by the application has the advantages of simple structure, easy popularization and application, and does not adopt a radar form in the distance measuring mode, but adopts an optical means, through the change of imaging information on the two detectors, the confidentiality can be effectively improved, the system has high precision, when the detonation distance is detected, the detonation precision of 0.2 m can be achieved, the data processing speed is fast, and compared with the traditional radar form, the cost is lower.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of guidance, and particularly relates to an optical seeker. BACKGROUND

[0002] In the field of seeker guidance and point detonation, radar is usually used to realize ranging and guidance function. The fire control radar has the disadvantages of active emission of electromagnetic waves, easy exposure of itself, becoming the target of the opponent's anti-radiation missile, and easy to be jammed. As long as the opponent takes electronic countermeasures, such as using electronic jamming or launching jamming bombs, the radar cannot work normally. The millimeter wave radar has the disadvantages of short detection distance, poor atmospheric transmission characteristics, and poor all-weather working capability.

[0003] Chinese patent CN111123288 A discloses a long-distance follow-up laser seeker which adopts a large-aperture transmission optical system, adopts a non-spherical large-lens optical system matched with a four-quadrant PIN laser detector plus a high-speed ADC direct sampling design scheme, reduces the cost while enhancing the received laser energy, and further matches the signal conditioning circuit to directly sample the laser detection signal, so as to realize long-distance detection. However, the structure of the seeker provided by the technical scheme is relatively complex, and in essence, it still uses signal reflection, and the resistance to electronic jamming is weak.

[0004] In addition, in the prior art, the optical design of an infrared / laser dual-mode seeker is often combined with a laser radar. Under the condition of using the same receiving aperture, an infrared imaging sensor and a laser radar imaging sensor are integrated into a small-sized seeker, the target position information is acquired by the laser radar, so as to make up for the disadvantage of the infrared that cannot measure the distance; the infrared guidance has high precision, and can effectively identify the characteristic information of the target object, and realize special position detonation. This way still uses the laser radar to realize ranging, and the electronic resistance is weak.

[0005] Using the optical form can effectively avoid the defects brought by the electronic form. Using the optical means can effectively combine the secrecy and high precision of laser detection, and use the self-radiation or active illumination means for the target object, to realize accurate guidance and point detonation. SUMMARY

[0006] In order to overcome the problems in the prior art, the present application provides an optical seeker based on optical imaging principle. The key components of the present application are composed of a fairing, an imaging system (a wide-angle optical system and a long-focus optical system), and the ranging is realized by completely using the difference of optical imaging information, the anti-interference ability is stronger, and the accurate guidance and point detonation can be realized.

[0007] In order to achieve the above technical effects, the technical scheme adopted by the present application is,

[0008] An optical seeker comprises:

[0009] Fairing, wherein the outer surface of the fairing is ellipsoidal;

[0010] The wide-angle optical system includes a fairing, a transmission lens group designed in a transmission manner, and a first detector; in the direction of light propagation, the above-mentioned optical components are arranged in sequence according to the light propagation order;

[0011] The telephoto optical system includes a fairing, an aberration-correcting lens, a coaxial Cassegrain lens group, a residual aberration-correcting lens group, and a second detector; in the direction of light propagation, the above-mentioned optical components are arranged in sequence according to the order of light propagation.

[0012] The aberration correction lens of the telephoto optical system has an opening, and the wide-angle optical system is nested between the telephoto optical system and the fairing.

[0013] The wide-angle optical system and the telephoto optical system are integrated and installed in the ellipsoidal fairing;

[0014] Infrared radiation emitted by a distant target passes through the aforementioned optical elements in sequence and then illuminates the first and second detector elements, thus forming an image.

[0015] As a preferred embodiment, the radius of curvature of the ellipsoidal fairing is 12~16mm.

[0016] As a preferred embodiment, the conicity of the ellipsoidal fairing is -0.5 to -0.8.

[0017] As a preferred embodiment, the wide-angle optical system includes the middle portion of the fairing; the telephoto optical system includes the edge portion of the fairing.

[0018] As a preferred embodiment, the ellipsoidal fairing is made of broadband zinc sulfide or germanium.

[0019] As a preferred embodiment, the distance between the principal surfaces of the wide-angle optical system and the telephoto optical system is greater than 500mm.

[0020] As a preferred embodiment, the wide-angle optical system has a full field of view ≥30°.

[0021] As a preferred embodiment, the full field of view of the telephoto optical system is ≥3°.

[0022] As a preferred embodiment, the first and second detectors are uncooled infrared focal plane detectors.

[0023] As a preferred embodiment, an aberration correction component is provided between the ellipsoidal fairing and the transmission lens assembly.

[0024] Preferably, the aberration correction component is an aspherical lens.

[0025] Advantages of this application:

[0026] 1. The header structure provided in this application is simple and easy to promote and apply;

[0027] 2. The ranging method does not use radar but optical means. By observing the changes in the imaging information on the two detectors, the confidentiality can be effectively improved.

[0028] 3. The system has high precision, achieving a detonation accuracy of 0.2m when detecting detonation distance.

[0029] 4. It has a fast data processing speed and is less expensive than traditional radar systems. Attached Figure Description

[0030] Figure 1 An imaging principle diagram of the optical seeker provided in this application;

[0031] Figure 2 This is a telephoto optical system provided in one embodiment of the present application;

[0032] Figure 3 This is a point array diagram of an imaging system for a telephoto optical system provided in one embodiment of this application;

[0033] Figure 4 This is a wide-angle optical system provided in one embodiment of the present application;

[0034] Figure 5 This is a point array diagram of an imaging system for a wide-angle optical system provided in one embodiment of this application;

[0035] Figure 6 This is an overall structural diagram provided in one embodiment of this application.

[0036] In the diagram: 1-Fairing; 2-Wide-angle optical system; 21-Transmission lens group; 22-First detector; 3-Telephoto optical system; 31-Aberration correction lens; 32-Coaxial Cassegrain lens group; 33-Residual aberration correction lens group; 34-Second detector. Detailed Implementation

[0037] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0038] To achieve the above-mentioned technical effects, the technical solution adopted in this application is as follows:

[0039] In one embodiment of the present invention, such as Figures 1~3 As shown, an optical seeker head is provided, comprising:

[0040] Fairing 1, wherein the outer surface of fairing 1 is ellipsoidal;

[0041] The wide-angle optical system 2 includes a partial fairing 1, a transmission lens group 21 designed according to the transmission form, and a first detector 22; in the direction of light propagation, the above-mentioned optical components are arranged in sequence according to the light propagation order.

[0042] The telephoto optical system 3 includes a partial fairing 1, an aberration-correcting lens 31, a coaxial Cassegrain lens group 32, a residual aberration-correcting lens group 33, and a second detector 34; in the direction of light propagation, the above-mentioned optical components are arranged in sequence according to the light propagation order.

[0043] The aberration correction lens 31 of the telephoto optical system 3 has a hole, and the wide-angle optical system 2 is nested between the telephoto optical system 3 and the fairing 1.

[0044] The wide-angle optical system 2 and the telephoto optical system 3 are integrated and installed in the ellipsoidal fairing 1;

[0045] Infrared radiation emitted by a distant target passes through the aforementioned optical elements in sequence and then illuminates the first detector 22 and the second detector 34, thus forming an image.

[0046] In the technical solution provided by this invention, the wide-angle optical system 2 achieves target identification and guidance by capturing the positional changes of the target object's imaging information on the detector; the telephoto optical system 3 is used to obtain the distance between the seeker and the target object based on the difference in image height of the target object on both the wide-angle and telephoto lens detectors, thus achieving pinpoint detonation; the wide-angle optical system 2 needs to be nested in the center of the small field-of-view aiming lens. Since the fairing 1 also has optical properties and a large curvature, it has a strong ability to deflect light and is also used as part of the wide-angle optical system 2 and the telephoto optical system 3. Multiple lenses are subsequently needed to correct aberrations, and its specific implementation principle is as follows: Figure 1 As shown.

[0047] H1 and H1 in the figure 、 These are the object-side and image-side principal planes of the fairing 1 plus the telephoto optical system 3, respectively; H2 and H2 、 These are the object-side and image-side principal planes of the fairing 1 plus the wide-angle optical system 2, respectively, where y is the target object height, and y1 is the image-side principal plane. 、 With y2 、 These are the image heights of the telephoto system and the wide-angle system, respectively. ω1 and ω2 are the object-side field of view angles of the two objectives, respectively. 、 and ω2 、 These are the image-side field of view angles of the two objectives, respectively.

[0048] like Figure 4 As shown, d represents the distance between the object planes of the two optical systems. For the same object, since the principal object planes of the two systems are not in the same position, the object distance relationship is as follows:

[0049] ……………………………………..(1)

[0050] According to the imaging formula of the optical system

[0051]

[0052] Where y' is the image height and f' is the focal length. The field of view of the object.

[0053] The formula can be further written as:

[0054] ……………………………………..(2)

[0055] Based on the above formula, we can obtain:

[0056] ………………………………..(3)

[0057] …………………………………..(4)

[0058] in and These are the focal lengths of the aiming lens and the wide-angle lens, respectively.

[0059] When the target object is very far away (where d is on the order of millimeters), at this point we have:

[0060] ……………………………………..(5)

[0061] According to equation (5), when the target object is far away, the ratio of the image height on the detector received by the telephoto lens and the wide-angle lens is a constant value, and YX does not work at this time.

[0062] when Sometimes:

[0063] ……………………………..(6)

[0064] Therefore, the distance l2 between the target and the seeker can be accurately obtained based on the change in the ratio of the image height on the first detector 22 and the second detector 34, thus achieving point-to-point detonation.

[0065] In the technical solution provided in this application, the fairing 1 is an indispensable part of the seeker head. It is a thin-shell structure assembly that can effectively reduce aerodynamic drag and interference, and protect the warhead (or submunition) from the influence of forces, heat, and other natural and nuclear environments. In this application, based on impact resistance and thermodynamic considerations, it is necessary to select some special materials for the design.

[0066] Based on the above principles, an optical seeker with a wavelength range of 8~14μm was designed, with the goal of achieving a seeker start-up working distance of greater than 500m and a detonation distance of no more than 5m.

[0067] In the design of the telephoto optical system 3, due to the small field of view and relatively large aperture of the system, a coaxial Cassegrain design is adopted for the purpose of weight reduction.

[0068] In the design of the wide-angle optical system 2, since the wide-angle structure has a small aperture, a transmission design can be adopted.

[0069] The optical component with the opening is the aberration correction lens 31. This optical component also plays the role of aberration correction in the telephoto optical system 3. It is necessary to make an opening in this component, which is equivalent to making an opening in the center of the second lens of the telephoto system so that the wide-angle system can be placed inside, further simplifying the size of the device. The size of the opening is related to the aperture of the wide-angle system.

[0070] As a preferred embodiment, the radius of curvature of the ellipsoidal fairing 1 is 12~16mm.

[0071] As a preferred embodiment, the conicity of the ellipsoidal fairing 1 is -0.5 to -0.8.

[0072] As a preferred embodiment, the wide-angle optical system 2 includes the middle portion of the fairing 1; the telephoto optical system 3 includes the edge portion of the fairing 1.

[0073] Furthermore, the ellipsoidal fairing 1 has a radius of curvature of 14.4 mm and a conic coefficient of -0.637.

[0074] As a preferred embodiment, the material of the ellipsoidal fairing 1 includes broadband zinc sulfide or germanium.

[0075] According to the requirements of the seeker, the fairing 1 was designed first. Based on the principles of aerodynamics, the fairing 1 should have characteristics such as large curvature, light weight and impact resistance. In this invention, since two systems need to be integrated inside, the internal space requirement is large. After comprehensive design consideration, an ellipsoidal fairing 1 was designed and key parameters were set to better integrate the optical system.

[0076] In one embodiment of the present invention, the distance between the principal surfaces of the wide-angle optical system 2 and the telephoto optical system 3 is greater than 500mm.

[0077] As can be seen from formulas (1) to (6), the larger the distance d between the main surfaces of the two systems, the farther the guide head can work. When designing the matching optical system, the distance between the main surfaces should be increased as much as possible in order to achieve a working distance of more than 500m.

[0078] As a preferred embodiment, the wide-angle optical system 2 has a full field of view ≥30°.

[0079] As a preferred embodiment, the full field of view of the telephoto optical system 3 is ≥3°.

[0080] In optical devices, a field of view of more than 25 degrees is generally considered a large field of view. Here, 30 degrees is selected to meet the wide-angle condition, which can capture more information about the target object and realize the guidance function. The telephoto system also needs to capture the target object, so this field of view can be appropriately reduced.

[0081] As a preferred embodiment, the first detector 22 and the second detector 34 are uncooled infrared focal plane detectors.

[0082] As a preferred embodiment, an aberration correction component is provided between the ellipsoidal fairing 1 and the transmission lens group 21.

[0083] Preferably, the aberration correction component is an aspherical lens.

[0084] Considering the surface parameters of the ellipsoid of fairing 1, which will bring about a large aberration, after aberration correction is performed by an aspherical lens behind the optical part of fairing 1, and then in conjunction with the telephoto system, aberration correction can be effectively achieved.

[0085] As a preferred embodiment, the second lens of the telephoto optical system 3 has an opening, and the wide-angle optical system 2 can be directly nested with the telephoto optical system 3.

[0086] Based on the performance parameters of the two systems, in order to maximize the distance between the main surfaces, the wide-angle system is placed in front of the telephoto system and they share the same fairing 1. Since the aperture of the telephoto part of the seeker is relatively large and sufficient space is reserved, the wide-angle optical system 2 can be directly nested in the telephoto optical system 3. Specific Implementation

[0088] In one specific embodiment of this application, a guide head system with the following specific parameters is designed.

[0089] The design parameters of the telephoto optical system are shown in the table below. During the design process of this invention, special attention should be paid to ensuring that the position of the main surface meets the requirements.

[0090] Table 1 Design parameters of telephoto optics

[0091] System performance Parameter Remark Central wavelength 10 μm \ Focal length 170.859 mm \ Object field angle ±1.5° \ System aperture 44 mm \ F number 2.1 \ Principal plane position 490 mm With respect to the first surface of the system

[0092] During the use of this product, aiming and guidance are required based on target information from the uncooled detector. Therefore, the requirements for image quality are not high, but the requirements for the imaging point pattern are relatively high. It is necessary to ensure that the energy concentration range of the light spot is basically within the Airy disk. The imaging point pattern of the telephoto system is as follows: Figure 5 As shown in the figure, the imaging spot is within the Airy disk range, which meets the project requirements.

[0093] The design parameters of the wide-angle optical system are shown in the table below.

[0094] Table 2 Parameters involved in wide-angle optics

[0095] System performance Parameter Remark Central wavelength 10 μm \ Focal length 23.675 mm \ Object field angle ±15° \ System aperture 14 mm \ F number 1.2 \ Principal plane position -42 mm With respect to the first surface of the system

[0096] Similarly, the wide-angle system imaging point map within the Airy disk area, such as Figure 6 As shown.

[0097] Based on the base parameters of the two systems, the distance between the main surfaces, d, is calculated to be 532 mm, which meets the design requirements.

[0098] Simulations were conducted based on the seeker head designed according to this invention. Since the distance between the main surfaces is 532mm, the seeker head can start working when the object distance is less than 500m. The detector can then be monitored based on y1. 、 / y2 、 The changes between these parameters are used to determine the distance between the seeker and the target.

[0099] Taking a detonation distance of 10m as an example, the table below shows the distance between the seeker and the target object at approximately 10m with an incident angle of 1°, y1 、 / y2 、 Changes between them:

[0100] Table 3 y1 、 / y2 、 Changes between

[0101] Object distance 4.8m 4.9m 5m 5.1m 5.2m y1 、 ]]> 1.68666 mm 1.68012 mm 1.67361 mm 1.66703 mm 1.66076 mm y2 、 ]] 0.194875 mm 0.19056 mm 0.18586 mm 0.18134 mm 0.17628 mm [y1 、 / y2 、 ]]> 8.65800 8.81675 9.00468 9.19284 9.42114

[0102] Obviously, when the distance between the seeker and the target is 10m, a change of 0.1m in the object distance results in a 6.5μm change in image height on the detector for the telephoto system and a 4.5μm change for the wide-angle system. When the object distance changes by 0.2m, the image height change can reach 13μm for the telephoto system and 9μm for the wide-angle system. Given that the detector pixel size is 12μm, combined with image processing techniques, image differentiation is entirely possible. Therefore, this invention can achieve a detonation accuracy of at least 0.2m. Alternatively, the detonation accuracy can also be determined by the target location y1. 、 / y2 、 The value allows for detonation at other distances.

Claims

1. An optical seeker, characterized in that, include: Fairing, wherein the outer surface of the fairing is ellipsoidal; The wide-angle optical system includes a partial fairing, a transmission lens group designed according to the transmission method, and a first detector; in the direction of light propagation, the above-mentioned optical components are arranged in sequence according to the light propagation order; The telephoto optical system includes a partial fairing, an aberration-correcting lens, a coaxial Cassegrain lens group, a residual aberration-correcting lens group, and a second detector; in the direction of light propagation, the above-mentioned optical components are arranged in sequence according to the order of light propagation. The aberration correction lens of the telephoto optical system has an opening, and the wide-angle optical system is nested between the telephoto optical system and the fairing. The wide-angle optical system and the telephoto optical system are integrated and installed in the ellipsoidal fairing.

2. The optical seeker head according to claim 1, characterized in that: The radius of curvature of the fairing is 12~16mm.

3. The optical seeker head according to claim 1, characterized in that: The cone coefficient of the fairing is -0.5 to -0.

8.

4. The optical seeker head according to claim 1, characterized in that: The wide-angle optical system includes the middle portion of the fairing; the telephoto optical system includes the edge portion of the fairing.

5. The optical seeker head according to claim 1, characterized in that: The fairing is made of broad-spectrum zinc sulfide or germanium.

6. The optical seeker head according to claim 1, characterized in that: The distance between the principal surfaces of the wide-angle optical system and the telephoto optical system is greater than 500mm.

7. The optical seeker head according to claim 6, characterized in that: The wide-angle optical system has a full field of view of ≥30°.

8. The optical seeker head according to claim 6, characterized in that: The full field of view of the telephoto optical system is ≥3°.

9. The optical seeker head according to claim 1, characterized in that: The first and second detectors are uncooled infrared focal plane detectors.

10. The optical seeker head according to claim 1, characterized in that: An aberration correction component is provided between the ellipsoidal fairing and the transmission lens assembly.

11. The optical seeker head according to claim 10, characterized in that: The aberration correction component is an aspherical lens.

Images