Star target simulator optical system based on projection technology

Abstract

The application discloses a star target simulator optical system based on projection technology, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a star map display device arranged in the order of the object side direction and arranged on the same optical axis; the first lens is a positive lens, the second lens is a negative lens, the third lens is a negative lens, the third lens and the second lens form a cemented lens group, the fourth lens is a positive lens, the fifth lens is a negative lens, the sixth lens is a positive lens, the sixth lens and the fifth lens form a cemented lens group, the seventh lens is a negative lens, and the eighth lens is a positive lens; the light emitted by the star map display device illuminated by a light source is emitted after sequentially passing through the eighth lens, the seventh lens, the sixth lens, the fifth lens, the fourth lens, the third lens, the second lens and the first lens. The application can realize high-precision imaging of star points on a fixed plane at a fixed distance.

Description

Technical Field

[0001] This invention relates to the field of ground calibration technology for star cameras, and more specifically to an optical system for a star target simulator based on projection technology. Background Technology

[0002] A star camera is a high-precision attitude measurement device that uses star imagery for navigation and positioning. It requires calibration before deployment. The star target simulator, a crucial component for ground calibration of the star camera, mainly consists of an optical system, a star map display device, a light source, interface drive circuitry, and a housing. Among these, the optical system is the most critical component, primarily used to simulate star points for imaging.

[0003] In current technology, optical systems for stellar target simulators all employ collimated imaging to image star points. However, this imaging method requires the stellar target simulator and the star camera to be coaxially aligned when calibrating, thus placing high demands on their field of view, coaxiality, and energy utilization; otherwise, the calibration accuracy will decrease. Summary of the Invention

[0004] To address the issue that traditional star target simulators suffer from reduced calibration accuracy due to factors such as coaxiality when calibrating star cameras, this invention provides an optical system for a star target simulator based on projection technology. This system enables high-precision imaging of star points on a fixed plane at a fixed distance, allowing the star camera to extract star points and complete calibration by capturing star images.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] An optical system for a star target simulator based on projection technology includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged coaxially from the object side, as well as a star map display device. The first lens is a positive lens, the second lens is a negative lens, the third lens is a negative lens, and the third lens and the second lens form a cemented lens group. The fourth lens is a positive lens, the fifth lens is a negative lens, the sixth lens is a positive lens, and the sixth lens and the fifth lens form a cemented lens group. The seventh lens is a negative lens, and the eighth lens is a positive lens. Light emitted by the star map display device, which is illuminated by a light source, passes through the eighth lens, the seventh lens, the sixth lens, the fifth lens, the fourth lens, the third lens, the second lens, and the first lens in sequence before exiting.

[0007] Furthermore, the first lens is made of H-ZK9B glass; the second lens is made of H-ZK50 glass; the third lens is made of F3 glass; the fourth lens is made of F3 glass; the fifth lens is made of F3 glass; the sixth lens is made of H-ZK50 glass; the seventh lens is made of H-ZK50 glass; and the eighth lens is made of H-ZK9A glass.

[0008] Preferably, the distance between the second lens and the first lens is 4.504 mm; the distance between the fourth lens and the third lens is 6 mm; the distance between the fifth lens and the fourth lens is 2.560 mm; the distance between the seventh lens and the sixth lens is 3 mm; and the distance between the eighth lens and the seventh lens is 2.295 mm.

[0009] Preferably, the first lens has a thickness of 4.243 mm, an incident surface radius of curvature of 34.871 mm, and an exit surface radius of curvature of -1438.873 mm; the second lens has a thickness of 5.802 mm, an incident surface radius of curvature of 13.059 mm, and an exit surface radius of curvature of 8.233 mm; the third lens has a thickness of 1.499 mm, an incident surface radius of curvature of 8.233 mm, and an exit surface radius of curvature of 6.765 mm; and the fourth lens has a thickness of 0.499 mm, an incident surface radius of curvature of -9.337 mm, and an exit surface radius of curvature of -9.22 mm. The thickness of the fifth lens is 1 mm; the thickness of the sixth lens is 2.051 mm, the radius of curvature of the incident surface of the fifth lens is -12.661 mm, and the radius of curvature of the exit surface of the fifth lens is 6.761 mm; the thickness of the sixth lens is 7.487 mm, the radius of curvature of the incident surface of the sixth lens is 6.761 mm, and the radius of curvature of the exit surface of the sixth lens is -12.8544 mm; the thickness of the seventh lens is 5.56 mm, the radius of curvature of the incident surface of the seventh lens is 38.863 mm, and the radius of curvature of the exit surface of the seventh lens is 12.494 mm; the thickness of the eighth lens is 4.701 mm, the radius of curvature of the incident surface of the eighth lens is 16.479 mm, and the radius of curvature of the exit surface of the eighth lens is -23.046 mm.

[0010] Furthermore, it also includes an aperture stop, which is positioned between the third lens and the fourth lens.

[0011] Preferably, the aperture stop is 5.045 mm apart from the third lens and 0.955 mm apart from the fourth lens.

[0012] Furthermore, it also includes a total internal reflection prism, which is disposed after the eighth lens. The light emitted by the star map display device illuminated by the light source enters the eighth lens after passing through the total internal reflection prism.

[0013] Preferably, the total reflection prism is spaced 2mm from the eighth lens, and the total reflection prism has a thickness of 20mm.

[0014] Preferably, the star map display device is spaced 4.591 mm from the total internal reflection prism.

[0015] Furthermore, the star map display device is a DMD display device used for dynamic display of the star map.

[0016] The present invention has the following beneficial effects:

[0017] This invention provides an optical system for a stellar target simulator based on projection technology. It changes the traditional collimation and imaging method of stellar target simulators, enabling high-precision imaging of star points on a fixed plane at a fixed distance. Therefore, the star camera can be calibrated by capturing star images, avoiding the influence of coaxiality and other factors that affect calibration when the stellar target simulator and star camera are coaxially docked, thus effectively improving calibration accuracy. Attached Figure Description

[0018] Figure 1 A schematic diagram of the structure of an optical system for a star target simulator based on projection technology provided in an embodiment of the present invention;

[0019] In the picture:

[0020] 1-First lens; 2-Second lens; 3-Third lens; 4-Fourth lens; 5-Fifth lens; 6-Sixth lens; 7-Seventh lens; 8-Eighth lens; 9-Total internal reflection prism; 10-Star chart display device; 11-Aperture;

[0021] Figure 2 A schematic diagram of the optical path of a star target simulator optical system based on projection technology is provided in an embodiment of the present invention;

[0022] Figure 3 An MTF curve of an optical system for a star target simulator based on projection technology provided in an embodiment of the present invention;

[0023] Figure 4 This is a field curvature distortion diagram of an optical system for a star target simulator based on projection technology, provided as an embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. It should be noted that similar or identical elements are referred to by the same reference numerals in the drawings or description.

[0025] like Figure 1As shown, the optical system of a star target simulator based on projection technology of the present invention includes a first lens 1, a second lens 2, a third lens 3, an aperture 11, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a total reflection prism 9, and a star display device 10 arranged sequentially from the object side direction; the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the total reflection prism 9, and the star display device 10 share the same optical axis.

[0026] Specifically, the first lens 1 is a positive lens, made of H-ZK9B glass, which is crown glass. The second lens 2 is a negative lens, made of H-ZK50 glass, which is also crown glass. The third lens 3 is a negative lens, made of F3 glass, which is flint glass. The fourth lens 4 is a positive lens, also made of F3 glass, which is flint glass. The fifth lens 5 is a negative lens, also made of F3 glass, which is flint glass. The sixth lens 6 is a positive lens, made of H-ZK50 glass, which is also crown glass. The seventh lens 7 is a negative lens, also made of H-ZK50 glass, which is also crown glass. The eighth lens 8 is a positive lens, made of H-ZK9A glass, which is also crown glass.

[0027] Specifically, the total internal reflection prism 9 is used to separate the imaging beam from the non-imaging beam, reducing the impact of stray light on the imaging of the optical system.

[0028] Specifically, the star map display device 10 is used for dynamic display of star maps and can be a DMD display device.

[0029] like Figure 2 The diagram shows the light propagation path of the optical system of the star simulator based on projection technology of the present invention. The light emitted by the star map display device 10, which is lit by the light source, passes sequentially through the total internal reflection prism 9, the eighth lens 8, the seventh lens 7, the sixth lens 6, the fifth lens 5, the fourth lens 4, the aperture 11, the third lens 3, the second lens 2, and the first lens 1 before exiting.

[0030] This embodiment provides an optical system for a stellar target simulator based on projection technology. By designing and optimizing lens parameters and lens spacing, an optical system with low distortion and high imaging quality is obtained. This optical system includes cemented doublet lenses and meniscus lenses, which can correct spherical aberration and chromatic aberration. Simultaneously, the use of cemented doublet lenses reduces the interface between air and glass, thereby reducing light loss and increasing image brightness. This projection-based optical system for a stellar target simulator achieves high-precision imaging of star points on a fixed plane at a fixed distance, breaking away from the collimated imaging method of traditional stellar target simulator optical systems. The star camera can be calibrated by capturing star images, avoiding interference from factors such as coaxiality during star camera calibration by the stellar target simulator, thus improving calibration accuracy.

[0031] In this embodiment, the parameters of each lens in the optical system of the star target simulator based on projection technology can be specifically set according to the actual imaging accuracy requirements. This embodiment provides a set of preferred parameters that can achieve high imaging accuracy, but is not limited to this embodiment.

[0032] In this embodiment, the thickness of the first lens 1 is 4.243 mm, the radius of curvature of the incident surface of the first lens 1 is 34.871 mm, and the radius of curvature of the exit surface of the first lens 1 is -1438.873 mm.

[0033] In this embodiment, the distance between the second lens 2 and the first lens 1 is 4.504 mm, the thickness of the second lens 2 is 5.802 mm, the radius of curvature of the incident surface of the second lens 2 is 13.059 mm, and the radius of curvature of the exit surface of the second lens 2 is 8.233 mm.

[0034] In this embodiment, the third lens 3 and the second lens 2 form a cemented lens group. The thickness of the third lens 3 is 1.499 mm, the radius of curvature of the incident surface of the third lens 3 is 8.233 mm, and the radius of curvature of the exit surface of the third lens 3 is 6.765 mm.

[0035] In this embodiment, the distance between the fourth lens 4 and the third lens 3 is 6mm, the thickness of the fourth lens 4 is 0.499mm, the radius of curvature of the incident surface of the fourth lens 4 is -9.337mm, and the radius of curvature of the exit surface of the fourth lens 4 is -9.221mm.

[0036] In this embodiment, the distance between the fifth lens 5 and the fourth lens 4 is 2.560 mm, the thickness of the fifth lens 5 is 2.051 mm, the radius of curvature of the incident surface of the fifth lens 5 is -12.661 mm, and the radius of curvature of the exit surface of the fifth lens 5 is 6.761 mm.

[0037] In this embodiment, the sixth lens 6 and the fifth lens 5 form a cemented lens group. The thickness of the sixth lens 6 is 7.487 mm, the radius of curvature of the incident surface of the sixth lens 6 is 6.761 mm, and the radius of curvature of the exit surface of the sixth lens 6 is -12.8544 mm.

[0038] In this embodiment, the interval between the seventh lens 7 and the sixth lens 6 is 3mm, the thickness of the seventh lens 7 is 5.56mm, the radius of curvature of the incident surface of the seventh lens 7 is 38.863mm, and the radius of curvature of the exit surface of the seventh lens 7 is 12.494mm.

[0039] In this embodiment, the distance between the eighth lens 8 and the seventh lens 7 is 2.295 mm, the thickness of the eighth lens 8 is 4.701 mm, the radius of curvature of the incident surface of the eighth lens 8 is 16.479 mm, and the radius of curvature of the exit surface of the eighth lens 8 is -23.046 mm.

[0040] In this embodiment, the aperture stop 11 is disposed between the third lens 3 and the fourth lens 4. The aperture stop 11 is 5.045 mm away from the third lens 3 and 0.955 mm away from the fourth lens 4.

[0041] In this embodiment, the total internal reflection prism 9 is disposed after the eighth lens 8, the total internal reflection prism 9 is 2mm apart from the eighth lens 8, and the thickness of the total internal reflection prism is 20mm.

[0042] In this embodiment, the star map display device 10 is disposed after the total internal reflection prism 9, and the star map display device 10 is spaced 4.591 mm from the total internal reflection prism 9. The star map display device 10 is a DMD display device.

[0043] Figure 3 and Figure 4 The figures show the MTF curve and field curvature distortion of the star simulator optical system based on projection technology according to this invention. The MTF value is around 0.7 at the spatial cutoff frequency of 65.8 lp / mm, and the maximum distortion across the entire field of view is 0.0289%. This indicates that the aforementioned star simulator optical system based on projection technology has good imaging quality.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An optical system for a stellar target simulator based on projection technology, characterized in that, The system includes a first lens, a second lens, a third lens, an aperture stop, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a total internal reflection prism, and a star map display device, arranged coaxially from the object side. The first lens is a positive lens, the second lens is a negative lens, the third lens is a negative lens, and the third lens and the second lens form a cemented lens group. The fourth lens is a positive lens, the fifth lens is a negative lens, the sixth lens is a positive lens, and the sixth lens and the fifth lens form a cemented lens group. The seventh lens is a negative lens, and the eighth lens is a positive lens. The light emitted by the star map display device, which is illuminated by a light source, passes through the total internal reflection prism, the eighth lens, the seventh lens, the sixth lens, the fifth lens, the fourth lens, the third lens, the second lens, and the first lens in sequence before exiting. The first lens has a thickness of 4.243 mm, an incident surface radius of curvature of 34.871 mm, and an exit surface radius of curvature of -1438.873 mm; the second lens has a thickness of 5.802 mm, an incident surface radius of curvature of 13.059 mm, and an exit surface radius of curvature of 8.233 mm; the third lens has a thickness of 1.499 mm, an incident surface radius of curvature of 8.233 mm, and an exit surface radius of curvature of 6.765 mm; the fourth lens has a thickness of 0.499 mm, an incident surface radius of curvature of -9.337 mm, and an exit surface radius of curvature of -9.221 mm. The thickness of the fifth lens is 2.051 mm, the radius of curvature of its incident surface is -12.661 mm, and the radius of curvature of its exit surface is 6.761 mm; the thickness of the sixth lens is 7.487 mm, the radius of curvature of its incident surface is 6.761 mm, and the radius of curvature of its exit surface is -12.8544 mm; the thickness of the seventh lens is 5.56 mm, the radius of curvature of its incident surface is 38.863 mm, and the radius of curvature of its exit surface is 12.494 mm; the thickness of the eighth lens is 4.701 mm, the radius of curvature of its incident surface is 16.479 mm, and the radius of curvature of its exit surface is -23.046 mm.

2. The optical system for a stellar target simulator based on projection technology as described in claim 1, characterized in that, The first lens is made of H-ZK9B glass; the second lens is made of H-ZK50 glass; the third lens is made of F3 glass; the fourth lens is made of F3 glass; the fifth lens is made of F3 glass; the sixth lens is made of H-ZK50 glass; the seventh lens is made of H-ZK50 glass; and the eighth lens is made of H-ZK9A glass.

3. The optical system for a stellar target simulator based on projection technology as described in claim 1, characterized in that, The second lens is 4.504 mm apart from the first lens; the third lens and the second lens form a cemented lens group; the fourth lens is 6 mm apart from the third lens; the fifth lens is 2.560 mm apart from the fourth lens; the seventh lens is 3 mm apart from the sixth lens; and the eighth lens is 2.295 mm apart from the seventh lens.

4. The optical system for a stellar target simulator based on projection technology as described in claim 1, characterized in that, The aperture is 5.045 mm from the third lens and 0.955 mm from the fourth lens.

5. The optical system for a stellar target simulator based on projection technology as described in claim 1, characterized in that, The total reflection prism is 2mm apart from the eighth lens, and the total reflection prism is 20mm thick.

6. The optical system for a stellar target simulator based on projection technology as described in claim 1, characterized in that, The star map display device is 4.591 mm away from the total reflection prism.

7. The optical system for a stellar target simulator based on projection technology as described in claim 1, characterized in that, The star map display device is a DMD display device used for dynamic display of star maps.

Images