An airborne infrared star sensor

Abstract

The application discloses an airborne infrared star sensor, and belongs to an astronomical measuring instrument used in the field of aircraft attitude control and autonomous navigation. The airborne infrared star sensor comprises a star sensor box unit, an optical assembly unit, a light shield, a power supply unit, an information processing unit, a detector driving and signal reading unit and a star infrared radiation detection unit. The power supply unit is used for converting a primary power voltage into a voltage required by internal circuit operation; the optical assembly unit is used for allowing star infrared radiation to enter the star infrared radiation detection unit; the star infrared radiation detection unit is used for receiving infrared radiation from stars; the detector driving and signal reading unit is used for converting optical signals detected by the star infrared radiation detection unit into electrical signals and inputting the electrical signals into the information processing unit; and the information processing unit is used for processing images output by the detector driving and signal reading unit, extracting star point information and obtaining aircraft attitude through calculation. The application provides technical support for an airborne astronomical autonomous navigation system.

Description

Technical Field

[0001] This invention relates to astronomical measurement instruments used in the field of aircraft attitude control and autonomous navigation, and particularly to an airborne infrared star sensor. Background Technology

[0002] Infrared star sensors are important attitude sensing instruments for aircraft. They can be used to measure the attitude signals of aircraft and, together with instruments such as gyroscopes and altimeters, can be used for astronomical autonomous navigation of aircraft.

[0003] Currently, satellite star sensors generally operate in the visible light band, while airborne and missile-borne star sensors are generally infrared. Airborne and missile-borne star sensors require the cooperation of a servo system to achieve attitude measurement and navigation of the spacecraft, and infrared star sensors can only track one infrared star.

[0004] An infrared star sensor typically consists of an infrared optical system, a bandpass filter, an infrared detector, and a circuit system.

[0005] When infrared star sensors are used in airborne or missile-borne applications, their ability to observe stars is insufficient due to the strong atmospheric background, especially during the day. Therefore, the field of view of the optical system of infrared star sensors is relatively small, generally around 1.5°. The same optical field of view can generally only track one infrared star, and a servo mechanism is required to track the observed infrared star. Due to the servo mechanism, the navigation system is characterized by large size, high power consumption, heavy weight, slow dynamic response, and low measurement accuracy. Summary of the Invention

[0006] To address the above technical problems, this invention provides an airborne infrared star sensor. This invention is based on infrared star detection technology, measures the directional vector of stars within the field of view of the infrared star sensor, and achieves all-weather navigation and positioning through a navigation algorithm. The specific technical solution is as follows:

[0007] An airborne infrared star sensor includes a star sensor housing unit, an optical component unit, a light shield, a power supply unit, an information processing unit, a detector driving and signal reading unit, and a stellar infrared radiation detection unit.

[0008] The power supply unit is used to convert the primary power supply voltage into the voltage required for the internal circuit to operate; the optical component unit is used to allow stellar infrared radiation to enter the stellar infrared radiation detection unit; the stellar infrared radiation detection unit is used to receive infrared radiation from the star; the detector drive and signal reading unit is used to convert the light signal detected by the stellar infrared radiation detection unit into an electrical signal and input it to the information processing unit; the information processing unit is used to process the image output by the detector drive and signal reading unit, extract star point information, and calculate the spacecraft attitude.

[0009] Furthermore, the star-sensor housing unit adopts an integrated design, with the power supply unit installed at its bottom and the information processing unit installed on its side wall; the optical component unit is inserted into the star-sensor housing unit and fixedly installed on the upper part of the star-sensor housing unit; the stellar infrared radiation detection unit is installed at the focal plane position at the rear end of the optical component unit, with its detection window facing the optical component unit; the detector drive and signal reading unit is installed on the back of the stellar infrared radiation detection unit; and the light shield is installed at the front end of the optical component unit.

[0010] Furthermore, the optical component unit is an infrared optical system, which adopts an 8-lens structure, including 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, and is fixed in the lens barrel respectively.

[0011] Furthermore, the first lens is installed in the mirror chamber and a pressure ring, the second lens is installed in the mirror chamber and a spacer ring, the third lens is installed in the mirror chamber and a spacer ring, the fourth lens is installed in the mirror chamber and a spacer ring and a pressure ring, the fifth lens is installed in the mirror chamber and a spacer ring, the sixth lens is installed in the mirror chamber and a spacer ring and a pressure ring, the seventh lens is installed in the mirror chamber and a spacer ring, and the eighth lens is installed in the mirror chamber and a spacer ring and a pressure ring.

[0012] Furthermore, the stellar infrared radiation enters the stellar infrared radiation detection unit through the eighth lens, seventh lens, sixth lens, fifth lens, fourth lens, third lens, second lens and first lens in the optical component unit for infrared radiation imaging.

[0013] Furthermore, the eight lenses of the optical component unit are arranged sequentially from the front end to the rear end, and there is a spacing between each lens; wherein, the spacing between the first lens and the second lens is 42.85mm, the spacing between the second lens and the third lens is 8.12mm, the spacing between the third lens and the fourth lens is 2.49mm, the spacing between the fourth lens and the fifth lens is 5.62mm, the spacing between the fifth lens and the sixth lens is 5.00mm, the spacing between the sixth lens and the seventh lens is 4.02mm, and the spacing between the seventh lens and the eighth lens is 1.20mm.

[0014] Furthermore, the distance between the photosensitive surface of the stellar infrared radiation detection unit and the optical rear end of the optical component unit is 1.78 mm.

[0015] Furthermore, the detector drive and signal reading unit is connected to the back of the stellar infrared radiation detection unit and is used to perform photoelectric conversion on the infrared radiation energy received by the stellar infrared radiation detection unit.

[0016] Furthermore, the first lens is a concave-planar lens, with its object-facing side being concave and its image-facing side being planar; the second lens is a convex-convex lens, with its object-facing side being convex and its image-facing side being convex; the third lens is a concave-concave lens, with its object-facing side being concave and its image-facing side being concave; the fourth lens is a convex-convex lens, with its object-facing side being convex and its image-facing side being convex; the fifth lens is a concave-concave lens, with its object-facing side being concave and its image-facing side being concave; the sixth lens is a convex-convex lens, with its object-facing side being convex and its image-facing side being convex; the seventh lens is a convex-concave lens, with its object-facing side being convex and its image-facing side being concave; and the eighth lens is a convex-concave lens, with its object-facing side being convex and its image-facing side being concave.

[0017] Furthermore, the first, fifth, and sixth lenses are made of F6 material, the second lens is made of SF1 material, and the third, fourth, seventh, and eighth lenses are made of SK16 material.

[0018] This invention offers the following advantages: It enables infrared star sensors to observe infrared stars in all-weather scenarios above 6km within the atmosphere, providing technical support for the engineering application of airborne astronomical autonomous navigation systems. It can be applied to various types of manned aircraft, wingmen, high-altitude long-endurance UAVs, and near-space vehicles. In scenarios where "satellite navigation denial is the norm and strong electromagnetic countermeasures are present throughout," it provides high-precision autonomous navigation support for aircraft.

[0019] The optical component unit of this invention adopts an 8-lens structure. Each lens is arranged sequentially from the front end to the rear end along the optical axis and fixed in the lens tube. Through the combination of concave-flat, convex-convex, concave-concave, convex-convex, concave-concave, convex-convex, convex-concave, convex-concave, and convex-concave surface types of the first to eighth lenses, the optical power is reasonably allocated, and aberrations such as spherical aberration, coma, astigmatism, field curvature, and chromatic aberration in infrared imaging are effectively corrected. This allows the infrared radiation of stars to be focused at the focal plane of the stellar infrared radiation detection unit with high quality, thereby improving the star point imaging quality and star point extraction accuracy, and providing a foundation for high-precision attitude calculation.

[0020] This invention limits the spacing between each lens: the distance between the first and second lenses is 42.85 mm, the distance between the second and third lenses is 8.12 mm, the distance between the third and fourth lenses is 2.49 mm, the distance between the fourth and fifth lenses is 5.62 mm, the distance between the fifth and sixth lenses is 5.00 mm, the distance between the sixth and seventh lenses is 4.02 mm, and the distance between the seventh and eighth lenses is 1.20 mm. This allows the optical component unit to achieve good imaging performance and a reasonable back working distance in the 1.4–1.7 μm infrared band. At the same time, it keeps the distance from the detector photosensitive surface to the optical back end at 1.78 mm, which facilitates the focal plane installation and detection window alignment of the stellar infrared radiation detection unit, and improves the optomechanical integration and assembly consistency.

[0021] This invention inserts the optical component unit into the star-sensor housing unit and fixes it to the upper part of the chassis. The stellar infrared radiation detection unit is installed at the focal plane position at the rear of the optical component unit. The detector drive and signal readout unit is installed on the back of the stellar infrared radiation detection unit, and the light shield is installed at the front of the optical component unit, forming an integrated optomechanical and electronic structure. This configuration allows for the compact integration of the optical system, detection system, and circuit system within a limited space, enabling the observation of infrared stars without additional servo mechanisms. This reduces size, power consumption, and weight, while improving dynamic response speed and measurement accuracy, thus meeting the application requirements of airborne platforms for high-precision autonomous navigation of infrared star sensors. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention.

[0023] Figure 2 This is a schematic diagram of the front cross-sectional structure of the present invention.

[0024] Figure 3 This is a cross-sectional view of the optical component unit in this invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other. To achieve the above objectives, this invention adopts the following technical solution.

[0026] like Figure 1 , Figure 2As shown, the infrared star sensor for airborne attitude determination within the atmosphere of this invention includes a star sensor housing unit 1, an optical component unit 2, a light shield 3, a power supply unit 4, an information processing unit 5, a detector drive and signal readout unit 6, and a stellar infrared radiation detection unit 7. An external power supply powers the infrared star sensor power supply unit 4, which converts the voltage required for the internal circuitry to operate. Through the optical component unit 2, the stellar infrared radiation detection unit 7 receives infrared radiation from stars. The detector drive and signal readout unit 6 and the information processing unit 5 then perform photoelectric conversion, image processing, star point extraction, and calculation on the infrared radiation energy received by the stellar infrared radiation detection unit 7 to obtain the aircraft's attitude.

[0027] The infrared star sensor adopts an integrated design. The power supply unit 4 is installed at the bottom of the star sensor housing unit 1, and the information processing unit 5 is installed on the side wall of the star sensor housing unit. The optical component unit 2 is inserted into the chassis and fixedly mounted on the upper part of the chassis. The detector drive and signal readout unit 6 is mounted on the back of the stellar infrared radiation detection unit 7, which is located at the rear focal plane of the optical component unit 2, with its detection window facing the optical component unit 2. A light shield 3 is mounted on the front of the optical component unit 2.

[0028] like Figure 3 As shown, the optical component unit 2 is the infrared optical system of the infrared star sensor, adopting an 8-lens structure. The first lens L1 is installed in the mirror chamber S1 and the retaining ring Y1; the second lens L2 is installed in the mirror chamber S2 and the spacer G1; the third lens L3 is installed in the mirror chamber S3 and the spacer G2; the fourth lens L4 is installed in the mirror chamber S3 and the spacer G3 and the retaining rings Y2 and Y3; the fifth lens L5 is installed in the mirror chamber S4 and the spacer G4; the sixth lens L6 is installed in the mirror chamber S4 and the spacer G5 and the retaining rings Y4 and Y5; the seventh lens L7 is installed in the mirror chamber S5 and the spacer G6; and the eighth lens L8 is installed in the mirror chamber S6 and the spacer G7 and the retaining ring Y6, all of which are fixed in the mirror tube T1. Stellar infrared radiation enters the stellar infrared radiation detection unit 7 through the eighth lens L8, the seventh lens L7, the sixth lens L6, the fifth lens L5, the fourth lens L4, the third lens L3, the second lens L2, and the first lens L1 in the optical component unit 2, and is used for infrared radiation imaging.

[0029] The parameters of the eight lenses in optical component unit 2 from front to back are listed in the table below.

[0030]

[0031] Lens spacing: L1 to L2 42.85mm, L2 to L3 8.12mm, L3 to L4 2.49mm, L4 to L5 5.62mm, L5 to L6 5.00mm, L6 to L7 4.02mm, L7 to L8 1.20mm.

[0032] The distance between the photosensitive surface of the detector and the optical back end is 1.78 mm.

[0033] The detector drive and signal reading unit 6 converts the light signal detected by the stellar infrared radiation detection unit 7 into an electrical signal and inputs it into the information processing unit 5.

[0034] The information processing unit 5 processes the image output by the detector driving and signal reading unit 6, extracts star point information, and calculates the attitude of the spacecraft.

[0035] The power supply unit 4 converts the primary power supply voltage input to the infrared star sensor into the voltage required for the internal circuit to operate.

[0036] This infrared star sensor is suitable for spacecraft altitudes of 6km-30km, with a stellar infrared radiation detection unit, operating in the band of 1.4~1.7μm, and an attitude accuracy of not less than 0.001° (1σ).

[0037] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An airborne infrared star sensor, characterized in that, It includes a star sensor housing unit, an optical component unit, a light shield, a power supply unit, an information processing unit, a detector drive and signal readout unit, and a stellar infrared radiation detection unit; The power supply unit is used to convert the primary power supply voltage into the voltage required for the internal circuit to operate; the optical component unit is used to allow stellar infrared radiation to enter the stellar infrared radiation detection unit; the stellar infrared radiation detection unit is used to receive infrared radiation from the star; the detector drive and signal reading unit is used to convert the light signal detected by the stellar infrared radiation detection unit into an electrical signal and input it to the information processing unit; the information processing unit is used to process the image output by the detector drive and signal reading unit, extract star point information, and calculate the spacecraft attitude.

2. The airborne infrared star sensor according to claim 1, characterized in that, The star-sensor housing unit adopts an integrated design, with the power supply unit installed at its bottom and the information processing unit installed on its side wall; the optical component unit is inserted into the star-sensor housing unit and fixedly installed on the upper part of the star-sensor housing unit; the stellar infrared radiation detection unit is installed at the focal plane position at the rear end of the optical component unit, with its detection window facing the optical component unit; the detector drive and signal reading unit is installed on the back of the stellar infrared radiation detection unit; and the light shield is installed at the front end of the optical component unit.

3. The airborne infrared star sensor according to claim 1, characterized in that, The optical component unit is an infrared optical system, which adopts an 8-lens structure, including 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, and is fixed in the lens barrel.

4. An airborne infrared star sensor according to claim 3, characterized in that, The first lens is installed in the mirror chamber and with a pressure ring; the second lens is installed in the mirror chamber and with a spacer ring; the third lens is installed in the mirror chamber and with a spacer ring; the fourth lens is installed in the mirror chamber and with a spacer ring and a pressure ring; the fifth lens is installed in the mirror chamber and with a spacer ring; the sixth lens is installed in the mirror chamber and with a spacer ring and a pressure ring; the seventh lens is installed in the mirror chamber and with a spacer ring; and the eighth lens is installed in the mirror chamber and with a spacer ring and a pressure ring.

5. An airborne infrared star sensor according to claim 3, characterized in that, Stellar infrared radiation enters the stellar infrared radiation detection unit through the eighth, seventh, sixth, fifth, fourth, third, second, and first lenses in the optical component unit for infrared radiation imaging.

6. An airborne infrared star sensor according to claim 3, characterized in that, The optical component unit has eight lenses arranged sequentially from front to rear, with spacing between each lens; the spacing between the first and second lenses is 42.85 mm, between the second and third lenses is 8.12 mm, between the third and fourth lenses is 2.49 mm, between the fourth and fifth lenses is 5.62 mm, between the fifth and sixth lenses is 5.00 mm, between the sixth and seventh lenses is 4.02 mm, and between the seventh and eighth lenses is 1.20 mm.

7. An airborne infrared star sensor according to claim 3, characterized in that, The distance between the photosensitive surface of the stellar infrared radiation detection unit and the optical rear end of the optical component unit is 1.78 mm.

8. An airborne infrared star sensor according to claim 1, characterized in that, The detector drive and signal reading unit is connected to the back of the stellar infrared radiation detection unit and is used to perform photoelectric conversion on the infrared radiation energy received by the stellar infrared radiation detection unit.

9. An airborne infrared star sensor according to claim 3, characterized in that, The first lens is a concave-planar lens, with its object-facing side being concave and its image-facing side being planar; the second lens is a convex-convex lens, with its object-facing side being convex and its image-facing side being convex; the third lens is a concave-concave lens, with its object-facing side being concave and its image-facing side being concave; the fourth lens is a convex-convex lens, with its object-facing side being convex and its image-facing side being convex; the fifth lens is a concave-concave lens, with its object-facing side being concave and its image-facing side being concave; the sixth lens is a convex-convex lens, with its object-facing side being convex and its image-facing side being convex; the seventh lens is a convex-concave lens, with its object-facing side being convex and its image-facing side being concave; and the eighth lens is a convex-concave lens, with its object-facing side being convex and its image-facing side being concave.

10. An airborne infrared star sensor according to claim 9, characterized in that, The first, fifth, and sixth lenses are made of F6 material, the second lens is made of SF1 material, and the third, fourth, seventh, and eighth lenses are made of SK16 material.

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