Short-wave infrared star sensor based on FPGA (Field Programmable Gate Array)

Abstract

The utility model provides a short-wave infrared star sensor based on an FPGA (Field Programmable Gate Array). The short-wave infrared star sensor comprises a lens and a camera, a detector and a circuit board are arranged in the camera; the camera is provided with a round hole at the position where the lens is installed, the inside of the round hole directly faces the focal plane of the detector, the outside of the round hole directly faces the lens, and the focal plane of the detector is located on the imaging focal plane of the lens; the detector is fixed on the circuit board and is a short-wave infrared light detector; the circuit board is fixed on the camera shell; an ADC is carried on the circuit board and is used for collecting signals of the detector; the circuit board is further provided with an FPGA for communication, control and algorithm processing. According to the utility model, through long-time exposure of the short-wave infrared camera, the capability of observing fixed stars such as low-brightness stars is improved, further the effectiveness of acquiring attitude information under any spatial orientation is greatly improved, and the device has the characteristics of simple structure, small size, light weight, low manufacturing cost, low power consumption, interference resistance and radiation resistance; the device is especially suitable for being used on a near-earth small satellite platform.

Description

Technical Field

[0001] The utility model relates to the technical field of space optical remote sensing, in particular to a short-wave infrared star sensor based on FPGA. Background Art

[0002] In the field of aerospace technology, a star sensor is a type of optical sensor that determines the attitude of a spacecraft by measuring the angular distance of stars through star images. A star sensor generally consists of an optical system, a detector circuit, star map recognition, and attitude calculation software.

[0003] Current star sensors generally use visible light detectors for stellar space image detection. They have a relatively complex structure, high cost, and high power consumption, and are not suitable for small satellite platforms.

[0004] In view of this, it is necessary to propose a new star sensor suitable for small satellite platforms. Utility Model Content

[0005] In order to solve the above problems, the utility model proposes a short-wave infrared star sensor based on FPGA, which improves the observation ability of low-brightness stars through long-term exposure of short-wave infrared camera, thereby greatly improving the effectiveness of attitude information acquisition under arbitrary space pointing, and also has the characteristics of simple structure, small size, light weight, low cost, low power consumption, anti-interference and anti-radiation, and is particularly suitable for use on near-Earth small satellite platforms. Suitable for the application of near-Earth small satellite platforms.

[0006] The utility model achieves the above-mentioned purpose through the following technical solutions:

[0007] The utility model proposes a short-wave infrared star sensor based on FPGA, comprising a lens and a camera; a detector and a circuit board are arranged in the camera; a circular hole is opened in the camera at the position where the lens is installed, the inside of the circular hole faces the focal plane of the detector, the outside of the circular hole faces the lens, and the focal plane of the detector is on the imaging focal plane of the lens; the detector is fixed on the circuit board, and the detector is a short-wave infrared light detector; the circuit board is fixed on the camera housing; an ADC is carried on the circuit board for collecting detector signals; and an FPGA is also carried on the circuit board for communication, control and algorithm processing.

[0008] Furthermore, the lens is mounted on the camera via threads, and the relative positions of the lens and the camera can be adjusted; a fixing screw is provided between the lens and the camera for locking the relative positions of the lens and the camera.

[0009] Furthermore, the spectral response range of the short-wave infrared light detector is a short-wave infrared spectrum with a wavelength of 0.9 to 1.6 um.

[0010] Furthermore, the FPGA is a low-power radiation-resistant chip.

[0011] The beneficial effects of the utility model are:

[0012] (1) Compared with the existing visible optical star sensors, the utility model improves the observation capability of low-brightness stars through the long exposure of the short-wave infrared camera, thereby greatly improving the effectiveness of obtaining attitude information under any spatial pointing, with an accuracy of 0.01° to 0.02°;

[0013] (2) The FPGA-based short-wave infrared star sensor of the utility model has the characteristics of simple structure, small size, light weight, low cost, low power consumption, anti-interference and anti-radiation, and is particularly suitable for use on near-Earth small satellite platforms. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of an embodiment of the utility model;

[0015] Figure 2 A circuit diagram of an embodiment of the utility model;

[0016] Figure 3 Schematic diagram of the working process of the embodiment of the present utility model.

[0017] In the figure: 100-lens, 200-camera, 201-detector, 202-circuit board. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0021] In the description of the present utility model, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the utility model product is usually placed when in use, or are directions or positional relationships that are usually understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present utility model.

[0022] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0023] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] The specific implementation of the utility model is described in detail below in conjunction with the accompanying drawings.

[0025] like Figure 1 As shown, the utility model proposes an embodiment of a short-wave infrared star sensor based on FPGA, including a lens 100 and a camera 200. A detector 201 and a circuit board 202 are arranged in the camera 200. The camera 200 is provided with a circular hole at the position where the lens 100 is installed, the inside of the circular hole faces the focal plane of the detector 201, and the outside of the circular hole faces the lens 100, and the focal plane of the detector 201 is on the imaging focal plane of the lens 100; the detector 201 is fixed on the circuit board 202, and the detector 201 is a short-wave infrared light detector; the circuit board 202 is fixed on the housing of the camera 200; the circuit board 202 is equipped with an ADC (analog-to-digital converter) for collecting detector signals; the circuit board 202 is also equipped with an FPGA (programmable logic array) for communication, control and algorithm processing.

[0026] In a specific implementation, the algorithms implemented on the FPGA include an image preprocessing algorithm, a star extraction algorithm, a star coordinate algorithm, a star focal length algorithm, and a star sensor attitude algorithm.

[0027] In some embodiments, the lens 100 is mounted on the camera 200 via threads, which plays a role in fixing and fine-tuning the focal length, and the relative position of the lens 100 and the camera 200 can be adjusted; a fastening screw is provided between the lens 100 and the camera 200 to lock the relative position of the lens and the camera.

[0028] In some embodiments, the spectral response range of the short-wave infrared light detector is the short-wave infrared spectrum with a wavelength of 0.9 to 1.6 um.

[0029] In some embodiments, the FPGA is a low power radiation resistant chip. The short wave infrared star sensor control and algorithm of the embodiment of the utility model is implemented in a low power radiation resistant FPGA on a circuit board.

[0030] The circuit structure of the embodiment of the utility model is as follows Figure 2 As shown, the image signal collected by the detector 201 is collected to the FPGA through the ADC. The FPGA is responsible for image algorithm processing, detector control and remote control and telemetry communication.

[0031] The working principle of the embodiment of the utility model is as follows Figure 3 As shown in the figure, the original star map is obtained through image acquisition, and after image processing, the star map is recognized, and finally the attitude calculation is performed. The above-mentioned image processing includes image bad pixel removal, image non-uniformity correction, image enhancement, image noise reduction, image segmentation and image star point extraction. Star map recognition calculates the star angle distance by pressing the pixel coordinates of the star points, and combines the ephemeris to search the star library to obtain the navigation star map. The attitude calculation solves the attitude of the star sensor through the navigation star coordinates, ephemeris and pixel coordinates.

[0032] The embodiment of the utility model adopts a short-wave infrared camera. Compared with a visible light camera, a short-wave infrared camera has a natural advantage in observing stars: for the observation of distant stars, long exposure is required, and short-wave infrared detectors have a higher full-well capacity than detectors in the visible light band, which improves the exposure and star measurement limit; at the same time, in the infrared band, the number of observable stars is much higher than the number of observable stars under visible light, and the higher surface density can significantly increase the sky coverage; in addition, the short-wave infrared camera has good penetrating imaging capabilities and can avoid the impact of the thin atmosphere on observation. Compared with existing visible optical star sensors, the short-wave infrared star sensor of the utility model improves the observation capability of low-brightness stars through the long exposure of the short-wave infrared camera, thereby greatly improving the effectiveness of obtaining attitude information under any spatial pointing, with an accuracy of 0.01° to 0.02°

[0033] The short-wave infrared star sensor based on FPGA in the embodiment of the utility model has the characteristics of simple structure, small size, light weight, low cost, low power consumption, anti-interference and anti-radiation, and is particularly suitable for use on near-Earth small satellite platforms.

[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A short-wave infrared star sensor based on FPGA, characterized in that: The invention comprises a lens and a camera; a detector and a circuit board are arranged in the camera; a circular hole is provided in the camera at the position where the lens is installed, the inside of the circular hole faces the focal plane of the detector, the outside of the circular hole faces the lens, and the focal plane of the detector is on the imaging focal plane of the lens; the detector is fixed on the circuit board, and the detector is a short-wave infrared light detector; the circuit board is fixed on the camera housing; the circuit board is equipped with an ADC for collecting detector signals; the circuit board is also equipped with an FPGA for communication, control and algorithm processing.

2. The short-wave infrared star sensor based on FPGA according to claim 1, characterized in that: The lens is mounted on the camera via threads, and the relative positions of the lens and the camera can be adjusted; a fixing screw is provided between the lens and the camera to lock the relative positions of the lens and the camera.

3. The short-wave infrared star sensor based on FPGA according to claim 1, characterized in that: The spectral response range of the short-wave infrared light detector is a short-wave infrared spectrum with a wavelength of 0.9 to 1.6 um.

4. The short-wave infrared star sensor based on FPGA according to claim 1, characterized in that: The FPGA is a low-power radiation-resistant chip.

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