A high dynamic star sensor based on emccd

Abstract

The invention discloses a high dynamic star sensor based on an EMCCD (electron multiplying charge coupled device). The high dynamic star sensor comprises an imaging assembly and a video circuit, wherein the imaging assembly comprises an EMCCD (12), a refrigerator (13), a refrigerator heat-conducting structure (14) and a sealing cavity shell (18), wherein the video circuit comprises an FPGA (field programmable gate array), a high-speed DAC (digital-to-analog converter), a high-voltage drive module, a clock drive module, an image sampling module and a refrigerator drive module; the FPGA is used for outputting a multiplying clock signal with adjustable amplitude and phase to the EMCCD through the high-speed DAC and the high-voltage drive module, and outputting a drive clock signal to the EMCCD through the clock drive module, and outputting a sampling timing sequence signal to the image sampling module; the image sampling module is controlled to collect an analogue image signal output by the EMCCD and convert into a digital image signal and then outputting to the FPGA; the FGGA is used for outputting the refrigerating control quantity to the refrigerator drive module according to the temperature collected by a thermistor; the refrigerator drive module is used for generating corresponding refrigerating current and outputting to the refrigerator. The star sensor disclosed by the invention has the advantages of high detection sensitivity, adjustable signal to noise ratio and high dynamic performance.

Description

technical field [0001] The invention relates to a high dynamic star sensor based on EMCCD (electron multiplication image sensor). Background technique [0002] The star sensor is an optical sensor with a star as the attitude reference source. It does not need a priori attitude and angular velocity information to capture and determine the attitude of the whole sphere autonomously. It has the advantages of high precision, almost no drift, and high reliability. It is a satellite The key attitude measurement component of . [0003] The factors affecting the dynamic performance of star sensors are relatively complex. The current mainstream research plan for high-dynamic star sensors is to comprehensively design indicators such as exposure time, lens aperture, and optical field of view, and to assist with software enhancement and other means to improve the detection of star sensors. capability to improve the dynamic performance of star sensors. However, these methods have certai...

AI Technical Summary

Problems solved by technology

[0013] An image intensifier is added to the front end of the image sensor to improve the detection capability of the star sensor. The image intensifier is generally composed of a photocathode, a microchannel plate (MCP), and a fluorescent screen. In addition, an additional optical relay device (optical fiber / lens) is required. The enhanced image is projected onto the image sensor of the star sensor to achieve the purpose of improving the detection sensitivity. The main disadvantages of this technology are: (a) The imaging process needs to undergo three conversions of photoelectricity, electrooptic and photoelectricity, and there are many imaging links. The noise is large; (b) the coupling loss of the optical relay component between the image intensifier and the image sensor is large, the image transmission quality will decrease, and more components will bring certain reliability problems; (c) the structure, The process is complicated, the maturity of the domestic process is not high, the performance is not stable, and the service life of the ground usually does not exceed 15000h; (d) the image intensifier and optical relay components have inherent low surface uniformity problems, and the surface uniformity is low when used for a long time. Uniformity also changes, thus affecting star sensor measurement accuracy and reliability

[0014] In view of the above-mentioned technical limitations, the current dynamic performance of mainstream star sensors is generally about 2° / s, and the scheme realized by image intensifier can reach about 10° / s, but the accuracy and reliability are slightly worse

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