Acta Photonica Sinica, Volume. 51, Issue 9, 0912003(2022)
An Event-based Method for Extracting Star Points from High Dynamic Star Sensors
Star sensor is a device that relies on measuring the pointing of the navigation star in the spacecraft coordinate system to determine the attitude of the spacecraft, and is the highest precision attitude sensor, whose accuracy can reach the angular second level, with the advantages of no drift, long working life, etc. It is a fundamental and critical device for the survival and performance improvement of spacecraft. It is of strategic importance in space applications such as remote sensing to the earth, deep space exploration and high precision detection. Most of the current star sensors use traditional optical sensors. Conventional star sensors use frame-based imaging modes, such as global exposure and roll-up exposure, which generate a frame of star image within a fixed exposure time (usually 100 ms). However, under the high dynamic conditions of large spacecraft maneuvers, this imaging mode produces motion blur and "star point trailing" effect, which, together with the noise effect, significantly reduces the signal-to-noise ratio of the star map, resulting in lower accuracy or even failure of star point extraction, and severely limits the dynamic performance of the star sensor. Star point center of mass extraction is a crucial part of the star sensor, which is directly related to the final attitude measurement accuracy of the star sensor. The sensitive navigation stars are long-range targets, and their orientations in the celestial coordinate system are high-precision astronomical observations with milliarcsecond accuracy and almost constant, so the final attitude accuracy of the star sensor depends on the extraction accuracy of the star point masses in the digital images. Therefore, the accuracy of the final solution of the star sensor depends mainly on the extraction accuracy of the star point center in the digital image. In the traditional star sensor, the average gray value of the whole image is used as the background noise gray value, and then the background noise is subtracted from the star point region gray value to obtain the corrected star point, and finally the exact center of the star point is calculated by the gray scale center method. In this paper, we propose an event-based star point extraction method for high-dynamics star point sensors to address the problem that the accuracy of star point center extraction decreases or even fails under high dynamics (≥3
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Sikang ZENG, Rujin ZHAO, Yuebo MA, Zifa ZHU, Yuping TANG, Zijian ZHU. An Event-based Method for Extracting Star Points from High Dynamic Star Sensors[J]. Acta Photonica Sinica, 2022, 51(9): 0912003
Category: Instrumentation, Measurement and Metrology
Received: Jan. 25, 2022
Accepted: Apr. 29, 2022
Published Online: Oct. 26, 2022
The Author Email: ZENG Sikang (zengsikang19@mails.ucas.ac.cn)