Research And Manufacturing On High Precision Sun Sensor For Image Stablization System

Among all the stars, the sun is the only one which we can “closely” observe in a long period. From long time ago, human started to observe the sun and never stops. In recent decades, we have made considerable progress in solar observation, and have got a lot scientific knowledge about sunspots, solar magnetic activity, solar wind and other solar phenomena. As human is getting more intersted in solar observation, it has entered the high-resolution and high-precision observation stage. Considering the demand for high-resolution observation, more and more solar observation satellites have been equipped with an independent image stablization system. In the image stabiliazation system, a high-precision sun sensor is responsible for detecting the positon of the sun image. It need to get the positon signal of the sun quickly and accurately, drive the tip-tilt mirror to change the optical path of the telescope, and improve the accuracy of the imaging telescope.In order to meet the needs of image stabilization system, high-precision sun sensor must have a sufficiently low noise perfomance, sufficiently high resolution and high response speed. Aiming at high resolution and low noise, we propose an effective devolopment program of high-precision sun sensor. In reference of existing mature image stabilization system on other solar observation satellites, we select four-quadrant detector(QD) as position sensitive detector in out high-precision sun sensor system. High-precision sun sensor system is consit of two parts: optical system and electronic system. The optical system is consist of a specific focal length(107.97mm) len and a narrowband filter, which can form a sun image on the four-quadrant detector(QD). Through the four-quadrant detector(QD), the optical signal is converted into electronic signal. And after two operational amplifers, an A/D converter and other processsors, the electronic signal is converted into digital signal, which could be stored and using for mathematical operations.In the paper, we propose a series of testing methods after the initial development of the high-precision sun sensor. All the choosing of test instrumens, building of test platform, and writing of test software are included. In the test of electronic system, we find out that the resolution of photocurrent is better than 3.1n A. On the optical test platform, we finished the test of the field of view, which turned out to be better than 95 arcmiute, and angular resolution, which turned out to be 0.15 arcsec at the center of the QD and 0.5arcsec at the edge.