Optimized design of sun sensor and centroid algorithm for small satellite mission

One of the most important components of attitude determination system for small satellite is sun sensor. In this paper design, development and calibration of 2-axis digital sun sensor using linear Photodiodes array is presented. Senor design comprises two linear arrays mounted orthogonally to provide Sun aspect angle in two axes. The Sun aspect angle is determined by the centroid based technique and implemented using FPGA. The proposed centroid algorithm is capable of obtaining the position of the centroid to an accuracy of sub pixel level which is desirable in such designs. A method of calibration using natural sun light is also presented. Commercial grade components were used which have resulted in development of low cost, light weight and power efficient sensor.