Active Pixel Digital Sun Sensor for Satellites

Abstract

Satellites use sun sensors as a reliable source of attitude determination during sunlit conditions while in orbit around the earth. This work elucidates the design and development of high precision and wide field of view digital sun sensor for space applications. Sun sensor employs active pixel image sensor along with processing techniques of feature extraction and image correlation. Software algorithm exploits the distinctive features of Active Pixel imaging Sensor (APS), in comparison to CCD based image sensor, for computationally efficient algorithm design. Sunlight falling on the sun sensor produces an image of the sun on image sensor. Software algorithm processes this image for noise removal, feature extraction, centroid analysis and sun vector calculations. Digital sun sensor, presented here, achieves 0.018 pixels (3σ) centroid accuracy with 120°×120°field of view.