An APS based Autonomous Star Tracker

This paper proposes an APS based Autonomous Star Tracker (AAST). The image sensor used in the star tracker is CMOS Active Pixel Sensor (APS). APS has many advantages to construct small, light weight, power saving and inexpensive star tracker for microsatellite application where power consumption and mass are critical. With the special design of optics, electronics and software, the proposed AAST can performance image sensing and process, star identification and attitude estimation all by itself and can output attitude data directly. The design concept of lower sensitivity with wider field of view enables the star tracker to perform whole sky independent star pattern recognition in the lost-in-space circumstance. These autonomous and independent features provide great convenience for the proposed star tracker to be applied in the future space mission. The total mass and power consumption of the AAST prototype are less than 10008 and 5W. The estimated accuracy is about 5" in the cross boresight direction and about 30" in the boresight direction.