Attitude stabilization using blurred star images for a nano-astrometry satellite mission

摘要

This research presents a new method to stabilize a 30 kg satellite attitude to a high accuracy using star blurred images. The method is intended to use on the Nano-JASMINE (Nano-Japan Astrometry Satellite Mission for INfrared Exploration) satellite, which is developed at Intelligent Space System Laboratory (ISSL) University of Tokyo in cooperation with National Astronomical Observatory of Japan (NAOJ). The objective of the mission is to measure the three dimensional positions of stars to an accuracy of 1.8 milli-arcsecond (mas). In order to get accurate star position data, Nano-JASMINE should be stabilized to better than 740 mas / 8.8 s accuracy during observation. To achieve the requirement, the satellite must determine the angular velocity to an accuracy of 5 × 10~(-8) rad/s and control angular velocity to an accuracy of 4 × 10~(-7) rad/s. Currently there are not sensors available for a micro-satellite to get accurate attitude information as is required by the mission. To achieve the requirement, the satellite uses star images obtained by a mission telescope. The angular velocity is determined by assessing the quality of a star image based on how blurred it appears. Based on simulation results, the research concludes that the use of star blurred image data to determine and to stabilize attitude is a feasible method for the Nano-JASMINE mission.