抄録
Tohoku University is now finishing the development of its second 50-kg class Earth observation microsatellite RISING-2. RISING-2 is equipped with four camera systems with eight different imaging sensors, including a 5-m ground resolution cassegrain mirror telescope with three fixed wavelength filters in red, green, and blue, as well as a liquid crystal tunable filter. RISING-2 aims to achieve agile high resolution multi-spectral Earth observations. For this mission, Tohoku University has been developing a precise and agile attitude control system including multiple sensors and actuators. The pointing error is required to be less than 0.1 deg and the pointing knowledge shall be better than 0.06 deg. The designed star sensor is based on CCD image sensor which has a flight heritage by the university's first satellite RISING. This system utilizes a pyramid algorithm for secure constellation identification and works with a maximum update frequency of 2 Hz. Its availability is also very high in terms of the satellite's operating angular velocity. In this paper, the system integration of the star sensor as well as the results of its ground based performance evaluation is described in detail.
