Hiroyuki KAWANO^*, Haruhiko SHIMOJI, Shoji YOSHIKAWA, Katsumasa MIYATAKE, Kazumori HAMA¹, and Shuji NAKAMURA¹

Mitsubishi Electric Corp., Advanced Technology R&D Center, Amagasaki, Hyogo 661-8661, Japan
¹Institute for Unmanned Space Experiment Free Flyer (USEF), Tokyo 101-0052, Japan

(Received October 1, 2007; Accepted January 8, 2008)

Alignment error of an image sensor relative to the optical axis of a star sensor head and alignment errors between four heads were calculated from pictures taken in an orbital experiment. When comparing the image sensor alignment parameters in the orbital test and a ground test, both values matched well. By determining the relative relationship of the four heads using four pictures taken at the same moment in orbit and uploading the parameters to the star sensor system in orbit, the estimated attitude error was improved from 0.29 to 0.17^°, though the accuracy was limited by the ± 0.2^° determination accuracy of the satellite itself. We estimated the attitude determination accuracy from separation angles between boresights of the four heads, calculated from pattern matching between downloaded pictures and a star catalogue. The estimated accuracy, in terms of potential optical performance, was 0.60 arcmin at 3σ, which is sufficient to satisfy the specification of 1 arcmin.

Key words: star sensor, orbital test, alignment, optical testing

^*E-mail address: Kawano.Hiroyuki@ap.MitsubishiElectric.co.jp