著者

SUGIMURA Nobuo HASHIMOTO Tatsuaki KUWAHARA Toshinori SAKAMOTO Yuji YOSHIDA Kazuya SATO Yuki TAKANO Tomohiro

出版者

一般社団法人 日本航空宇宙学会

雑誌

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN

巻号頁・発行日

vol.14, no.30, pp.Pf_97-Pf_103, 2016

被引用文献数

1

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<p>A new star sensor for a microsatellite was developed for accurate and reliable attitude detection. Microsatellite RISING-2, which was launched on May 24, 2014, has raised some issues with regard to the functionality of its star sensor. It is confirmed that white spots caused by space radiation and the stray light of sunshine induce a false detection of the satellite's attitude, which imposes significant limitations on satellite operations. To make improvements, the brightness value of the picture was studied. This paper proposes avoidance algorithms for white spots and stray light. The effects of these algorithms were validated to process the flight data from RISING-2 in a software simulation. The soundness of the star sensor is indicated via attitude detection tests against several star patterns using real flight images taken by RISING-2. Thereafter, avoidance algorithms were integrated in a newly developed processing board. In this board, the avoidance algorithm for white spots was composed using both a hardware logic filter and a software filter. The avoidance algorithm for stray light was expressed using only a software filter. During the programming of these algorithms, the functionality of the satellite's attitude detection was verified in a generic test environment. This system displays the entire sky view of stars on a monitor and enables attitude detection tests for all star images regardless of time or location. As a result, the satellite's attitude was detected normally by this board. Finally, the effectiveness of the software filter for the avoidance algorithm for white spots was confirmed by using sample photographs, including those with white spots.</p>

著者

SAKAMOTO Yuji TANABE Yuta YAGISAWA Hitoshi SUGIMURA Nobuo YOSHIDA Kazuya NISHIO Masanori NAKAJO Tomoyuki AKIYAMA Hiroaki

出版者

THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES

雑誌

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN (ISSN:18840485)

巻号頁・発行日

vol.12, no.29, pp.Tf_7-Tf_12, 2014

被引用文献数

2

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The 2-unit size cubesat RAIKO is a nanosatellite developed by Tohoku University and Wakayama University. This paper shows the mission and system specifications. The satellite was released to space on October 4, 2012 from International Space Station, which was the 419-km alt. circular orbit. The techniques for 50-kg microsatellites by Tohoku University are transferred to this satellite, so a lot of functions are included although the power and mass budgets are strongly restricted. The primary missions are the photo storage by different 3 optical sensors, the de-orbit mechanism experiment by expandable thin films, and Ku-band downlink communication experiment. The satellite operation was finished by orbital decay on August 6, 2013. The telemetry data were successful received in total 123 passes, in which total 63 photo images were obtained and maximum 100 kbps (200 ksps) downlink was successful. Using color CMOS camera, gradually separating ISS could be confirmed. From analysis of house-keeping data, the solar generation power in sunshine was 3.38 W (no paddles) to 5.77 W (with paddles) in average, the temperature of onboard computer was in the range of 20.8 to 28.7 deg C, and the battery temperature was 4.2 deg C in average. The real flight data from the 10-month operation will be precious information for future nanosatellite projects.