In this paper, an attitude detection system with capturing omni-directional image for ultra-small satellite on orbit is described. To detect the attitude angle for ultra-small satellite called as “Cubesat” on orbit, the omni-directional camera with strong distortion is adapted to the satellite to specify relative direction of some celestial bodies such as Sun and center of the Earth from the view of the satellite on orbit. Then it is revealed that a pixel grid of capturing image with strong distortion for the omni-directional camera is formulated as direction vector to analyze some fixed points from the satellite. The authors conduct the satellite attitude detection system on orbit that solar and center of the Earth relative direction from the satellite are determined by capturing image with omnidirectional camera even if the figure of the sun and the Earth is not appeared directly on the image. Then the solar and center of the Earth direction are introduced by the calculation of the Earth outline of capturing image, it is possible that an attitude angle of the satellite is calculated by relationship between the satellite position on orbit and these two fixed points consisted of the solar and center of the Earth direction. To confirm validity of the proposing attitude detection system, a numerical analyzing for the attitude detection by using a sample image with including Earth outline model is calculated. Moreover, some experiments on orbit are executed, capturing image from launched small satellite on orbit is analyzed and evaluated.
