Attitude estimation for a spin stabilized spacecraft from Doppler shift

摘要

An optical sensor or a magnetometer has been used to determine the attitude of a spacecraft. However, a small spin stabilized satellite such as a sub-satellite of the Japanese lunar explorer SELENE has no attitude sensor, because the weight and electric energy are limited. An observed Doppler frequency shift results from the orbital motion and the spin of an antenna. Therefore, the attitude or the direction of the spin axis can be estimated from the analysis of Doppler shift caused by spin motion. There are some examples of attitude estimation from Doppler, but the nutation and an antenna phase pattern were not taken into account. In this paper, the new attitude estimation method is proposed considering the two effects. The simulation shows that the attitude can be estimated within the error of 0.5 degrees from Doppler data.