Satellite Attitude Sensing Model and Their S/w Development

Abstract

We have developed an attitude sensing S/W system, one of modules of Mission Analysis System(MAS), which simulates attitude sensing data as almost the same as the real sensor of a satellite in orbit. When attitude elements(¥á,¥ä) of a satellite and positions of Earth, Moon, and Sun are given, the S/W system calculates look angles and dihedral angles of each celestial bodies relative to the rotations axis of the satellite. It consists of two sub-modules : One is ephemeris service module which consider the perturbations of four planets(Venus, Mars, Jupiter, Saturn) for positions of Sun and Moon and 4 x 4 earth gravitational potential terms for a satellite's position. The other is attitude simulation module which generates attitude sensing data. Varying the rotational axis of a satellite and it's orbital elements, we simulated the generating attitude sensing data with this S/W system and discussed their results.