Earth Oblateness Effect on Satellite Attitude Determination with Dual Cone Scanning Earth Horizon Sensor Modeling

Earth horizon sensor (EHS) is an attitude determination hardware able to measure the roll and pitch angles ofsatellites. These sensors are suitable in near-earth orbits and produced in statics and dynamics models. Dual-conescanning earth horizon sensor (dual-cone SEHS) is a dynamics type with one infrared detector mounted on a motor.The optical system designed is a way that it can detect two cones of space. In this paper, the dual-cone SEHS has beenmodeled by considering the earth as a sphere and the roll and pitch angles were obtained. But in reality, the earth is anoblate sphere, thus an investigation on the effect of earth oblateness has been performed to obtain the error ofdetermination comparing to the simple model in a selected mission. According to the simulation with considering theearth as an ellipsoid, the error in roll and pitch angle increased in comparison to the spherical earth.

Keywords:

Error Analysis , Double-cone scanning earth horizon sensor , Earth oblateness