Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2005.1739.1743ChouraquiS.M. BenyettouA. Si Mohammed102005510The orientation (Roll, Pitch, Yaw) of the spacecraft on its orbit is defined with respect to the vehicle`s reference frame.
The attitude of spacecraft can be determined from one or a combination of the following sensors: gyroscope, sun sensor, star
sensor, horizon sensor and magnetometer. In this study we are going to give a mathematical model of the earth horizon sensor to obtain the horizon vector pairs which are used by a vector state filter to estimate the satellite attitude.]]>Wertz, J.R.,1978Steyn, W.H.,1995Hoots, F.R. and R.L. Ronald,1998Chouraqui, S.,2000Hashida, Y.,1997