Use of spaceborne GPS Navigation sensor for autonomous LEO orbit determination

In this paper, a simple but fairly accurate algorithm, to determine orbit of the Low Earth Orbit (LEO) satellite, in its real time and with low computational burden is reported. This is done by using raw navigation solution provided by GPS Navigation sensor. A fixed step-size Runge-Kutta 4^th order numerical integration method is selected for orbit propagation. Both, the Least square and Extended Kalman Filter (EKF) orbit estimation algorithms are developed and the results of the same are compared with each other. The least square algorithm converges after seven iterations. In the case of EKF, the algorithm converges after three iterations. Hence, EKF algorithm satisfies the criterions of low computation burden which is required for autonomous orbit determination.