Simulation of land mobile satcom links using different orbits and modulation modes

The use of SATCOM systems is an essential part of today's worldwide communications. As the portion of satellite orbits in low altitudes increases, Doppler shifts often influence the received signal. Prior to the removal of this eefect, the exact course and the amount of the Doppler must be known. Therefore this paper derives the equations to calculate the orbit and the Doppler shift and shows the behaviour and the effects caused by LEO and HEO satellites. Finally a method is proposed to compensate this influence.