Abstract—Accurate prediction and modelling of GPS satellite signal propagation characteristics is necessary in all precise navigation solution applications such as aircraft navigations, missile guidance and surveying. The signal propagation characteristics severely affect the quality, availability and continuity of the system. The received signal strength of a GPS satellite at a given location on or near the earth surface can be predicted by analyzing the propagation characteristics of the channel with an appropriate propagation model. There are two types of variations that occur in a GPS signal when it is travelling from the satellite to receiver on the earth’s surface. They are: large-scale variations and small scale variations. Large-scale variations in a signal are mainly due to the path loss and shadowing. These variations depend on the distance, carrier frequency and atmospheric conditions. Secondly, the variations those characterize the rapid fluctuation of the received signal strength over very short travel distance is known as small-scale variations. These are mainly due to multipath reflections and doppler shift which degrades the quality of the signal received particularly in urban environments. The large scale propagation characteristics of GPS channel were investigated in this paper. The propagation characteristics of GPS signal was analyzed by considering the factors like carrier frequency and distance between obstacle and receiver.

Index Terms—GPS, Navigation, Pathloss, Large-scale variations

Cite: G Sasi Bhushana Rao, G Sateesh kumar and I Silpa, "MODELLING OF GPS SIGNAL LARGE SCALE PROPAGATION CHARACTERISTICS IN URBAN AREAS FOR PRECISE NAVIGATION," International Journal of Electrical and Electronic Engineering & Telecommunications, Vol. 1, No. 1, pp. 116-122, October 2012...