GPS User Position Using Extended Linearization Technique
The position of a GPS receiver can be determined by obtaining pseudoranges from a minimum of four different GPS satellites. The measured ranges do not represent the true ranges as the signal coming from a GPS satellite will be contaminated by various errors like Ephemeris error; Propagation error in the form of Ionospheric and Tropospheric delays; Satellite and Receiver clock biases with respect to GPS Time (GPST); Multipath error etc. Most of these errors can be estimated accurately and can be accounted for. As it is easy to implement, most of the GPS receivers employ former method for fixing the user position when a great degree of accuracy is not required.