Implementation of Signal Acquisition and Tracking for GPS-Based Software Defined Radio Receiver

Abstract

“Global Positioning System (GPS)” is extensively used for various satellite-based navigation applications. Nowadays, a software-defined GPS receiver has been developed since it is low cost, flexible and able to use in developing more advanced navigation processing algorithms. To implement a GPS software receiver, it is necessary to process three main modules: acquisition, tracking and navigation demodulation for the position, velocity and time (PVT) solution. Signal acquisition estimates the two parameters from the incoming satellite signal, and signal tracking keeps track of them as they change in time. These two parameters are the code phase, the delay time between receiver and satellites, and the Doppler frequency shift instigated by the satellites’ movement relative to the receiver. This study mainly discusses the operation of signal acquisition and tracking. The theoretical study and simulation of the results are described and tested using MATLAB programming language. The input GPS signal is acquired from an antenna system in GPS and an RF front-end portion.