The code and carrier tracking loops for GPS signal

Abstract

In order to determine position, GPS receiver needs to know navigation message which is obtained by demodulating received signal. Demodulating process requires the local harmonic signal and received signal must have pretty good phase alignment. So the phase locked loop is employed to track phase of received signal. This paper implements the phase locked loop to track the GPS signal. Basic principle of phase locked loop signal is presented. Then different types of phase locked loop with different architectures and types of the filter are implemented. Results of implementation show performance of the loops. The tracking loop is carried out in MATLAB using samples of intermediate frequency signal recorded from a GPS front-end.