ENHANCED ADAPTIVE CARRIER TRACKING LOOP FOR GNSS RECEIVER

Abstract

MATLAB-Simulink is useful tool to analysis the signal processing part of GNSS receiver. Carrier tracking loop (CTL) used in GNSS receiver are closed loop systems, designed from their continuous time transfer function. In this thesis GNSS signals are generated in Simulink by Binary o set Carrier (BOC) and Binary Phase Shift Keying (BPSK) modulation. GNSS signal comprises of PRN code, C/A code, navigation bits and high frequency carrier signal. Transmitted signal is received at GNSS receiver front end down converted to Intermediate frequency (IF) . Digital IF signal is correlated with locally generated code replica, signals are feed into carrier tracking loop each and every information of tracked signal is automatic upgraded by feedback loop lter. In proposed work low C/N0 signals tracked accurately and results are validating the proposed work. Tracking error and jitter is an important parameter to show the tracking performance of Carrier tracking loop. Tracking jitter behavior with low C/N0 GNSS signals has been studied. Hence large variation in input frequency of GNSS signal could be estimated for bi-phase signal of GNSS receiver. Simulation studies demonstrates the suitability of the carrier tracking loop of GNSS receiver. Simulation results are validate the proposed model.