A new fuzzy bandwidth carrier recovery system in GPS for robust phase tracking

Fast carrier recovery loops are essential in high-dynamic global positioning system receivers. A new digital phase-locked loop (DPLL) system incorporating a fuzzy bandwidth controller (FBC) is presented in this letter. The FBC provides a time-varying bandwidth and adjusts the loop filter coefficients to improve DPLL tracking capability. When the phase error or phase difference error becomes large in the presence of significant accelerations, the loop bandwidth increases adaptively and performs rapid locking. Simulation results show that our receiver does achieve a superior performance over conventional tracking loops in terms of shorter settling time and wider frequency ramp range, while preventing the occurrence of cycle slipping.