Development of Code and Phase Tracking Algorithms for GNSS signals in low C/N and high dynamics scenarios

Global Navigation Satellite Systems (GNSS) receivers working in high dynamic situations usually exhibit poor tracking performance, especially in attenuated signals scenarios. Classic Phase Lock Loops (PLL) are suboptimal in compensating effects of noise and dynamics simultaneously. One solution consists in process and noise modeling with an iterative estimation methodology like the Kalman filter and its nonlinear implementations. Purpose of this study is to compare the performance of the Extended Kalman Filter (EKF) approach to the more innovative Unscented Kalman filter (UKF), through the implementation of a complete multi-constellation software receiver (RF front end, acquisition, tracking, navigation message decoding and position computation sw modules). A feedback strategy will be described as well as simulation and real time results. Preliminary results show good performance of the new approach if compared to the classic EKF solution.