Performance Analysis of Vector Tracking Algorithms for Weak GPS Signals in High Dynamics

Abstract

This paper explores the ability of vector tracking algorithms to track weak Global Positioning System (GPS) signals in high dynamic environments. Traditional GPS receivers use tracking loops to track the GPS signals. The signals from each satellite are processed independently. In contrast, vector-based methods do not use tracking loops. Instead, all the satellite signals are tracked by a lone Kalman filter. The Kalman filter combines the tasks of signal tracking and navigation into a single algorithm. Vector-based methods can perform better than traditional methods in environments with high dynamics and low signal power. A performance analysis of the vector tracking algorithms is included. The ability of the algorithms to operate as a function of carrier to noise power density ratio, user dynamics, and number of satellites being used is explored. The vector tracking methods are demonstrated using data from a high fidelity GPS simulator. The simulation results show the vector tracking algorithms operating at a carrier to noise power density ratio of 19 dB-Hz through 2 G, 4 G, and 8 G coordinated turns. The vector tracking algorithms are also shown operating through 2 G and 4 G turns at a carrier to noise power density ratio of 16 dB-Hz.