A design method and performance analysis of vector-based tracking loop receiver

GPS signal can't be tracked effectively by traditional scalar tracking loop when receiver works in lower carrier-to-noise power density ratio (C/N ₀) environment. Therefore, a vector-based tracking loop receiver design method is presented in this paper. The relationships among C/N ₀, measurement noise variance and predicted pseudorange variance are analyzed. Actual pseudoranges and pseudorange-rates errors are considered as statement information, receiver locally generated pseudoranges and pseudorange-rates errors are used as measurement information to build the Extended Kalman Filter (EKF). Vector-based tracking feedback loop is accomplished through calculating line-of-sight vector between the receiver and visible satellites, which is updated with time. Position Dilution of Precision (PDOP) is given through adopting actual satellite ephemeris. The simulation results show that, at the same C/N₀, not only the vector tracking loop has lower predicted pseudorange variance, but also the performance of positioning error is better compared with scalar tracking loop.