Frequency estimation for high dynamic GPS signals based on vector tracking

A method of estimating high dynamic GPS signal parameters based on Vector Frequency Lock Loop (VFLL) is proposed. Instead of tracking the Doppler frequency of individual channel using the traditional loop, the VFLL tracking the velocity, acceleration .etc states of the GPS receiver from the measure value of all the channels. In vector mode, the navigation processor controls the carrier numerically controls oscillators (NCOs) based on the most recent velocity solution of the receiver. The major advantage of this method is that the velocity estimation from all the channels can be more accurate than Doppler frequency estimation from individual channel. In this paper the VFLL architecture is given, and the system dynamics equation and measure equation of the navigation processor are discussed in detail. The performance of the VFLL is tested using simulation, because it is inherently scenario dependent. From the simulation results, it can be seen that estimation performance is improved compared with scalar method.