GPS multipath signal estimation based on all phase DFT

The GPS multipath signal model is given and analyzed. The all phase DFT (apDFT) is proposed as a new spectral analysis way, which makes full use of (2N - 1) samples to do linear transform into N point sequence called all phase signal. Phase difference method is integrated with apDFT to determine the accurate signal frequency through calculating the two phase value for the two sequences' DFT result, i.e. one is from point 1 to point (2N-1) and the other is from (N + 1) to (3N -1) separately. The application of the proposed method on GPS multipath signal estimation is analyzed, which has multiple frequencies components. Monte Carlo simulation results based on GPS simulator data show that the apDFT and the integration with phase difference method could give the accurate frequency and precise phase estimation in both ideal and noisy environments.