A Doppler frequency estimation algorithm based on band mismatch

Abstract

The Doppler frequency shift can make a mismatch in frequency band between the linear frequency modulation (LFM) signal and its matched filter. The amplitude and delay of the output pulse are based on the degree of the mismatch. An algorithm of Doppler frequency estimation is proposed basing on the amplitude of the output pulse. The algorithm sets a group of matched filters whose middle frequencies increase in an established pattern. When the echo pulse goes through them, the outputs will appear in different amplitudes and delays. The Doppler frequency is calculated by the two pulses whose amplitude is the biggest. The delay of echo will be compensated by the estimated Doppler frequency, which may achieve the target's precise location. Compared to standard processing of matched filtering, this algorithm dosen't cost more time. In addition, the Hyper-Rayleigh limit estimation can be achieved in the condition of a appropriate signal-to-noise ratio (SNR). The principle is discussed in this paper, and the simulation illustrates the feasibility and effectiveness of the algorithm.