Maximum likelihood distance estimation algorithm for multi‐carrier radar system

Abstract

In this study, a maximum likelihood distance estimation algorithm is proposed for a multi-carrier radar system to estimate the time delay of non-integer sampling intervals. Particularly, the equivalent relationship between time domain delay and frequency domain phase shift and the relationship between target delay and channel impulse response is used. The idea of maximum likelihood estimation is to find the estimation value that maximises the likelihood function. Therefore, the core idea of this algorithm is the peak search. First, channel estimation is performed on the sampled signal in frequency domain to obtain the channel impulse response. Second, phase compensation and peak search is done to estimate the target delay. Finally, for multiple estimation results, the authors statistic the probability density distribution of the target. In addition, they deduce the Cramer–Rao bound (CRB) of the variance of time delay estimation. The measurement accuracy of the algorithm that they proposed approaches the CRB in the high signal-to-noise regime.