High-Precision Time Delay Estimation Algorithm of Wideband Signal with Low Signal-to-noise Ratio

Abstract

Traditional time delay estimation algorithms are limited by the requirement of unwrapping phase ambiguity and sample interval. Especially with low signal-to-noise ratio (SNR), the accuracy of time delay estimation cannot be improved. The signals launched by modern radars are always wideband signals. According to the relationship between time domain and frequency domain, this paper converts time delay estimation into frequency estimation. Then, the time delay can be estimated by the discrete Fourier transform (DFT) based on the search of time delay. The precision of this algorithm is not limited by the sample interval and the algorithm is able to adapt to the low SNR. The algorithm is simple and suitable for engineering implementation. It can be carried out in real time processing. The simulation results show that the algorithm can achieve very high precision of time delay on the condition of certain band width.