High-Precision Time Delay Estimation Algorithm Based on Multi-Path Fractional Farrow Structure

Interference propagation delay estimation is a key technique for locating interference sources. However, the traditional delay estimation can only be accurate to the sampling interval, or it has its own shortcomings in low complexity and improving the accuracy of delay estimation. In this paper, a high-precision interference delay estimation algorithm based on four-branch Farrow structured fractional delay filter is proposed by combining generalized cross correlation and fractional delay filter. The cross-correlation can be used to estimate the time delay, and the fractional delay filter can realize the non-integer delay and the accurate delay estimation of the interference signal. Under the premise of reducing the processing complexity and ensuring the amplitude-phase characteristics of the filter, the approximation of the ideal fractional delay filter is realized, which breaks the limit of the sampling rate and improves the estimation accuracy of the delay error of interference propagation. The experimental results indicate that with the receiver sampling rate of 25 MHz and the sampling interval of 40 ns, the estimation accuracy of interference propagation delay exceeds 10 ns.