Improved time delay estimation in the presence of interference

This paper presents a technique for obtaining unbiased time delay estimates in the presence of interference. The proposed technique is based on a modified "matched filter" concept wherein the anticipated, noise-free Generalized Cross Correlator (GCC) output between two sensors is matched to the received noisy GCC under a Least-Mean-Square (LMS) error criterion. Separate estimates of the target power, target time delay, interference power, interference time delay, and noise power are obtained provided the spectral shapes of the target and interference are known. The performance of this technique is evaluated analytically and compared to simulation results as a function of signal-to-noise ratio (SNR), interference-to-noise ratio (INR), time-delay separation, and signal and interference spectra.