High resolution multipath time delay estimation for broadband random signals

We examine the limits to multipath time delay resolution for broadband random signals. We first derive Cramer-Rao bounds for both two path and three path cases to establish baseline performance for unbiased estimation. We then compare the bounds with computer simulation. For the two path case we implement a maximum likelihood estimator while for the three path case we estimate the delays using the Modified Forward Backward Linear Prediction algorithm developed for high resolution frequency estimation. It is shown that both techniques achieve performance close to the Cramer-Rao bound.