Cramér-Rao lower bound on time of arrival estimates for an envelope-detected pulse

The pulse time of arrival is an important parameter estimated in an electronic warfare receiver. The Cramér-Rao bound provides a lower bound on the variance of unbiased parameter estimates. In the past, time of arrival performance has been compared to a bound derived under Gaussian assumptions. However, these estimates are frequently computed from the pulse envelope, which exhibits Rician statistics that are approximately Gaussian only at high signal-to-noise ratios. This correspondence derives the Rician Cramér-Rao bound on time of arrival estimation accuracy.