Maximum likelihood range localization of waves propagating in a random ocean

We propose a statistical signal processing solution to the problem of finding a monochromatic source propagating in a random media. The media is fully parameterized by two variables, range X and scattering strength /spl gamma/, which in turn depend upon the physical parameters of the problem. We observe M independent intensity measurements, each drawn form the generalized gamma distribution. The parameters of the distribution are related to the physical parameters, X and /spl gamma/. Maximum likelihood estimates are obtained and the Cramer Rao lower bound is derived. The results show that we can estimate the range to a precision of about 20%, for ranges up to half the distance to the focus of the medium. Simulation results verify both the normality of the estimates and the validity of the CRLB as a predictor of the estimator precision at these ranges. The practical value of this method will depend on our ability to gather enough independent measurements, and on the accuracy of the statistical models.