Cramer-Rao bound for passive localization of a moving source in ocean acoustics

The Cramer-Rao lower bound for passive localization of a moving source from large aperture vertical arrays in the context of normal modes is studied. To accomplish this, matched field processing for locating a point acoustic source in the ocean using a vertical array is extended to treat a moving source problem. The extension involves both temporally nonstationary and spatially inhomogeneous nature of the sound field generated by a time-harmonic point source moving uniformly in a stratified oceanic waveguide. A closed-form expression of the optimum potential resolution is derived based on the Cramer-Rao bound. The lower bounds provide physical insight into how each mode contributes to the localization process and can be easily evaluated for a wide range of source positions in a sound channel using eigenfunctions, eigenvalues, and the number of modes involved.<>