Model-independent range localization of a moving source in shallow water

A method for range localization with a single sensor in an ocean waveguide is derived. Range localization typically requires an accurate environmental acoustics model used for processing acoustic data on a multi-element array. Recently, an alternative method for estimating range has emerged based on the waveguide invariant which still requires either an array of sufficient horizontal extent or data from a moving source for which range rate is known. In analogy to the waveguide invariant derivation, it is shown that the magnitude of the square of the difference between the acoustic field at two different ranges contains information about the range interval, Delta r. Since the range interval is manifest in the time interval, Delta t between field measurements, range rate can be ascertained. Experimental results confirm this single sensor localization method. (C) 2012 Acoustical Society of America. [http://dx.doi.org/10.1121/1.4748795]