Determining low‐frequency source location from acoustic phase measurements Free

For low‐frequency cw sound sources in shallow water, the time rate‐of‐change of the measured acoustic phase is well approximated by the time rate‐of‐change of the source‐receiver separation distance. An algorithm for determining a locus of possible source locations based on this idea has been developed. The locus has the general form of a hyperbola, which can be used to provide a bearing estimation at long ranges, and an estimate of source location at short ranges. The algorithm uses only acoustic phase data and receiver geometry as input, and can be used even when the source frequency is slightly unstable and/or imprecisely known. The algorithm has been applied to data from low‐frequency experiments (20–300 Hz), both for stable and unstable source frequencies, and shown to perform well. [Work supported by ONR and WHOI Academic Programs Office.]