Acoustic Near-Field Source-Localization by Two Passive Anchor-Nodes

A new scheme is herein proposed to localize an acoustic source. This new method blends the "received signal strength indication" (RSSI) approach of geolocation, and the acoustic vector-sensor (AVS) (a.k.a., vector-hydrophone) based direction-finding (DF). Unlike customary RSSI-based source-localization, this proposed approach needs only two (not three or more) passive anchor-nodes: 1) one pressure-sensor, and 2) one physically compact triad of three (collocating, but orthogonally oriented) acoustic velocity-sensors. The latter can estimate the direction-of-arrival (DOA) of an emitter, regardless of that emitter's arbitrary/unknown center-frequency, bandwidth, spectrum, and near-field/far-field location. This triad's DOA estimates can be "distributed processed," locally, apart from the pressure-sensor's measured power, to estimate the emitter's radial distance. This proposed algorithm is noniterative, requires no initial estimate, is closed form, and can accommodate any prior known propagation-loss exponent.