Compact acoustic transceivers for inter-vehicle localization and coordination

Multiple reports have demonstrated that acoustic transceivers, when used in a bi-static setup, can facilitate inter-vehicle localization and coordination in underwater environments. To capture the range, Angles of Arrival (AoAs) and Doppler estimates required for such schemes, acoustic transceivers need to be equipped with a 3-D array of at least four receiving elements and at least one transmitting element, along with interfaces that enable accurate timing. We are developing low-cost, compact acoustic systems for this application that are suitable for mobile underwater platforms. The designed transceivers use a Raspberry Pi and a customized ADC/DAC circuit for waveform transmissions and eight-channel reception. A software library built in the Rust programming language has been developed to perform real-time signal processing, including carrier modulation/demodulation, waveform transmission and recording, preamble detection, ranging, AoA estimation, frequency-shift keying, and Doppler estimation. Lake tests will be performed with an autonomous underwater vehicle to demonstrate real-time data communication and relative localization from the developed acoustic transceivers. We will present field test measurements and performance metrics from lake tests. [Work supported by NSF (CNS#2016726 and CNS#2048188) and USGS grants (G23AC00157).]