Towards a transiting ocean observer network with passive acoustic localization

Most underwater soundscape recording systems are limited to a single hydrophone without peripheral, time-synchronized environmental sensing, meaning that local environmental parameters and directional soundscape information are lost. PLUTOS (Passive Localized Underwater Transiting Observing System) is currently under development to provide multi-modal sensing capability relating acoustic, physical, and eDNA sampling in a low-cost underwater drifting or moored package. Based on the AcSense stack with creative commons non-commercial hardware, the objective is flexible multi-drifter sensing of acoustic, environmental, and biological parameters in a package that is accessible to academic users. A novel soundscape-relative localization method provides a pathway to a passive acoustic approach for underwater localization. We present the initial system integration, simulation, as well as field deployment and data analysis of the prototype that included synchronous 8-channel hydrophone array recording with CTD and pumped eDNA sampler. The system design includes an objective of multiple drifting systems including hydrophone arrays to disambiguate time and space signals in ocean properties in addition to triangulation of sound sources [Work funded by NSF.]