SeaDARTstation - Compact Multimodal Data Acquisition Platform for Underwater EM (UEM) Sensors

Green Geophysics with subcontractor Enthalpion Energy has proven capability managing complex engineering design and geophysical field projects. Green has worked closely with project subcontractor Enthalpionís president for the past dozen years to manage teams of technicians and engineers to undertake continental-to-local scale geo-electromagnetic survey operations, and to support and develop large arrays of electromagnetic sensors and data acquisition systems.ÝOur track record designing and fabricating marine and terrestrial systems for low power, miniaturized, high fidelity extended duration measurement, and real-time telemetry is key to our success. The President of Enthalpion has nearly five decades of experience designing, building and deploying electromagnetic monitoring instrumentation and associated processing and analysis software, for marine environmental monitoring, magnetotelluric and controlled source electromagnetic methods applications on land and at sea.ÝGreen Geophysicsí project electronics engineer has worked closely with the President of Enthalpion for over 13-years, and has extensive hardware, software as well as mechanical design experience specific to marine and terrestrial electromagnetic monitoring instrumentation.ÝOur team recently released the innovative DART series of low power, highly capable instrument platforms. The baseline DART system, packed in a compact cylindrical housing contains high-speed 32-bit digitizers, an internal three-axis fluxgate magnetic field sensor, external electric field sensors and optional induction coil magnetic field sensors. The DART has an internal web server and uses wifi for command and control, with real-time telemetry options on land using LTE and/or Starlink. While in production for use on land, a marine version of the system, SeaDART, has been taken to prototype level to provide a client with an electromagnetic sensor suite for an autonomous submersible vehicle.ÝWe propose to develop SeaDARTstation, a new seafloor configuration of the DART marine product line to meet or exceed all requirements for the UEM specified for SBIR Topic N251-050. A novel three-axis electric field sensor array, articulated to fold flat against the compact cylindrical body of the SeaDARTstation while stowed, will expand on deployment to provide separation between pairs of miniature, solid-state nonpolarizing silver-silver chloride electrodes to provide sensitive measurement of vector electric fields, with sensitive vector magnetic field measurements provided by an integrated fluxgate magnetic field sensor, all within the DC-to-20 Hz frequency band and beyond. Optionally, our UEM can integrate induction coil magnetic field sensors into the articulating electric field sensor arms to boost detectability of smaller or more distant targets at higher frequencies. An acoustic release system with failsafe timer will release a drop weight to facilitate surface retrieval of the SeaBASEstation UEM.