Applied At-Depth In-Ocean Differential Electrostatics -- An Experimental Study [Report]

NESL Technical Report #: 2012-4-1


Abstract: Nocturnal oceanic animals and those that live at depth can- not rely upon optical notions of vision to navigate, hunt, or avoid preda- tors. Instead, many rely upon an electroreceptive capability achieved through a dense grid of electric field (Voltage) sensors arrayed along both sides of the body and concentrated around the head. Our prior works have detailed the creation of an engineered sensor which mirrors this biological system and demonstrated its ability to “visualize” targets with different conductivities from the background ocean environment – a process we entitle Biomimetic Electrostatic Imaging (BEI). Our prior imaging studies were performed in the laboratory in a well controlled ocean-simulant tank. This work chronicles our effort to validate beyond the laboratory. To better evaluate the potential capabilities of BEI in the actual ocean, an expedition was undertaken to the Pacific Ocean to a site in the coastal city of Marina Del Rey, California. A six and half hour study was conducted by a cantilevered purpose-built robotic gantry system (figure 1), which collected over 10,000 data points at 635 micron-square resolution, resulting in the highest resolution study ever reported. A mathematical model is derived from first principals and used to corroborate the findings. Several smaller studies are also included to present data relevant to design optimization. The improved BEI system described within increased detection range by 97% and range-power efficiency by as much as 150% over our previous report without a corresponding increase in the false positive rate. We also report sensing and excitation ranges 7× their respective electrode separation distances – the furthest ever reported.

Date: 2012-05-01

NESL Document?: Yes

Document category: Report