Chemical Plume Tracing Experimental Results with a REMUS AUV

Olfactory-based mechanisms have been hypothesized for biological behaviors including foraging, mateseeking, homing, and host-seeking. Typically, olfactorybased mechanisms proposed for biological entities combine a large-scale orientation behavior based in part on olfaction with a multisensor local search in the vicinity of the source. Long-range olfactory based search is documented in moths at ranges of 100-1000 m and in Antarctic procellariiform seabirds over thousands of kilometers. Autonomous underwater vehicles (AUVs) capable of such chemical plume tracing feats would have applicability in searching for environmentally interesting phenomena, unexploded ordinance, undersea wreckage, and sources of hazardous chemicals or pollutants. This article presents an approach and experimental results using a REMUS AUV to find a chemical plume, trace the chemical plume to its source, and maneuver to reliably declare the source location. The experiments were conducted in November 2002 at San Clemente Island, California using a plume of Rhodamine dye developed in a turbulent fluid flow (i.e., near shore ocean conditions).