Reza Ghaffarivardavagh, Sayed Saad Afzal, Osvy Rodriguez, and Fadel Adib.2020. Underwater Backscatter Localization: Toward a Battery-Free Underwater GPS. InProceedings of the 19th ACM Workshop on Hot Topics in Networks(HotNets ’20)

Abstract

Can we build a battery-free underwater GPS? While underwater lo-calization is a long-studied problem, in this paper, we seek to bringit to battery-free underwater networks [13,20]. These recently-introduced networks communicate by simply backscattering (i.e.,reflecting) acoustic signals. While such backscatter-based communi-cation enables them to operate at net-zero power, it also introducesnew and unique challenges for underwater localization.We present the design and demonstration of the first underwaterbackscatter localization (UBL) system. Our design explores vari-ous challenges for bringing localization to underwater backscatter,including extreme multipath, acoustic delay spread, and mobility.We describe how an adaptive and context-aware algorithm mayaddress some of these challenges and adapt to diverse underwaterenvironments (such as deep vs shallow water, and high vs low mo-bility). We also present a prototype implementation and evaluationofUBLin the Charles River in Boston, and highlight open problemsand opportunities for underwater backscatter localization in oceanexploration, marine-life sensing, and robotics.