EchoBLUE is an accurate, scalable, and low power system that enables full 3D localization of robots in complex, unstructured underwater environments.
Localization is a critical task for underwater robots, yet today’s underwater localization systems are limited along one or multiple axes: accuracy, scalability, or energy consumption (i.e., longevity). EchoBLUE addresses these limitations by leveraging underwater bacskcatter nodes as location anchors.
How does it work?
In EchoBLUE, an underwater robot transmits SONAR-style (FMCW) signals, and leverages ultra-low power underwater backscatter nodes as location anchors. EchoBLUE's design introduces two key innovations. The first is a novel doppler compensation mechanism that enables it to accurately self-localize under mobility: the technique employs a cross-chirp mechanism that exploits the quad-band nature of the resulting backscatter response to overcome the range-doppler ambiguity. Second, it introduces the first semi-passive underwater retrodirective backscatter design and uses it for location anchors; this design achieves wide bandwidth to backscatter the full FMCW signal, enabling fine-grained localization.