Relative navigation for command and control of multiple low-cost autonomous underwater vehicles

Abstract

A long-held goal of autonomous underwater vehicle (AUV) research has been the coordinated use of multiple vehicles for novel applications. Unfortunately, the underwater domain poses significant challenges for navigation and communication—sophisticated navigational sensors increase vehicle price, size, and power use, and acoustic communications are limited in bandwidth and channel capacity. These factors make multi-vehicle deployments rare and limited in scale, with operators commanding each AUV individually and with limited coordination. In this work, we describe an operating paradigm that enables user-friendly command and control of multiple AUVs. Each vehicle uses a custom low-power, low-cost acoustic system to navigate and receive operator commands, consisting of a passive hydrophone array and timed acquisition and processing boards which enable the vehicle to self-localize relative to a synchronized acoustic beacon. By selecting between various beacon-transmitted signals, all vehicles can be simultaneously commanded to switch between behaviors. Additionally, a consequence of beacon-relative navigation is that movement of the beacon results in the concurrent movement of all AUVs. This system is ideal for multi-vehicle operations using inexpensive, miniature AUVs, as it does not require conventional high-cost navigational sensors or acoustic modems, and its passive nature and associated operating scheme enable the deployment of an arbitrarily large number of AUVs. [Work supported by Battelle, ONR, Lincoln Laboratory, DARPA.]