A network protocol for multiple AUV localization

With maturing of AUV technology and underwater acoustic modem technology, networks of AUVs have come into the focus of research on future systems for ocean observation and monitoring. In this paper, we propose a networking algorithm for communication within a group of AUVs deployed on a cooperative mission in an area covering several square kilometers. The algorithm is based on a time-scheduled operation which enables the AUVs to locate each other by measuring the inter-vehicle signal propagation delays and by exchanging localization maps. The vehicles transmit high-rate PSK signals which can directly be used for delay measurements. At the end of every time-slot, assigned for transmission from a single vehicle, each of the receiving vehicles updates its map based on the newly measured delay from the transmitting vehicle, the stored value of own map, and the value of the map as known by the currently transmitting vehicle. The so-built map may be used directly for localization, and also in a routing table for subsequent location-based dynamic routing of data packets. An example system provides a delay resolution on the order of tenth of a millisecond, and a map updating interval on the order of ten seconds. The basic algorithm operation is demonstrated using a network of several vehicles.