AOSN (Autonomous Ocean Sampling Networks) -- Multiple Vehicle Operations

In 1995 the current generation of oceanographic field programs were fundamentally limited by too few measurements, taken too slowly, at too great a cost. A new approach to more economical access to the ocean was to use many small, low-cost AUVs operating from a network of moorings. Such an approach, dubbed "Autonomous Ocean Sampling Networks" was developed in a multi-institutional effort lead by MIT Sea Grant. The ONR (Office of Naval Research) funded project ($11.3 M over five years) was aimed at deploying Odyssey II AUVs, buoyancy-driven gliders, and drifters in the Labrador Sea during the winter of 1998. In addition Odyssey IIb AUVs were used by collaborating institutions to develop and demonstrate docking and autonomous power-transfer techniques: capabilities designed to permit long-endurance deployments of the vehicles. Team members included the Woods Hole Oceanographic Institution, Scripps, the Applied Physics Laboratory at the University of Washington and Northeastern University. Additional deployments of the AOSN systems occurred in Monterey Bay in 1999 and 2000. NRaD, The U.S. Navy's Research and Development division is basing their Distributed Surveillance Sensor Network on AOSN.

The ocean is tremendously underobserved due to both technical and economic obstacles. This project is helping to overcome these obstacles.

The ultimate goals have been to create and demonstrate a reactive survey system capable of long-term, unattended deployments in harsh marine environments. Specific objectives were to create small, high-performance mobile platforms capable of deployments lasting several months; to create an infrastructure that supports the control, data recovery and energy management of remotely deployed mobile platforms; to demonstrate these capabilities in sciencedriven field experiments; and to develop adaptive sampling strategies to most efficiently meet deployment objectives. Both propeller-driven survey vehicles (see Autonomous Underwater Vehicles article in Design and Marine Robotics section on page 35) and buoyancy-driven glider vehicles have been pursued. Elements of the supporting infrastructure are moorings, docking stations, acoustic communications, two-way satellite communications, and the Internet. Integral to this work have been several science-driven experiments, each chosen to focus instrumentation development and to convincingly demonstrate new capabilities. The first deployment in Haro Strait during June-July 1996 focused on coordinated platform operations, adaptive sampling, and communications; the second deployment in the Labrador Sea, January-April 1998, was designed to demonstrate long-term deployment and remotely controlled operations; and the final phase of the effort, conducted in Monterey Bay during August-September 1999 and 2000, integrated the resulting operational capabilities with modeling systems in an extended-deployment experiment, focusing on internal tidal waves and bores.