A summary of MIT AUV Lab operations at GOATS 2000 is available in PDF format.

In partnership with the SACLANT Undersea Research Centre Massachusetts Institute of Technology (MIT) has taken important steps towards adapting the new Autonomous Ocean Sampling Network (AOSN) technology to performing mine countermeasures (MCM) operations in very shallow water (5-15 m). The AOSN paradigm consists of a network of small and inexpensive Autonomous Underwater Vehicles (AUV), tied together by emerging high performance acoustic communication technology, and equipped with sensors for rapid environmental assesment and a suite of sonar systems, for example.

The scientific objective was to measure 3-dimensional scattering from proud and buried targets, and reverberation, in very shallow water, insonified by a parametric sonar. These measurements are used for validating new numerical models of target scattering and reverberation, developed at MIT, and for identifying features of the scattered field, such as three-dimensional radiation patterns and resonant features, which robustly identifies targets in the reverberation background. Such features will form the basis for developing new multi-platform sonar concepts for MCM which can be implemented within the size and power constraints of the AOSN.

The technological objectives of the experiment were to demonstrate the feasibility of using small AUV's as acoustic platforms for measuring scattering and reverberation from the seabed, and to investigate the navigation and control performance of such vehicles in very shallow water. The use of AUV's for rapid environmental assessment in very shallow water was also investigated.

The acoustic experiments were supported by environmental assessment measurements,
including boomer, side scan and multi-beam sonar surveys, stereo photography and underwater video. Core samples were collected for sediment analysis.

GOATS`98 and ’00 Operational Scenario
The experiment involved both of the Centre's ships and a laboratory established on shore. T/B Manning was used for deploying sources and fixed acoustic arrays in 15 meter water outside the pier in Marciana Marina, Elba. The shore laboratory was used for controlling the sources and recording the large amounts of data recorded by the fixed arrays.

The Alliance, mostly anchored 600 meter off shore, was used as control center for the experiment, and as a platform for operating an MIT Odyssey AUV, which had been equipped with an acoustic receiving capability, developed and built at the Centre. Once launched from the Alliance, the AUV would transect to the test area and measure the acoustic field produced by the insonified targets, accurately navigated by acoustic means. Once the programmed survey pattern was completed, the AUV would return to Alliance for recovery and data offload.

GOATS Future
The GOATS`98 and ’00 experiments demonstrated that small, inexpensive vehicles can be operated reliably in very shallow water, launched from a surface ship off-shore. It was also demonstrated that autonomous underwater vehicles are extremely useful as acoustic platforms. A Joint Research Project between the Centre and MIT is underway, with a follow-up experiment in 2002 to operate additional experimental systems, resolve network control issues and evaluate the benefits to MCM of measuring the same target scattering from different moving platforms shall be investigated.

*The MIT component of GOATS`98 was supported by the US Office of Naval Research, in part by the Ocean Modeling and Prediction Program and the Ocean Acoustics Program.