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Escalating national interest in the coastal ocean underscores the need for high‐quality surface current data that can improve our understanding of surface circulation and its impact on societal and environmental issues related to coastal pollution, beach restoration, oil spill mitigation, and coastal air‐sea interaction. Coastal regimes exposed to strong ocean currents,surface waves, and winds during storm conditions may frequently require beach renourishment to restore valuable beaches that are key to local economies. Maintaining water quality is a problem, too, particularly where shipping dominates the traffic in and out of harbors. These environmental issues are increasingly difficult to manage due to evolving oceanic and atmospheric conditions. Inferring evolving spatial patterns of the coastal ocean current fields from single‐point measurements such as moorings or drifters that propagate away from divergent flow regimes is difficult at best. The Doppler radar technique is one approach that effectively measures the evolution of surface current fields in near‐real time.

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This paper presents a study of the effects of compass bias on navigational accuracy of autonomous underwater vehicles. Low cost vehicle systems utilize a magnetometer, and Doppler sonar for dead reckoning, and a DGPS fix when surfaced. By learning the compass bias from a few DGPS fixes, the navigational errors can be bounded with only a small number of fixes. The study is conducted using the Florida Atlantic University OEX vehicle and a large set of data obtained from a 3.5 Km run including several segments at different headings so that the dependency of compass error on actual heading could be evaluated.

Bathymetry, current and CTD measurements in shallow waters on the continental shelf off the coast of Florida, using a small, mobile, autonomous underwater vehicle (AUV) platform equipped with a 1200kHz broad band ADCP, are described. Florida Atlantic University's AUV, the Ocean Explorer, which was used in the mission, is a 7ft long versatile, Gertler body which can perform pre-programmed underwater missions to a depth of 1000ft. At a speed of 1-2 m/s, it can perform missions over a period of several hours, collecting in-situ oceanographic data and storing it on an on-board data-logger. The vehicle may also carry a side-scan sonar or a small-scale custom turbulence measurement package or other instruments for subsidiary measurements. The versatility of the AUV allows measurement of oceanographic data over a substantial region, the motion of the platform being largely decoupled from that of the sea surface.In the missions of Dec. 5 and 11, 1997, 'lawn-mower pattern' AUV surveys were conducted over 1 km 2 regions on the east coast of Florida, north of Fort Lauderdale, at depths of 7m and 3m respectively in a water column where depth ranged from 10 -32m. During Dec. 5, the region was subjected to a cold front from the northwest. Local wind measurements show presence of up to 10m/s winds at temperatures of up to 10-15 0 C below normal for the time of the year. The fixed ADCP indicates occurrence of significant internal wave activity in the region. The data collected using the mobile AUV is utilized to develop a map of the bottom topography and examine current, temperature and density variations in the context of the background information from the fixed systems. The work described here is a significant step in the development of an autonomous oceanographic sampling network, illustrating the versatility of an AUV platform. The data collected during the missions described will form part of a bank for information on the impact of a cold front on shallow sub-tropical waters. We expect to repeat the missions during other such fronts.