The design of a low power-consumption Decca Navigator/Argos drifting buoy for high-resolution frequent position-fixing

Drifting buoys containing platform transmitter terminals (PTTs) for the Argos satellite global positioning system are frequently used by oceanographers to provide a large-scale view of ocean currents. However, the position fixes provided are neither accurate enough nor sufficiently frequent for such buoys to be used to study small-scale circulation effects in shallow coastal waters. In order to satisfy the demand for high resolution position fixing and dense sampling in time in order to resolve small scale features of the flow, a drifting buoy was developed which combines the advantages of Argos and the Decca Navigator System (DNS). A specially-developed DNS receiving subsystem computes position fixes at predetermined intervals to an accuracy of a few tens of meters under optimum conditions. The interval between position fixes may be varied from 5 to 75 min