A GPS-TRACKED SURFACE DRIFTER WITH CELLULAR TELEMETRY CAPABILITIES

A location/data telemetry system has been configured for expendable su rface drifters in coastal waters. The system is composed of a commerci al microcontroller, a Global Positioning System (GPS) receiver, and a cellular phone with an integral modem. Drifter positions are periodica lly recorded by the microcontroller, which relays stored positions and ancillary data to an autonomous host computer on shore. Options inclu de the capability to sample and store data from extremal sensors, remo tely change mission parameters after deployment, such as sampling and reporting intervals, and a ''sleep'' mode to conserve power Two surfac e platforms have been configured with the position/telemetry system. O ne is the spherical fiberglass hull of the World Ocean Circulation Exp eriment (WOCE) Surface Velocity Program, and the second is a modified Coastal Ocean Dynamics Experiment (CODE) surface drifter. Field tests indicate the surface drifters are capable of reliable communication in Florida coastal waters at least 30 km offshore under Low sea state. T he initiation of global cellular phone coverage within the next few ye ats should provide an increased capability for tracking surface curren ts and the trajectories of drifting objects with this system.