The Argos satellite system has been used to locate and telemeter data from drifting buoys almost since its inception in the late 1970's. With the advent of low cost GPS in the early 1990's, Argos-only drifters were joined by GPS/Argos buoyscapable of higher accuracy positioning and many more positions per day than Argos alone. A number of innovative satellite systems, newly available or planned for the near future, have significant implications for drifting buoy design. The newtechnologies fall into two categories: positioning and telemetry.Currently civilian GPS receivers have a rated positional accuracy of 100 meters and a typical 2DRMS accuracy of 30-40 meters. Using currently available Wide Area Differential GPS (WADGPS) postprocessing techniques, 2DRMS accuracies of 2-3 meters have been achieved. The Wide Area Augmentation System (WAAS) being deployed by the US Federal Aviation Administration for precision aircraft navigation will soon provide differential correction data via geosynchronous satellites in real time. WAAS signals can be received by GPS receivers with no additional hardware or power requirements. Positional accuracies of 2 meters have been reported from WAAS system tests. WAAS should be available in the continental US by mid 2000 and WAAS-compatible systems are beingdeveloped in Europe and elsewhere.
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