Advances in autonomous GPS Lagrangian buoys

Drifting buoys with onboard position receivers have provided valuable Lagrangian current data since their introduction in the mid-1980s. Current autonomous buoys with Global Positioning System (GPS) receivers provide data with quality and quantity unobtainable with ARGOS-only positioning. Advances in hardware, software, and pricing are rapidly broadening the range of applications for these buoys. The author has been constructing autonomous GPS drifters for three years. By using a loosely-coupled electronics design, five major engineering revisions have been possible in that period, reflecting the great advances made in the enabling technologies. This design progression is discussed, along with the specifications made possible by the current technology. A new enabling technology (Orbcomm) is considered as to its applicability to GPS drifting buoys and its potential competition with current telemetry methods of VHF packet radio and ARGOS.