A new Global Positioning System drifter buoy

A low cost GPS (Global Positioning System) drifter buoy platform has been developed to greatly improve Lagrangian current measurements. The GPS drifter has provided improved spatial and temporal resolution over Argos drifters and its practical, lightweight housing allows easier handling than Loran drifters. A simple differential technique was used to improve accuracy and overcome the intentional downgrading that is imposed on GPS by the use of selective availability. The drifters also feature a thermistor chain that obtains temperature profiles immediately below the surface. Eleven of these drifters were built and successfully tested in Lake Huron. The differential accuracy was determined experimentally to be on the order of 15 meters.<>