This describes a remotely trackable drifter system enabling up to ten units to be monitored from a shore or vessel station. Detailed descriptions. Individual drifters are equipped with a Global Positioning System sensor, radio modems and they transmit their position to the station. Each component has been tested and proved under field conditions. If differential correction is not undertaken, accuracy of about 100 m can be expected. If differential correction of data is completed, accuracy of better than 10 m can be expected.