A microsatellite system for fine tracking of drifting buoys

Drifting buoys follow the currents and therefore they are an excellent tool for the study of water circulation in the oceans. Furthermore they usually carry other measuring sensors that provide environmental information. Systems for the tracking of moving objects in the ocean already exist that use NOAA satellites as tele-communication carrier and the Doppler effect for the bidimensional localization of the mobile. This implies a well defined configuration of the tracking satellites that allows only one position measurement per day, The existance of the Global Positioning System and of commercial telecommunication satellites specifically devoted to the acquisition of environmental data can be exploited for the accurate tracking of drifting buoys. Moreover such systems can offer a direct access to the acquired data. One system under development and validation, based on an operational microsatellite constellation, is described