For more than 30 years, drifting buoys had been sending their observations ashore thanks to the Argos system, exclusively. Argos data are processed by CLS in Toulouse (France) and in Largo (USA). For many years, data are sent onto the GTS in FM18 BUOY and FM94 BUFR (unvalidated template), in parallel.
Since 2008, Iridium Short Burst Data (SBD) is more and more used for the transmission of drifting buoy data ashore. Several centres are processing the raw data in order to send them onto the GTS in FM18 BUOY. Out of them, some are transmitted in FM94 BUFR (unvalidated template), in parallel.
Although never validated by WMO, a template has been widely used for many years. It should be now replaced by TM315009 recently validated. GTS headers for ship data start with character string 'IOB'.