359° (for example from a gyro compass) True bearing at own position: 0 to 359° UTC seconds: The seconds field of the UTC time when these data were generated. A complete timestamp is not present. In addition, the following data are broadcast every 6 minutes: IMO ship identification number: a seven digit number that remains unchanged upon transfer of the ship's registration to another country Radio call sign: international radio call sign, up to 7 characters, assigned to the vessel by its country of registry Name: 20 characters to represent the name of the vessel Type of ship/cargo Dimensions of ship, to nearest meter Location of positioning system's (e.g., GPS) antenna on board the vessel: in meters aft of bow and meters port or starboard Type of positioning system: such as GPS, DGPS or LORAN-C. Draught of ship: 0.1–25.5 meters Destination: max. 20 characters ETA (estimated time of arrival) at destination: UTC month/date hour:minute Optional: high precision time request, a vessel can request other vessels provide a high precision UTC time and datestamp Detailed description: Class B units Class B transceivers are smaller, simpler and lower cost than Class A transceivers. Each consists of one VHF transmitter, two VHF Carrier Sense Time Division Multiple Access (CSTDMA) receivers, both alternating as the VHF Digital Selective Calling (DSC) receiver, and a GPS active antenna. Although the data output format supports heading information, in general units are not interfaced to a compass, so this data is seldom transmitted. Output is the standard AIS data stream at 38.400 kbit/s, as RS-232 and/or NMEA formats. To prevent overloading of the available bandwidth, transmission power is restricted to 2 W, giving a range of about 5–10 mi. Four messages are defined for class B units: Message 14 Safety Related Message: This message is transmitted on request for the user – some transceivers have a button that enables it to be sent, or it can be sent through the software interface. It sends a pre-defined safety message. Message 18 Standard Class B CS Position Report: This message is sent every 3 minutes where speed over ground (SOG) is less than 2 knots, or every 30 seconds for greater speeds. MMSI, time, SOG, COG, longitude, latitude, true heading Message 19 Extended Class B Equipment Position Report: This message was designed for the SOTDMA protocol, and is too long to be transmitted as CSTDMA. However a coast station can