The Research On Marine Meteorological Broadcast Based On AIS

The ships in voyage are often vulnerable to storms and thunderstorms. Timely and correctly acquiring weather information of the passing sea area is important to safe-voyage and estimating the time of arrival.Today, network is very popular, and you could get into Internet everywhere in the world. In some places, you could even get into Internet wirelessly. You could get weather information easily from the Internet, and also you could get information about condition and height of wave in some sea area. If we could send the information we get from internet to ships timely, the information will play an important role in safe-voyage.AIS is a kind of ship navigation system developing from 90s last century. AIS(Automatic Identification System), is mainly used in collision avoidance, and is also used in other areas, such as ship identification, ship distress alert, notice SOG and COG, destination and so on. In these AIS messages, message 12 and 14 are addressing safe-related message and safe broadcast-related message. If we could add weather information in these messages, we will broadcast the weather information to certain area or certain ships via AIS system.This paper combine both mentioned above, through connect to Internet, AIS shore stations get certain weather information, using popularly used network language HTML, and jthen store these information in XML format. Via the program tool VC++language, import sea weather information extracted from XML file to functional message written in accordance with the standard. And then send AIS message information by the format of cipher.The PC on shore station send the packaged AIS message to communication control module, through maritime electronic communication interface, that is RS232 or RS485. Then the communication control module analysis AIS message received from serial port, convert these information into HDLC data, adding training sequence, starting bits, frame checksum sequence, ending flag, buffer bits and so on, and transport these information through VHF antenna. The ships installed with AIS equipment could receive these weather information via VHF antennas of themselves, thus realize broadcasting weather information via AIS messages.