The Research On The Development And Application Of AIS Equipment In In-land Rivers

As an important supplement of radar and other navigation equipments, AIS (Automatic Identify System), having the VHF digital communications system, is able to precisely transmit the name, shipping length, shipping width, sea gauge, heading status and other shipping information of a ship to the ships nearby, so as to provide important references for the navigation safety. Being relatively mature, the device has been widely used in marine technology. With the increasingly urgent demand for marine monitoring, AIS is being made more widespread in the Yangtze River and other major inland waterways. The information provided by AIS has been the focus of the maritime sectors all the time, and its demand is becoming stronger and stronger. Relative to the common digital wireless communication systems, AIS is strict with working frequency, frequency stability, rise time and other parameters, so it is dominated by the imported product enterprises. Until recent years, only a handful of domestic manufacturers are gradually rising up.This study makes an effort to develop a set of completely autonomous AIS equipment. At present, it has been successfully developed, and is running on 43 commercial ships to serve the maritime safety.In chapter 2, starting from the AIS baseband signal, the bottom equipment GMAK (Gaussian Filtered Minimum Shift Keying) and the realization process of DSK signal modulation-demodulation mechanism are studied in detail. And then, the application of a special chip CMX7042 in AIS is introduced. And finally, the fast software modulation-demodulation method based on RISC (Reduced Instruction Set Computing) CPU is discussed and practiced, and has some progresses in the signal modulation.In chapter 3, the focus is on how to obtain the precise world standard time with GPS as the standard, and make the pulse time to bring into correspondence with the its second of world time, and the difference has to be under the AIS international standard. Also, the interrupt control demand of AIS equipment is analyzed, and the system interrupt operation mode is introduced.In chapter 4, regarding the Shanghai Wusong AIS signal status as the object of the research, the number of all classes of ships in inland river AIS is analyzed, and the existing problems in AIS popularizing are studied, including a considerable number of ships with inaccurate time-align, over-stability of transmitted power, and the planning shortage of the AIS channels themselves.In chapter 5, the application of AIS in navigation mark field is described, and the broad prospect and technical proposal of AIS in the aid-to-navigation field are presented. Considering the power shortage of AIS, a way to integrate AIS and ZigBEE into the navigation mark is put forward. Along with AIS system entering into inland river navigation mark, a set of ZigBEE frequency spectrum coexisting with AIS are developed, which are used to meet the requirements, such as navigation mark telemetering and telemonitoring, ship notification etc. All of these works provide attempts for the further application of ZigBEE in ships.Under the help of the relative maritime sectors and enterprises, the commissioning products are developed successfully, have been installed on all classes of ships. Until now, all the products operate well with stable performance and high precision, and play important roles in the ship operation and navigation safety.