The IEC61162 protocol analysis and simulation
|School||University of Electronic Science and Technology|
|Course||Electronics and Communication Engineering|
|Keywords||automatic identification system AIS SOTDMA (Self-organized TDMA) simulation software protocol DLL|
AIS is a typical civil CNI system, which actually is a communication data link system integrating communication, navigation and identification functions all together. This kind of system does not require infrastructure support such as base stations. Ad hoc TDMA communication is the core of AIS technology, providing strong self-organizing and self-recovering networking communication capability. This system is an automatic message broadcasting system adopting SOTDMA protocol, using VHF maritime mobile band and operating on automatic and continuous state. This system exchanges information between ship and ship and also between ship and shore, such as ship ID (MMSI), dynamic information (e.g. position, heading, speed), static information or voyage information (ship name, call sign, destination port, etc.) and related safety information, which may include navigation safety information, navigation mark information, meteorological and hydrographic information, course correction information, etc..To meet commonality requirement of maritime product, International Electrotechnical Commission (IEC) issued IEC 61162 standard, which gives a mandatory specification of data format and interface level between AIS product, facilitating their interconnection and interoperation with other maritime electronic product. IEC 61162 is an important protocol for AIS transponder to interconnect and interoperate with external equipment. Analysis of IEC 61162 data protocol is of great importance to establishing a complete AIS system. AIS transponder acquires operating status of external equipment, collects data and connects other input devices via IEC 61162 protocol. Meanwhile, also through this protocol, AIS transponder can send data received from VHF data link to display terminal or other corresponding equipment for processing.This paper,in accordance with features and performance requirements of AIS transponder, with the perspective of actual product design, gives the design analyses of SOTDMA algorithm, transmission functional module and reception functional module that AIS transponder involves, and further detailed analysis and circuit design of frequency synthesis and AGC circuits, as well as theoretical estimation of AIS transmission channel link using wireless communication theory. On this basis, protocol analysis, software design and simulation implementation of AIS external interfaces are described in details.As International Maritime Organization (IMO) issued the mandatory installation requirement and the self location reporting feature of AIS target can be used to automatically monitor and track surrounding ships, which is beneficial to shore/port ship management, maritime ship safe navigation and timely avoidance, therefore, the relevant administrative organizations have used AIS in many applications such as maritime area awareness, maritime surveillance, search and rescue, environmental protection monitoring, ship fleet management, smuggling suppression and anti-terrorism fighting.