Optimization And Implementation Of The SOTDMA And CSTDMA Algorithm In AIS System

Automatic identification system is a kind of fast developed nav-aids equipments in recent years. It periodically broadcasts static and dynamic information of the ship, which makes the ship "visible", to protect the safety of the ship and people. After years of development, AIS has been basically popularized. However, most of the domestic AIS equipments are imitation of imported products, and can not be in full compliance with international standards. It is obvious that there are significant gaps between domestic and foreign enterprises. This study is aimed at reducing the huge gaps.Based on international standards ITU1371-4and IEC61162, the research studied the core technology and theory. It implemented the SOTDMA, CSTDMA algorithms in AIS and AIS slot load tester. The research transplanted p,C/OS embedded real-time operating system kernel on ARM7processor and designed a modular and multi-process software system architecture. Based on the designed software system, it also designed and implemented AIS slot load tester and analyzed data of the tester, then improved the previous design.This research implemented SOTDMA and CSTDMA algorithms of AIS based on embedded system and designed AIS slot load tester. With the implemented tester, it also improved the previous designed code. This research is part of a nation-supported program "Key technology and system development of AIS/GNSS shipborne navigation equipment" of Dalian maritime university.