Research And Simulative Implementation Of AIS

As rapid development of navigation technology, vessels develop towards large-scale and high speed. And the density of vessels becomes more and more larger as the increase of sea service. Traditional equipments can’t satisfy the needs of vessel management. AIS is widely used under this condition.Compared with traditional equipments, AIS has more advantages such as it can provide more accurate positioning information and has week influence related to the weather and terrain, and in addition, it can provide abundant dynamic and static information. At the same time, AIS can allocate transmission slots in the condition of no base station using different types of TDMA in different working stage. So IMO forces most of the ships to equip this system to improve the security, and that leads to the widespread use of AIS in the world.Based on the deep research of AIS, this paper simulatively implement this system using software and hardware. The main tasks are:a. We simulate the time slot allocation protocol using NS2and realize the automatic allocation of transmission slot protocol, and then analyse the relationship among the probability of failure of slot allocation, network volume and message report rate based on the simulation results.b. We simulate AIS using hardware, including NRZI, HDLC protocol, GMSK/FM. And then we realize the time slot allocation protocol and transmit data in the appropriate slots.c. We implement upper computer software using VC6.0, and receive data from the simulative system via serial port to test if the system works correctly. At last we take advantage of the Google map to show the GPS information and meet the demand of positioning.At last this paper analysises the communication results of the simulative device. The results show that this device has high positioning accuracy and can communicate normally.At the same time the slot allocation protocol conforms with the regulations that published by ITU.