船载AIS信道接入协议的改进与仿真

发布时间：2018-01-03 05:06

本文关键词：船载AIS信道接入协议的改进与仿真　出处：《大连海事大学》2017年硕士论文　论文类型：学位论文

【摘要】：船载自动识别系统(Automatic Identification System,AIS)通过自组织时分多址接入(Self-organized Time Division Multiple Access,SOTDMA)协议实现信道接入和设备间互相通信的功能。随着经济的发展,船舶交通越来越繁忙,因而在交通流密度大的水域,会发生船载AIS发射的时隙冲突,从而造成信息发射失败。对于岸上监控系统表现为监控目标较长时间不更新位置,若更新后,还会出现跳跃现象。这给航行安全和海事监管带来了隐患。因此,研究链路层AIS信道接入协议的性能,降低时隙冲突率对AIS的标准发展及实际应用都很有必要。本文主要工作有:(1)深入分析了 AIS工作原理,重点探讨了链路层的关键技术和AIS工作流程。之后结合AIS工作流程,对SOTDMA协议时隙冲突率分析的理论模型进行了研究。(2)利用Visual Studio开发工具,使用C++对AIS的SOTDMA协议进行仿真,实现了船舶之间的自组织通信以及船舶发射时隙的自主预约功能。之后设置不同的船舶数量以及报文报告间隔,进行仿真实验,重点研究了 AIS的时隙冲突率性能。(3)验证仿真系统的可靠性。将不同场景下得到的仿真结果和理论值进行比较,分析发现时隙冲突率比较接近,变化趋势也一致。之后对真实AIS数据的时隙冲突率进行统计,并在水域真实场景中进行仿真实验。通过对比,发现时隙冲突率结果的差值在可接受范围内,验证了仿真系统的可靠性。(4)针对船舶密集的水域中时隙冲突率比较高的状况,提出了一种改进的时隙预约算法。从仿真结果可以看出,相同负载下,改进的时隙预约算法冲突率更低。
[Abstract]:Automatic Identification System. AIS) Self-Organized Time Division Multiple Access via self-organized time-division multiple access (TDMA). SOTDMA) protocol realizes the function of channel access and communication between devices. With the development of economy, ship traffic becomes more and more busy, so it is in the waters with high traffic density. The time slot conflict of shipborne AIS launch will occur, which results in the failure of information launch. For the onshore monitoring system, the monitoring target does not update its position for a long time, if the position is updated after updating. There will also be jump phenomenon, which brings hidden trouble to navigation safety and maritime supervision. Therefore, the performance of link layer AIS channel access protocol is studied. It is necessary for the standard development and practical application of AIS to reduce the time slot collision rate. The main work of this paper is to analyze the working principle of AIS. The key technologies of link layer and AIS workflow are discussed in detail, and then combined with AIS workflow. The theoretical model of slot collision rate analysis for SOTDMA protocol is studied. (2) Visual Studio is used to develop the model. C is used to simulate the SOTDMA protocol of AIS. The self-organizing communication between the ships and the autonomous reservation function of the ship launch time slot are realized. Then the different number of ships and the report interval are set, and the simulation experiment is carried out. The reliability of the simulation system is verified by the performance of the slot collision rate of AIS. The simulation results under different scenarios are compared with the theoretical values, and it is found that the slot collision rate is close to that of the simulation system. The change trend is also consistent. Then the real AIS data slot collision rate is counted and simulated in the real water scene. Through the comparison, it is found that the difference of the slot conflict rate results is within the acceptable range. The reliability of the simulation system is verified. (4) an improved slot reservation algorithm is proposed to solve the problem of high slot collision rate in ship dense waters. From the simulation results, it can be seen that under the same load. The improved slot reservation algorithm has a lower collision rate.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U675.7

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