AIS信号接收解调算法研究与实现
发布时间：2019-03-19 19:53
【摘要】：船舶自动识别系统(Automatic Identify System,简称AIS)是一种操作在海上甚高频(Very High Frequency,简称VHF)频带的自动连续广播系统,用于实现船舶与船舶间、船舶与基站间的相互通信。为了扩大AIS的覆盖范围,星载AIS应运而生,它为全球所有装有AIS设备的海上移动装置提供基本的监测信息。然而星载AIS也带来了多普勒频偏和多信号碰撞的问题。因此研究星载条件下AIS信号的接收解调技术具有重要的理论意义和应用价值。本文根据AIS信号处理系统的实际需求,确定了基于TI公司低功耗浮点处理器TMS320C6748和Xilinx公司Artix-7系列FPGA的硬件平台。在对AIS信号解调算法及其分离技术进行了大量仿真研究的同时,在该平台上实现了AIS信号解调算法。本文主要研究内容有：重点研究了AIS信号的非相干解调算法。分别讨论了帧头检测、频偏估计及符号定时技术,并给出了不同测频和定时方法的比较。同时就频偏和定时对信号解调性能的影响进行了大量的仿真分析。提出了星载条件下的多信号分离算法。星载AIS由于覆盖范围大而易引起多信号碰撞,当两路AIS信号幅度差异较大时,可以先解调幅度较大的信号,然后根据解调得到的符号序列以及幅度、相位和时延等参数估计值重构出幅度较大的信号,从而实现同信道干扰下AIS信号分离。实现了基于Xilinx Artix-7平台的信号帧头检测模块和基于TI TMS320C6748平台的AIS基带信号解调模块。对于每一模块的具体实现方法给出了详细说明。深入分析了实现过程中遇到的问题并给出实际解决方案。实现了FPGA与DSP之间的EMIF通信,DSP与PC的UART通信,并对整个系统进行了功能和性能的测试,测试结果都满足实际需求。
[Abstract]:Ship automatic Identification system (Automatic Identify System,) is an automatic continuous broadcast system which operates the VHF (Very High Frequency, (VHF) band at sea. It is used to realize the communication between ship and base station. In order to expand the coverage of AIS, Spaceborne AIS emerged as the times require. It provides basic monitoring information for all marine mobile devices equipped with AIS equipment in the world. However, spaceborne AIS also brings the problems of Doppler frequency offset and multi-signal collision. Therefore, it is of great theoretical significance and application value to study the receiving and demodulating technology of AIS signal under spaceborne conditions. According to the actual requirement of AIS signal processing system, the hardware platform based on low-power floating-point processor TMS320C6748 of TI company and Artix-7 series FPGA of Xilinx company is determined in this paper. Based on the simulation of AIS signal demodulation algorithm and its separation technology, the AIS signal demodulation algorithm is implemented on this platform. The main contents of this paper are as follows: the non-coherent demodulation algorithm of AIS signal is studied in detail. The frame head detection, frequency offset estimation and symbol timing techniques are discussed respectively, and the comparison of different frequency measurement and timing methods is given. At the same time, the effect of frequency offset and timing on signal demodulation performance is simulated and analyzed. A multi-signal separation algorithm under spaceborne conditions is proposed. Spaceborne AIS is easy to cause multi-signal collision because of its wide coverage. When the amplitude difference between two AIS signals is large, the signals with larger amplitude can be demodulated first, and then according to the demodulated symbol sequence and amplitude, The parameters such as phase and time delay are used to reconstruct the signals with larger amplitude, so that the AIS signals can be separated under co-channel interference. The frame header detection module based on Xilinx Artix-7 platform and the AIS baseband signal demodulation module based on TI TMS320C6748 platform are implemented. The detailed implementation method of each module is given in this paper. In-depth analysis of the problems encountered in the process of implementation and practical solutions are given. The EMIF communication between FPGA and DSP and the UART communication between DSP and PC are realized. The function and performance of the whole system are tested, and the test results meet the actual requirements.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U675.7
[Abstract]:Ship automatic Identification system (Automatic Identify System,) is an automatic continuous broadcast system which operates the VHF (Very High Frequency, (VHF) band at sea. It is used to realize the communication between ship and base station. In order to expand the coverage of AIS, Spaceborne AIS emerged as the times require. It provides basic monitoring information for all marine mobile devices equipped with AIS equipment in the world. However, spaceborne AIS also brings the problems of Doppler frequency offset and multi-signal collision. Therefore, it is of great theoretical significance and application value to study the receiving and demodulating technology of AIS signal under spaceborne conditions. According to the actual requirement of AIS signal processing system, the hardware platform based on low-power floating-point processor TMS320C6748 of TI company and Artix-7 series FPGA of Xilinx company is determined in this paper. Based on the simulation of AIS signal demodulation algorithm and its separation technology, the AIS signal demodulation algorithm is implemented on this platform. The main contents of this paper are as follows: the non-coherent demodulation algorithm of AIS signal is studied in detail. The frame head detection, frequency offset estimation and symbol timing techniques are discussed respectively, and the comparison of different frequency measurement and timing methods is given. At the same time, the effect of frequency offset and timing on signal demodulation performance is simulated and analyzed. A multi-signal separation algorithm under spaceborne conditions is proposed. Spaceborne AIS is easy to cause multi-signal collision because of its wide coverage. When the amplitude difference between two AIS signals is large, the signals with larger amplitude can be demodulated first, and then according to the demodulated symbol sequence and amplitude, The parameters such as phase and time delay are used to reconstruct the signals with larger amplitude, so that the AIS signals can be separated under co-channel interference. The frame header detection module based on Xilinx Artix-7 platform and the AIS baseband signal demodulation module based on TI TMS320C6748 platform are implemented. The detailed implementation method of each module is given in this paper. In-depth analysis of the problems encountered in the process of implementation and practical solutions are given. The EMIF communication between FPGA and DSP and the UART communication between DSP and PC are realized. The function and performance of the whole system are tested, and the test results meet the actual requirements.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U675.7
【相似文献】
相关期刊论文 前10条
1 黄智杰,易志强,张明,王匡;新一代卫星电视标准中解调算法的研究[J];浙江大学学报(工学版);2005年08期
2 居滋培;华闰祺;白凌;;微波复合调制信号解调算法分析与实现[J];上海理工大学学报;2009年04期
3 黄赞武;魏学业;刘泽;;冲击干扰下高压不对称脉冲特征频率提取算法[J];铁道学报;2012年12期
4 刘东华;章兰英;侯孝民;郑海昕;;PCM/FM信号软件化解调算法研究[J];遥测遥控;2007年01期
5 韩涵;龚e，
本文编号：2443844
本文链接：https://www.wllwen.com/kejilunwen/chuanbolw/2443844.html
