【作者】 王霄琼；

【导师】 索继东；

【作者基本信息】 大连海事大学 ， 信息与通信工程， 2010， 硕士

【摘要】 随着海上交通运输业的发展,海上安全问题越来越引起人们的关注。航海雷达系统是海上目标检测的主要技术之一。在现代航海雷达系统中,要求雷达数据处理子系统能够在强干扰下正确地检测出微弱的回波信号,提高雷达系统的检测率。本论文的研究课题来源于交通部基础研究科技项目“航海雷达中频信号数字处理方法的研究”,本论文主要完成其中的杂波处理与信号检测方法的研究内容。以往的目标检测都是在视频信号上进行的,它只对回波幅度进行检测,而丢掉了信号的相位和频率的信息。本论文是在雷达回波信号的中频域上直接采样并进行数字下变频,将中频信号下变频为I／Q两路基带信号,I／Q两路信号保留了原信号中所有的信息,所以可以达到提高检测效率的目的。在对雷达回波信号进行检测的时候采用幅相联合的方法。由于可以从下变频后的I／Q两路信号的幅值信息经过计算得到回波的幅值包络信息,所以在回波幅度检测方面采用的是传统的视频检测的方法—滑窗检测和双极点滤波器。本论文对两种检测方法进行了详细的分析,并对两种算法的系统稳定性、信噪比改善等系统功能做了比较。在强干扰的情况下,我们对小信号进行检测时可以利用回波相位的信息,获取目标的信息。由于无目标距离单元和有目标回波距离单元的相位变化是不同的,针对此特点,本论文提出了一种相位的检测方法—参考单元相位比较法,并且对这种算法做了详细的说明,通过大量的MATLAB实验仿真验证了算法的可实行性。基于DSP环节,主要是基于赛迪公司提供的高速四通道数据采集板SDZ605来完成雷达目标检测。论述了基于DSP的软硬件开发平台的滑窗检测器、双极点滤波器的软件实现及优化处理。并通过仿真结果论证算法的可行性。更多还原

【Abstract】 With the development of maritime transportation, maritime security raises more and more concerns. Marine radar system is one of the main techniques for target detection. In modern marine radar systems, radar data processing subsystem is required to correctly detect the weak echo signals under strong interference, so as to improve the detection rate of the marine radar system.This thesis, depriving from the basic Sci& Tech researching project of "the research of digital processing method of intermediate frequency signal for marine radar " supported by the Ministry of Communication, is mainly researching on the processing method of improving the digital receiver dynamic range of intermediate frequency signal. Usually the radar video signal is used to detect, but it only utilizes the amplitude of the signals and lost the information of phase and frequency of radar signals. In this design, radar signal is sampled at IF and executed DDS, IF signal will become two signals of baseband signal-I/Q, I/Q signals keep all the information of the original signal down, so it can improve the efficiency of the detection.The method of amplitude-phase union is used to detect radar signal. As the envelope of amplitude information of the echo signals can be obtained by the amplitude of down-conversion I/Q signals through some algorithms, so on the amplitude detection, two traditional methods of the video detection are used-Moving window detector、Two-Pole filter. A comparison on system stability, the improving of SNR of two algorithms by Matlab emulation is made.However, when the echo signals are completely overwhelmed by noise, a threshold may not be used to distinguish between target signal and noise, then the echo phase information can be used to obtain the information of object. As the change of the phase of non-target-echo units are different from target-echo units, according this character, a method of phase detection is proposed in this paper-Reference Unit of Comparative Law. And a detailed description of this method is given, and the feasibility is verified by a large number of MATLAB simulation experiments.In the section of the implementation based on DSP, This high-speed four-channel data acquisition board SDZ605 provided by SDRising is used in this design, hardware and software development platform based on DSP which moving window detector、two-pole filter are implement are discussed. And the feasibility of the algorithm is validated by the result of the emulation.更多还原