【作者】 刘洁；

【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】 随着我国国民经济的快速增长和对内对外贸易量的不断增大,海上交通运输更加繁盛。航海雷达系统是海上目标探测的主要技术之一,为了能够正确检测目标,在现代雷达接收机中,大动态范围是非常重要的。现代的雷达接收机要求能够实现宽的输入带宽、高的灵敏度和分辨率、大的动态范围、采用数字化处理和具有多信号处理能力,完成对雷达信号的接收工作。动态范围和灵敏度都是宽带数字接收机的关键性能指标。过采样技术和增益控制是解决宽带数字中频接收机的大动态范围问题可行方案,可以提高接收机小信号的检测能力。增益控制可以增大接收机的动态范围,防止强信号引起过载。本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”,本文主要研究提高中频信号数字接收动态范围的处理方法。首先,介绍了雷达接收机的各种动态范围的定义,线性动态范围、增益受控动态范围和无杂散动态范围(SFDR)等,本文中主要接收了这三种不同的动态范围定义。另外在本文中还简单介绍了几种接收动态范围的表示方法以及提出了几种提高动态范围的技术。其次,介绍了中频采样在雷达信号处理中的应用和过采样技术及其噪声整形、FFT提高接收机动态范围的技术。还研究了动态范围的相关参数,分析了扩大接收机动态范围的常规方法,如灵敏度时间控制、自动增益控制、中频限幅器和对数放大器等,并分别指出常规方法应用于宽带数字接收机的局限性。最后,本文基于赛迪雷达信号采集处理平台SDZ605的DSP设计了过采样处理方法。本文的主要研究工作和结果不仅可以提高雷达接收机的测量动态范围,对今后雷达数字中频接收机的设计实现的研究也具有一定的理论和实际意义。更多还原

【Abstract】 With the rapid growth of China’s national economy and internal and external trade volume increasing, shipping becomes more and more prosperous. Marine radar system is one of the main techniques of the target detection at sea, in the modern radar receivers, in order to detect the correct target, high dynamic range is very important.Modern radar receiver requires achieving a wide bandwidth, high sensitivity and resolution, wide dynamic range, digital signal processing and multi-processing capabilities to complete the work of the radar signal reception. Dynamic range and sensitivity are the key characters of broadband digital receiver. Over sampling and gain control are possible methods to solve the problem of large dynamic range for wideband digital IF receiver, and they can improve the receiver’s capabilities to detect small signals. Gain control can increase the dynamic range of the receiver, and to prevent strong signals cause overload. 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.First, it introduces a variety definition of radar receiver dynamic range, the linear dynamic range, gain controlled dynamic range and spurious free dynamic range (SFDR), etc. This paper mainly introduces the three different definitions of dynamic range. Also in this paper introduces several representations of dynamic range and proposes several techniques to improve dynamic range.Then, it introduces the applications of the IF sampling in radar signal processing, and the over sampling and noise shaping techniques and FFT to improve the receiver dynamic range technology. The corresponded parameters for the dynamic range improvement are analyzed. The traditional methods of increasing the dynamic range of the receivers, such as Sensitivity Time Control (STC), Automatic Gain Control (AGC), and band-pass Intermediate Frequency (IF) limiting, are researched. It is pointed out the limitation of the traditional technologies in increasing the dynamic range in wideband digital receiver.Finally, this thesis, based on the DSP of SDZ605 SAIDI radar signal sampling and processing platform, designed the method of over-sampling processing.The main research results can not only be directly applied to improve the dynamic range of the radar receiver, but also have a certain theoretical and practical significance for the future research of radar IF receiver.更多还原