气象雷达中解模糊处理的实现方法研究

发布时间：2018-03-08 06:09

本文选题：气象雷达　切入点：DPRF速度扩展　出处：《西安电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：气象雷达是大气监测的一个主要手段,但由于气象雷达的工作波长较短,在一定的发射重复频率下,可能会同时存在速度模糊和距离模糊问题。而模糊问题的存在会引起谱矩参数估计不准确,还会造成雷达难以观察和预测一些特殊的气象现象。针对这一问题本文主要讨论了气象雷达信号处理算法中解模糊的实现方法。其主要内容有:1.对气象雷达的回波特性进行讨论。分析了时域特性和频域特性,仿真构建了一种常见的气象回波高斯模型,给出了工程上常用的两种谱矩估计算法,时域PPP法和频域FFT,同时分析了这两种谱矩估计的性能,并给出实测回波图。2.对解速度模糊的实现方法进行了分析与讨论。说明了判别速度模糊的方法,讨论了几种解速度模糊的方法,包括软件法、DPRF速度扩展法以及三PRF法等,其中,主要讨论了工程上常用的DPRF速度扩展法,针对在DPRF扩展速度中存在部分速度区域的再次模糊的问题,结合仿真分析,对原始的速度扩展公式作了一些相应的改进,使得修正后的速度估计公式真正解决了某一范围内存在的速度模糊的问题。3.对气象信号处理中的解距离模糊方法进行了一系列的讨论与仿真分析。简单说明了随机相位编码法解距离模糊的原理以及其在工程实现中存在的问题,针对问题给出了一种改进后的SZ-2相位编码,主要讨论了SZ-2相位编码的相关技术问题,包括SZ(8/64)相位编码、FIR带阻滤波器的设计以及在解距离模糊时对于地物杂波抑制的处理技术等问题,同时进行了仿真分析,而且通过仿真将高斯自适应频域滤波与时域上四阶IIR高通椭圆滤波器抑制的性能进行了对比,得出高斯自适应频域滤波在地物杂波抑制上具有更好的效果,以及简单阐述了SZ-2相位编码的性能。本文是在实现气象雷达常规处理的基础上,分别对解速度模糊和解距离模糊采用DPRF速度扩展法和SZ-2相位编码技术,并编写了相应的DSP程序。实验结果表明:这两种方法都达到较好的效果。
[Abstract]:Meteorological radar is one of the main means of atmospheric monitoring. However, due to the short working wavelength of meteorological radar, at a certain transmitting repetition rate, There may be both velocity ambiguity and distance ambiguity, and the existence of fuzzy problems may lead to inaccurate estimation of spectral moment parameters. It is also difficult for radar to observe and predict some special meteorological phenomena. This paper mainly discusses the method of resolving ambiguity in the signal processing algorithm of meteorological radar. The main contents of this paper are: 1. The characteristics of time domain and frequency domain are analyzed. In this paper, a common Gaussian model of meteorological echo is constructed, and two common spectral moment estimation algorithms, time-domain PPP method and frequency-domain PPP method, are given. The performance of these two spectral moments estimation is also analyzed. The realization method of velocity ambiguity solution is analyzed and discussed. The methods to distinguish velocity ambiguity are explained, and several methods to resolve velocity ambiguity are discussed, including software method, DPRF velocity expansion method and three PRF method, etc. This paper mainly discusses the DPRF speed expansion method commonly used in engineering. Aiming at the problem of re-blurring part of the velocity region in the DPRF expansion speed, combined with the simulation analysis, some corresponding improvements are made to the original velocity expansion formula. The modified velocity estimation formula can really solve the problem of velocity ambiguity in a certain range. 3. A series of discussion and simulation analysis on the method of resolving distance ambiguity in meteorological signal processing are carried out. The principle of resolving distance ambiguity by computer phase coding method and its problems in engineering implementation. In this paper, an improved SZ-2 phase coding is presented, and the related technical problems of SZ-2 phase coding are discussed. Including the design of the phase coded Fir band-stop filter and the processing technology of ground clutter suppression when the distance is blurred, the simulation analysis is also carried out. Moreover, the performance of Gao Si adaptive frequency domain filter and fourth order IIR high pass elliptic filter in time domain is compared by simulation. It is concluded that Gao Si adaptive frequency domain filter has better effect on ground object clutter suppression. Based on the conventional processing of meteorological radar, the DPRF velocity expansion method and SZ-2 phase coding technique are used to solve the velocity ambiguity and range ambiguity, respectively. The corresponding DSP program is written and the experimental results show that the two methods achieve good results.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN959.4

【共引文献】