基于Chirp子脉冲频率步进信号的低空动目标检测技术

【作者】 梁冬青；

【导师】 陈祝明；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2006， 硕士

【摘要】 探测低空与超低空动目标是雷达研究领域的重要内容之一,高分辨率是解决这个问题的重要途径之一。Chirp子脉冲频率步进信号兼有频率步进信号和线性调频信号的优点,是一种高距离分辨力信号。本文对Chirp子脉冲频率步进信号特性进行了研究,并对研究过程中出现的各种问题进行了分析并提出了解决方案;同时,对Chirp子脉冲频率步进信号在低空动目标检测领域的应用进行了研究,为Chirp子脉冲频率步进信号的实际应用提供了理论依据。首先,本文对Chirp子脉冲频率步进信号进行了波形分析,研究了Chirp子脉冲频率步进信号的模糊特性、频谱结构以及合成高分辨距离像的基本过程,讨论了Chirp子脉冲频率步进信号的高距离分辨力和宽带频谱特性。其次,本文对Chirp子脉冲频率步进信号的多普勒效应进行了分析和仿真,在此基础上,分析了对其进行运动补偿的思路,提出了采用最小脉组误差准则进行运动补偿的方法。还对Chirp子脉冲频率步进信号中距离像的混叠和冗余问题进行了分析,指出这些现象是Chirp子脉冲频率步进信号对不同参数的选取引起的。文中总结了Chirp子脉冲频率步进信号参数选取的方法,提出了采用参数选取和目标抽取相结合的方法来解决Chirp子脉冲频率步进信号中距离像的混叠和冗余问题。再次,本文分析了Chirp子脉冲频率步进信号和Chirp信号的回波模拟问题,在此基础上,对Chirp子脉冲频率步进信号和Chirp信号对低空动目标检测的性能进行了比较,结果显示Chirp子脉冲频率步进信号具有较好的性能。据此,提出了Chirp子脉冲频率步进信号在低空动目标检测应用中的系统实现方案。最后,本文就Chirp子脉冲频率步进信号通过频率分集和高距离分辨力消除多路径进行了分析仿真。随后提出了在杂波背景下对动目标进行运动补偿的方法:在同一频点发射两个Chirp子脉冲,在脉压后进行对消,以此来提高信杂比,然后利用最小脉组误差准则进行运动补偿。最后,本文利用上述方法就Chirp子脉冲频率步进信号在低空动目标检测中的应用作了系统地仿真。更多还原

【Abstract】 Detecting target at low-altitude is one of important problems for radar. Based on high distance resolution is an important method of resolving this problem. Chirp-subpulse stepped frequency signal is one of the high distance resolution signals with merits of stepped-frequency signal and chirp signal. This dissertation analyses the characteristics of chirp-subpulse stepped frequency signal, and analyses and resolves kinds of problems in chirp-subpulse stepped frequency signal. This dissertation studies the use of chirp-subpulse stepped frequency signal in low altitude moving target, and studies and provides theoretical basis for practical application of chirp-subpulse stepped frequency signal and processing techniques.First, this dissertation analyses the waveform of chirp-subpulse stepped frequency signal, studies and simulates the ambiguity characteristics, the spectrum structure and the basic process to obtain high resolution range profiles, and discuss this signal’s high range resolution characteristic and wide spectrum characteristic.Secondly, based on the analysis and simulations of the Doppler time-shift for chirp-subpulse stepped frequency signal, this dissertation analyses the velocity compensation method for moving targets in chirp-subpulse stepped frequency signal, and presents a method for compensation of targets’velocity base on the least burst error rule. This dissertation analyses problems of profile aliasing and redundance in chirp-subpulse stepped frequency signal, points out that these problems are resulted from different parameters of chirp-subpulse stepped frequency signal. This dissertation summarizes the method to select parameters of chirp-subpulse stepped frequency signal, presents a method to resolve profile aliasing and redundance in chirp-subpulse stepped frequency signal by the target pick-up algorithm and selecting parameters.Thirdly, this dissertation analyses the echo simulation of chirp-subpulse stepped frequency signal and chirp signal. And the detection capability of chirp-subpulse stepped frequency signal and chirp signal in low altitude moving target is compared. The results show that chirp- subpulse stepped frequency is better. Hereby, this dissertation present system project with chirp-subpulse stepped frequency signal in更多还原