基于非起伏目标的相参积累TBD方法研究

【作者】 王瑞军；

【导师】 张晓玲；

【作者基本信息】 电子科技大学 ， 信号与信息处理， 2011， 硕士

【摘要】 近年来,目标雷达反射截面积(RCS)减小了一到两个数量级,进而降低了目标发现概率。面对弱小目标的威胁,检测前跟踪(TBD)方法是一种有效的目标检测技术。然而现有的TBD方法在多帧回波间进行联合处理时均使用了非相参积累,使得算法积累效率较低,在低信噪比情况下往往需要对较多帧的回波进行处理才能得到较好的检测效果,数据处理量大,实时性差。本论文针对上述问题对TBD方法进行了研究。通过分析相参雷达的多帧回波数据模型及相参积累的前提条件,针对非起伏目标提出了三种基于多帧间相参积累的TBD方法。这些方法通过多帧回波的相参积累实现了输出SNR的提高。基于相参积累的TBD方法改善了目标能量的积累效率,能够在较少帧的回波数据下有效的提高目标的发现概率。本文的主要内容有:1.研究了多帧回波相参积累TBD方法的可行性及存在的困难。首先建立了多帧回波的相参数据模型,通过数据模型的分析,指出多帧回波相参积累的TBD方法理论上切实可行。然后对相参积累TBD方法存在的技术难点进行了分析,指出在相参积累过程中减少噪声对能量积累的影响、补偿目标回波走动及改善相参TBD方法算法复杂度等问题是实现相参TBD方法所需要解决的困难。2.提出了三种基于相参积累的TBD方法。针对相参积累TBD方法所面临的困难,文章在多帧回波数据下通过数据拼接、回波方位选取及噪声置零、走动补偿等措施实现了多帧回波间的相参积累。根据距离走动补偿方法的不同分别提出了基于径向速度估计的相参积累TBD方法、基于radon变换的相参积累TBD方法以及基于keystone变换的相参积累TBD方法。详细介绍了三种方法的原理、处理流程及优缺点;最后通过仿真实验验证了三种算法的有效性并通过仿真实验对三种相参积累TBD方法的性能进行了比较,指出基于keystone变换的相参积累TBD方法检测性能良好且运算量小,为三种方法中最优。。3.相参积累TBD方法实时性研究。针对基于keystone变换的相参积累TBD方法运算复杂的问题,在合理的雷达系统参数范围内,对该方法进行了算法优化,并设计了相应的并行处理流程,使得该方法运行时间大大缩短。更多还原

【Abstract】 In the recent few years, the RCS magnitude of radar has decreased for one to two times through the stealth measures. All these treatments make them difficult to be found. Facing the threat of weak targets, the track-before-detect skill has a good effect. However, the existing TBD methods use non-coherent integration among multi-frame echoes and they have low effect in detection. So it need more date to get wonderful result and this causing the complexity computation.According to the above problem, in this paper we make a study of TBD using coherent integration. In the studying, we analysis the model of echoes and indicate the problems of coherent integration then we gave a research of coherent TBD method. For the features of weak targets, this technology enhances the target SNR by coherent integrating of multi-frame echo. This process can further improve the detection probability of enemy targets with less data.The main contents are as follows:a) Researched the feasibility of coherent TBD method and its difficulties. First, We gave the coherent mathematical model and analyzed the coherent TBD method, indicated that the method is practicable. Then the difficulty of the idea was analyzed. It pointed out that the less target echo, target migration and complexity computation were the problems that the method needing to solve.b) Proposed three methods of TBD basing coherent integration. For the problems of coherent TBD, after connected multi-frame echoes, selected the azimuth, zeroed the noise and compensated migration, the method realized coherent integration by FFT. In this paper three coherent TBD methods were proposed according the difference of compensation method: coherent integration TBD method basing velocity estimating; coherent integration TBD method basing radon transforming and coherent integration TBD method basing keystone transforming. And the thesis discussed the processes and principles of these methods in detailed. At last, thesis tested and verified that these new methods through simulation and compared the performance of these three methods through simulation experiment at first, and pointed out that the coherent integration TBD method basing keystone transforming is the best..c) Researched the instantaneity of coherent TBD. For the problem of complexity computation, thesis analyzed the system parameters design. Under these parameters we gave a parallel processing program which reduced the running time of coherent TBD method.更多还原