基于知识辅助的机载雷达杂波仿真与抑制方法研究

发布时间：2018-04-22 04:03

本文选题：机载雷达 + 知识辅助　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：机载雷达下视工作时接收到的地杂波功率较强,而且当雷达工作在复杂地形环境中时,杂波呈现出明显的非均匀性,这为机载雷达检测运动目标带来了困难,因此需要对雷达杂波特性进行分析,并对机载雷达的杂波抑制技术进行研究。但获取雷达实测数据的周期长而且成本高,因此需要利用计算机仿真的办法来模拟杂波数据。空时自适应处理技术联合空域和时域信息进行二维自适应滤波,能够在抑制杂波的同时保证目标的相干处理增益,是机载雷达杂波抑制的一项关键技术。为了获得最优的空时自适应处理性能,理论上用于估计杂波统计特性的独立同分布样本数不应少于系统自由度的两倍。但实际杂波的非均匀性导致训练样本数不够,严重降低空时自适应处理性能。本文围绕非均匀杂波的仿真和抑制方法展开研究。论文内容可以概括如下:1、分析了机载雷达杂波信号的数学模型和空时自适应处理基本原理,并对几种常用的降维空时自适应处理方法进行了仿真分析。2、针对非均匀杂波的仿真方法,提出了一种基于数字高程和地表覆盖的机载雷达杂波仿真方法,解决了包括坐标系变换、遮挡判断和杂波功率、导向矢量计算等一系列问题,提出了将通道失配和内部杂波运动融合到杂波仿真中去的方法。仿真结果表明,所提的基于地理环境先验知识的杂波仿真方法能够有效模拟机载雷达接收到的非均匀杂波。3、在非均匀杂波抑制方面,首先分析了分段处理和广义内积这两种方法在非均匀杂波抑制方面的应用,然后提出了一种在阵元-多普勒域进行色加载滤波处理的方法,并分析了当存在通道失配以及内部杂波运动情况下该方法的杂波抑制性能。仿真实验表明,该色加载滤波方法能提高雷达系统对目标的检测性能。
[Abstract]:The ground clutter received by airborne radar is very strong, and when the radar is working in complex terrain environment, the clutter presents obvious heterogeneity, which makes it difficult for airborne radar to detect moving targets. Therefore, it is necessary to analyze the clutter characteristics of radar and study the clutter suppression technology of airborne radar. But the period of acquiring radar data is long and the cost is high, so it is necessary to simulate clutter data by computer simulation. The space-time adaptive processing technique, which combines spatial and temporal information with two-dimensional adaptive filtering, can suppress clutter and ensure the target's coherent processing gain. It is a key technology of airborne radar clutter suppression. In order to obtain the optimal space-time adaptive processing performance, the number of independent co-distributed samples used to estimate the statistical characteristics of clutter should not be less than twice the degree of freedom of the system. However, the inhomogeneity of the actual clutter results in insufficient number of training samples, which seriously reduces the performance of space-time adaptive processing. This paper focuses on the simulation and suppression of heterogeneous clutter. The contents of this paper can be summarized as follows: 1. The mathematical model of airborne radar clutter signal and the basic principle of space-time adaptive processing are analyzed. Several commonly used space-time adaptive processing methods are simulated and analyzed. Aiming at the non-uniform clutter simulation method, an airborne radar clutter simulation method based on digital elevation and ground coverage is proposed. A series of problems, such as coordinate system transformation, occlusion judgment, clutter power and guidance vector calculation, are solved, and a method of merging channel mismatch and internal clutter motion into clutter simulation is proposed. The simulation results show that the proposed clutter simulation method based on the prior knowledge of geographical environment can effectively simulate the non-uniform clutter .3 received by airborne radar. In this paper, the application of piecewise processing and generalized inner product in heterogeneous clutter suppression is analyzed, and then a method of color loaded filtering in array element Doppler domain is proposed. The clutter suppression performance of this method is analyzed under the condition of channel mismatch and internal clutter motion. Simulation results show that this method can improve the detection performance of radar system.
【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】：TN959.73

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