【作者】 施龙飞；

【导师】 肖顺平；

【作者基本信息】 国防科学技术大学 ， 信息与通信工程， 2007， 博士

【摘要】 随着雷达极化信息处理技术的不断进步,以及越来越多的具备极化测量能力的新型雷达的出现,极化信息在雷达抗干扰中的应用正逐步受到重视。论文以雷达极化抗干扰为研究内容,针对现有雷达抗干扰中亟待解决的一些难题,充分挖掘极化信息处理的潜力,针对性地开展了极化抗干扰方法的研究。主要内容包括:针对噪声压制式干扰的自适应极化对消、干扰背景下雷达目标的极化增强、转发式假目标干扰的极化鉴别以及低空目标镜像角闪烁干扰的极化抑制等问题,作为基础性内容,论文对雷达极化测量方法首先进行了研究。极化测量是极化信息处理的前提,极化抗干扰面临的巨大挑战对极化测量性能提出了更为苛刻的要求,现有的分时极化体制和同时极化体制均已不能满足。论文提出了一种复合编码同时极化测量体制,该体制用“正交地址码+伪随机码(或线性调频脉冲)”的复合编码代替了传统同时极化体制所采用的伪随机码序列组,能够同时获得良好的自相关特性和互相关特性,为多假目标的极化鉴别等极化抗干扰方法提供了性能良好的平台。自适应极化对消器(Adaptive Polarization Canceller,APC)是对抗噪声压制式干扰应用最普遍的一种极化滤波器,随着战场电磁环境的恶化,以及数字信号处理技术在现代雷达中的广泛应用,以相关反馈环电路为核心的传统自适应极化对消器已不再适用。为此,论文研究了APC的迭代滤波算法,该算法收敛速度快,稳定性好。对雷达极化进行优化可以抑制干扰、增强目标,实现信干比的最大化,从而提高雷达对目标的检测概率和测量精度。囿于极化雷达的发展水平,现有雷达极化优化算法中很少对发射极化和接收极化进行联合优化,因而限制了极化优化处理的增益。论文研究了干扰背景下雷达发射、接收极化的联合优化算法,在抑制干扰的同时使目标接收功率最大化,相比于已有的极化对比增强算法,不仅先验知识要求少(目标散射矩阵、干扰极化状态均未知),而且避免了繁琐的优化计算过程。高逼真度假目标干扰是雷达面临的一大威胁,通过提取和利用极化域特征差异来鉴别真、假目标是对抗多假目标的一条重要途径。现有假目标大体可分为固定极化和极化调制两种,论文分别利用它们与目标回波矢量迥异的极化比不变性和张量积矩阵空间散布性进行鉴别。在“目标”间互扰较小的情况下,具有很高的鉴别率,在假目标数目较大、“目标”间互扰较大的情况下,鉴别率有所下降,但通过适当调整门限可以有效地予以改善。低空突防目标在“远距离区”的多径效应对雷达仰角测量的影响构成一个两点源角闪烁模型。论文研究了一种两点源角闪烁干扰的极化抑制方法,该方法利用两点源相对幅度比对称时,角闪烁线偏差正、负相消的有利特性,优化设计了发射极化。仿真实验表明,该方法相比于普通极化分集方法,具有更佳的抑制性能,可较明显地降低角闪烁线偏差的起伏。论文以战场电磁环境为背景,充分考虑了工程应用中的重要影响因素,在极化测量仿真平台上进行了仿真验证,所提出的极化抗干扰方法具有向工程应用方向发展的潜力。论文的研究拓展了雷达极化抗干扰技术的外延,丰富了雷达极化信息处理理论的内涵。更多还原

【Abstract】 With the development of the radar polarization processing technology and the emerging of the new type radar with polarization measure abilities, the application of polarization information in radar interference suppressing is regarded more and more. Taking the radar interference suppressing in polarization field as a major content, the potential of polarization information processing is digged in this thesis. And the suppression of radar interference using polarization information is studied aiming some difficulties facing in radar warfare nowadays. The major content includes: the adaptive polarization canceller for suppressing the noise jamming, the optimization of receiving and emitting polarization simultaneously on the interference background, the distinguishing of active decoy in polarization field, the angle glint suppressing of invading target at low altitude using polarization information. And the polarization measurement is studied as a basement.As the precondition of polarization processing, the polarization measurement is demanded to be more precise by the interference suppression in polarization field on the more complicated electronic warfare background, and the traditional measurement method couldn’t be satisfied anymore. In this thesis an instantaneous polarization measurement method using composite coded signal is produced. In this method, a code compounded with orthonormal code and PN code is used to replace the traditional PN code. The better auto correlation and cross correlation character is obtained. A better platform is provided by this method for the interference suppression algorithms such as multi-decoy distinguish.The Adaptive Polarization Canceller (APC) is the most popular polarization filter to suppress the noise jamming nowadays. With the wide usage of digital technology in radar signal processing, the traditional adaptive polarization canceller, which is built on the correlation feedback circuit, isn’t applicable in the modern radar and wickeder electronic battle field anymore. So, the APC iterative algorithm is studied in this thesis. This algorithm can converge more quickly, be more stable.To optimize the radar polarization can suppress interference signal, and enhance target echo and achieve signal-to-interference ratio maximization, improve radar target detection probability and measurement precision. On account of the limited development level of polarimetric radar, the joint optimization of transmitting polarization and receiving polarization is involved rarely in the existing radar polarization optimization algorithm, therefore the polarization optimization gains is limitted. The joint optimization algorithm of transmitting polarization and receiving polarization is studied in this paper, where interference suppressing and the maximization of target receiving power are achieved at the same time. Compared to the existing polarization contrast enhancement algorithms, not only less priori knowledge is demanded (target scattering matrix and interference polarization state are unknown), but to avoid the cumbersome optimizing calculation process.The high-fidelity active decoy is a great threat to radar. The real target and the decoy can be distinguished by using the different character of the targets and the interference in polarization field. The decoys are categorized into stable polarization decoy and modulation polarization decoy. They are distinguished of the target scattering vectors by using the widely difference of polarization ratio stability and tensor multiple matrix distribution character. When the impack between targets (including the real targets and the decoys) is small, the distinguish performance is very well. The performance is descent a certain extent when the decoy number is bigger and the impack between the targets is stronger. This performance can be effectively improved by setting a adaptive limit.The angle measurement of the invading target at low altitude in ’remote area’ can be affected by the multiple paths. This can be simplified by two-spot angle glint model. An polarization diversity method is produced to suppression the angle glint interference. The positive value of angle glint error can be decreased by the negative value, when the amplitude rates are symmetrical. Using this character, a better suppression performance can be obtained statistically by designing the emitting polarization. It is testified by the experiment results that this polarization diversity method has a better angle glint error suppression performance comparing with the common polarization diversity.The interference suppression methods are studied in this thesis with fully consideration of the engineering realization. The polarization information processing is analyzed in the frame of radar signal processing. The algorithm is testified on the polarization measurement simulation platform, and these interference suppressing methods have the potential to be developed in the engineering realization. The interference suppressing technology is extended and the polarization information processing theory is enriched in this thesis..更多还原