利用信号非圆特征的鲁棒波束形成算法研究

发布时间：2018-02-28 23:09

本文关键词： 阵列信号处理鲁棒波束形成非圆信号对角加载非圆特征恢复孔径扩展　出处：《北京理工大学》2014年博士论文　论文类型：学位论文

【摘要】：非圆信号在实际通信与信息处理系统中的应用十分广泛，如AM、BPSK、ASK、UQPSK、QPSK、QAM、GMSK等调制信号。本文工作主要围绕利用信号非圆特征的鲁棒波束形成理论与方法研究展开，主要研究成果与创新点有： (1)针对对角加载技术的加载量确定问题，提出一类利用信号非圆特征恢复思想构造代价函数确定正则化参数（对角加载量）的鲁棒波束形成方法，称为NRDL（Noncircularity Restoral for Diagonal Loading）方法。与现有方法相比，新方法可自动计算最优加载量，对指向误差也具有更好的鲁棒性。在NRDL方法基础上，本文还提出了两种改进的NRDL类方法：波束空间投影（Beamspace Projected， BP-）非圆特征恢复对角加载（BP-NRDL）方法和方位角搜索（Azimuth Searching，AS-）非圆特征恢复对角加载（AS-NRDL）方法。其中前者使用波束空间投影实现对干扰的预滤波后，再使用NRDL方法确定对角加载量；后者在NRDL方法的基础上，通过非圆率最大化准则进一步调整和修正期望信号方位角，通过降低导向矢量指向误差提升波束形成器鲁棒性。BP-NRDL方法性能优势明显，但要求期望信号非圆率与干扰互异；AS-NRDL方法性能优于一般的NRDL方法，且对期望信号与干扰的非圆率互异性无要求。 (2)提出了一种新的利用信号非圆特征的鲁棒广义旁瓣相消器。新方法通过对约束矩阵增加导数约束构造阻塞矩阵，保证阻塞矩阵对期望信号成分的完全抑制，从而提高鲁棒性，称为导数约束广义旁瓣相消器（Derivative Constrained Generalized SidelobeCanceller，，DC-GSC）。期望信号为完全非圆信号时，还可利用非圆特性扩展阵列虚拟孔径，有效提升波束形成器的鲁棒性，称为非圆导数约束广义旁瓣相消器（NoncircularDerivative Constrained Generalized Sidelobe Canceller，NCDC-GSC）。DC-GSC和NCDC-GSC的最优权矢量均为闭式求解，与现有对角加载类方法相比运算量明显降低，且性能更优。 (3)利用干扰信号空域信息的鲁棒波束形成方法研究近几年受到较多关注，本文提出了两种联合利用期望信号非圆特征和干扰空域信息的鲁棒波束形成方法：导数约束非圆率最大化方法在进行干扰空域预滤波后，利用非圆率最大化准则确定最优权矢量，称为DC-NORM（Derivative Constrained Noncircularity-Rate Maximization）方法；宽线性导数约束方法则利用期望信号非圆特性扩展阵列虚拟孔径后，再进行干扰空域预滤波，称为WLDC（Widely Linear Derivative Constrained）方法。两种方法的权矢量均为闭式求解，运算量较小，且对于干扰信号的强非圆特征不敏感，即在干扰信号非圆率大于期望信号，或非圆率存在一定误差的情况下，两种新方法均能保持良好的鲁棒性。另外DC-NORM和WLDC方法均可推广至移动式干扰的应用背景，且无需满足训练数据不含期望信号成分的要求。 (4)探究了信号高阶非圆特性在鲁棒波束形成方法中的利用潜力，提出了两种基于高阶非圆特征恢复的对角加载鲁棒波束形成方法：HNRDL （High-orderNoncircularity Restoral Diagonal Loading）和AS-HNRDL（Azimuth Searching High-orderNoncircularity Restoral Diagonal Loading）方法。与WCPO和RCB等其他主流方法相比，HNRDL方法无需用户参数即可实现最优对角加载量的全自动计算，存在较大指向误差时，也能保持明显的性能优势；与仅利用期望信号二阶非圆特性的波束形成方法相比，HNRDL和AS-HNRDL方法同时适用于BPSK、UQPSK等二阶非圆信号和QPSK、QAM等更高阶非圆信号，适用的应用场合更加广泛。高阶非圆信号在实际系统中的广泛应用使该研究成果具有广阔的应用前景。
[Abstract]:Non circular signals used in the actual communication and information processing system is very extensive, such as AM, BPSK, ASK, UQPSK, QPSK, QAM, GMSK modulation signal. This paper mainly focuses on the use of robust non circular beam signal characteristics of the formation of research theories and methods, the main research achievements and innovations:
(1) for loading the diagonal loading technique to determine the problem, put forward a kind of using the signal non circle feature recovery thought constructs the cost function of the regularization parameter (diagonal loading) robust beamforming method, called NRDL (Noncircularity Restoral for Diagonal Loading) method. Compared with the existing methods, the new method can automatically calculate the optimal the loading quantity, also has better robustness to the pointing error. On the basis of NRDL method, this paper also put forward two improved NRDL methods: beam space projection (Beamspace Projected, BP-) - circular feature recovery (BP-NRDL) method of diagonal loading and azimuth search (Azimuth Searching, AS-) - circular feature recovery diagonal loading (AS-NRDL) method. The former used beam space projection pre filtering on interference, and then use the NRDL method to determine the amount of diagonal loading; the latter on the basis of NRDL method, through Non-circular rate maximization criterion further adjust and modify the desired signal azimuth, by reducing the steering vector pointing error beamforming performance is significantly enhance the robustness of.BP-NRDL method, but the requirements of the desired signal and interference of different non circularity; AS-NRDL NRDL method is better than common, and non circle to the desired signal and interference rate no mutual specific requirements.
(2) this paper presents a robust generalized sidelobe canceller non circle features a new signal. Using the new method by adding derivative constraint structure on constraint matrix block matrix, which block matrix suppression of the desired signal component completely, so as to improve the robustness, called derivative constraints generalized sidelobe canceller (Derivative Constrained Generalized SidelobeCanceller, DC-GSC). The desired signal is completely non circular signals, can also use the non circle characteristics of virtual aperture extension of the array, effectively enhance the robustness of the beamformer, called non circle derivative constrained generalized sidelobe canceller (NoncircularDerivative Constrained Generalized Sidelobe Canceller, NCDC-GSC.DC-GSC and NCDC-GSC) the optimal weight vector are closed to solve compared with the existing class, the diagonal loading method was obviously decreased, and the performance is better.
(3) the formation of research method has been paid more attention in recent years with the robust beam interference signal spatial information, this paper proposes two robust beam combined signal and interference characteristics of non circular spatial information using expectation formation methods: derivative constraints non-circular rate maximization method in interference spatial pre filtering, using non-circular rate maximum of the criteria for determining the optimal weight vector, called DC-NORM (Derivative Constrained Noncircularity-Rate Maximization) method; wide linear derivative constraint method is the use of non expected signal circle characteristics of virtual aperture extension of the array, then the interference of spatial pre filtering, called WLDC (Widely Linear Derivative Constrained) method. The weight vector of the two methods were closed solution, little computation, and the interference signal is not sensitive to strong non circular features, namely in the interference signal of non-circular rate is greater than the desired signal, or non circularity exists In the case of a certain error, the two new methods can maintain good robustness. Besides, DC-NORM and WLDC methods can be extended to the application background of mobile interference, and do not need to meet the requirements of training data without expected signal components.
(4) to explore the potential of using high order signal characteristic circle method in formation in the proposed two robust beam, robust diagonal loading beamforming method based on high-order recovery circle features: HNRDL (High-orderNoncircularity Restoral Diagonal Loading) and AS-HNRDL (Azimuth Searching High-orderNoncircularity Restoral Diagonal Loading) method. Compared with WCPO and RCB etc. the main method, the HNRDL method without user parameters can realize automatic calculation of optimum diagonal loading factor, there is a big point error, also can maintain the performance advantages; and using only the desired signal beam two order non characteristic circle forming method compared with HNRDL and AS-HNRDL method is applicable to both BPSK, UQPSK and other two non order circular signal and QPSK, QAM and other higher order circular signal applications more widely. High order circular signals in the actual systems. Extensive application makes the research achievements have a broad application prospect.

【学位授予单位】：北京理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN911.7

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