基于规则子阵的数字波束形成及旁瓣对消

发布时间：2018-06-12 22:29

本文选题：数字波束形成 + 旁瓣对消　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：未来复杂、多变的海战环境要求舰载相控阵雷达在各种条件下自适应工作,使雷达与使用环境始终处于最佳的匹配状态。近几年来,数字波束形成的应用和实时自适应处理技术的发展使舰载相控阵雷达的自适应能力提高到一个新水平。数字波束形成是采用数字技术实现瞬时多波束,能够对干扰源自适应瞄零,有很强的自适应处理能力,并可获得超分辨率和超低旁瓣性能。雷达系统中,如何使得阵列方向图的旁瓣得以有效地改善已经成为一个基本且十分关键的问题,对于规则数字子阵,可以利用在阵元上采用两种不同形式的加权方法来达到对和差波束的旁瓣进行同时抑制的效果,分别是用于降低和波束旁瓣的Taylor加权和用于降低差波束旁瓣的Bayliss加权。而针对共形面阵,也要整体考虑幅度加权的方法,但是由于共形阵列不再是均匀阵列,幅度加权时需要优化设计来达到低的副瓣,采用加权与目标方位和俯仰无关的权矢量来降低复杂度,且要尽量减少信噪比(SNR)的损失。随着雷达技术的发展以及现代海事战场需求的持续增加,自适应旁瓣对消技术已成为雷达系统至关重要的部分,它是信号处理技术与天线技术相结合的产物,已成为抑制阵列天线旁瓣干扰的有效方法,在雷达中的应用也变得越来越广泛。在有源干扰存在的情况下,通常人们采用能够使得对消剩余输出最小的准则即最小均方准则(LMS),自适应地改变辅助天线的加权系数,使得干扰信号的输入功率达到最小,在方向图上具体表现为:在干扰信号的接收方向上形成空间零点,从而实现对旁瓣干扰的抑制。自适应阵列系统中,存在若干影响旁瓣对消系统性能的重要因素,诸如量化噪声、通道噪声、通道不一致性、目标回波信号、干扰带宽、天线之间的距离、不同的数字波束形成方法等。而对于辅助通道的选取,包括辅助天线的数目选择,辅助天线的位置选择等,更是影响旁瓣对消性能的关键因素。本文基于数字波束形成的理论研究,采用一种新的权值优化方法来实现低副瓣的和差波束形成,并考虑单元方向图因素的影响,分析有向阵元对形成折面阵的和差波束方向图所造成的影响。另外基于自适应旁瓣对消的理论基础,对影响旁瓣干扰对消性能的几个重要因素进行仿真,包括干扰信号的带宽、天线之间的距离、不同辅助天线个数以及天线机械扫描对旁瓣对消性能造成的影响,给出仿真结果,并进行相应的分析。针对项目需求,对旁瓣对消系统的辅助通道的选取提出不同的方案设计及对应的性能分析,建立仿真模型,根据性能分析结果优化辅助通道的选取。最后结合方案设计,对旁瓣对消系统的各个功能模块进行了详细介绍并结合其程序设计给出相应的实现流程。
[Abstract]:In the future, the complex and changeable naval battle environment requires shipborne phased array radar to work adaptively under various conditions, so that the radar and the operational environment are always in the best matching state. In recent years, the application of digital beamforming and the development of real-time adaptive processing technology have improved the adaptive capability of shipborne phased array radar to a new level. Digital beamforming uses digital technology to realize instantaneous multi-beam, which can self-adaptively aim at zero to interference source, has strong adaptive processing ability, and can obtain super-resolution and ultra-low sidelobe performance. In radar system, how to improve the sidelobe of array pattern effectively has become a basic and critical problem. Two different weighting methods can be used to simultaneously suppress the sidelobe of the sum beam, I. E. Taylor weighting for reducing the sidelobe and Bayliss weighting for reducing the sidelobe of the differential beam. For conformal array, the amplitude weighting method should be considered as a whole, but because conformal array is no longer uniform array, it is necessary to optimize design to achieve low sidelobe when amplitude weighting. Weighted weight vectors independent of target azimuth and pitch are used to reduce complexity and SNR loss is minimized. With the development of radar technology and the increasing demand of modern maritime battlefield, adaptive sidelobe cancellation technology has become the most important part of radar system. It is the result of combining signal processing technology with antenna technology. It has become an effective method to suppress array antenna sidelobe interference, and has become more and more widely used in radar. In the presence of active jamming, the least mean square criterion, which can minimize the residual output of cancellation, is usually adopted to adaptively change the weighting coefficient of the auxiliary antenna, so that the input power of the interference signal is minimized. In the pattern, the spatial zero is formed in the direction of receiving the interference signal, which can suppress the sidelobe interference. In adaptive array systems, there are several important factors that affect the performance of sidelobe cancellation systems, such as quantization noise, channel inconsistency, target echo signals, interference bandwidth and the distance between antennas. Different digital beamforming methods and so on. The selection of auxiliary channels, including the number of auxiliary antennas and the position of auxiliary antennas, is a key factor affecting the performance of sidelobe cancellation. Based on the theoretical research of digital beamforming, a new weight optimization method is used to realize low sidelobe sum difference beamforming. The effect of directed array elements on the sum difference beam pattern of a folded plane array is analyzed. In addition, based on the theoretical basis of adaptive sidelobe cancellation, several important factors affecting the performance of sidelobe interference cancellation are simulated, including the bandwidth of interference signal, the distance between antennas, The effects of different number of auxiliary antennas and antenna mechanical scanning on the sidelobe cancellation performance are presented. The simulation results are given and the corresponding analysis is carried out. According to the requirements of the project, different scheme design and corresponding performance analysis are put forward for the selection of auxiliary channel of sidelobe cancellation system. The simulation model is established, and the selection of auxiliary channel is optimized according to the result of performance analysis. Finally, each function module of the sidelobe cancellation system is introduced in detail with the scheme design, and the corresponding realization flow is given in combination with the program design.
【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】：TN958.92

【参考文献】