论地对空雷达干扰系统在局部战争中的作用及其发展

文章介绍了从地对空干扰机的发展概况,从单一干扰轰炸瞄准雷达,发展成地对空干扰系统和系列,可以干扰空载作战飞机雷达、导弹制导雷达、精密制导雷达、预警机雷达、星载探测雷达等,分析了这些雷达的干扰原理、干扰方法和干扰机的布局。文章对新体制雷达的干扰压制系数进行了分析,导出各类新体制雷达的干扰压制系数表达式,并提供了计算机仿真和实际试验的结果。文章分析了90年代以来两次现代化局部战争,地对空干扰系统若能发挥作用,将使被入侵国家的损失率下降,使入侵者的损失率升高。地对空干扰系统具有攻防兼备的立体干扰系列功能,需要经费较低,很适合于第三世界国家的需求,具有广泛的发展前景。     

针对警戒雷达的机载远距离支援干扰动态压制区域研究

从传统的雷达干扰方程出发,根据作战体系中远距离支援干扰所面临的实际问题,利用空间几何关系分析了远距离支援中干扰机动态情况下雷达干扰方程;从能量的角度出发,建立了动态描述雷达压制距离的方法,该方法可有效描述出针对警戒雷达的动态压制区域,通过典型数据进行仿真验证了该方法的有效性.     

气象探测雷达模拟训练系统的研制

介绍了气象探测雷达模拟训练系统的组成、工作原理、主要技术及该模拟训练系统的硬件电路设计与软件设计．该系统是专为某种气象探测雷达模拟训练设计，达到了不使用雷达、不放探空气球即可对操作手进行全仿真训练的目的，具有很高的实用性和可操作性．     

储频式雷达干扰机的数字射频存储系统设计方法

随着科技的发展,雷达技术已经广泛应用于人类社会中,为人类社会活动提供许多方便。现在雷达技术主要运用于抗干扰信号等方廊,由于信息时代的到来,传统的雷达干扰方法已经不能适应现代化技术的需求,而数字射频存储器的使用不仅可以对雷达信号进行很长时间的储备,而且能快速、准确的监测信号,为雷达技术的进一步发展提供了有效的技术手段。本文提出一种应用于储频式雷达干扰机的数字射频存储（DRFM）系统设计方法,夯析DRFM系统的一般实现方法。     

声学精度靶工作原理及其误差分析

介绍了基于地面声学传感器布阵的声学精度靶的工作原理和定位公式，进行了初步的仿真验证，最后分析了影响其靶位估计精度的主要因素．     

基于多元方差分析的一种雷达精度检飞数据处理方法

为了更深入的分析雷达精度检飞数据,更科学的评估雷达的战术性能,本文提出采用单因素多元方差分析方法来处理雷达精度检飞数据。以探测距离为影响雷达探测精度的主因素,建立多元方差分析模型。比较三部雷达的测量误差离差阵的仿真结果表明,离差阵可以全面反应雷达探测精度性能。该数据处理方法不但能够得到等效于传统处理方法的结果,而且能够进一步分析探测距离对雷达探测精度的影响程度。     

雷达实时回波模拟系统设计

为解决飞行试验中大型雷达系统评估以及验证复杂度和成本逐步上升的问题,利用数字化模拟技术设计一套雷达实时回波模拟系统。针对应用领域雷达探测空间的各项干扰源多并且分布随机的特点,利用数字化模拟技术进行系统仿真设计。该系统采用模块化设计,设计各项干扰源的功能模型和状态模型,可灵活配置雷达探测空间的目标、环境及干扰因素。试验结果表明:该系统通用性强、成本低、操作灵活,可解决飞行试验过程中日益复杂的雷达系统评估和验证的难题。     

宽带DRFM干扰机信号处理模块设计

目的:提高数字射频存储器(DRFM)干扰机的瞬时带宽、处理能力和灵活性等性能。方法:结合DRFM原理与信道化接收技术,提出了高性能宽带DRFM干扰机信号处理模块的设计方案,并据此采用先进的信号处理器件和高性能ADC、DAC设计硬件平台,完成相应的软件设计。结果:对硬件平台的性能参数进行测试,实验表明其瞬时带宽可达4 GHz,信号最大存储深度约为200 ms,最小转发延迟约为600 ns。结论:该原型机可实现对新体制雷达的有效干扰。     

煤矿井下巷道底板涌水段裂隙探测技术

通过对进行地质物理特征的研究，克服煤矿井下巷道空间较小和金属设施，对雷达发射的电磁波能形成较强干扰，成果探测底板涌水段裂隙，为下一步治理奠定了基础。     

瞬变电磁金属干扰特征及校正方法研究

金属体对瞬变电磁法探测结果的影响较大，研究其影响规律并对干扰数据校正是瞬变电磁法资料解释及处理中的重要内容。论文首先在全空间瞬变电磁场的理论基础上，研究了均匀介质中全空间条件下瞬变电磁场的传播规律和视电阻率计算。然后设计井下金属体干扰实验方案，根据实际情况在井下进行现场探测实验，根据实际探测数据，总结了特定地质条件下瞬变电磁场的分布规律，并分析了金属体对于全空间瞬变电磁场响应的影响规律。根据其影响规律推导金属体干扰的校正函数，并对干扰数据进行校正。最后结合实际探测进行应用，得到校正成果并分析校正效果及其意义。研究表明：金属体对瞬变电磁响应的干扰存在一定规律，通过对金属体干扰的数据进行校正处理能够得到较好的探测效果。     

Photorefractive processing for large adaptive phased arrays

An adaptive null-steering phased-array optical processor that utilizes a photorefractive crystal to time integrate the adaptive weights and null out correlated jammers is described. This is a beam-steering processor in which the temporal waveform of the desired signal is known but the look direction is not. The processor computes the angle(s) of arrival of the desired signal and steers the array to look in that direction while rotating the nulls of the antenna pattern toward any narrow-band jammers that may be present. We have experimentally demonstrated a simplified version of this adaptive phased-array-radar processor that nulls out the narrow-band jammers by using feedback-correlation detection. In this processor it is assumed that we know a priori only that the signal is broadband and the jammers are narrow band. These are examples of a class of optical processors that use the angular selectivity of volume holograms to form the nulls and look directions in an adaptive phased-array-radar pattern and thereby to harness the computational abilities of three-dimensional parallelism in the volume of photorefractive crystals. The development of this processing in volume holographic system has led to a new algorithm for phased-array-radar processing that uses fewer tapped-delay lines than does the classic time-domain beam former. The optical implementation of the new algorithm has the further advantage of utilization of a single photorefractive crystal to implement as many as a million adaptive weights, allowing the radar system to scale to large size with no increase in processing hardware.     

Acoustooptic processor for adaptive radar noise environment characterization

A new 2-D acoustooptic processor that estimates the angular as well as spectral distributions of jammers in the far field of an adaptive phased array radar is described. The operating modes of the system are discussed together with the estimation accuracy achieved. Experimental results are presented to illustrate the operation of the processor, and different acoustooptic cell operating modes are discussed.     

Metamaterial Inspired Radar Absorbers: Emergence,Trends and Challenges

The advances in metamaterial science and technology have raised the expectations of camouflage or stealth researchers to one order higher in terms of absorption characteristics. As metamaterial inspired radar absorbing structures are proving themselves as a good candidate with near unity absorption, feasibility towards hardware realization is necessary. Hence an extensive literature survey of metamaterial inspired radar absorbing structure has been carried out and reported in this paper along with the challenges and material issues. The various types of metamaterial structures that can be used as absorber have been provided along with simulation figures. To make the review more useful, graphene and carbon nanotube (CNT) based radar absorbing structures are also included along with their simulation and fabrication techniques.     

Mutual interference and low probability of interception capabilities of noise radar

Recently, there has been considerable interest in noise radar over a wide spectrum of applications, such as through-wall surveillance, tracking, Doppler estimation, polarimetry, interferometry, ground penetrating or subsurface profiling, detection, synthetic aperture radar (SAR) imaging, inverse SAR imaging, foliage penetration imaging etc. Major advantages of using noise in the transmit signal are its inherent immunity from radio frequency and electromagnetic interference, improved spectrum efficiency, and hostile jamming as well as being very difficult to detect. The basic theory of digital signal processing in noise radar design is treated. The theory supports the use of noise waveforms for radar detection and imaging in such applications as covert military surveillance and reconnaissance. It is shown that by using wideband noise waveforms, one can achieve high resolution and reduced range estimation ambiguity. Mutual interference and low probability of interception capabilities of noise radar are also evaluated. The simulation results show the usefulness of the noise radar technology to improve on conventional radars.     

Direction-of-arrival estimation in radar systems: moving window against approximate maximum likelihood estimator

In this study, we compare two radar target direction-of-arrival (DOA) estimation algorithms: the classical moving window (MW) estimator, implemented in many real radar systems and the approximate maximum likelihood (AML) estimator. The first technique exploits multiple detections in the same time-on-target and the second one exploits the fact that the radar antenna mechanical scanning impresses an amplitude modulation on the signals backscattered by the target. Performances of the two estimators are numerically investigated through Monte Carlo simulation and compared in terms of root-mean-square-error (RMSE), probability of detection and probability of target splitting, the latter being defined as the probability of detecting more than one target when instead only one is present in the cell under test. Numerical results show that the AML estimator generally outperforms the classical MW estimator, also in terms of robustness to target splitting.     

机载摄影稳定平台的自抗扰控制

针对航空摄影稳定平台中非线性、多干扰的控制问题,采用自抗扰控制方法对三框架稳定平台进行分散独立控制。利用拉格朗日定理建立了考虑外部干扰的三框架结构稳定平台的动力学方程。设计独立的扩张状态观测器对每个环架的未知模型动态与外部扰动进行动态估计和补偿,采取非线性状态反馈控制以提高系统的控制性能。通过仿真和实验证明采用该方法设计的控制器不仅能满足系统稳态精度的要求,而且有效抑制了负载变化和不确定性扰动对系统的影响,提高了系统的稳定性和适应性。     

一种改进的Weibull分布杂波仿真方法

针对目前Weibull分布杂波仿真中没有考虑线性滤波器物理可实现性问题,首先深入研究了该杂波模 型的统计特性及其ZMNL仿真方法;在此基础上,引入最小相位特性与复倒谱技术,提出了一种物理可实现的滤 波器产生方法,同时详细阐述了物理可实现Weibull分布杂波随机序列产生的流程;最后,进行了仿真实验,仿 真结果证明了该方法的准确性和有效性。该方法产生的杂波可用于雷达信号模拟、雷达图像分析及雷达最优信 号处理器设计。     

Order adaptive local polynomial FT based interference rejection in spread spectrum communication systems

Methods for jammer rejection in the spread spectrum communications, based on the time-frequency representations, have been proposed in order to improve the desired signal receiving performances. In this paper nonstationary jammers were considered and the local polynomial Fourier transform (LPFT) was used to represent the received corrupted signal. Time-varying filtering was implemented in optimal LPFT domain, having in mind that the LPFT is linear with respect to the signal. An order adaptive algorithm of the LPFT calculation is presented. Performance of the proposed nonparametric method is tested in the presence of linear and sinusoidal FM interferences in the noisy signal, without any a priori assumption about the jammer form. The proposed method may be successfully extended to the case of multiple jammers. Obtained results in terms of the bit error rate (BER) values show the achieved improvements. Procedure for an efficient optimization of the first-order LPFT is presented.     

基于无偏转换的雷达配准算法

在多雷达数据处理系统中,雷达本身的系统偏差是影响目标跟踪和数据融合质量的一个重要因素.为了使融合结果更加准确可靠,本文提出了基于无偏转换的雷达配准算法.该算法是通过无偏转换把其它雷达的测量转换到主雷达下,利用各雷达相对主雷达的测量差值,采用Kalman滤波器实时估计出各雷达的系统偏差(方位和距离),从而进行配准.仿真实验结果表明这种算法是有效的.     

基于嵌入超表面的雷达吸波结构带宽拓展方法研究

提出了一种基于嵌入十字形超表面的雷达吸波结构带宽拓展方法,仿真了超表面的十字形参数变化对结构材料吸波性能的影响,通过十字形结构单元的表面电流情况分析了产生共振的原因;仿真和实验结果都表明所设计的超表面嵌入雷达吸波结构后,在16.6 GHz附近增加了一个较大吸收峰,峰值达到了-33.4 dB,在雷达吸波结构材料厚度及面密度基本不变的情况下拓宽了其高频吸波效果。