反向交叉眼对单脉冲雷达干扰效果分析及仿真验证

交叉眼干扰被认为是对单脉冲雷达干扰最有效的方式之一。基于雷达方程建立了隔离平台回波下的两点源反向交叉眼干扰模型，推导了交叉眼干扰欺骗角一般性公式，研究了干扰机发射天线间距、干扰平台旋转角和干扰机相对雷达之间距离等参数变化对角度欺骗效果的影响，并依据单脉冲雷达接收机获取角度的信息处理流程，建立了单脉冲雷达接收机仿真模型，对交叉眼数学模型的正确性和局限性进行了分析。研究结果表明：单脉冲雷达越靠近两点源交叉眼干扰机中心线、干扰机两发射天线间距越大、与干扰机距离越近时，角度欺骗效果越好；单脉冲雷达的欺骗角度随着与干扰机距离的接近呈指数式增大；数学模型和仿真模型计算的单脉冲雷达角度误差最大值随干扰机天线与雷达天线中心连线的夹角的增大呈指数化增长。研究可为交叉眼干扰工程设计作参考。     

Multi-function radar emitter identification based on stochastic syntax-directed translation schema

To cope with the problem of emitter identification caused by the radar words＇ uncertainty of measured multi-function radar emitters, this paper proposes a new identification method based on stochastic syntax-directed translation schema（SSDTS）. This method, which is deduced from the syntactic modeling of multi-function radars, considers the probabilities of radar phrases appearance in different radar modes as well as the probabilities of radar word errors occurrence in different radar phrases. It concludes that the proposed method can not only correct the defective radar words by using the stochastic translation schema, but also identify the real radar phrases and working modes of measured emitters concurrently. Furthermore, a number of simulations are presented to demonstrate the identification capability and adaptability of the SSDTS algorithm.The results show that even under the condition of the defective radar words distorted by noise,the proposed algorithm can infer the phrases, work modes and types of measured emitters correctly.     

Effective Antenna Pattern of Scanning Radars

It is shown that weather radar signal averaging causes a broadened apparent pattern of the scanning radar antenna. The apparent pattern is obtained by convolving the original pattern with the averaging circuit impulse response. Echo displacement and pattern broadness are examined for square law, linear, and logarithmic detectors having exponential and finite time integrators.     

智能化雷达对抗情报处理技术研究

随着雷达技术的迅猛发展,雷达信号的密度、复杂程度都大幅度提高,这就增加了雷达信号的不确定性因素。本文讨论了粗糙集理论、模糊集理论、证据理论和可能性理论等人工智能技术在雷达对抗情报处理中的应用。对雷达辐射源的型号和工作模式识别、雷达网信息以及所属平台信息的推理技术进行了探索研究,给出了研究建议。     

Propagation velocity uncertainty on GPR SAR processing

To detect buried landmines, Planning Systems Incorporated (PSI) has developed a ground-penetrating synthetic aperture radar (GPSAR) system. Since the electromagnetic wave propagation velocity in the soil depends on many factors, velocity uncertainty is inevitable. However, we have observed that, unlike conventional airborne/spaceborne synthetic aperture radar (SAR) systems, the PSI GPSAR system is very robust against the velocity uncertainty under mild conditions. Theoretical analysis is provided to explain this observation. Although our discussion is based on the PSI GPSAR system, it applies to other GPR-based (ground-penetrating radar) landmine detection systems as well.     

机载气象雷达回波信号仿真系统

设计了一个机载气象雷达回波信号仿真系统,可用于高保真雷达回波信号的生成与演示。基于高保真风场建模数据,依照真实机载气象雷达的扫描方式初始化仿真参数,对风场数据进行机载气象雷达回波仿真,得到了可靠的仿真数据,并对可靠性进行验证。该系统采用C#与Matlab联合编程的方法进行实现,可实现的功能包括各种气象目标在不同模式下的雷达回波仿真,雷达回波数据正确性的验证及展示。得到的信号可为机载气象雷达信号处理和数据处理算法的开发提供数据支持。     

纳米力学测试系统位移传感器校准装置

介绍了用激光干涉方法对纳米力学测试系统位移传感器进行校准的方法,并建立了校准装置;采用平衡式光学系统设计,干涉系统的抗干扰能力得到了显著提高,通过零位移测量实验对装置的稳定性进行了验证;用校准装置对TriboIndenter纳米力学测试系统的位移传感器进行了校准实验,测量不确定度分析结果表明该系统测量压头位移的准确度可以达到纳米量级。     

软件雷达技术研究综述

从较为成熟的软件无线电技术出发,介绍了软件雷达的基本概念、通用结构、通用信号处理平台和适用于软件雷达的数据结构,总结了软件雷达的优越性能和发展趋势。     

An Empirical Formula for the Radar Cross Section of Ships at Grazing Incidence

From a collection of measurements of the radar cross section of ships at grazing incidence, an empirical formula is presented that relates cross section to radar frequency and ship displacement.     

直觉模糊熵在雷达目标识别中的应用

直觉模糊熵是不确定性推理领域中一个重要概念.针对雷达目标识别系统的复杂性,介绍了直觉模糊集的基本概念,分析了满足直觉模糊集熵的性质,提出了一种基于直觉模糊熵的雷达目标识别结果的检验方法.实验结果表明了该方法具有灵活性、合理性和可信性.     

About classical problems of airfoil drag

The drag of airfoils has long been determined from measurements in the wake behind the airfoil. The well-known formula of Squire and Young can be used to transfer the measured data to infinity downstream of the airfoil, where an exact relation to the drag exists. The Squire–Young formula is reviewed and an uncertainty in its derivation is discussed. A new formula of the same type is then derived, which also contains an uncertainty. This uncertainty can be reduced by experimental and numerical investigations of the wake displacement. Conversely, the displacement and the momentum of the wake must be investigated to reduce the uncertainty of the Squire–Young formula. In the second part of the paper, the determination of the drag directly by integration of the skin friction is investigated. Such a calculation is not difficult if the boundary-layer characteristics are computed numerically. An additional pressure drag must be regarded in this case. A new formula for the pressure drag is derived which shows that the uncertainty of the Squire–Young type formulas is contained in the evaluation of the pressure drag. This is another reason for further research on wake displacement.     

基于VxWorks的末制导雷达通用信号处理平台设计

通用的雷达信号处理平台在中断响应、数据传输等方面对系统的实时性和可靠性要求较高,在设计时有必要采用高性能的实时操作系统,同时采用PCI总线来保证高速的数据传输。为此,基于实时操作系统VxWorks,以高性能微处理器PowerPC7457为核心,采用PCI总线机制,借鉴软件模块化思想,构建了通用的雷达信号处理平台。可用于信号处理算法的开发验证,具有较高的实时性和扩展性。     

Multiple moving target detection and trajectory estimation using a single SAR sensor

A novel methodology is presented for determining the velocity and location of multiple moving targets using a single strip-map synthetic aperture radar (SAR) sensor. The so-called azimuth position uncertainty problem is therefore solved. The method exploits the structure of the amplitude and phase modulations of the returned echo from a moving target in the Fourier domain. A crucial step in the whole processing scheme is a matched filtering, depending on the moving target parameters, that simultaneously accounts for range migration and compresses two-dimensional signatures into one-dimensional ones without losing moving target information. A generalized likelihood ratio test approach is adopted to detect moving targets and derive their trajectory parameters. The effectiveness of the method is illustrated with synthetic and real data covering a wide range of targets velocities and signal-to-clutter ratios (SCRs). Even in the case of parallel to platform moving target motion, the most unfavorable scenario, the proposed method yields good results for, roughly, SCR > 10 dB.     

调频连续波毫米波雷达信号处理软件分析

雷达在其发展前期,连续波雷达由于收发隔离等问题不易解决,应用受限制。但是随着技术的发展,这些问题得到改善,连续波雷达越来越受到人们的关注。文章针对现有调频连续波雷达平台,通过分析研究雷达平台,介绍信号处理软件的设计思路与系统结构,设计与开发了信号处理软件。在此基础上,对雷达功能设计实现进行分析,对软件各模式功能进行实验测试,验证了其功能实现及测量精度,并进一步研究调频连续波雷达毫米波雷达用于导弹近程制导的可行性,介绍了调频连续波毫米波雷达的性能,指出其用于末端制导的缺陷并给出改善方法。     

复杂航迹和起伏地形条件下机载聚束SAR 空变运动补偿

 运动补偿是雷达平台机动飞行条件下合成孔径雷达(SAR)实现精确聚焦成像的前提,而如何精确实现运动误差的空变补偿(误差补偿随目标距离、方位和高度位置的变化而变化)目前还存在很大的挑战。本文提出了一种新的三阶运动补偿方法,能够有效解决复杂雷达航迹和地形起伏条件下运动误差的空变补偿问题。该方法首先以场景中心为参考进行空不变运动补偿,然后以多个子场景中心为参考进行空变运动补偿,最后再利用极坐标格式算法(PFA)统一补偿每个像素的空变误差。仿真数据处理结果验证了本文方法的有效性。     

MIMO雷达射频隐身性能优化的目标跟踪算法

随着现代战场中电子对抗的日益激烈,雷达的生存环境受到了严重的威胁。射频（RF）隐身技术是一种提高雷达及其运载平台战场生存能力的重要途径。为提高雷达射频隐身性能,针对具有MIMO探测模式的新体制雷达提出了隐身性能优化的目标跟踪算法。该算法基于射频隐身性能优化模型,通过自适应控制系统的子阵划分个数、平均发射功率、波束驻留时间以及采样周期,在满足系统跟踪性能要求的前提下优化系统射频隐身性能,其中的射频隐身性能综合考虑了截获因子及采样周期。仿真结果表明,与传统相控阵雷达相比,本文所提出的目标跟踪算法使MIMO雷达具有更好的射频隐身性能。     

HRR Detector for Slow-Moving Targets in Sea Clutter

The radar detection of targets in the presence of sea clutter has historically relied upon the radial velocity of targets with respect to the radar platform either by exploiting the relative target Dopplers (for targets with sufficient radial velocity) or by discerning the paths targets traverse from scan to scan. For targets with little to no radial velocity component, though, it can become quite difficult to differentiate targets from the surrounding sea clutter. This paper addresses the detection of slow-moving targets in sea clutter using a high resolution radar (HRR) such that the target has perceptible extent in range. Under the assumption of completely random sea clutter spikes based on an epsiv-contaminated mixture model with the signal and clutter powers known, optimal detection performance results from using the likelihood ratio test (LRT). However, for realistic sea clutter, the clutter spikes tend to be a localized phenomenon. Based upon observations from real radar data measurements, a heuristic approach exploiting a salient aspect of the idealized LRT is developed which is shown to perform well when applied to real measured sea clutter.     

飞行模拟器动力学控制的研究

针对如何获取运动平台的实时加速度和在精确跟踪加速度的同时限制位移,建立了系统动力学模型以计算加速度,使用虚拟弹簧法限制位移。在Matlab环境下,搭建了整个伺服控制系统。仿真结果表明,控制系统在保证平台位移不脱离限制区域的基础上,实现了加速度的精确跟踪。     

机载MIMO雷达空时自适应杂波对消器

针对机载多输入多输出(MIMO)雷达杂波分布呈现空时耦合特性,提出一种空时自适应杂波对消器.利用机载MIMO雷达的脉冲回波数据,构造杂波对消器的系数矩阵.通过空时自适应杂波对消器的预处理,可以有效地抑制杂波,并通过与常规空时处理算法的级联,最终可以有效提高动目标的检测性能.实现了由传统地基雷达杂波对消器向机载运动平台的推广.仿真结果表明,这种自适应杂波对消器不仅适用于正侧视雷达,对于非正侧视雷达也同样适用.     

Maritime border control multisensor system

This focuses on the classification task performed into a multi-sensor system for the coastal surveillance. The system is composed of two platforms of sensors: a land-based platform equipped with a land based radar, an Automatic Identification System (AIS) and an infrared camera (IR); an airborne platform carrying an airborne radar that can operate in a spotlight Synthetic Aperture Radar (SAR) mode, a video camera, and a second IR camera. The tasks performed by the system are the detection, tracking, identification, and classification of multiple targets, the evaluation of their threat level, and the selection of an intervention on them. The classification algorithm implemented inside the system exploits an analytical approach based on the confusion matrix (CM) of the imaging sensors that belong to the system. Some measures of effectiveness (MoE) of the system are evaluated, considering both cases where an ideal error-free classification process and a non-ideal classification process are performed.