用导航卫星作为辐射源的双(多)基地雷达系统可行性研究

简要介绍了基于外辐射源的无源探测雷达的工作原理；在深入研究非合作式双（多）基地雷达的工作原理的基础上，结合对空中目标，尤其是隐身目标进行探测的要求，提出了一种基于导航卫星信号的星地双（多）基地雷达系统，对导航卫星信号用于外辐射源进行目标探测的可行性进行了分析；研究了系统的工作原理、探测性能，并对系统功能实现的难题进行了分析。     

独立双基地雷达接收系统

独立双基地雷达具有许多独特的优点和潜在能力。独立的双基地雷达接收系统协同非配合的发射站工作的时间同步信息和发射波束指向信息可以从接收信号中提取。本文论述作者所研制的非相参独立双基地雷达接收系统的结构、原理、同步精度和试验运行概况,详细介绍获取上述同步信息的方法和关键技术的解决办法。本文最后提出一种将数字波束形成(DBF)技术与独立双基地同步系统相结合的新型独立双基地雷达系统的结构和特点。     

非合作双基地雷达测距方法与精度分析

介绍了非合作双基地雷达的基本几何关系,讨论了非合作双基地雷达中4个重要参数(基线距离、双基地距离差、发射站目标方位角、接收站目标方位角)的测量方法,利用这4个参数可构成4种测距算法。在考虑基线距离误差的情况下,推导了这4种算法的测距误差公式。仿真结果表明,各算法测距精度与双基地雷达的几何结构有关,通过优化可得空间测距精度最高区域。实际系统的测距方案应根据所能测出的参数进行选择,同时应注意各算法的适用区域。     

双（多）基地雷达的探测范围和定位精度的分析

双(多)基地雷达体制在“四抗”性能上具有单基地雷达无法比拟的优点,其定位精度与探测范围等主要战术技术参数与常规雷达有很大不同,影响它的因素是相当复杂的。在探测范围分析中,文中推导出了它的计算公式;在定位精度分析中,考虑了目标从不同方向进入系统探测区时,其定位精度曲线,并提出改善定位精度的方法,值得注意的是:当目标进入基线附近时,其定位精度变差,此时正是雷达系统呈现较大的双基角β,发现目标的概率变大。因此,对隐身目标就有发现目标与测量精度的矛盾存在,这是双(多)基地雷达的一个突出的、值得重视的问题。     

双基地制导雷达反隐身性能建模与仿真

为满足防空系统抗击隐身目标的需求,提出了一种计算双基地制导雷达RCS和导弹发射距离的方法.基于单双基地雷达的RCS特性,建立了双基地制导雷达探测距离随站间距离变化的数学模型.最后以正面抗击F-117A为例进行单双基地对比仿真,证明了双基地制导雷达反隐身的可行性.     

“双(多)基地雷达数字波束形成器”通过技术鉴定

由丁鹭飞教授等所承担的”双(多)基地雷达数字波束形成器”课题日前通过了机电部电了科学研究院主持的技术鉴定。“双(多)基地雷达数字波束形成器”是“七五”军事电子预研项目“双(多)基地雷达体制研     

双基地MIMO雷达目标定位及互耦自校正算法

利用均匀线阵互耦矩阵的带状和对称Toeplitz特性,提出了一种基于旋转不变技术估计目标参数(ESPRIT)的双基地多输入多输出(MIMO)雷达目标定位及互耦自校正算法.该算法通过ESPRIT算法中子阵的选取,将目标二维方位角估计与互耦参数估计相"去耦",角度估计过程不需任何互耦矩阵信息,且估计精度高、分辨力强;基于对目标二维方位角的估计,算法还可以精确地估计出互耦矩阵,从而实现双基地MIMO雷达的互耦自校正.该算法对目标二维方位角与互耦矩阵的估计不涉及任何角度搜索和迭代过程,具有较小的运算量.计算机仿真结果证明了该算法的正确性和可行性。     

空基双基地雷达地面杂波分辨单元面积计算方法

针对空基双基地雷达杂波仿真中，地面杂波分辨单元面积的计算问题，通过建立空基双基地雷达几何关系，分析了其距离特性，提出了一种宽波束发射、窄波束接收，空间同步方式的空基双基地雷达系统杂波仿真中双基地雷达杂波分辨单元的计算方法。该方法利用双基地雷达距离特性和面积分的方法，推导出了由接收机带宽和波束宽度决定的杂波分辨单元面积的精确解析式。     

天空双基地雷达体制分析及参数设计

鉴于天空双基地雷达在兼顾单基地天基预警雷达的优势的同时能克服其信噪比偏低的缺点,在单基地天基预警雷达的基础上,对天空双基地雷达的几何模型、雷达距离方程及相关概念等方面进行了分析。然后综合考虑信号衰减、接收信噪比以及距离模糊等方面因素,对系统的载频、卫星轨道高度和脉冲重复频率等参数进行了设计。最后进行了仿真验证。理论分析和仿真结果表明：信号信噪比能达到可检测水平,且无距离模糊。     

双基地偏振雷达探测时小旋转椭球雨滴的侧向散射特性

从旋转椭球粒子散射理论出发,给出单个小旋转椭球雨滴在入射不同偏振波时的散射函数,并对其在不同仰角情况的数学图形和物理意义做了讨论,为推导基于椭球雨滴群的双基地偏振雷达方程、研究椭球雨滴群对双基地线偏振雷达探测能力的影响、处理和分析双基地偏振雷达资料,提供了理论依据.     

Method of co-channel interference cancellation for the GSM based PBR

In passive bistatic radar, especially in the global system for mobile communication based passive bistatic radar, there are not only strong direct signal and multipath, but also co-channel interference. It is difficult to suppress co-channel interference using temporal adaptive cancellation without the samples of interference. Aiming at the problem of co-channel interference signals existing in the echo channel, a method of co-channel interference cancellation for passive bistatic radar is proposed. First, low sidelobe spatial filtering is used to remove the remote weak interference, at the same time the strong interference is suppressed to a certain extent. Then, the direct signal and multipath signal coming from the main station are suppressed by using temporal adaptive cancellation. Finally, the remaining interference is further cancelled by a robust adaptive beamformer. The performance and calculation of the proposed method are verified by theoretical analysis and simulation.     

BRVAAF and performance analysis for target detection

A bistatic range-velocity-acceleration ambiguity function (BRVAAF) is proposed. The model of radar measurements of an accelerating target involving the time delay, Doppler frequency and Doppler rate is given. The relationships between these measurements and the parameters of the bistatic geometry, target position, velocity and acceleration are derived. Moreover, the effects of the bistatic geometry factors on these measurements are analyzed. Besides, the two relationships of the bistatic integration loss and the bistatic optimum integration time with these factors are built and their change trends are described respectively. This research is helpful to analyze the influences of the bistatic geometry factors on the target detection and signal processing. Supported by the National Natural Science Foundation of China (Grant No. 60232010), the National Natural Science Foundation of China for Distinguished Young Scholars (Grant No. 60625104) and the Advanced Research Project (Grant Nos. 51307060504, 9140A07040806BQ01)     

MIMO双基地雷达多目标角度-多普勒频率联合估计

为了实现无同步双基地雷达多目标参数估计,建立了多输入多输出(MIMO)双基地雷达多目标信号处理模型,提出了一种多目标角度-多普勒频率联合估计算法.该算法首先对MIMO接收机输出的虚拟阵列多目标回波数据进行解相干处理,然后基于传播算子,构造特殊矩阵.通过特征参数与待测参数之间的对应关系,实现了多目标发射角、接收角和双基多普勒频率的联合估计.该算法不涉及多维非线性谱峰搜索,只需一次特征值分解,且估计出的参数可自动配对.仿真结果证明了所提算法的正确性和有效性.     

Application of Modified SPECAN Algorithm in Parasitical BiSAR

Global navigation satellite system (GNSS) can be employed as a transmitter to composite bistatic synthetic aperture radar (BiSAR). As GNSS signal is quite different from the traditional radar signal, modified spectral analysis (SPECAN) algorithm is proposed and applied in the BiSAR system. The modifications include Doppler centroid compensation, range curve correction and azimuth processing method. The modified SPECAN algorithm solves the imaging problem under the condition of huge range migration, long synthetic aperture time and phase-coded signal. The proposed algorithm is verified by experiment results.     

具有垂直基线的双基机载雷达杂波谱距离依赖性分析

在实际中,双基机载雷达接收发射载机经常不会在同一个高度,会导致在两载机之间产生垂直基线．首先对双基雷达的一般构型进行分析,然后从双基平飞正侧机载雷达的回波多普勒数学表达式上分析了当两载机高度之间存在垂直基线的情况下对杂波多普勒频率的影响．接着对四种典型构型的双基机载雷达进行了计算机仿真建模,分析了垂直基线对双基机载雷达回波的具体影响,发现了适当的垂直基线能够缓解双基机载雷达的杂波距离依赖性,能够提高双基雷达地面动目标检测性能．     

Analysis of physical layer security performance for satellite communication systems

Due to the openness of the wireless medium and construction of the space-ground integrated information network,satellite communication (SATCOM) systems are facing severe security challenges.Physical layer security technology can guarantee secure satellite communication and effectively prevent the channel from being eavesdropped.By taking into account the space-ground integrated information network,a security performance analysis framework is developed for the SATCOM system with the existence of a ground eavesdropper and a satellite eavesdropper.Based on the Rayleigh fading channel and Shadowed-Rician fading channel,eavesdropping models of two eavesdroppers are provided,respectively.Regarding the non-collusion and collusion strategies employed at eavesdroppers,the exact expressions for average secrecy capacity (ASC) and secrecy outage probability (SOP) are derived under the two strategies,respectively.Simulation results show that a growing transmit power can improve ASC with SOP unchanged at the same time.Reducing the signal noise ratio at the satellite eavesdropper can provide a better secrecy performance for the SATCOM system than decreasing the signal noise ratio at the ground eavesdropper.     

基于GNSS-R双站SAR的模型分析

针对导航卫星作为双站SAR辐射源的系统模型进行了分析研究：建立了基于导航卫星信号的双站SAR系统的几何模型;给出了回波信号表达式并进行了仿真验证;分析并确定了信号处理中的关键参数——积分时间;推导得出平飞正侧视模式下的瞬时距离历程,并讨论了瞬时距离历程泰勒级数近似展开式。仿真结果验证了模型正确性,积分时间的确定和瞬时距离历程的分析为成像处理提供了基础。