The transmit antenna beampattern of the phased array radar is only a function of angle,limiting its ability to discriminate the targets from the same direction.Recently,the waveform diverse array radars expand the ang...The transmit antenna beampattern of the phased array radar is only a function of angle,limiting its ability to discriminate the targets from the same direction.Recently,the waveform diverse array radars expand the angle-dependent beampattern to an angle-time-range-dependent three-dimensional function by modulating the frequencies/time delays/phases across different transmit antenna elements.In this respect,extra Degrees-of-Freedom(DOFs)in the range domain are achieved,which opens up an innovative way to fulfil the tasks with enhanced system performance by jointly using the angle and range information.This paper summaries the developments of waveform diverse radars,including the Frequency Diverse Array(FDA),the Space-Time-CirculatingArray(STCA),and the Element-Pulse-Coding(EPC)frameworks,with emphasis on the analysis of the range-dependent beampattern from the basic properties upon how it is controlled.Moreover,the most recent advances of utilizing such a range-dependent beampattern in target detection,parameter estimation and identifiability,clutter suppression,jammer suppression and Synthetic Aperture Radar(SAR)imaging are discussed.展开更多
A geoacoustic inversion method is proposed based on the modal dispersion curve of two-wideband explosive signals for range-dependent environment. It is applied to the wideband explosive sound source data from the Sout...A geoacoustic inversion method is proposed based on the modal dispersion curve of two-wideband explosive signals for range-dependent environment. It is applied to the wideband explosive sound source data from the South China Sea in 2012. The travel time differences of different modes at various frequencies and distances are extracted by warping transform. The mean bottom acoustic parameters are inverted by matching the theoretical modal time differences to that of the experimental data. The inversion results are validated by using other explosive signals at different distances.展开更多
频率分集阵列(Frequency Diverse Array, FDA)是作为一种全新的电扫描雷达体制,其方向图所具有的时间-距离-角度三维相关特性在电子对抗和安全通信等领域有广阔的应用前景。一维均匀线性FDA阵列(Uniform Linear Array Frequency Diverse...频率分集阵列(Frequency Diverse Array, FDA)是作为一种全新的电扫描雷达体制,其方向图所具有的时间-距离-角度三维相关特性在电子对抗和安全通信等领域有广阔的应用前景。一维均匀线性FDA阵列(Uniform Linear Array Frequency Diverse Array, ULFDA)的发射方向图存在角度-距离耦合问题,针对这一问题,在对称子阵密度锥削阵结构的基础上,通过正弦频控函数取代原有的均匀线性函数,得到了FDA的点状波束指向控制方法。此外,针对FDA方向图的时变问题,得到了基于子阵结构的密度锥削阵sin-FDA主波束在角度维指向固定、距离维变化时的结论。展开更多
不同于传统相控阵,频控阵(Frequency Diverse Array,FDA)在所有阵元间引入频率偏差,可以生成具有精准指向特性的点状辐射方向图,有效克服传统相控阵方位角相关性导致的接收方向射频信号安全性下降的问题。作为与传统相控阵的本质区别,FD...不同于传统相控阵,频控阵(Frequency Diverse Array,FDA)在所有阵元间引入频率偏差,可以生成具有精准指向特性的点状辐射方向图,有效克服传统相控阵方位角相关性导致的接收方向射频信号安全性下降的问题。作为与传统相控阵的本质区别,FDA阵元频偏设置直接影响FDA辐射方向图的形状。为了生成理想的点状方向图,提出了一种Zadoff-Chu FDA(ZC-FDA)稳健波束成形方案,利用Zadoff-Chu序列调整阵元频偏,消除FDA辐射方向图周期性,抑制距离-方位角耦合性。与现有FDA系统相比,ZC-FDA方案在理想点状辐射方向图生成和波束旁瓣水平抑制方面具有明显优势。展开更多
共形频控多输入多输出(Frequency diverse array multiple input and multiple output,FDA-MIMO)系统的波束图由俯仰角、方位角、距离三维信息控制,能够进一步提高系统的自由度。随着人们对高分辨目标探测性能以及高空气动力学性能的需...共形频控多输入多输出(Frequency diverse array multiple input and multiple output,FDA-MIMO)系统的波束图由俯仰角、方位角、距离三维信息控制,能够进一步提高系统的自由度。随着人们对高分辨目标探测性能以及高空气动力学性能的需求增加,研究共形FDA-MIMO阵列波束图综合方法很有意义。本文详细推导了共形FDAMIMO系统的信号建模和波束图分析的数学过程,并提出一种基于参数迭代的发射接收联合权向量优化算法以得到高分辨率的波束图。该算法首先建立一个二阶锥规划(Second-order cone programming,SOCP)模型,并利用交替方向乘子法(Alternating direction method of multipliers,ADMM)实现参数分离,原问题分为两个子问题。最后分别对各个子问题进行优化。数值仿真表明所提算法相比于传统算法性能更有优势,同时其收敛性得到验证。此外,为进一步分析系统特性,本文讨论了不同系统参数,如发射阵列阵元数、接收阵列阵元数、频控阵频偏大小以及不同频偏方式对本文所提算法下的波束图影响。展开更多
频率分集阵(Frequency Diverse Array,FDA)雷达不同天线单元的发射载频存在微小的差异,从而带来了发射方向图距离角度时间依赖的特性,这一特性提供了FDA雷达新的信息和信号处理灵活度,也带了新的技术问题。该文综述了FDA天线技术及雷达...频率分集阵(Frequency Diverse Array,FDA)雷达不同天线单元的发射载频存在微小的差异,从而带来了发射方向图距离角度时间依赖的特性,这一特性提供了FDA雷达新的信息和信号处理灵活度,也带了新的技术问题。该文综述了FDA天线技术及雷达应用的相关研究进展,并重点从雷达系统理论与工程应用的角度,着重分析了相干FDA雷达和正交FDA雷达两种体制的技术特点,指出FDA雷达在抗干扰、抗模糊中的应用优势,梳理了FDA雷达技术的难点和研究方向。展开更多
基金supported in part by the National Nature Science Foundation of China(Nos.62101402,61931016,62071344)China Postdoctoral Science Foundation(Nos.2021TQ0261,2021M702547)Young Elite Scientists Sponsorship Program by CAST(2021QNRC001).
文摘The transmit antenna beampattern of the phased array radar is only a function of angle,limiting its ability to discriminate the targets from the same direction.Recently,the waveform diverse array radars expand the angle-dependent beampattern to an angle-time-range-dependent three-dimensional function by modulating the frequencies/time delays/phases across different transmit antenna elements.In this respect,extra Degrees-of-Freedom(DOFs)in the range domain are achieved,which opens up an innovative way to fulfil the tasks with enhanced system performance by jointly using the angle and range information.This paper summaries the developments of waveform diverse radars,including the Frequency Diverse Array(FDA),the Space-Time-CirculatingArray(STCA),and the Element-Pulse-Coding(EPC)frameworks,with emphasis on the analysis of the range-dependent beampattern from the basic properties upon how it is controlled.Moreover,the most recent advances of utilizing such a range-dependent beampattern in target detection,parameter estimation and identifiability,clutter suppression,jammer suppression and Synthetic Aperture Radar(SAR)imaging are discussed.
基金Supported by the National Natural Science Foundation of China under Grant No 11174235the Fundamental Research Funds for the central Universities of Ministry of Education of China under Grant No 3102014JC02010301
文摘A geoacoustic inversion method is proposed based on the modal dispersion curve of two-wideband explosive signals for range-dependent environment. It is applied to the wideband explosive sound source data from the South China Sea in 2012. The travel time differences of different modes at various frequencies and distances are extracted by warping transform. The mean bottom acoustic parameters are inverted by matching the theoretical modal time differences to that of the experimental data. The inversion results are validated by using other explosive signals at different distances.
文摘频率分集阵列(Frequency Diverse Array, FDA)是作为一种全新的电扫描雷达体制,其方向图所具有的时间-距离-角度三维相关特性在电子对抗和安全通信等领域有广阔的应用前景。一维均匀线性FDA阵列(Uniform Linear Array Frequency Diverse Array, ULFDA)的发射方向图存在角度-距离耦合问题,针对这一问题,在对称子阵密度锥削阵结构的基础上,通过正弦频控函数取代原有的均匀线性函数,得到了FDA的点状波束指向控制方法。此外,针对FDA方向图的时变问题,得到了基于子阵结构的密度锥削阵sin-FDA主波束在角度维指向固定、距离维变化时的结论。
文摘不同于传统相控阵,频控阵(Frequency Diverse Array,FDA)在所有阵元间引入频率偏差,可以生成具有精准指向特性的点状辐射方向图,有效克服传统相控阵方位角相关性导致的接收方向射频信号安全性下降的问题。作为与传统相控阵的本质区别,FDA阵元频偏设置直接影响FDA辐射方向图的形状。为了生成理想的点状方向图,提出了一种Zadoff-Chu FDA(ZC-FDA)稳健波束成形方案,利用Zadoff-Chu序列调整阵元频偏,消除FDA辐射方向图周期性,抑制距离-方位角耦合性。与现有FDA系统相比,ZC-FDA方案在理想点状辐射方向图生成和波束旁瓣水平抑制方面具有明显优势。
文摘共形频控多输入多输出(Frequency diverse array multiple input and multiple output,FDA-MIMO)系统的波束图由俯仰角、方位角、距离三维信息控制,能够进一步提高系统的自由度。随着人们对高分辨目标探测性能以及高空气动力学性能的需求增加,研究共形FDA-MIMO阵列波束图综合方法很有意义。本文详细推导了共形FDAMIMO系统的信号建模和波束图分析的数学过程,并提出一种基于参数迭代的发射接收联合权向量优化算法以得到高分辨率的波束图。该算法首先建立一个二阶锥规划(Second-order cone programming,SOCP)模型,并利用交替方向乘子法(Alternating direction method of multipliers,ADMM)实现参数分离,原问题分为两个子问题。最后分别对各个子问题进行优化。数值仿真表明所提算法相比于传统算法性能更有优势,同时其收敛性得到验证。此外,为进一步分析系统特性,本文讨论了不同系统参数,如发射阵列阵元数、接收阵列阵元数、频控阵频偏大小以及不同频偏方式对本文所提算法下的波束图影响。
文摘频率分集阵(Frequency Diverse Array,FDA)雷达不同天线单元的发射载频存在微小的差异,从而带来了发射方向图距离角度时间依赖的特性,这一特性提供了FDA雷达新的信息和信号处理灵活度,也带了新的技术问题。该文综述了FDA天线技术及雷达应用的相关研究进展,并重点从雷达系统理论与工程应用的角度,着重分析了相干FDA雷达和正交FDA雷达两种体制的技术特点,指出FDA雷达在抗干扰、抗模糊中的应用优势,梳理了FDA雷达技术的难点和研究方向。
