基于压缩感知的圆阵自适应数字波束形成算法

根据目标在空间的稀疏性,在圆形面阵的接收端,提出了一种基于压缩感知的自适应数字波束形成算法.该算法在不改变波束性能与天线口径的前提下,可以大大减少实际的阵元数目,是一种新的稀布阵方法.在阵元稀布的情况下,根据压缩感知的压缩采样理论,先用重构算法恢复缺失通道的回波信息,然后利用恢复得到的信号计算自适应权系数,得到理想的自适应数字波束方向图.不同信噪比和干噪比情况下的仿真结果验证了所提算法的正确性和有效性.     

基于压缩感知的均匀圆阵方向不变波束优化方法

针对现有的方向不变波束形成算法在阵元个数确定以后,其波束的主瓣与旁瓣水平无法进一步改善的情形下.本文基于均匀圆阵在现有方向不变波束形成方法的基础上,通过引入压缩感知理论(Compressed Sens-ing,CS),提出了一种可以进一步改善波束主瓣与旁瓣水平的方法.该方法使用压缩感知理论对信号进行压缩采样和稀疏重构,...     

基于自调整映射法则的矩形稀布阵列优化方法北大核心CSCD

针对多约束条件下的矩形稀布阵列优化问题,提出了一种基于自调整映射法则的矩形稀布阵列优化方法。该方法首先提出一种新的最优化问题用于确定阵元坐标矩阵维数以平衡放置阵元数的自由度和阵列孔径可调整空间,并引入用于稀疏阵元的阵元状态矩阵;其次,构建自调整映射法则,对矩形阵列不同方向进行相应的映射,并对阵列短轴方向进行自调整,使得阵元位置满足最小阵元间距,避免出现不可行解;然后,通过粒子群优化算法优化阵元位置得到最优阵元坐标;最后,考虑适应度函数为单波束指向和多波束指向,对算法进行仿真验证。仿真结果发现该算法可以满足多约束条件并有效降低阵列的峰值旁瓣电平,从而提高矩形稀布阵列的性能。     

结合压缩感知模型的稀疏阵列波束形成方法

本文从稀疏阵列入手,将稀疏阵列接收数据模型转化为更高自由度下的单快拍接收数据模型,并将压缩感知模型引入稀疏阵列信号处理问题中,从理论上证明了其可行性。在等效单快拍数据下,利用稀疏重构算法准确估计信源方位和功率,进而对传统MVDR波束形成器进行优化。仿真结果表明,采用压缩感知模型实现稀疏阵列的波束形成,能够将稀疏阵列和压缩感知算法两者的优势结合,在阵列阵元数较少的条件下达到更高的自由度,同时具备良好的波束形成器性能。     

子阵平滑对小快拍数下CAB算法的改善

研究了子阵空间平滑自适应阵列方法对CAB算法性能的改进。数字波束形成是DBF雷达实现的关键技术。在诸多数字波束形成算法中，由于CAB算法在较高信干噪比条件下具有较快的收敛速度，因此具有较强的优势。但是该算法在较少的快拍数情况下不能保证在输出SINR收敛并趋向于最优值的同时保持较低的自适应旁瓣电平。因此，采用空间子阵平滑方法并利用子阵级自适应处理结构来等效提高CAB算法的快拍数，从而抑制干扰和噪声。仿真结果证明了该方法的有效性。     

基于CIC 内插时延的宽带数字阵列波束形成

针对宽带数字阵列采用传统窄带波束形成方法导致的方向图指向偏移、主瓣畸变问题,提出了一种基CIC内插的时延补偿方法。该方法不仅通过内插的方式实现宽带数字阵各个阵元时延的精确补偿,而且所需的乘法运算次数不随数字阵列合成波束数的增加而增加。仿真结果表明:该方法应用于宽带数字阵列多波束形成时,处理性能与基于分数时延滤波方法相当,但需要的乘法运算次数明显少于后者,因此具有很好的工程实现价值。     

基于压缩感知DOA估计的稀疏阵列设计

根据格拉姆(Gram)矩阵优化测量矩阵的方法,给出了一种基于压缩感知波达方向(DOA)估计的均匀线阵的稀疏阵列设计方法.该方法不需要对阵列的输出数据进行压缩采样,直接利用稀疏阵列的输出数据,然后利用稀疏恢复算法求解DOA估计信息.实验仿真证明,相比于原均匀线阵,所提方法在阵元数目较少且信噪比较低的情况下具有更好的DOA估计性能.     

基于特征矢量稀疏重构的欠定DOA估计算法

针对信源数多于阵元数,阵列测向欠定问题,利用最小冗余线阵的阵列扩展能力,以较少的阵元获得较大的阵列孔径,同时将最小冗余线阵与压缩感知理论相结合,提出一种基于特征矢量稀疏重构的欠定DOA估计算法.所提算法能以较少的阵元数估计更多信源的来波方位,具有信源过载能力,同时能降低稀疏重构运算的复杂度,增强了算法的鲁棒性、精确性,性能优于MUSIC算法,实验结果表明该方法是有效的.     

均匀线阵阵元缺损对波束方向图影响的分析

当均匀线阵中某些阵元损坏时,该阵元无法接收入射信号,会导致波束形成结果与正常情况出现差别.在不进行加窗处理的情况下,波束方向图变化不大,主瓣幅度稍有减小,主瓣宽度和主副比也略有变化.然而对于锥化波束形成,波瓣的主瓣幅度、主副比和主瓣宽度受到明显影响,且与缺损阵元在线阵中的位置有着肾密的联系,当缺损阵元处于线阵中心时,波瓣性能受到严重影响.讨论了阵元缺损对波束形成的影响,通过比较缺损阵元在不同位置时的锥化波束形成波瓣性能变化,得知阵元离线阵中心越近对波瓣影响越大,因而要优先保证线阵中心阵元完好.     

用于自适应数字波束形成的稳健子阵异步RLS算法

提出了一种修正的递归最小二乘自适应算法--稳健子阵异步递推最小二乘算法(MSARLS)--用于自适应数字波束形成.该算法综合运用稳健估计和子阵异步递推技术.改进后的算法,不但大大减少了运算量,而且增强了算法抗突发强干扰的性能.另还给出了计算的理论分析和计算机仿真结果.     

A DBF self-beam steering array antenna for mobile satelliteapplications using beam-space maximal-ratio combination

This paper proposes a diversity-receiving array antenna scheme achieved by digital beamforming (DBF) for the purpose of self-beam steering toward the unknown direction-of-arrival (DOA) of a modulated signal in a mobile satellite communications environment. This scheme uses a multibeam former with a spatial fast Fourier transform (FFT) for the received baseband signals to coarsely acquire the attenuated signal. It also uses a self-phasing processor (SPP) applied to the multibeam outputs for precise acquisition and tracking. In the SPP, maximal-ratio combining is achieved with simple digital numerical operations in the complex baseband, allowing for rapidity and stability in beamforming. As a result, the array antenna steers its receiving beam toward the DOA automatically without the need for nonlinear optimization methods. Moreover, the beam is steered toward the DOA of multipath signals according to their signal levels, leading to the optimal cophase recombination of all correlated signals, which improves the quality of the total receiving signal. This paper discusses the scheme, and its performance is evaluated by computational simulation and experiments conducted in a radio anechoic chamber     

一种新的数字阵列雷达接收机技术

高速ADC和先进DSP器件的进展使数字波束形成智能天线的实现成为现实。在传统的M单元天线阵系统中,每一单元都有各自的接收通道和ADC,设备量大。文中提出了一种适合于多通道数字阵列雷达接收系统的新型数字接收机结构,其主要思想是基于多个不同信号的带通采样原理实现数字阵列雷达接收机,新接收机结构使IF接收通道和基带采样ADC显著减少,功耗大大降低。阐述了数字阵列接收的数据模型和工作原理,分析了多信号带通采样信号频率和采样率的关系,给出了采样率选取的约束条件。新接收机在降低设备量的同时,还减小了接收系统通道间幅一相不一致性失真。     

Microstrip Yagi array antenna for mobile satellite vehicleapplication

A novel antenna structure formed by combining the Yagi-Uda array concept and the microstrip radiator technique is discussed. This antenna, called the microstrip Yagi array, has been developed for the mobile satellite (MSAT) system as a low-profile, low-cost, and mechanically steered medium-gain land-vehicle antenna. With the antenna's active patches (driven elements) and parasitic patches (reflector and director elements) located on the same horizontal plane, the main beam of the array can be tilted, by the effect of mutual coupling, in the elevation direction providing optimal coverage for users in the continental United States. Because the parasitic patches are not connected to any of the lossy RF power distributing circuit the antenna is an efficient radiating system. With the complete monopulse beamforming and power distributing circuits etched on a single thin stripline board underneath the microstrip Yagi array, the overall L -band antenna system has achieved a very low profile for vehicle rooftop mounting, as well as a low manufacturing cost. Experimental results demonstrate the performance of this antenna     

Analysis and design of a continuous-wave terahertz photoconductive photomixer array source

An array of photoconductive photomixer/antenna elements as a continuous-wave terahertz source is proposed, and its radiation characteristic is studied. Employing photomixer/antenna elements in an array configuration increases available terahertz power, while each of the array elements consumes optical power less than its maximum sustainable power. A few microwatt terahertz power is achievable from a typical array structure. It is shown that the radiated beam can be steered by changing the angle between the two exciting laser beams.     

数字阵列天线接收通道宽带信号校准与波束形成技术研究

 本文提出了一种简洁、实用的天线接收通道宽带信号校准方法.该方法采用零中频信号处理技术,通过理论分析将数字阵列天线接收通道宽带线性调频信号校准分为通道间的时间和相位校准,证明了接收通道间宽带线性调频信号相位校准可以转化为单频信号进行,给出了接收通道间宽带信号的幅度校准方法和时间校准允许的误差范围.在通道校准基础上,采用脉冲压缩技术合成了宽带天线方向图.实验结果表明,本文方法是有效、可行的.     

A Novel Receiver Architecture for DBF Antenna Array

The developments of the high speed analog to digital converters （ADC） and advanced digital signal processors （DSP） make the smart antenna with digital beamforming （DBF） a reality. In conventional M-elements array antenna system, each element has its own receiving channel and ADCs. In this paper, a novel smart antenna receiver with digital beamforming is proposed. The essential idea is to realize the digital beamforming receiver based on bandpass sampling of multiple distinct intermediate frequency （IF） signals. The proposed system reduces receiver hardware from M IF channels and 2M ADCs to one IF channel and one ADC using a heterodyne radio frequency （RF） circuitry and a multiple bandpass sampling digital receiver. In this scheme, the sampling rate of the ADC is much higher than the summation of the M times of the signal bandwidth. The local oscillator produces different local frequency for each RF channel The receiver architecture is presented in detail, and the simulation of bandpass sampling of multiple signals and digital down conversion to baseband is given. The principle analysis and simulation results indicate the effectiveness of the new proposed receiver.     

一种小尺寸极化阵列及其高精度定位波束形成

提出一种偶极子天线单元构成的极化敏感阵列用于全球卫星导航信号的接收,经过阵列信号波束形成后,在抗干扰的同时保留卫星导航信号中载波相位测量值的准确性,可用于基于载波相位测量的高精度差分定位。与传统的圆极化天线阵列相比,该阵列具有阵元构造简单、尺寸小的特点。通过建立极化阵列接收信号模型,分析了天线极化和波束形成算法对卫星导航信号相位的影响,给出了相适应的相位中心稳定的数字波束形成算法。仿真验证了分析的正确性和算法的有效性。     

Hybrid MUSIC Dolph–Chebyshev algorithm for a smart antenna system

This paper presents practical design of a smart antenna system based on direction‐of‐arrival estimation and Dolph–Chebyshev beam forming. Direction‐of‐arrival estimation is based on the multiple signal classification algorithm for identifying the directions of the source signals incident on the sensor array comprising the smart antenna system. The smart antenna system design involves a hardware part, which provides real data measurements of the incident signals received by the sensor array. This paper presents the Dolph–Chebyshev method for the synthesis and design of antenna arrays with periodic element spacing. A Field‐Programmable Gate Array implementation is presented for an antenna array application employing digital beamforming. The array comprises 10 elements, equal in number receiving radio frequency and intermediate frequency components, as well as a Spartan‐3E Field‐Programmable Gate Array‐based unit, which is responsible for the control of the array. Low‐cost and switched‐beam, and fully adaptive antenna array suitable for 2‐GHz applications are proposed in this paper. Copyright © 2013 John Wiley & Sons, Ltd.