导航卫星阵列天线的快速现场系统校准算法

阵列天线接收处理全球卫星导航信号时,由于天线和射频前端的非理想性,会在不同方向卫星信号中引入不同的载波相位偏差,从而破坏卫星导航接收机距离观测量准确性。针对此问题,提出了一种易实现的卫星导航阵列天线的快速现场系统校准算法。校准过程分为通道校准和天线校准：通过开机和周期进行的通道校准实现阵列天线接收射频前端的通道响应测量;通过与接收处理不同卫星基带数据的数字接收机配合,实现阵列天线的现场阵列流形矢量校准。仿真验证了所提校准算法的正确性和有效性。     

共形天线阵元位置误差校正的辅助阵元法

共形天线的安装和测量以及载体平台表面的变形和振动均会引起阵元位置误差,严重影响 共形天线的测向性能。通过设置４个方位未知的精确校正的辅助阵元,实现了共形天线大尺度三维 的阵元位置误差校正。给出了阵元位置误差条件下共形天线导向矢量的方位依赖的幅相误差等效 表示模型;基于子空间原理得到等效的方位依赖的幅相误差估计,进而得到共形天线阵元的三维位 置误差估计。该方法可以实现共形天线校正信源来波方位和阵元三维位置误差的联合但“去耦”估 计。计算机仿真结果验证了共形天线阵元位置误差校正的辅助阵元法的有效性     

阵列天线因随机振动引起的测向误差分析及校准

针对阵列天线受舰船甲板低频机械随机振动引发振子位移变化导致的测向误差问题,建立了天线振子随机振动误差模型,仿真分析了天线阵列3个轴向随机振动模式对测角接收信号的影响,提出了一种基于多个接收机在不同位置同时测量的测角误差校正方法.该方法采用最小二乘法得到多个误差校准矢量,通过调用天线波束指向扇区内校准矢量的方法进行误差补偿,解决了低频随机振动模式下阵列天线测角误差的校准问题.该方法已应用到舰载微波着舰引导系统数据解算中.     

有源相控阵天线的近场校准

为实现对相控阵天线的校准,降低幅相误差和阵元失效对天线性能的影响,提出了一种考虑互耦效应的近场校准方法。在利用近场扫描法完成逐一通道校准的基础上,使用旋转矢量法进行二次校准。在应用旋转矢量法（ REV)时,为使被测信号的变化明显,将大规模相控阵天线分为中间、边缘区域进行分区校准。通过二次校准可判定阵元是否失效,提高相控阵天线的幅相一致性;通过分区校准减小阵元间互耦的影响,缩短校准时间。仿真结果表明：此方法用于大型相控阵的校准具有较高的准确性,可改善校准结果。     

一种均匀圆阵的校正方法

幅度增益和相位误差使得高分辨率的参数估计算法的性能下降,特别是相位的误差,将会引起参数估计的偏离.所以对于阵列天线各通道的校正是很有必要的.文中提出了通道的一种校正方案,用于减小各信道的不一致性.方案的基本思想是在圆形阵列的圆心处放置一个辅助天线,辅助天线将接收到的信号再发送到阵列天线各通道,联系辅助天线和各阵列天线的...     

均匀圆阵中的波束合成技术

针对均匀圆阵天线的阵列布局,建立了天线阵列对信号的接收模型,提出了一种实用的直接加权波束合成技术。在分析了系统误差来源并修正了系统误差校准模型的基础上,给出了详细的波束合成理论推导。结合实际系统给出了工程上的具体实现,并运用正交校准技术对由设备通路引起的系统误差进行校准。对该算法进行计算机仿真验证其可行性,并与实际效果图进行比较,指出算法的优点和不足。所给出的理论和方法都通过了工程检验,具有一定的实用性。     

Analysis of Single‐RF MIMO Receiver with Beam‐Switching Antenna

This paper proposes a single‐RF MIMO receiver that adopts a beam‐switching antenna (BSA) instead of a conventional array antenna. The beauty of the proposed single‐RF MIMO receiver with BSA is that it can be deployed in a very small physical space while achieving a full spatial multiplexing gain. Our analysis has revealed that the use of a BSA inevitably results in the spectrum spreading effect at the RF output, which in turn causes an SNR decrease and adjacent channel interference (ACI). Two novel receiver techniques are proposed to mitigate the issues of redundant sub‐band suppression and ACI avoidance. Numerical analysis results verify the performance improvement from the proposed receiver techniques.     

多馈源空间馈电阵列误差校正

空间馈电阵列是相控雷达天线的一个重要发展方向,阵列误差校正技术则是大多数阵列信号处理方法在工程实现中的重要保障条件,本文针对一种多馈源空间馈电阵列模型,利用主阵面上Ｔ／Ｒ模块中的移相器,提出了一种阵列误差校正方法,计算机仿真结果证明了其有效性。     

基于HFSS的智能天线自适应算法的研究

以3G基站系统智能天线阵列为研究对象,在研究了常用智能天线自适应算法的基础上,针对常用算法测向精度有限以及来波方向估计过程的复杂性等问题,通过在接收机的输出端引入阵列导向矢量信号,利用阵列导向矢量的特殊性质,得出了一种改进后的自适应算法。采用该算法的智能天线阵列,不仅具有较强的波束搜索能力和抗干扰性能,而且不存在复杂的来波方向估计过程。最后通过对8元直线型智能天线阵列的HFSS仿真实验,得出了SINR、驻波比、方向图等特性曲线,验证了该算法的可行性。     

Convergence analysis of a CM array for CDMA systems

The incorporation of directional sensitivity, provided by so-called adaptive antennas is useful in suppressing interfering signals that arise from spatially distinct mobile sources. The problem is that in a cellular radio environment where multipath exists, the standard adaptive antenna using reference signals may not properly lock on the desired signal. This is because the signal correlation matrix processed by the antenna may then be close to singular and standard algorithms fail. Also, most standard algorithms need to cooperate with the receiver for the spatial discrimination of signals. A smart antenna utilizing a blind algorithm is of interest since the antenna may not need to get any feedback from a receiver for the adjustment of weight coefficient for spatial processing and can stand alone to be plugged into any kind of receiver structure.In this paper, we address the convergence property of a Constant Modulus Algorithm which is a blind algorithm and, if employed, can provide no need for an antenna to cooperate with a receiver attached. By identifying a relationship between the weight coefficients and output signal amplitude, we also evaluate the performance of such a stand-alone antenna plus a CDMA matched filter reception. Our results show that for a three element CM array, the BER of a desired user with the other interfering users is much better than a conventional correlation receiver for a single user case since the array suppresses interferences and achieves array gain in SNR.     

一种短波有源天线供电转换器的设计

设计了一种短波有源天线供电转换器,利用直流信号和高频信号的频率差异,通过一条传输线路完成射频信号的传输和天线放大器的直流供电,根据射频器件的高频特性实现2路信号的隔离和复用,采用ADS射频仿真软件建立仿真模型。仿真结果显示在工作带宽内射频阻抗特性和直流电压平稳。制作了一台四通道短波有源天线供电转换器,在1．5～30 M Hz的工作频率范围内实测结果和仿真计算结果相吻合,可与宽带接收机实现良好的匹配。同时,供电转换器各通道之间幅度和相位一致性很好,还可满足一些有源阵列天线的需求。     

智能天线阵列误差校正算法的实验验证

阵列误差的校正是智能天线技术实用化的关键所在。对各种阵列误差进行了深入分析并建立了数学模型。阵列误差可以用一个误差矩阵来表征,通过对误差矩阵的估计,能够恢复理想的阵列流型。实验结果表明,这种阵列误差校正方法能够有效减小各阵元通道之间的差异,改善了系统的性能。     

基于三相幅度测量的相控阵天线快速校准方法

提出了一种基于三相幅度测量的相控阵天线快速校准方法。该方法将天线阵列进行分组,利用每种分组在三种配相下的阵面合成场幅度测量值,可解算出各个天线单元的初始幅相值。该方法仅需幅度测量,避免了相位测量误差影响单元幅相值的计算精度,而且所需幅度测量次数仅为(2N+1)次,可显著提高校准时效性。另外,利用分组思想,同时改变多个单元相位,使总辐射场的幅度变化显著,提升校准准确性。仿真结果表明:校准后相位均方根误差为2.2°,幅度均方根误差为0.2 dB。     

Implementation of Filter Bank–Based RF Transceiver for TV White Space

This paper presents a general‐purpose design scheme of a filter bank (FB)–based radio frequency (RF) transceiver that operates across the entire ultra‐high frequency (UHF) TV band from 470 MHz to 698 MHz and complies with the TV white space (TVWS) regulatory requirements. To this end, an intermediate frequency (IF) band‐pass filter (BPF) with a sharp skirt characteristic is considered as a solution for handling the incoming signals from a baseband modem. Specifically, an FB‐based BPF structure with four ceramic resonator filters that effectively rejects unwanted signals is proposed to extract a desired signal in the TV band. Achievable data rates of a cognitive radio system (CRS) employing the proposed FB‐based RF transceiver at the application layer are investigated in both wired and wireless environments. The service coverage of the CRS network is measured according to several modulation and coding schemes (MCSs) of the CRS. The results show that the coverage of a wireless network in a nearly open area can be extended by more than 9.3 km in the TVWS. Experimental results also confirm that the proposed FB‐based RF transceiver is adequate for utilization in TVWS applications.     

基于软件无线电的天线阵方向图测量

本文设计了一种基于软件无线电的天线阵方向图测量实验。在1.5GHz频段下,手动搭建了一个以单极天线为单元的4元天线阵,并使用两台软件无线电设备USRP 2920分别连接单极天线和天线阵列以作为发射机和接收机。实验将发射机围绕接收机作圆周运动,记录发射天线所在方位角与接收信号的幅值强弱,在极坐标系内即可绘制出天线阵列在水平面内的实测方向图。本实验的测试结果与计算结果基本一致。     

改进的GPS抗干扰自适应天线阵性能研究

文章提出了一种用于GPS接收机的新型抗干扰自适应天线阵,并给出了对其方向图和输出信干噪比的仿真过程.比较了在相同的信号环境时,该天线阵与常用的均匀直线阵、等间隔圆形阵的性能.结果表明,使用该自适应阵可以改善天线阵的方向图,提高输出信号干扰噪声比SINR,增强接收机的抗干扰能力.     

阵列天线抑制欺骗式导航干扰信号方法研究

针对欺骗式干扰影响飞行器卫星导航信号后引起的定位测姿错误问题,提出了一种适用于飞行器导航的基于阵列天线的欺骗式干扰检测和消除方法.使用接收阵列天线的载波相位双差测量值作为干扰检测依据,通过载波相位单差测量方程求出干扰信号的方向矢量,给出了提高干扰方向测量精度的方法,并使用其正交向量在干扰方向形成零陷,同时通过调整波束指向,在待测信号方向形成阵列增益,以达到抗干扰和增强导航信号的目的.使用这种方法可以对导航信号中的欺骗式干扰信号进行有效的识别和消除,适用于复杂环境下的飞行器导航.     

Nonlinear optimization for adaptive antenna array receivers with a small data‐record size

Design of a nonlinear adaptive antenna array receiver is a challenging task in wireless communications due to the limited number of antenna elements and the presence of correlated signals, which directly affect the performance of an antenna array. More importantly, a conventional nonlinear array receiver is often associated with a high computational complexity that undermines its applicability in practice. In this paper, we present a new approach to adaptive beamforming receiver that provides superior performance in antenna array overloading and in the presence of correlated signals with a low complexity. In particular, the proposed receiver requires a small data‐record size to estimate the beamformer weights, which is beneficial in applications with fast fading channels. Simulation examples illustrate the performance improvement of the proposed array receiver when it is compared to the conventional beamformers. Copyright © 2008 John Wiley & Sons, Ltd.     

数字阵列天线接收波束形成方法及实验研究

针对数字阵列天线的发展需求,介绍了用快速傅里叶变换法、数字混频低通滤波法、多相滤波正交下变频法等3种数字接收机通道内信号的幅度、相位计算方法,给出了数字阵天线接收通道的内校准法和外校准法,以及校准后的天线方向图计算公式,并用实验结果检验了上述方法的有效性。     

基于阵列天线测量装备的标校方法研究

介绍了一般测量装备的标校方法及步骤,对基于阵列天线测量装备的标校方法做了进一步论述。利用此标校方法,解决了基于阵列天线的测量装备测量数据处理的精确度问题,通过测量值与提供的真值比较,结果表明该标校方法合理实用并且精度较高,提高了装备保障水平,该研究成果可为靶场其他测量装备的标校提供借鉴。