基于近场校正的相控阵天线低副瓣方向图综合

相控阵天线单元存在着幅度和相位误差,这些误差的综合作用会导致天线方向图副瓣电平达不到优化设计结果。提出了一种基于近场幅相校正的相控阵天线低副瓣综合方法,首先采用近场单通道测量方法,得到相控阵天线阵面的实测幅相值;然后采用非线性二乘法对天线单元幅度和相位进行优化综合;最后根据优化幅相值对实测幅相值进行修正,获得相控阵天线阵面幅相配置参数。方向图实测结果表明该方法可行、有效。     

一种基于海洋回波的单极子/ 交叉环天线相位校正方法

高频地波雷达(HFSWR)使用多重信号分类算法MUSIC 算法估计信号源的到达角时,接收通道幅相特性的不一致会使MUSIC 算法的分辨性能下降,甚至完全失效。文中针对单极子/ 交叉环天线提出一种基于海洋回波的相位校正方法:首先,预选出一阶谱区的大信噪比谱点;然后,结合天线三通道相位中心一致的特性进行有效谱点的筛选;最后,利用有效谱点的相位差均值估计出相位误差。将该方法应用于北部湾海域收集的实测数据处理中,验证了方法的有效性。     

相频扫描阵列通道幅相测试方法研究北大核心CSCD

相频扫描阵列具有频扫低成本和相扫控制灵活等优点,被广泛用于军事和民事。该类阵列的增益、相位扫描面波束副瓣等受通道的幅度相位一致性影响较大,需要经过校准补偿以获得高性能波束。准确高效的通道幅相测试方法是进行校准的前提和基础。文中首先分析了组成相频扫描阵列的波导缝隙天线近场区域的辐射特性,得出在柱面波区域进行取样的可行性。在此基础上提出了扫描架逐行移动取样以及中场取样两类共五种测试方法,并给出了程差的幅相补偿方法。计算了各测试方法所引入的系统误差,分析了它们各自的适用场合。最后对比其中两种测试方法在某相频扫描阵列样机中的幅相测试结果,并给出了补偿校准后的波束测试结果,验证了文中所提出测试方法的准确性和有效性。     

有源相控阵雷达天线实时校正方法

针对有源相控阵天线的超低副瓣、高增益及精确波束指向等性能的实现进行分析研究。首先分析一般相控阵雷达天线及其校正耦合网络的结构,并对实时校正的原理以接收校正为例进行详细的阐述,最后通过某有源相控阵雷达天线实测数据验证该方法的有效性及可行性。     

单脉冲和差通道幅-相失衡分析与改善

为了提高单脉冲和差通道的幅相一致性,以降低测角误差,研究了幅相失衡的机理及解决途径。对此,结合单脉冲和差测角体制,分析和差通道幅相失衡的原理,并仿真其对测角特性的影响。最后,在分析理论校正模型的基础上,提出了基于FPGA的数字式校正方案,并给出了实现流程。实践表明,该方法具有较好的可行性,能有效控制和差信号的一致性。     

相控阵发射系统中幅相校准方法研究

提出了一种相控阵发射系统中闭环幅相校准开关阵的方案。从工程实现的角度介绍了校准开关阵的设备组成、特点和性能,论述了相控阵发射系统中幅相校准的原理、分类和实现方式,并详细推导单信道实现幅相检测的算法。该算法利用同一信道幅相误差稳定的特点,建立多组功率测量值的方程,并联立求解出各通道相对基准信道的幅度差和相位差。理论分析和工程实践均验证了该方案的有效性和实用性。     

基于模糊控制的自适应幅相补偿控制系统

针对数字阵列在使用过程中存在的性能退化问题,利用模糊控制相关理论建立了自适应幅相补偿控制器模型,并设计了新型数字阵列自适应幅相补偿控制系统。该控制系统能够智能、实时地对数字阵列进行监测,并根据阵面状态对各通道幅相进行动态调整,实现数字阵列性能的优化。该系统在未来数字相控阵雷达设计中具有很大的工程意义。     

基于通道合成的数字阵列通道校准方法

通道校准是数字阵雷达的重要技术之一,校准精度影响波束指向、副瓣电平等多个波束形成指标,从而影响整个雷达性能。随着数字阵列规模的不断提升,通道校准对测试时间和测试精度的要求也随之提高。文中首先介绍了一种基于通道合成的数字阵列通道校准方法原理和组成,给出了该测试方法的校准算法;然后,与传统数字阵列通道校准方法的信噪比、记录量、测试时间、幅相标准差等校准性能进行比较;最后,给出了实际测量形成的天线方向图,验证了该方法的有效性。     

基于幅相量化的数字射频存储技术

提出了一种新的基于幅相量化的数字射频存储(DRFM)技术,阐述了它的工作原幅相/相幅转换器的设计思路.通过将幅相量化DRFM与传统的幅度量化和相位量化DRFM的性能进行比较,分析其特点与优势.最后使用软件对此系统进行建模仿真.     

Improved calibration method for airborne ATI-SAR baseline

Airborne Along-Track Interferometric Synthetic Aperture Radar (ATI-SAR) baseline error is a main error resource affecting the precision of velocity measurement of moving objects and therefore should be calibrated externally. The Jet Propulsion Laboratory (JPL) has proposed a calibration scheme for tasks of PacRim98 and PacRim2000 based on several static objects on the ground. In this paper, the influence of phase center uncertainty on baseline determination by using PacRim method proposed by JPL is analyzed. According to the analysis, the phase center uncertainty can cause a constant part of error to the result of baseline calibration. In order to deal with this problem, an improved calibration method on the basis of sensitivity equations and some ground moving targets, whose velocities are already known, is proposed in this paper. The simulation results show that our proposed calibration method has improved the accuracy of baseline calibration and has obviously prohibited the effect of antennas?? phase center uncertainty.     

微波稀布阵雷达发射阵列的幅相误差校正

建立了微波稀布阵综合脉冲孔径雷达发射阵列的幅相误差模型,研究了基于近场窄脉冲和基于远场直达波的2种幅相误差校正方法:前者通过近场天线接收不同频率窄脉冲并进行通道分离、频谱分析等处理后提取幅相误差;后者通过远场天线接收直达波并在去调频后再提取幅相误差。前者运算量较小适用于工程实现;而后者运算量较大,在接收站定位精度较高时这种方法可获得较高的估计精度。仿真结果表明2种方法均能较好地估计幅相误差。     

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。     

Method for Analog Circuit Soft-Fault Diagnosis and Parameter Identification Based on Indictor of Phase Deviation and Spectral Radius

The soft fault induced by parameter variation is one of the most challenging problems in the domain of fault diagnosis for analog circuits. A new fault location and parameter prediction approach for soft-faults diagnosis in analog circuits is presented in this paper. The proposed method extracts the original signals from the output terminals of the circuits under test (CUT) by a data acquisition board. Firstly, the phase deviation value between fault-free and faulty conditions is obtained by fitting the sampling sequence with a sine curve. Secondly, the sampling sequence is organized into a square matrix and the spectral radius of this matrix is obtained. Thirdly, the smallest error of the spectral radius and the corresponding component value are obtained through comparing the spectral radius and phase deviation value with the trend curves of them, respectively, which are calculated from the simulation data. Finally, the fault location is completed by using the smallest error, and the corresponding component value is the parameter identification result. Both simulated and experimental results show the effectiveness of the proposed approach. It is particularly suitable for the fault location and parameter identification for analog integrated circuits.     

An Agile VCO Frequency Calibration Technique for a 10-GHz CMOS PLL

This paper reports an agile VCO frequency calibration technique and its application on a 10-GHz CMOS integer-N phase-locked loop. The proposed calibration method accomplishes efficient search for an optimum VCO discrete tuning curve among a group of frequency sub-bands. The agility is attributed to a proposed frequency comparison technique which is based on measuring the period difference between two signals. Other mixed-signal circuits are also developed to facilitate this approach. The PLL incorporating the proposed calibration technique is implemented in a 0.18-mum CMOS process. The measured PLL phase noise at 10 GHz is -102 dBc/Hz at 1-MHz offset frequency and the reference spurs are lower than -48 dBc. The PLL consumes 44 mW in the low-current mode. The calibration time is less than 4mus     

相控阵雷达接收通道校准方法仿真

接收通道校正是保证接收波束形成性能的重要环节。构建了内场校准和外场校准相结合的通道校准方法的仿真模型。仿真结果验证了该方法可以明显改善第一副瓣水平,减小幅相误差对系统性能的影响。     

基于自校准技术的半球谐振陀螺正交误差的辨识补偿

在静电刚度校正技术的基础上,结合自校准算法,该文提出了一种实时辨识补偿正交误差的理论模型,并在两件套平面电极的半球谐振陀螺上进行了理论仿真和实验验证。结果表明,该方法不仅适用于半球谐振陀螺的力平衡和全角两种工作模式,还适用于虚拟进动的情况。此外,该文提出的补偿方法不会影响正交环路的控制精度,且对陀螺检测和驱动电路的增益和相位误差不敏感。     

Research on Properties of Devices for Shaping and Processing of Signals Based on Amplitude Modulation of Many Components

Devices for shaping and processing of signals based on known varieties of digital amplitude-phase modulation are considered. Their disadvantages are exposed during realization of modulation and demodulation of the signals that are characterized by non-rectangular signal constellations. There are explored properties of devices for shaping and processing of signals based on a new variety of signal modulation, namely amplitude modulation of many components (AMMC). The results of carried out researches show that advantages of proposed AMMC modulator are simplification of phase modulated or amplitude-phase modulated signal shaping, in particular AMMC signal shaping, and improve of modulator internal interference protection. Advantages of AMMC demodulator are simplification of phase modulated or amplitude-phase modulated signal processing, in particularAMMC signal processing, and improve of demodulator internal interference and zero drift protection at its practical realization. The proposed AMMC modulator and demodulator can be applied for shaping and processing of signals based on known and new varieties of amplitude-phase modulation.     

基于虚拟相位靶标的光栅投射三维测量系统标定

采用虚拟相位靶标方法实现光栅投射轮廓测量中三维空间坐标的标定,探讨了X、Y方向和高度Z方向标定的原理与关键技术,并对虚拟相位靶标进行了试验研究。实验结果表明：采用该方法只需要1个参考面图像序列就可实现X、Y方向坐标标定,简化了现有标定方法中至少需要采集2个图像序列的繁琐过程,而且标定后X、Y方向误差仅为0．1mm和0．2mm,高度Z方向的误差最大不超过0．2mm,标准偏差不超过0．040mm。     

高功率雷达空间功率合成效率研究

高功率微波空间功率合成效率直接关系到高功率雷达输出功率的大小,重点研究高功率雷达空间功率合成效率问题。首先推导出高功率微波空间合成效率公式;然后分析了影响合成效率的相位误差、目标位置误差、时延误差和阵元间距误差等因素;最后提出一种幅度-相位联合调整的方法,通过增加幅度调整电路和相位调整电路,减小通道的幅相误差,提高空间功率合成效率。     

基于基频分量消光的1/4波片快轴标定方法

提出了一种基于基频分量消光的波片快轴标定方法,并利用琼斯矩阵对其标定原理进行了分析.激光器、起偏器、相位调制器、待标定1/4波片、检偏器和光电探测器构成标定光路,起偏器、检偏器的透光轴与相位调制器的振动轴分别成 45°和0°夹角.准直激光束依次经过起偏器、相位调制器、待标定1/4波片和检偏器,由光电探测器接收.理论分析表明该标定方法标定精度主要取决于检偏器的定位误差.实验验证了该标定方法的有效性,1/4波片快轴标定结果的最大偏差为0.043°,标准差为0.012°,标定精度为0.05°.