圆轨迹运动误差检测与信号处理

本文对精密仪器和机械中常见的运动形式——圆轨迹运动的误差建模、检测和识别进行了系统深入的研究。所提出的基于统计Ｂａｙｅｓ分类器的时域相关特征识别技术和基于距离测量分类器的频域谱线特征识别技术对实际圆轨迹运动误差的识别取得了满意的效果。该结果为精密仪器和机械圆轨迹运动精度的调试和误差控制提供了新的重要手段。

轴系扭振测试分度误差补偿方法及程序实现

对于扭转振动的测试目前普遍采用非接触测量法,使用这种方法时分度装置的分度误差对于测量结果有很大的影响;详细的阐述了分度误差的补偿原理,给出了基于LabVIEW编写的分度误差的补偿程序。由测试结果可以发现,经过分度误差补偿后的数据曲线变得光滑平顺,明显的减小了分度误差对于测量结果的影响,使测试结果更加精确。

用于磁光盘误码率测试的信号处理系统

研制了一种用于磁光盘误码率测试的信号处理系统。对信号再生电路的结构与设计要点进行了详细的阐述；并提出了一种采用“采集－暂存”结构的磁光盘盘面数据采集仪。研究结果表明，该信号处理系统引入的判决误码率与磁光盘原始误码率的下限值相比，还要低３～４个数量级，能够充分满足磁光盘误码率测试的要求。

基于信号子空间处理的DPCA运动误差校正方法

在机载SAR/GMTI应用中,雷达平台运动误差常使得偏置相位中心天线(DPCA)失效,限制其实际应用。文中推导并仿真了运动误差引起DPCA杂波抑制性能下降的情况,提出基于信号子空间处理的解决方法,对β失效、偏航和俯仰姿态误差以及位置误差等多种情况分别进行了分析和误差校正。仿真结果表明,该方法可使DPCA对运动误差的敏感度下降,从而提高杂波抑制性能,扩大DPCA的适用范围,具有一定的工程参考价值。

Autofocus technique for ISAR imaging of uniformly rotating targets based on the ExCoV method

The inverse synthetic aperture radar (ISAR) imaging can be converted into a sparse reconstruction problem and solved by the l1norm minimization algorithm. The basis matrix in sparse ISAR imaging is usually characterized by the unknown rotation rate of a moving target, thus the rotation rate and the sparse signal should be jointly estimated. Especially due to the imperfect coarse motion compensation, we consider the phase error correction problem in the context of the sparse signal reconstruction. To address this issue, we propose an iterative reweighted method, which jointly estimates the rotation rate, corrects the phase error and reconstructs a high resolution ISAR image. The proposed method gives a gradual and interweaved iterative process to refine the unknown parameters to achieve the best sparse representation for the ISAR signals. Particularly, in ISAR image reconstruction, the l1norm minimization algorithm is sensitive to user parameters. Setting these user parameters are not trivial and the reconstruction performance depends significantly on their choices. Then, we consider an expansion-compression variance-component (ExCoV) based method, which is automatic and demands no prior knowledge about signal-sparsity or measurement-noise levels. Both numerical and electromagnetic data experiments are implemented to show the effectiveness of the proposed method. It is shown that the proposed method can estimate the rotation rate and correct the phase errors simultaneously, and its superior performance is proved in terms of high resolution ISAR image. © 2017 Beijing Institute of Aerospace Information.