基于蒙特卡罗方法的冷原子干涉仪物理仿真

由于现有的噪声分析方法无法很好地评估在复杂环境下冷原子干涉仪的输出特性,本文提出了一种新的冷原子干涉仪仿真方法,可以模拟大动态条件下各项噪声及其之间的耦合对冷原子干涉仪的影响。利用单粒子波包演化的处理方式对冷原子干涉仪进行全过程物理建模,并采取蒙特卡罗方法对大量确定初态的原子进行全过程统计,最终得到冷原子干涉仪在多种噪声同时存在的情况下的响应。该方法主要优势体现在能够对噪声耦合情形进行高精度仿真,并且可以根据实际数据对干涉仪输出进行实时处理,以提升冷原子干涉仪的性能指标。     

一种干涉SAR复图像数据的快速仿真方法

为了给干涉测高算法提供具有先验知识的干涉数据,进行算法的定量可控误差分析,以完成算法性能的定量评估,针对干涉SAR(合成孔径雷达)数据仿真进行了深入的研究.考虑多种因素,推导出用于干涉SAR仿真的一种仿真模型,能快速完成干涉SAR面目标复图像的仿真;并提出迭代插值算法反推雷达斜距,既很好地去除了干涉SAR仿真中的奇异点效应,又提高了仿真速度.能够为图像配准、相位解缠产生数据源,也可进行基线估计.计算机仿真结果表明,新仿真模型具有快捷、灵活、多功能性,迭代插值算法也具有快速准确性.     

动态三维流场的全息层析干涉测量

设计了一种适用于拍摄大视角动态全息图的光照，用精心选模的高性能调Ｑ Ｎｄ：ＹＡＧ倍频脉冲激光器拍摄了几种动态三维流场的双曝光全息图，在用层析法对双高斯函数的温度场作了模拟验证性计算的基础上，给出了双芯乙醇灯温度场的两个横截面上温度分布的重建结果。     

基于云纹干涉与钻孔法的等离子热障涂层残余应力实验研究

应用云纹干涉法与钻孔法结合的光测力学实验方法,研究了等离子热障涂层基体材料镍基高温合金DZ125的残余应力。通过实验和计算获得了等离子喷涂工艺下基体DZ125的残余变形场、残余应变场和残余应力,并描述了其主要特征。结果表明,采用云纹干涉法与钻孔法结合测定热障涂层残余应力具有全场测量和高灵敏度等优点,这对于采用光学手段研究热障涂层残余应力有着积极的意义。     

连线干涉测量信号处理方法及实验验证

干涉测量技术是深空探测任务中高精度获取导航数据观测量的重要技术手段。阐述连线干涉测量原理,详细推导干涉测量信号处理算法,用于准确提取反映航天器测角信息的时延观测量。分析信号处理数学模型,通过仿真验证算法的有效性。由于连线干涉测量具有严格的时间同步特性,同时消除了传播介质公共误差对信号的影响,通过搭建连线干涉测量实验系统实际采集地球同步卫星信号进行分析,结果表明实验成功获取了清晰的干涉条纹,得到高精度的时延观测量信息,从而验证了连线干涉测量信号处理方法的有效性。     

高超声速轴对称模型密度场的激光全息干涉测量

激光全息干涉技术在 2 0 0m自由飞弹道靶的初步应用中 ,对高速和高超声速的轴对称模型周围气流密度场定量测量进行了初步探索。给出了 M =2 .2的弹头和M =2 .45、Φ =2 0mm的球标模以及M =9.35的钝锥模型的全息干涉图和处理结果 ,同时与钝锥模型的理论数值计算结果进行了比较 ,首次在弹道靶上获得了流场密度的定量结果。     

Ka波段机载双模式干涉SAR系统设计及测量精度分析

为解决传统干涉合成孔径雷达(SAR)系统只能顺轨干涉或交轨干涉,无法兼顾高精度高程测量和速度测量的问题,开展了Ka波段机载双模式干涉SAR系统设计与干涉测量精度分析。基于Ka波段电磁波波长短、干涉相位敏感度好的特点,利用较短的干涉基线在同一干涉SAR系统中实现高精度干涉测高与测速,并介绍了所设计的Ka波段机载双模式干涉SAR验证系统。仿真结果表明:该系统具备高效率、高精度干涉测量能力,可获得亚米级的绝对测高精度和0.1 m/s的测速精度。     

InfraRed Astronomy Satellite Swarm Interferometry (IRASSI): Overview and study results

The far-infrared (FIR) regime is one of the few wavelength ranges where no astronomical data with sub-arcsecond spatial resolution exist yet. Neither of the medium-term satellite projects like SPICA, Millimetron or OST will resolve this malady. For many research areas, however, information at high spatial and spectral resolution in the FIR, taken from atomic fine-structure lines, from highly excited carbon monoxide (CO) and especially from water lines would open the door for transformative science. These demands call for interferometric concepts. We present here first results of our feasibility study IRASSI (Infrared Astronomy Satellite Swarm Interferometry) for an FIR space interferometer. Extending on the principal concept of the previous study ESPRIT, it features heterodyne interferometry within a swarm of five satellite elements. The satellites can drift in and out within a range of several hundred meters, thereby achieving spatial resolutions of <0.1 arcsec over the whole wavelength range of 1–6 THz. Precise knowledge on the baselines will be ensured by metrology methods employing laser-based optical frequency combs, for which preliminary ground-based tests have been designed by members of our study team. We first give a motivation on how the science requirements translate into operational and design parameters for IRASSI. Our consortium has put much emphasis on the navigational aspects of such a free-flying swarm of satellites operating in relatively close vicinity. We hence present work on the formation geometry, the relative dynamics of the swarm, and aspects of our investigation towards attitude estimation. Furthermore, we discuss issues regarding the real-time capability of the autonomous relative positioning system, which is an important aspect for IRASSI where, due to the large raw data rates expected, the interferometric correlation has to be done onboard, in quasi-real-time. We also address questions regarding the spacecraft architecture and how a first thermomechanical model is used to study the effect of thermal perturbations on the spacecraft. This will have implications for the necessary internal calibration of the local tie between the laser metrology and the phase centres of the science signals and will ultimately affect the accuracy of the baseline estimations.     

Denoising methods in interferometric SAR images processing

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干涉SAR图像的降噪方法及水平地形效应消除

考察不同滤波器抑制干涉SAR(Synthetic Aperture Radar)图像噪声的效果.为有效地使用低通滤波处理,首先对原始干涉图像进行水平地形效应消除,保证图像信号频率的中心在零频处,降低由干涉SAR系统几何结构引起的信号频率偏移对滤波效果的影响.同时水平地形效应消除后的干涉SAR相位图可直观地反映地形的拓扑结构.实际数据处理结果证明本文提出的水平地形效应消除算法及滤波算法的可行性及有效性.