一种基于LPF+POD的星光导航气动光学效应研究方法  

An LPF + POD Based Method to Study Aero-Optical Effect of Starlight Navigation

作　　者：杨博[1] 陈子匀 刘孝孝[2] 胡静[1] 

机构地区：[1]北京航空航天大学宇航学院,北京100191 [2]北京航空航天大学仪器科学与工程学院,北京100191

出　　处：《宇航学报》2016年第1期74-83,共10页Journal of Astronautics

基　　金：国家重点项目基金(91016004)

摘　　要：为便于研究CCD安装窗口附近湍流对星光产生的气动光学效应及星光传输过程中的能量衰减规律,提出一种低通滤波(LPF)与本征正交分解(POD)融合的高超声速流场中星光传输特性的分析方法,该方法通过对流场的结构分析,提取其相干结构和非相干结构,将湍流对星光产生的气动光学畸变模拟为低频可建模部分和正态分布部分,由此可定性地研究星光在高超声速流场中的传输机理,并采用两种评价方法验证了POD提取特征的可靠性和真实性。流场结构对星光传输产生光程差的仿真表明,大尺度相干结构造成最主要的气动光学畸变,其光程差有明显的建模特性,而非相干成分造成的光程差具有接近正态分布的统计特性,两者互不相关,且其低频部分贡献主要的星图畸变。对不同马赫数的流场进行仿真得到的气动光学畸变特性与流场结构特性相符,这说明从研究流场关键成分对星图成像的影响来揭示星光的气动光学效应特性是合理和有效的。In this paper, a new fusion method combining Low Pass Filter （LPF） with Proper Orthogonal Decomposition （POD） for analyzing the optical transmission effect of the starlight in hypersonic environment is proposed to study the aero- optical effect and the law of energy attenuation caused by turbulent flow field near the CCD installed window. This method is used to analyze the flow-field structures and extract the coherent structures and incoherent structures, the aero-optical distortion can be simulated as the low-frequency modeling part and the normally distributed part. And two evaluation methods are used to prove reliability and authenticity of the extracted features of POD in this paper. The simulation results indicate that the Optical Path Difference （OPD） produced by the large-scale coherent structures has basically captured the main aero-optical distortion caused by the original flow field, and the OPD has obvious modeling features. However, the 0PD caused by the incoherent components has the statistical feature of normal distribution. And the two parts are uneorrelated each other, and the low-frequency part contributes the main star map distortion. In this paper, the features of the aero-optical distortion simulated in flow field with different Mach numbers accord with that of flow-field structures, and it indicated that researching the influences of key components of the flow-field on star map imaging to reveal the aero-optical features of the starlight is reasonable and effective.

关 键 词：高超声速流场 星光传输 气动光学 星图畸变 

分 类 号：TP273.2[自动化与计算机技术—检测技术与自动化装置]