典型区域气候下的D-InSAR大气形变误差分析

D-InSAR atmospheric deformation error analysis in representative areas with different climate

利用单站全球导航卫星系统(Global Navigation Satellite System,GNSS)精密单点定位原理(Precise Point Positioning,PPP)解算天顶方向的对流层大气天顶延迟,并对其一天内的变化进行统计平均,结合经典的Kolmogorov-Obukhov"2/3"扰动理论和随机场理论,基于对流层天顶延迟与大气折射率的时变相关性获得大气结构常数的平方C^2_n,通过计算我国北京、上海、昆明、乌鲁木齐四个典型区域在不同时间的C^2_n,评估各区域大气环境的湍流特性对不同基线长度的合成孔径雷达差分干涉(Differential Interferometry Synthetic Aperture Radar,D-InSAR)系统形变误差的影响.计算结果表明:对于基线距离较长的合成孔径雷达(Synthetic Aperture Radar,SAR)系统来说,大气湍流的影响不容忽略,尤其是当大气结构常数的数量级在10^(-14)m^(-2/3)以上时,形变误差基本会达到厘米级.准确获取雷达成像时间内的大气结构常数,对进一步降低D-InSAR系统的形变误差起到举足轻重的作用.

By using the precise point positioning with GNSS single station receiver,a method of esti-mating atmospheric structure constant C 2n is introduced based on the time correlation of tropospheric zenith delay and atmospheric refractive index which uses classical Kolmogorov-Obukhov“2/3”turbulence theory and random field theory.By computing C 2n in Beijing,Shanghai,Kunming and Urumchi,the D-InSAR de-formation errors are analyzed at different areas,and the results show that if the baseline is larger than 1km and C 2n is larger than 10 -1 4 m-2/3 ,the deformation errors is at centimeter-scale.It is essential to obtain the C 2n exactly during the imaging time of SAR,and the deformation error of D-InSAR can be decreased signifi-cantly.