干渉型SAR計測に及ぼす湿潤大気遅延効果とGPS水蒸気情報の利用

抄録

Wet atmospheric propagation path delay is one of the most important measurement error factors in repeat-pass Interferometric SAR (INSAR) technique for wet regions such as Japan. Its influence can not be neglected for the measurement accuracy of several meters in elevation and several centimeters in surface deformation. The theoretical analysis of height and displacement error by atmospheric phase change for JERS-1/SAR data has showed some severe error even for slight atmospheric inhomogeneity.
The simultaneous observation by water vapor radiometer (WVR) at GPS stations in Izu district for about a year has been carried out. The comparison between GPS and WVR wet delay has induced that correlation coefficient was 0.99 and r. m. s. wet delay was about 1.1cm except for rainy day. It was showed that the wet delay information of GPS network would be useful and efficient in the quantitative evaluation of wet atmospheric delay effect.
In order to evaluate wet delay effect appeared on INSAR data, we have applied GPS network data to actual phase of two pairs of differential SAR interferogram. The result has concluded that INSAR residual phase change was successfully extracted by using high coherent interferogram but was not very accurately evaluated by GPS delay due to the serious noise factors.