联合SAR相位和振幅信息校正电离层延迟相位

电离层延迟是合成孔径雷达差分干涉测量(DInSAR)的误差源之一,对长波段SAR数据影响尤为严重。文中提出联合SAR相位和振幅信息精确测量方位向偏移,并基于方位向偏移构建模型校正DInSAR电离层延迟相位。选取覆盖2008年汶川地震的ALOS PALSAR(轨道号471)同震干涉对为实验数据,进行电离层延迟校正实验和精度分析。结果表明,实验同震干涉对中电离层贡献相位达17rad,对应约32cm的视线向形变误差,经过校正后地震远场形变均方根减小59%。对比传统方法校正结果,所提方法可有效提高电离层延迟相位校正精度。

Correcting the ionosphere phase delay by the integration of SAR phase and amplitude information

Ionosphere delay is one of the error sources in Differential Interferometric Synthetic Aperture Radar(DInSAR),especially for the SAR systems with long wavelength.This paper proposes a method by the integration of SAR phase and amplitude information for measuring the azimuth offset of a SAR pair. The determined azimuth offset is then used to correct the ionosphere phase delay based on a correction model.For inferring the efficiency and precision of the proposed method,this paper applies the method to one ALOS PALSAR(Path 471)coseismic interferometric pair that covers the Wenchuan 2008(China). The testing result shows that the maximum ionosphere phase delay in the coseismic SAR pair is about 17 rad,corresponding to the deformation error of about 32 cm in line of sight.The coseismic displacements in the far field have a reduction of its standard deviation with 59 %.The proposed method can improve the correction precision in the mitigation of ionosphere phase delay,compared with the conventional correction method.