基于稳定点加权的GBSAR大气扰动校正方法

GBSAR Atmospheric Turbulence Calibration Based on Weighted Stable Points

为解决地基合成孔径雷达变形监测中大气扰动对监测精度的影响问题,基于方位向大气扰动的相关特性,提出了一种基于稳定点加权的地基合成孔径雷达大气扰动校正新方法.该方法基于稳定像元推算大气扰动因子,利用大气扰动因子长度去除受扰动剧烈的影像,根据像元间距离加权获取非稳定像元大气扰动因子,从而校正非稳定点大气扰动,推算出变形信息.隔河岩大坝IBIS-L变形监测实验结果表明:雷达视线向大气扰动对变形的影响最大达75 mm;通过新方法校正后,大气扰动明显减小,变形监测精度提高到1 mm,且变形趋势与同期大坝垂线监测结果一致.

Atmospheric disturbance is one of the key factors affecting the accuracy of ground based synthetic aperture radar （GBSAR） interferometry for deformation monitoring. Considering the correlation of atmosphere delay with azimuth direction, a new GBSAR atmospheric turbulence calibration method based on distance-weighted stable points is proposed. In this method, the atmospheric disturbance factor is first calculated from the stable points, and the images which are severely affected by atmospheric disturbance are removed using the length of the atmospheric disturbance factor. Then, the atmospheric disturbance factor of unstable pixels are obtained by distance-weighting of stable points to calibrate the atmospheric disturbance on unstable pixels and derive the final product of deformation information. As a case study, the proposed method was applied to the deformation monitoring of Geheyan dam using the IBIS-L GBSAR system. The results show that the maximum deformation affected by the atmospheric disturbance along the radar line of sight （LOS） reaches 75 mm, but the influence is significantly reduced after the calibration with the presented method. The accuracy of the deformation monitoring was improved to 1 mm, and the monitored deformation trend has a good agreement with the plummet measurements.