融合GPS与DInSAR的区域地表三维形变获取研究

Study on 3D Deformation of Regional Surface by Integrating GPS and DInSAR

合成孔径雷达差分干涉测量(DInSAR)是监测地表形变的有效方法,而地表形变是三维形变,因水平方向形变信息的不敏感性,通过DInSAR视线向形变难以获得准确的三维形变信息。综合GPS水平形变精度高、DInSAR垂向精度高和空间分辨率高的特点,研究融合GPS与DInSAR获取区域地表三维形变。首先介绍GPS水平形变、DInSAR垂向形变与三维视线向形变以及三维视线向转化为三维形变的理论基础;然后以雄安新区为例,开展三维视线向形变与DInSAR视线向形变的比较,两者存在较好的相关性,存在一定的偏差;其次针对短时形变监测和长期地表形变监测的需求,通过不同时间间隔的GPS、DInSAR形变结果,分别构建了基于SAR重访周期和一年间隔的DInSAR视线向形变校正模型,并以实测GPS、DInSAR结果进行模型可靠性验证;最后将三维视线向形变转化为水平方向形变和垂向形变,该三维形变在保证精度的基础上保留了SAR数据的高空间分辨率特征。研究结果表明:对于SAR重访周期时间间隔来说,DInSAR视线向形变与三维视线向形变差异较小,仅存在1 mm的校正,说明对于短时期来说,水平方向的形变微小。对于1年时间间隔来说,DInSAR校正后的视线向形变与三维视线向形变的平均偏差为0.34 mm,均方根误差为0.49 mm,其误差均小于校正前的DInSAR形变。

Differential synthetic aperture radar interferometry(DInSAR)is an effective method to monitor the surface deformation,while the surface deformation is three-dimensional deformation.Due to the insensitivity of horizontal deformation information,it is difficult to obtain accurate three-dimensional deformation information through DInSAR Los deformation.Based on the characteristics of high horizontal deformation accuracy of GPS,high vertical deformation accuracy of DInSAR and high spatial resolution,the fusion of GPS and DInSAR to obtain the three-dimensional surface deformation of the region is studied.Firstly,the theoretical basis of GPS horizontal deformation,DInSAR vertical deformation translated three-dimensional Los deformation is introduced.Then,taking Xiongan new area as an example,the three-dimensional Los deformation and DInSAR Los deformation is compared.Secondly,to meet the needs of short-term deformation monitoring and long-term surface deformation monitoring,through the deformation results of GPS and DInSAR at different time intervals,the Los deformation correction model of DInSAR based on the revisit period and one-year interval of SAR was constructed,and the reliability of the model is verified by the measured GPS and DInSAR results.Finally,the three-dimensional Los deformation was transformed into horizontal deformation and vertical deformation,which preserves the high spatial resolution characteristics of SAR data on the basis of ensuring the accuracy.The results show that the difference between DInSAR Los deformation and three-dimensional Los deformation is small for the time interval of SAR revisit period,with only a correction of 1 mm,indicating that for a short period of time,the horizontal deformation is small.For the 1-year interval,the average deviation between the Los deformation after DInSAR correction and the 3D Los deformation is 0.34 mm,and the RMS error is 0.49 mm,both of which are smaller than the DInSAR deformation before the correction.The results of this study can be used to obtain the three-dimensional deformation of the regional surface quickly and provide a reference for post-deformation analysis.