Ground-based InSAR Real-time Deformation Monitoring Based On Three-dimensional Phase Unwrapping Technology

Ground-based InSAR(GB-InSAR)technology has a high sampling frequency and a large amount of image data,and it is one of the main methods for slope deformation monitoring.Traditional data processing methods based on PS and SBAS have low real-time processing efficiency.The accumulated large amount of data increases the computational burden of the computer,and the monitoring results cannot be obtained in real time.Ground-based InSAR real-time monitoring technology means that the images are processed in a short time after they are acquired,and the deformation information of the monitored area is retrieved.The study of high-precision ground-based InSAR real-time monitoring methods can improve the timeliness of slope monitoring,which is conducive to rapid response to geological disasters,and is of great significance.To this end,this paper analyzes in detail the important factors that affect the accuracy of ground-based InSAR real-time deformation monitoring,such as atmospheric correction,high-quality point selection,and image grouping methods.And introduce the idea of StaMPS time series analysis method in spaceborne InSAR,and propose a real-time data processing method of ground-based InSAR based on three-dimensional phase unwrapping technology.The specific work is as follows:(1)Analyze and compare the correction accuracy of different atmospheric correction methods.The influence of atmospheric delay and interference are basically proportional to the interval time.This article conducts atmospheric correction experiments on two scene interferograms generated by interference with a time interval of 1 hour and 10 hours,using the primary,quadratic linear atmospheric model and the three-dimensional atmospheric model respectively.experiment.Through experiments,it is concluded that the atmospheric delay correction of the three-dimensional atmospheric model can achieve the best results.(2)A multi-threshold PS point selection method is proposed.The number of PS points determines the quality and efficiency of real-time monitoring.In order to select the appropriate number and distribution of PS points,this paper adds an intensity threshold on the basis of the amplitude dispersion index threshold and the coherence threshold double threshold method.Experiments have proved that the proposed multi-threshold point selection method can better ensure the quality of point selection when rapid deformation occurs.When the deformation is slow,the accuracy of the proposed method is also better than the traditional double-threshold point selection method.(3)The three-dimensional phase unwrapping technology based on ground-based InSAR is studied.The experimental results of the phase unwrapping show that the traditional two-dimensional phase unwrapping cannot accurately restore the true phase and the inverted deformation is quite different from the actual one.The three-dimensional phase unwrapping method that adds the time dimension can solve it well.The influence of factors such as atmospheric delay caused by a long baseline on the inversion of phase unwrapping and deformation results is consistent with the actual situation.Based on the above work,this paper proposes a ground-based InSAR real-time monitoring method based on three-dimensional phase unwrapping technology and selects 16-day monitoring data collected in Hebei Malanzhuang Iron Mine MIMO-SAR for experimental verification.Experimental results show that the proposed method can achieve millimeter-level monitoring accuracy of the target area,and it is also suitable for ground-based radar data with low sampling frequency.