CN-117289268-B - Method, system and computer readable medium for correcting atmospheric delay of time sequence InSAR monitoring data

CN117289268BCN 117289268 BCN117289268 BCN 117289268BCN-117289268-B

Abstract

The invention provides an atmospheric delay correction method, an atmospheric delay correction system and a computer readable medium of time sequence InSAR monitoring data, which can be used for accurately estimating and correcting the InSAR atmospheric delay in a mountain canyon area, reading relevant information of the time sequence InSAR high coherence point based on an input SAR image, such as phase, elevation, initial deformation rate, unwrapping closed loop error and the like, carrying out window segmentation on an InSAR interferogram through a sliding multi-window with a certain overlapping degree, iteratively estimating linear model parameters in each window, and finally outputting estimated average deformation rate of each point and time sequence deformation quantity. According to the invention, the atmospheric delay correction of the InSAR monitoring data in the mountain canyon area with vertical layering leading can be realized, an effective way is provided for the InSAR technology at the mountain canyon Gu Ou time sequence to overcome the influence of atmospheric delay, and the precision and the applicability of the InSAR technology at the surface deformation monitoring of the mountain canyon Gu Ou are improved.

Inventors

LIU CHUANXIN
SHENG LEI
ZHANG LEI
LI JING
ZHOU XIAOMIN
ZHOU AO

Assignees

苏交科集团股份有限公司

Dates

Publication Date: 20260505
Application Date: 20230823

Claims (10)

1. An atmospheric delay correction method of time sequence InSAR monitoring data, which is characterized by comprising the following steps: (1) The DS-InSAR technology is used for fusing the distributed scatterer and the permanent scatterer and carrying out phase stability analysis to obtain a high-coherence measuring point winding phase; (2) 3D phase unwrapping is carried out, and measured point unwrapping phase values of all interferograms are obtained; (3) According to the preset window size and window moving step length, mutually independent window segmentation is carried out on each interferogram, and point location information, unwrapping phase, initial deformation rate and elevation value in each window are obtained; (4) Screening stable points according to the initial deformation rate or the updated average deformation rate in a certain window i, then establishing a linear model equation of phase and elevation on the screened stable points, solving linear model parameters of each time phase of the window by adopting a least square method, and calculating tropospheric delay phases of all measurement points in the window according to elevation values; (5) Subtracting the troposphere delay phase calculated for the first time by each window from the initial unwrapping phase to obtain an atmospheric delay correction phase, re-estimating the deformation rate of each point by adopting a weighted least square method, and repeating the processing of the step (4) to estimate the atmospheric delay phase again; (6) Calculating root mean square of difference between two adjacent estimated atmospheric delay phases of each interferogram in window i, and calculating average value of all interferograms, judging termination threshold value when estimation of atmospheric delay phase is completed at least three times If the atmospheric delay phase is smaller than the preset threshold value, carrying out estimation of the next window, if not, returning to the step (4) to continue estimation of the atmospheric delay phase, wherein the termination threshold value is set Representing two adjacent times The difference between the two, Representing the root mean square of two times of atmospheric delay phase parameter estimation for a certain window; (7) After the estimation of the atmospheric delay phase is completed in all windows, linear model parameters in the centers of all windows are interpolated to all measurement points by a double-tone and spline interpolation method, and the atmospheric delay of all measurement points is calculated by combining the elevations of all the points; (8) Subtracting the atmospheric phase delay of the measuring point from the winding phase of the measuring point, re-carrying out 3D phase unwrapping, further judging whether the change value DeltaU of the percentage of the error-free points of the two unwrapping times in the number of measuring points of all interferograms is smaller than a threshold value setting, if so, stopping iteration, otherwise, returning to the step (3); (9) After the atmospheric delay correction is finished, removing residual turbulence delay by a space-time filtering method; (10) And modeling by deformation information to obtain the average deformation rate and time series deformation quantity of each point after atmospheric correction.
2. The method for correcting the atmospheric delay of the time-series InSAR monitored data according to claim 1, wherein in the step (3), each interferogram is subjected to independent window division using a rectangular moving window having an overlapping degree, wherein the azimuth/distance width and the window sliding step length of the rectangular moving window are respectively denoted as S windows and S steps and S windows ＝2S steps .
3. The method for atmospheric delay correction of time-series InSAR monitored data according to claim 2, wherein in the step (3), I windows are obtained by dividing independent windows of each interferogram, and the number of windows is calculated by the following formula: Wherein S range is the number of interferogram distance direction pixels, S azimut h is the number of interferogram azimuth pixels, Representing a down-rounding operator; within the range of each window, the vertical stratification dominant tropospheric delay phase and elevation satisfy the following linear relationship: Wherein, phi i,n represents the troposphere delay phase at any point in the ith moving window of the nth SAR image acquisition time, n=1, 2, & gt, N, i=1, 2, & gt, I, k i,n is the slope, the scale size of the vertical stratification atmospheric delay of the troposphere is reflected, h i,n represents the elevation value in km; for the intercept, a large scale tropospheric component and a portion of the turbulence delay component are represented.
4. The atmospheric delay correction method of time-series InSAR monitored data of claim 3, wherein the 3D phase unwrapping comprises: the unwrapping phase for J points within the ith moving window of the M interferograms is expressed as follows: Wherein H i represents an elevation value matrix, A i represents a linear transformation coefficient matrix from SAR images to interference image pairs, and the combination condition of main images and auxiliary images of each pair of interference images is recorded; the method comprises the steps of expressing tensor product, wherein X i represents an unknown parameter matrix to be solved in a linear model, wherein the unknown parameter matrix comprises linear model slope and intercept of each time phase, E is a unit column vector, phi i is a column vector formed by M interference unwrapping phase values of each point in a window, and RES i represents residual phases after terrain and orbit errors are removed, wherein the residual phases comprise deformation signals, residual turbulence and random noise.
5. The method for correcting the atmospheric delay of the time-series InSAR monitored data according to claim 1, wherein in the step (4), the points with the absolute values of the deformation rates smaller than the empirical threshold are screened as stable points and weights are set, and a weight matrix P is established according to the initial deformation rates, expressed in the following form: P=1/(1+|v sta |),|v sta |≤v thr ; Wherein v sta represents the deformation rate of the stable point, and v thr is the empirical threshold of the deformation rate, which is set to 5mm/a.
6. The method for correcting the atmospheric delay of the time-series InSAR monitoring data according to claim 1, wherein in the step (5), after the tropospheric delay phase estimation within the range of the first window, the preliminary tropospheric delay phase of each point is obtained, the deformation rate of each point is estimated again after subtracting the obtained tropospheric delay phase from the unwrapped phase, and the stable point is screened again according to the new deformation rate until the difference between the estimated tropospheric delay phases of two adjacent times is within the expected range.
7. The method for atmospheric delay correction of time-series InSAR monitored data according to claim 1, wherein in said step (6), a termination threshold value of an atmospheric delay phase difference estimated two times before and after the same window is calculated And further judging the relation between the atmospheric delay phase and the preset threshold value, if the atmospheric delay phase is smaller than the preset threshold value, estimating the next window, otherwise, returning to the step (4) to continue estimating the atmospheric delay phase of the current window: First, the root mean square of two atmospheric delay phase parameter estimations for a window is defined Wherein, the The difference between the estimated troposphere delay phases before and after the mth interference point J is represented, wherein M is the number of interferograms, and J is the number of measuring points in a window; then, to Differential to obtain new window cycle termination threshold I.e. at least three window parameter estimations are made, when two adjacent window parameter estimations are made And when the difference is smaller than a preset threshold value, the change degree of the difference between the two adjacent parameter estimation results meets the expectation, namely the troposphere delay model parameter estimation result tends to be stable.
8. The method for correcting the atmospheric delay of the time-series InSAR monitored data according to claim 1, wherein in the step (8), after subtracting the atmospheric delay phase from the initial winding phase before the atmospheric delay correction, the 3D phase unwrapping is performed again, and the change value Δu of the percentage of the error-free points of the two unwrapping before and after the number of the measurement points of all the interferograms is calculated: wherein U i+1 and U i respectively represent the percentage of the unwrapping error-free points of the atmospheric delay phase obtained by the i+1st and i-th estimation and all the interference patterns after removal to all the points, N mp represents the number of measuring points, M represents the number of the interference patterns, and the error-free points refer to points with the absolute value of unwrapping closed loop residual points smaller than 1 rad.
9. A computer system, comprising: One or more processors; a memory storing instructions operable; Wherein the instructions, when executed by the one or more processors, implement the process of the atmospheric delay correction method of time-series InSAR monitored data of any one of claims 1-8.
10. A computer readable medium storing a computer program, the computer program comprising instructions executable by one or more computers which, when executed by the one or more computers, perform the process of the method of atmospheric delay correction of time series InSAR monitored data of any one of claims 1-8.

Description

Method, system and computer readable medium for correcting atmospheric delay of time sequence InSAR monitoring data Technical Field The invention relates to the technical field of InSAR monitoring, in particular to an atmospheric delay correction method, an atmospheric delay correction system and a computer readable medium of time sequence InSAR monitoring data. Background The frequent occurrence of landslide and other geological disasters in mountain areas causes serious economic and personnel losses, and the identification, monitoring and early warning of hidden dangers of landslide and other geological disasters in mountain canyon areas are called as serious test of current area development. The time sequence InSAR technology has the advantages of all-weather, large scale and the like, is applied to deformation monitoring in landslide, earthquake, mining area, city and the like, and generates good social benefit and economic benefit. However, in the high mountain Gu Ou, the time sequence InSAR is severely affected by seasonal vertical stratification delays in tropospheric delays, so that deformation monitoring results are severely disturbed, and the delays have a large correlation with the terrain. Disclosure of Invention In view of the drawbacks and shortcomings of the prior art, a first aspect of the present invention provides an atmospheric delay correction method for time-series InSAR monitoring data, including: (1) The DS-InSAR technology is used for fusing the distributed scatterer and the permanent scatterer and carrying out phase stability analysis to obtain a high-coherence measuring point winding phase; (2) 3D phase unwrapping is carried out, and measured point unwrapping phase values of all interferograms are obtained; (3) According to the preset window size and window moving step length, mutually independent window segmentation is carried out on each interferogram, and point location information, unwrapping phase, initial deformation rate and elevation value in each window are obtained; (4) Screening stable points according to the initial deformation rate or the updated average deformation rate in a certain window i, then establishing a linear model equation of phase and elevation on the screened stable points, solving linear model parameters of each time phase of the window by adopting a least square method, and calculating tropospheric delay phases of all measurement points in the window according to elevation values; (5) Subtracting the troposphere delay phase calculated for the first time by each window from the initial unwrapping phase to obtain an atmospheric delay correction phase, re-estimating the deformation rate of each point by adopting a weighted least square method, and repeating the processing of the step (4) to estimate the atmospheric delay phase again; (6) Calculating root mean square of difference between two adjacent estimated atmospheric delay phases of each interferogram in window i, and calculating average value of all interferograms, judging termination threshold value when estimation of atmospheric delay phase is completed at least three times If the atmospheric delay phase is smaller than the preset threshold value, the estimation of the next window is carried out, if not, the estimation of the atmospheric delay phase is carried out continuously in the step (4) in a returning way, wherein, (7) After the estimation of the atmospheric delay phase is completed in all windows, linear model parameters in the centers of all windows are interpolated to all measurement points by a double-tone and spline interpolation method, and the atmospheric delay of all measurement points is calculated by combining the elevations of all the points; (8) Subtracting the atmospheric phase delay of the measuring point from the winding phase of the measuring point, re-carrying out 3D phase unwrapping, further judging whether the change value DeltaU of the percentage of the error-free points of the two unwrapping times in the number of measuring points of all interferograms is smaller than a threshold value setting, if so, stopping iteration, otherwise, returning to the step (3); (9) After the atmospheric delay correction is finished, removing residual turbulence delay by a space-time filtering method; (10) And modeling by deformation information to obtain the average deformation rate and time series deformation quantity of each point after atmospheric correction. According to a second aspect of the present invention, there is also provided a computer system comprising: One or more processors; a memory storing instructions operable; wherein the instructions, when executed by the one or more processors, implement the foregoing process of the atmospheric delay correction method of time-series InSAR monitor data. According to a third aspect of the present invention, there is also provided a computer readable medium storing a computer program comprising instructions executable by one or more compu