Decision Fusion of D-InSAR and Pixel Offset Tracking for Coal Mining Deformation Monitoring

Depin Ou,Jianwei Ding,Yu Chen,Qian Du,Kun Tan

doi:10.3390/rs10071055

Abstract

Ground surface subsidence is a universal phenomenon in coal mining areas which can cause serious damage to the surrounding environment. In this paper, we consider the use of differential interferometric synthetic aperture radar (D-InSAR), multi-temporal InSAR (MT-InSAR), and the pixel offset tracking technique to monitor the surface deformation of a coal mining area. In this study, we use the two-pass D-InSAR method to generate 19 interferometric image pairs from 20 TerraSAR-X SpotLight images. The results show that D-InSAR can be used to obtain high accuracy surface deformation in the mining areas where there is no high gradient deformation, and the pixel offset tracking method offers advantages in those areas where high gradient deformation is found, but its performance is not stable. This means that the unilateral use of these technologies cannot obtain reliable subsidence information in mining areas. Therefore, it is essential to find a new way to integrate the respective advantages of these different methods. In this paper, a new fusion method combining the D-InSAR result with the offset tracking result based on a spatial decorrelation distribution map is proposed to obtain the subsidence results in a mining area. To ensure the reliability of the results, a decision rule is proposed for the spatial decorrelation distribution map, which is generated manually by union analysis in ArcGIS. In the experiments, the mean absolute error of the fusion result is 0.0748 m, while that of D-InSAR is 0.1890 m, and that of offset tracking is 0.1358 m. It is therefore clear that the proposed fusion method is more reliable and more accurate than the use of individual methods, and it may be able to serve as a reference in mining subsidence monitoring.

Highlights

China, one of the largest coal producing and consuming countries, has many coal mines
We proposed a new fusion method based on a spatial decorrelation distribution map which is generated by union analysis in ArcGIS
The results indicated that when using the differential interferometric synthetic aperture radar (D-InSAR) technique in the mining surface subsidence monitoring, a good performance can be obtained in mining areas where there is linear or low-gradient subsidence

Summary

Introduction

One of the largest coal producing and consuming countries, has many coal mines. Land subsidence caused by coal mining activities can lead to surface collapse and water accumulation. It can result in ground cracking and damage to infrastructures and buildings and can endanger the safety of human life and property [1]. It is necessary to monitor the dynamics of the ground surface in coal mining areas in order to provide useful information for mining subsidence management. The conventional precision leveling, global navigation satellite system (GNSS) measurement and the subsequently developed differential interferometric synthetic aperture radar (D-InSAR) techniques are commonly used in ground surface deformation monitoring [2,3]. With the rapid development of SAR satellite technology and the expansion of its application field, it is becoming more and more difficult to satisfy the requirements of surface deformation monitoring with conventional D-InSAR techniques. The MT-InSAR techniques cannot work when the deformation in the mining area exceeds the limit of the phase measurement [21]

Results

Discussion

Conclusion