An improved method of three-dimensional displacement field generation in mining areas with a single InSAR pair

Abstract

ABSTRACT An improved method combining a probability integral method and interferometric synthetic aperture radar (InSAR) for retrieving three-dimensional (3D) displacement field caused by coal mining is proposed. In this paper, fully considering dip angles of coal seams, we improved the method of obtaining 3D deformation using the linear relationship between horizontal displacement and surface tilt. Compared with the former method ignoring dip angles of coal seams, the improved method is more accurate in retrieving 3D displacement in mining areas. The improved method is first validated with a simulated coal seam with a dip angle of about 25°. The root-mean-square errors (RMSEs) in the Up-Down, East-West and South-North directions are 23.4, 33.0 and 8.0 mm, respectively. Finally, real SAR data are used to retrieve the 3D displacement fields of the Number 15235 working face of the Jiulong coal mine with a dip angle of about 13°. Due to the lack of field observations to evaluate horizontal displacement accuracy, Up-Down displacement is compared with leveling data. The RMSEs of the improved and former methods are 6.4 and 7.1 mm, respectively. The real data also indicate that the improved method is more accurate. In summary, the improved method is effective for obtaining a 3D displacement field, especially in the inclined coal seams mining area.