Reducing the Residual Topography Phase for the Robust Landscape Deformation Monitoring of Architectural Heritage Sites in Mountain Areas: The Pseudo-Combination SBAS Method

Hang Xu,Fulong Chen,Wei Zhou,Cheng Wang

doi:10.3390/rs14051178

Abstract

Monitoring deformation of architectural heritage sites is important for the quantitative evaluation of their stability. However, deformation monitoring of sites in mountainous areas remains challenging whether utilizing global navigation satellite system (GNSS) or interferometric synthetic aperture radar (InSAR) techniques. In this study, we improved the small baseline subset (SBAS) approach by introducing the pseudo-baseline combination strategy to avoid the errors caused by inaccurate external DEM, resulting in robust deformation estimations in mountainous areas where the architectural heritage site of the Great Wall is located. First, a simulated dataset and a real dataset were used to verify the reliability and effectiveness of the algorithm, respectively. Subsequently, the algorithm was applied in the landscape deformation monitoring of the Shanhaiguan section of the Great Wall using 51 Sentinel-1 scenes acquired from 2016 to 2018. A thematic stability map of the Shanhaiguan Great Wall corridor was generated, revealing that the landscape was generally stable save for local instabilities due to to unstable rocks and wall monuments. This study demonstrated the capabilities of adaptive multitemporal InSAR (MTInSAR) approaches in the preventive landscape deformation monitoring of large-scale architectural heritage sites in complex terrain.

Highlights

Using satellites as platforms, spaceborne remote sensing technologies can gather largescale ground information without contacting the targets, which is both cost-effective and labor-saving [1,2]
We proposed an improved small baseline subset (SBAS) algorithm based on a pseudo-baseline combination strategy to reduce the residual topography effect in mountainous areas caused by inaccurate external digital elevation models (DEM)
SBASmethod, method,which whichcan caneffectively effectivelyreduce reducethe theresidual residualtopography topography pseudo-combination effect introduced by the inaccurate external in mountainous area

Summary

Introduction

Spaceborne remote sensing technologies can gather largescale ground information without contacting the targets, which is both cost-effective and labor-saving [1,2]. As one branch of active spaceborne remote sensing, spaceborne synthetic aperture radar (SAR) uses microwaves to acquire ground surface information and can work night and day and in all weather conditions [3,4]. Based on the phase information of SAR signals, interferometry synthetic aperture radar (InSAR) has the ability to monitor ground deformation with millimeter accuracy [5]. Reliable deformation monitoring of heritage structures and their surroundings is important for health assessments and stability monitoring of these historical properties [15–18]. Traditional geodetic measurements such as those from global navigation satellite systems (GNSS) and leveling, and other on-site

Methods

Findings

Discussion

Conclusion