A hybrid method for MT-InSAR phase unwrapping for deformation monitoring in urban areas

Abstract

• A hybrid method is proposed to enhance the phase unwrapping of MT-InSAR in urban. • Consideration of the impact of building height and spatial network structure. • Improvements in phase unwrapping allow for better geocoding of coherent points. The accuracy of phase unwrapping in multi-temporal interferometric synthetic aperture radar (MT-InSAR) technology affect closely on the accuracy of ground deformation monitoring. In the urban area, urban infrastructures such as high-rise buildings present additional challenges to phase unwrapping due to the sudden elevation changes. The failure rate of phase unwrapping is often much higher in such areas, bringing more biases to the estimated deformation and height values. We propose a new method for MT-InSAR phase unwrapping especially for deformation monitoring in urban areas. The method isolates the propagation path of information by considering the building height information of a study area. Two quality controllers are also developed to refine the arc observation network structure for network adjustment and to correct the phase unwrapping errors. The proposed method is tested using both simulated and real datasets. The results show that the building height and the geolocation of the coherence points were estimated much more accurately, demonstrating the effectiveness of the proposed method in monitoring deformation of urban area.