Drone-borne Differential SAR Interferometry

Dieter Luebeck,Bárbara Teruel,Luciano P Oliveira,Leonardo S Bins,Laila F Moreira,Christian Wimmer,Hugo E Hernandez-Figueroa,Gian Oré,Lucas H Gabrielli,Juliana A Góes,Marlon Alcântara

doi:10.3390/rs12050778

Abstract

Differential synthetic aperture radar interferometry (DInSAR) has been widely applied since the pioneering space-borne experiment in 1989, and subsequently with the launch of the ERS-1 program in 1992. The DInSAR technique is well assessed in the case of space-borne SAR data, whereas in the case of data acquired from aerial platforms, such as airplanes, helicopters, and drones, the effective application of this technique is still a challenging task, mainly due to the limited accuracy of the information provided by the navigation systems mounted onboard the platforms. The first airborne DInSAR results for measuring ground displacement appeared in 2003 using L- and X-bands. DInSAR displacement results with long correlation time in P-band were published in 2011. This letter presents a SAR system and, to the best of our knowledge, the first accuracy assessment of the DInSAR technique using a drone-borne SAR in L-band. A deformation map is shown, and the accuracy and resolution of the methodology are presented and discussed. In particular, we have obtained an accuracy better than 1 cm for the measurement of the observed ground displacement. It is in the same order as that achieved with space-borne systems in C- and X-bands and the airborne systems in X-band. However, compared to these systems, we use here a much longer wavelength. Moreover, compared to the satellite experiments available in the literature and aimed at assessing the accuracy of the DInSAR technique, we use only two flight tracks with low time decorrelation effects and not a big data stack, which helps in reducing the atmospheric effects.

Highlights

Differential synthetic aperture radar interferometry (DInSAR) became popular after the launch of the ERS-1 satellite in 1991
The results presented in this letter focus on the L-band HH-polarization for the DInSAR, in which the radar transmits and receives horizontally polarized waves
The digital surface model (DSM) is determined by using the cross-track interferometry information provided by the two C-band antennae

Summary

Introduction

Differential synthetic aperture radar interferometry (DInSAR) became popular after the launch of the ERS-1 satellite in 1991. Relevant satellite-borne DInSAR results already appeared in 1989 when Gabriel et al [1] made two interferograms from three SAR images, taken from the same area at different times. Satellite-borne DInSAR systems present an operational limitation due to the fixed orbits of the satellites, as DInSAR only measures displacement in the line-of-sight direction, and to retrieve a 3-D deformation map, information from at least three viewing angles is required. Some methods accomplish this by acquiring quasi-simultaneous SAR images with different squint angles [2,3]. Other methods use multi-interferograms from more than three directions [4] or the multiple aperture interferometry technique [5,6], which measures displacement in the along-track direction

Methods

Discussion

Conclusion