G004-0009
Mobile Mapping of Surface Displacements Using a Novel Compact UAV-Borne / Car-Borne InSAR System
Mobile Mapping of Surface Displacements Using a Novel Compact UAV-Borne / Car-Borne InSAR System
Wednesday, 9 December 2020
Poster
Abstract:
Flexible mobile mapping of surface displacements with repeat-pass interferometry from moving platforms such as cars and UAVs has been a rather unexplored field.
In this contribution we address this topic comprehensively: we demonstrate InSAR-based measurement of surface displacements with our novel car-borne and UAV-borne L-band SAR system setup at three different test sites in Switzerland.
The reduced temporal decorrelation at L-band is an important advantage and a complementary property as compared to high-frequency (quasi-)stationary systems. While the sensitivity to line-of-sight displacements is lower, the longer wavelength permits to acquire longer interferometric time intervals also in natural terrain and in adverse conditions, in which the decorrelation time at X- or Ku-band (the frequencies of many stationary terrestrial radar interferometers) can be in the order of minutes or less. Terrestrial synthetic aperture radar acquisitions from a car driving on a road or acquisitions from a UAV allow to obtain synthetic aperture lengths of 100m and more which yields high-resolution SAR imagery also at lower frequency such as L-band. At the same time the view geometry can be chosen to offer line-of-sight views to landslides that complement the view geometries available from spaceborne SAR systems. Then, using a time-domain back-projection image focusing approach, it is ensured that even for curvilinear paths (e.g. a car driving along a curved road) high-quality SAR images and interferograms with good spatial resolution are obtained.
Based on these properties we show that such a mobile InSAR system fills a current gap in terms of available InSAR systems for displacement monitoring.
We show the potential and discuss the challenges and the limitations of this novel InSAR-based mobile mapping system.
We do so with the help of three repeat-pass interferometry showcases (see also attached image):
1) car-borne mapping of surface displacements of fast-moving land slide and surrounding area,
2) car-borne mapping of surface displacements of a glacier,
3) UAV-borne mapping of surface displacements of a steep slope with various land covers.
The three test cases show that UAV-borne and car-borne interferometric displacement measurements at L-band are feasible with high quality over various natural terrain.
In this contribution we address this topic comprehensively: we demonstrate InSAR-based measurement of surface displacements with our novel car-borne and UAV-borne L-band SAR system setup at three different test sites in Switzerland.
The reduced temporal decorrelation at L-band is an important advantage and a complementary property as compared to high-frequency (quasi-)stationary systems. While the sensitivity to line-of-sight displacements is lower, the longer wavelength permits to acquire longer interferometric time intervals also in natural terrain and in adverse conditions, in which the decorrelation time at X- or Ku-band (the frequencies of many stationary terrestrial radar interferometers) can be in the order of minutes or less. Terrestrial synthetic aperture radar acquisitions from a car driving on a road or acquisitions from a UAV allow to obtain synthetic aperture lengths of 100m and more which yields high-resolution SAR imagery also at lower frequency such as L-band. At the same time the view geometry can be chosen to offer line-of-sight views to landslides that complement the view geometries available from spaceborne SAR systems. Then, using a time-domain back-projection image focusing approach, it is ensured that even for curvilinear paths (e.g. a car driving along a curved road) high-quality SAR images and interferograms with good spatial resolution are obtained.
Based on these properties we show that such a mobile InSAR system fills a current gap in terms of available InSAR systems for displacement monitoring.
We show the potential and discuss the challenges and the limitations of this novel InSAR-based mobile mapping system.
We do so with the help of three repeat-pass interferometry showcases (see also attached image):
1) car-borne mapping of surface displacements of fast-moving land slide and surrounding area,
2) car-borne mapping of surface displacements of a glacier,
3) UAV-borne mapping of surface displacements of a steep slope with various land covers.
The three test cases show that UAV-borne and car-borne interferometric displacement measurements at L-band are feasible with high quality over various natural terrain.