A seamless multitrack multitemporal InSAR algorithm

Abstract

The zones of overlap between adjacent Synthetic Aperture Radar (SAR) satellite tracks are illuminated twice more frequently than elsewhere in the SAR scene. Here, an alternative approach is presented to combine the overlapping segments of SAR images acquired at adjacent tracks and generate accurate and high spatiotemporal resolution map of the surface deformation field. To this end, a new approach is developed to unify the datums. Effects due to the difference in look angle between two overlapping tracks and atmospheric delay are estimated and removed using Kalman and wavelet-based filters. This approach is first tested at Hawaii Island, where tracks 200 and 429 of Envisat C-band satellite overlap over the Kilauea south flank. The obtained time series improves the temporal sampling rate by a factor of two and comparison with GPS time series demonstrates that the presented method accurately measures the nonlinear deformation field. The advantages of this method are further demonstrated by combining SAR data sets acquired by Envisat C-band and ALOS L-band satellites over the San Francisco Bay Area, California. The validation test shows that the seamless combination of C-band and L-band time series accurately measures the surface deformation at higher resolution.

The Use of C-/X-Band Time-Gapped SAR Data and Geotechnical Models for the Study of Shanghai’s Ocean-Reclaimed Lands through the SBAS-DInSAR Technique

“…The latter assumption is reasonable, as the soil consolidation stages, as well as the mechanisms induced by the weight of the buildings, which have been built in the new city, are, at most, responsible for vertical movements of the terrain. Nevertheless, the lack of sufficiently large archives of time-overlapped ascending/descending SAR images over Lingang New City (with respect to the reclaimed areas) makes the measurement of the east-west deformation rates directly from SAR data unreliable, as shown, for instance, by using the methods in [55,[70][71][72][73][74][75]. Moreover, such a strategy can be extended to other cases where deformation components in east-west directions cannot be considered negligible.…”

“…Moreover, such a strategy can be extended to other cases where deformation components in east-west directions cannot be considered negligible. This can be done by effectively combining the strategies adopted here, and the combination methods discussed in [55,[70][71][72][73][74][75], which exploit SAR data acquired by multiple sensors and different orbital positions (e.g., from ascending and descending passages). In addition, the adopted combination scheme can be further generalized to the point where more than two time-gapped sequences of SAR images are available.…”

The Joint Use of Multiple Satellite SAR Data and Geotechnical Models for the Study of the Shanghai Ocean-Reclaimed Lands

“…The latter hypothesis is reasonable since the soil consolidation stages as well as the mechanisms induced by the weight of the buildings, which have been built in the new city, are at most responsible for vertical movements of the terrain. Nonetheless, the lack of sufficiently large archives of time-overlapped ascending/descending SAR images over the Lingang New City (just in correspondence to reclaimed areas) has made unreliable the measurement of the East-West deformation rates directly from SAR data, as provided for instance by using the methods in [73][74][75][76][77][78][79]. Moreover, such a strategy can generally be extended in other cases where deformation components in East-West directions cannot be considered negligible, by profitably combining the strategies here adopted and the combination methods discussed in [73][74][75][76][77][78][79] that exploit SAR data acquired by multiple-sensors and different orbital positions (e.g., from ascending and descending passages).…”

A Review of Interferometric Synthetic Aperture RADAR (InSAR) Multi-Track Approaches for the Retrieval of Earth’s Surface Displacements

“…In particular, the combination of multiplatform (multi-angle) LOS displacement time series can improve our ability to retrieve the 3-D, i.e., East-West (E-W), North-South (N-S), Up-Down (U-D) components of the measured surface displacement; thus, overcoming the main limitation of DInSAR to measure only the satellite LOS projection of the displacement. Such a problem has already been faced in the literature and a few technical solutions capable of combining multiple-orbit/multiple-angle DInSAR-based measurements, as well as merging DInSAR data products with other external information (such as the one derived from GPS stations), have been proposed [124][125][126][127][128][129][130][131][132][133][134][135]. Let us first consider the combination of InSAR data acquired from two satellites flying along ascending and descending orbits The SBAS-DInSAR technique has been successfully applied also to investigate mass movements, as the Ivancich landslide affecting the city of Assisi, Central Italy.…”