Abstract
This article deals with the analysis of InSAR performance for large-scale deformation measurement. The study evaluates the use of models, especially numerical weather prediction reanalysis, to mitigate disturbances in SAR interferograms. The impact of such corrections is evaluated by analyzing short-time baseline phase variograms in order to derive a lower bound for the interferometric accuracy, especially at large distances. The variance is then propagated from single interferograms to deformation rates. Finally, using GNSS measurements, the predicted error bars are validated on a large Sentinel-1 data set.
Highlights
T HE Sentinel-1 mission [1] systematically provides SAR data suitable for interferometric applications with a swath width of 250 km
The use of numerical weather prediction (NWP) became a valuable tool for systematic correction of both SAR group and phase delays, improving the performance and capabilities of the techniques [16]–[20]. Starting from this basis, this article first investigates interferometric performance at large distances when ECMWF ERA5 NWP data were used for the corrections
2) Performance may be site dependent, but the target of 1 mm/y at 100 km is achievable in five years given good weather models or in general where the errors are small due to reduced atmospheric delay, i.e., over the Tibetan Plateau
Summary
T HE Sentinel-1 mission [1] systematically provides SAR data suitable for interferometric applications with a swath width of 250 km. The use of numerical weather prediction (NWP) became a valuable tool for systematic correction of both SAR group and phase delays, improving the performance and capabilities of the techniques [16]–[20] Starting from this basis, this article first investigates interferometric performance at large distances when ECMWF ERA5 NWP data were used for the corrections. It is implicitly assumed that the residual error of signals related to the ionosphere, SETs, and orbit state vectors is negligible compared with the tropospheric signal that becomes the limiting factor for interferometric performance at large distance, as verified in the Appendix. Violation of this assumption leads to an underestimation of the tropospheric component.
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