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Published June 2012 | public
Journal Article

Multi-Link InSAR Time Series: Enhancement of a Wrapped Interferometric Database

Abstract

Ground surface deformation, in particular of tectonic or volcanic origin, might be monitored from time series of SAR interferograms. Conventional approaches require unwrapping of the interferograms. This is most often a limiting factor because the deformation signal is often obscured by decorrelation noise, baseline and topography compensation residuals and atmospheric effects. We present here a method that produces denoised wrapped phase time series. It can be used as a pre-processing to exploit wrapped phase time series or to facilitate unwrapping. The different paths linking two dates are combined in order to derive the most likely estimate of the phase difference between these dates. The result is called a Multi-Link SAR (MuLSAR) interferogram. We demonstrate the performance of the technique on a synthetic database and on a real database of ENVISAT images. The phase standard deviation is reduced from 0.94 rad to 0.60 rad for the synthetic database and from 1.09 rad to 0.89 rad for the real database. In addition to providing denoised interferograms the technique enhances the temporal resolution of an interferometric database as it is possible to compute a MuLSAR from pairs of images for which no interferogram could be produced due to geometric or temporal decorrelation. The method enhances the exploitation of large database especially when affected by temporal decorrelation.

Additional Information

© 2012 IEEE. Manuscript received September 29, 2011; revised December 19, 2011 and March 23, 2012; accepted March 30, 2012. Date of publication June 14, 2012; date of current version June 28, 2012. This work was supported in part by the Commissariat à l'Energie Atomique et aux Energies Alternatives, the Keck Institute for Space Studies (California Institute of Technology), and the Gordon and Betty Moore Foundation. The authors would like to thank Christelle Baudry for interferometric processing of the ENVISAT database, Gilles Peltzer, Renaud Binet, and the anonymous reviewers for useful comments and suggestions.

Additional details

Created:
August 22, 2023
Modified:
October 18, 2023