Small BAseline Subset – SBAS 

During the past 30 years, Differential Synthetic Aperture Radar Interferometry (DInSAR) has been proven to be an effective technique for studying the deformation processes related to both natural and man-made hazards. DInSAR uses the phase difference (interferogram) between two distinct SAR images acquired at different times over the same scene, permitting retrieval of the projection in the radar line-of-sight (LOS) of the ground deformation that occurred between the two acquisition times, with a centimeter accuracy. Being an active microwave Earth Observation (EO) technique, space-borne DInSAR represents a very powerful tool for the estimation of ground deformation, thanks to its characteristics of a large spatial coverage, cost effectiveness, and all-weather operability.

Although the DInSAR methodology was originally designed to study single event deformation phenomena, it significantly moved toward the development of multitemporal DInSAR approaches thanks to the availability of large SAR data archives. The multitemporal DInSAR algorithms properly combine the information obtained from a set of independent interferograms to retrieve the temporal evolution of the detected surface (deformation time-series) and corresponding mean deformation velocity maps. Among these, the Small BAseline Subset (SBAS) algorithm computes displacement time series with sub-centimeter accuracy by dealing with different spatial scales and multisensor data.

As its name suggests, the SBAS approach relies on an appropriate combination of differential interferograms produced by data pairs characterized by small temporal and orbital separation (baseline) in order to limit the noise (decorrelation) phenomena affecting the interferometric phase signals. We further remark that the SBAS approach has been successfully exploited for the investigation of different scenarios, such as volcanoes, tectonics, landslides, and anthropogenic-induced land motions.

In the last years, a parallel version of the SBAS algorithm, referred to as P-SBAS (Parallel-SBAS) approach, which is able to properly exploit distributed computing infrastructures, such as grid and cloud computing (CC) environments, has been developed. In this context, the EarthConsole® P-PRO platform is suitable to built-up a tool, which is available via the web, aimed at generating in an unsupervised way, surface deformation mean velocity maps and time series through the P-SBAS algorithm. The direct access of EarthConsole® P-PRO environment to the ESA Heritage Missions SAR data, together with a user-friendly interface, allows the development of an on-demand P-SBAS processing web tool addressed to scientists that are less expert on interferometric SAR data processing.

The P-SBAS algorithm, which takes benefit from High Performance Cloud Computing resources, has been integrated in EarthConsole® P-PRO platform to provide users with a service for the generation of Earth’s surface deformation time series and, more generally interferometric products (also single interferograms), in an unsupervised way. The EarthConsole® P-PRO platform flexibility and user-friendly interface allows users to perform SBAS-InSAR processing from ERS and ENVISAT SAR acquisitions on a distributed computing environment in a reasonable time.

The aim of this activity is to provide the Earth Observation community with an automatic tool for improving the surface deformation analyses and thus making advances in understanding different geophysical phenomena.

Small BAseline Subset (SBAS) Wiki