Persistent Scatterer Pair Interferometry: Approach and Application to COSMO-SkyMed SAR Data

Abstract

Persistent scatterer interferometry is a widely used technique to detect and monitor slow terrain movements, with millimetric accuracy, from satellite synthetic aperture radar (SAR) data. We have recently proposed a method, named persistent scatterer pair (PSP), aimed at overcoming some limitations of standard techniques. The PSP method is characterized by the fact of exploiting only the relative properties of neighboring pairs of points for both detection and analysis of persistent scatterers (PSs), intended in the general sense of scatterers that exhibit interferometric coherence for the time period and baseline span of the acquisitions, including both point-like and distributed scatterers. Thanks to the pair-of-point approach, the PSP technique is intrinsically not affected by artifacts slowly variable in space, like those depending on atmosphere or orbits. Moreover, by exploiting a very redundant set of pair-of-point connections, the PSP approach guarantees extremely dense and accurate displacement and elevation measurements, both in correspondence of structures and when the backscattering is weak or distributed as in the case of natural terrains. In all cases, the measurements keep the full resolution of the input SAR images. In this work, the qualifying characteristics of the PSP technique are described, and several application examples and validation tests based on COSMO-SkyMed data are reported, which demonstrate the validity of the proposed approach.

Subsidence Trends of Volturno River Coastal Plain (Northern Campania, Southern Italy) Inferred by SAR Interferometry Data

“…overall [19]. The spatial distribution of the mapped velocity classes displays a common general trend in the six datasets, even though some differences are present in the different maps (Figure 4).…”

“…The interferometric processing was performed both at the national scale, within the frame of the Not-Ordinary Plan of Environmental Remote Sensing [23,24] by means of the Persistent Scatterer Pair (PSP) technique [19,28,29], and at a regional scale, within the activities of the TELLUS Project [13,[20][21][22] by means of the Permanent Scatterers (PS-InSAR) standard technique [27]. The Volturno plain is characterized by a locally high concentration of infrastructure (roads, railways, etc.)…”

“…The PSP technique [19,28,29] overcomes some limitations of other PS standard methods. Due to the pair-of-point approach, the PSP outputs are not affected by artifacts that are slowly variable in space, similar to those depending on atmosphere or orbits.…”

“…Due to the pair-of-point approach, the PSP outputs are not affected by artifacts that are slowly variable in space, similar to those depending on atmosphere or orbits. This approach guarantees very dense and accurate displacement measurements both for anthropic structures and natural terrains [19].…”

“…This difference depends on the adopted procedure. For example, using the PSP technique for ERS-1/2 and ENVISAT data processing results in a denser distribution of points for the measurement of displacement [19].…”