Validation of PSI displacements at a bidirectional corner reflector

Abstract

The team developed a bidirectional corner reflector (CR) with the goal of achieving displacements from Sentinel-1 ascending and descending passes for the same point. From those observations, vertical and horizontal displacements are being determined and their uncertainty is being assessed through comparison to levelling and GNSS measurements. The bidirectional CR is composed by two rectangular trihedrals with the vertical axis in common. A GNSS antenna is permanently installed on that axis and the base where the reflector is installed enables it to move along pre-defined directions. The reflector vertical displacements are also being monitored through levelling every two weeks. This CR is part of an infrastructure installed in LNEC, which also includes two individual triangular trihedral CRs. One of those is also installed on a movable base, in order to allow the comparison between CRs of different shapes. Two evaluations of the measurements’ uncertainty will be presented: one with all the CRs being static and another one with the CRs moving along the line-of-sight of the descending pass. Uncertainty assessment for displacements along other directions will be performed in the future.