InSAR observations and analysis of the Medicina Geodetic Observatory and CosmoSkyMed images

We have observed some discrepancies between installed geodetic instruments including global positioning systems (GPS) and very long baseline interferometry (VLBI) in the Medicina Geodetic Observatory (MGO). This study overcomes the above-mentioned discrepancies. We analysed several CosmoSkyMed images utilizing the interferometric synthetic aperture radar (InSAR) technique to improve the understanding of 3D surface displacements. The MGO is in a rural area, and the radar coherence is low; therefore, the coverage of permanent scatterers (PS) is limited. In ascending mode, the closest scatterer to the MEDI GPS station shows that the surface displacements are as large as 0.72 ± 1.45 mm/year along the line of sight (LOS) direction. The GPS height projected on the LOS vector shows a rate of 0.92 ± 0.04 mm/year of displacements. In descending mode, the closest scatterer to MEDI shows that the displacement is at a rate of − 0.1 ± 0.51 mm/year along the LOS direction, and the MEDI projected on the LOS vector is at a rate of 0.91 ± 0.002 mm/year. In this study, the deformation rates and their standard deviations stress that the GPS and PS-InSAR have different values. Despite a large (32-m-diameter parabolic antenna) VLBI telescope, we do not observe a single PS on the telescope for ascending and descending passes due to the frequent movements of the VLBI telescope in different directions.