InSAR datum connection using GNSS-augmented radar transponders

Deformation estimates from Interferometric Synthetic
Aperture Radar (InSAR) are relative: they form a ‘free’
network referred to an arbitrary datum, e.g. by assuming a reference
point in the image to be stable. However, some applications
require ‘absolute’ InSAR estimates, i.e. expressed in
a well-defined terrestrial reference frame, e.g. to compare
InSAR results with those of other techniques. We propose a
methodology based on collocated InSAR and Global Navigation
Satellite System (GNSS) measurements, achieved by
rigidly attaching phase-stable millimetre-precision compact
active radar transponders to GNSS antennas. We demonstrate
this concept through a simulated example and practical case
studies in the Netherlands