Geodetic network design for InSAR using reflectors and transponders

Applying time-series InSAR to measure crustal deformation in vegetated non-urbanized areas often yields a low density of measurement points (persistent scatterers or PS). Algorithmic improvements and new sensors with better revisit times can improve measurement densities, but there still exist areas with heavy decorrelation from where almost no coherent information can be extracted. We propose a new scheme that determines the optimal density and locations of introduced in situ devices (e.g. passive corner reflectors or active transponders) for measuring deformation within the constraint of a desired optimality criterion. The scheme digests, as input, prior knowledge of the expected deformation signal, (probable) PS locations, PS quality and device measurement precision. We demonstrate this scheme through a simulated dataset and a ground subsidence case study in the Netherlands.