MONITORING LAND SUBSIDENCE WITHIN THE VENICE LAGOON WITH SAR INTERFEROMETRY ON TRIHEDRAL CORNER REFLECTORS

Before the summer of 2007 58 square Trihedral Corner Reflectors (TCR) were installed in salt marshes within the Venice Lagoon where anthropogenic structures completely lack or few constructions are scattered at a distance from one another too large to reliably resolve the radar phase ambiguity on ERS and ENVISAT interferometric point target analysis. An optimal TCR network has been established taking into account the location of "natural" point targets in ERS and ENVISAT SA R interferometric analyses and keeping to a value of about 1 km the maximum distance between the TCR or between an "artificial" and the adjacent "natural" reflectors. In this contribution we discuss the set-up of the TCR, their backscattering intensity response on ENVISAT ASAR and TerraSAR-X images, and the approach followed to measure the ground displacement in areas of particular interest within the Venice Lagoon.