Land motion in the urban area of Nottingham observed by ENVISAT-1

A ZWD correction method is also presented and results are shown, which improve upon those without the correction. The ZWD estimates are produced using an undifferenced global navigation satellite system GNSS processing technique known as PPP. This, coupled with the chosen PSI method, provides a low noise solution when compared to similar experiments involving the integration of GNSS and interferometric synthetic aperture radar InSAR data. The results show that there is good temporal and spatial correlation between the PPP ZWD estimates and the PSI-derived atmospheric phase contributions. Noticeable improvements in the PSI solution when comparing before and after processing runs to precise levelling observations are shown.