Mitigation of thermal expansion phase in persistent scatterer interferometry in an urban environment

In an urban environment the differential phase due to thermal expansion of structures is relevant. Uncorrected, the thermal expansion phase leads to a loss of persistent scatterers and increased errors in the deformation time series. In the upper part of tall buildings the thermal expansion phase can vary strongly over time which may result in a complete lack of displacement information if uncompensated. The objective of our work was to estimate and mitigate the thermal expansion phase in our PSI processing. As a result it became possible to include tall buildings into the PSI solution and the accuracy of the solution was improved for all scatterers affected by thermal expansion.