Motus inter corpora relativus tantum est: a guide on the analysis and interpretation of InSAR time series data

Hanssen, R. (Speaker)

Activity: Talk or presentationTalk or presentation at a conference


Interferometric SAR time series data are becoming easily accessible to larger groups of end users. They typically have a diverse background, shifting from scientists in the geophysical domains towards asset managers, construction engineers, public officials, or private parties. Yet, the time series InSAR data, particularly the estimated kinematic parameters, are hard to interpret unambiguously. The first problems to encounter include the effective representation and visualization of the spatio-temporal datasets. In Stevens’ taxonomy, InSAR data are of the interval-type, but are often misinterpreted as ratio-type. This relates to the double-difference nature of the estimators, which are essentially datum-free: their normal equation matrices are datum-free or singular. Here we present an interpretation statement, or guide, named Motus inter corpora relativus tantum est, in the words of Christiaan Huygens (1652), claiming that movement between bodies is always and in all aspects relative. Apart from interpretation concerning the relativity of the data, the guide discusses how ‘scatterers’ should be interpreted, how well their 3D position can be estimated, and how this relates to the idealization accuracy. The quality of the data is explained in terms of precision and reliability, and the application of statistical testing to provide an optimal model formulation.
Period27 Jun 2015
Event title26th IUGG general assembly, Prague, Czech Republic
Event typeConference
Degree of RecognitionInternational


  • InSAR
  • Geodesy
  • Deformation
  • Height