Validation framework of InSAR.Hungary using EGMS and EPND: Methodology and Results

This work demonstrates a validation framework applied to InSAR.Hungary, designed to evaluate its results against independently implemented scientific datasets, including other InSAR solutions and GNSS-based deformation fields over Hungary. The InSAR.Hungary validation was conducted with respect to the European Ground Motion Service (EGMS) and the D2200 realization of the EPN Densification, focusing on L3 product-level deformation rates in both the East-West and Vertical directions. The framework enables quantitative and statistical comparison between InSAR.Hungary and the reference datasets, including the use of statistical methods, spatially structured resampling strategies, and hypothesis testing procedures. Its main goal is to determine whether observed differences are attributable to random spatial processes or are influenced by structural bias. While both InSAR.Hungary L3B and EGMS L3 products include low-frequency deformation components derived from least-squares collocation velocity models (which are also based on EPN Densification), we further validated the L3B results against the D2200 realization of EPN Densification to assess how well the L3B components reflect observed GNSS deformation rates. The results are illustrated for qualitative interpretation, while numerical and statistical analyses provide quantitative support for the validation findings.