The main aim of the article was to analyse the actual accuracy of determining the vertical movements of the Earth’s crust (VMEC) based on time series made of four measurement techniques: satellite altimetry (SA), tide gauges (TG), fixed GNSS stations and radar interferometry. A relatively new issue is the use of the persistent scatterer InSAR (PSInSAR) time series to determine VMEC. To compare the PSInSAR results with GNSS, an innovative procedure was developed: the workflow of determining the value of VMEC velocities in GNSS stations based on InSAR data. In our article, we have compiled 110 interferograms for ascending satellites and 111 interferograms for descending satellites along the European coast for each of the selected 27 GNSS stations, which is over 5000 interferograms. This allowed us to create time series of unprecedented time, very similar to the time resolution of time series from GNSS stations. As a result, we found that the obtained accuracies of the VMEC determined from the PSInSAR are similar to those obtained from the GNSS time series. We have shown that the VMEC around GNSS stations determined by other techniques are not the same.

This study aims to develop an absolute model of contemporary Vertical Crustal Movements (VCM) and Vertical Land Movements (VLM) in an area of Poland based on GNSS solutions. Velocities at permanent stations were subjected to geological, tectonic, hydrological and mineral information analyses. Reliability analysis and estimation of velocities at individual GNSS stations, comparative analysis of results and spatial analysis were carried out. Vertical velocities were determined using four computational strategies. Daily satellite data in the ITRF2014 system collected from permanent GNSS stations of the Polish part of the ASG EUPOS system were obtained from the Polish Main Office of Surveying and Cartography. All the data were from the 2011 to 2021 time period (approx. 11 years) and obtained in Rinex format. Time series from the Precise Point Positioning (PPP) solution calculated using GipsyX software were used. The absolute vertical crustal velocities obtained for Poland mostly vary between +1.0 and −1.0 mm/yr, which is 95% of the values obtained within local extremes. This region of Poland can be considered tectonically stable and the developed VCM model correlates with the geological and tectonic structure of the region. Taking into account the influence of tectonics, geology, hydrology and location of mineral resources has allowed better interpretation of vertical velocities and correction of the associated model. The proposed computational strategy based on combining data sets developed by different methods gave good results.

We investigate the possibility of using Differential interferometric synthetic aperture radar (DInSAR) to develop models of vertical crustal movements (VCMs). We determined VCM using the DInSAR method in the locations of four Polish GNSS stations: Borowa Góra, Borowiec, Lamkówko, and Józefosław. They are included in the International GNSS service and EUREF permanent GNSS networks. All Sentinel-1A and 1B satellite data were from 2020, and the time intervals of the created interferograms are 12 days, 24 days, and 336 days for each of the orbits: ascending and descending. We verified the calculated results of VCM based on GNSS data recorded by individual stations. We developed reference data with the precise point positioning (PPP) method. We confronted them with the Nevada Geodetic Laboratory service. The GNSS data covered larger time intervals than the synthetic aperture radar (SAR) data. To calculate daily positions with the PPP method we used GipsyX software. The obtained results of the directions of displacement are convergent between SAR and GNSS data. The values differ from each other, both between the types of orbits and GNSS data. The obtained results allow us to assume that SAR data developed using the DInSAR method may provide additional support in the development of VCM models in the Polish area, but they cannot be the only source of such results.

 The absolute values of VLM and VCM are mostly from +1mm/yr to-1mm/yr. The area of Poland can be considered tectonically stable.  The developed VCM model correlates with the geological and tectonic structure of the region.  The method of combining WAV sets based on different computational strategies yielded good results.

This study compared two approaches to integrating leveling and GNSS data to develop relative vertical movements of the Earth’s crust. Novel approaches were tested using transformation and hybrid grid adjustment. The results from double-leveling measurements in Poland were used as test data, and GNSS measurements developed using the PPP technique were used as Supplementary Data. The least squares method was used for the adjustment, and the isometric, conformal and affine methods were used for the transformation, with and without Hausbrandt correction. So-called pseudo-nodal points, i.e., points identified as common in both networks, whose weight was determined according to the assumptions of scale-free network theory, were used as integration points. Both integration methods have similar results and are suitable for integrating leveling and GNSS data to determine the relative vertical movements of the Earth’s crust. The average unit error m₀ of the transformation was 0.1 mm/yr and the average error after adjustment of the hybrid network was 0.1 mm/yr. The use of the Hausbrandt correction does not significantly improve the transformation results. A 12-parameter affine transformation is recommended as the transformation method.