Satellite Laser Ranging is one of the four fundamental geodetic space techniques for the accurate determination of geodetic key parameters related to the Earth’s geometry, rotation and gravity field. As the current global SLR station distribution is quite inhomogeneous, a simulation study has been performed in order to determine locations on Earth where additional SLR sites will be most valuable for an improvement of the results, the Antarctic region having been identified as a first priority.

This paper describes an approach to model VTEC solely from NRT GNSS observations by generating a multi-scale representation (MSR) based on B-splines. The unknown model parameters are estimated by means of a Kalman filter. A number of products are created which differ both in their spectral and temporal resolution. The validation studies show that the product with the highest resolution, based on NRT input data, is of higher accuracy than others used within the selected investigation time span.

Regularization is indispensable in regional gravity field modelling. In this paper, we propose two new approaches for the regularization parameter determination, which combine the L-curve method and variance component estimation (VCE). The performance of each method is studied for combining heterogeneous observations using spherical radial basis functions. The results show that our newly proposed methods are decent and stable for regularization parameter determination.

Knowledge of the dynamic ocean topography (DOT) enables studying changes of ocean surface currents. The DOT can be derived by satellite altimetry measurements or by models. However, in polar regions, altimetry-derived sea surface heights are affected by sea ice. Model representations are consistent but impacted by the underlying functional backgrounds and forcing models. The present study compares results from both data sources in order to investigate the potential for a combination of the two.

We provide a surface-kinematics model for the Alpine region based on high-level data analysis of 300 geodetic stations continuously operating over 12.4 years. This model includes a deformation model, a continuous velocity field, and a strain field consistently assessed for the entire Alpine mountain belt. Horizontal and vertical motion patterns are clearly identified and supported by uncertainties better than ±0.2 mm a⁻¹ and ±0.3 mm a⁻¹ in the horizontal and vertical components, respectively.

The water levels of the Mekong River are observed with the SAR altimeter measurements of CryoSat-2. Even small rivers in the river system with a width of 50 m can be observed due to the higher resolution of the SAR measurements. To identify the rivers regardless of a land-water-mask we employ an unsupervised classification on features derived from the SAR measurements. The river water levels are validated and compared to gauge and Envisat data which shows the good performance of the SAR data.

The determination of ionospheric key quantities such as the maximum electron density of the F2 layer, the corresponding F2 peak height and the F2 scale height are of high relevance in 4-D ionosphere modeling to provide information on the vertical structure of the electron density distribution. This paper discusses mathematical correlations between these parameters as derived from FORMOSAT-3/COSMIC radio occultations and regionally parameterized by means of polynomial B-splines.