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GNSS reflectometry (GNSS-R) a technique for the study of variations in the height of sea level and inland waters, and for the study of soil moisture, based on the comparison of the direct and reflected noise signal. The main advantage of this method is that allows the connection between sea level measurements and the global reference frame. The purpose of this contribution is to present the GNSS-R analysis service at the Geodesy department of the National Geographic Institute of Spain and to compare the sea level time series determined by means of GNSS-R with tide gauge measurements. Two different GNSS-R methods using multi-constellation and multi-frequency data are compared: Lomb-Scargle Periodogram and Inverse Modelling. This analysis is performed for 3 GNSS antennas collocated to tide gauges along the Spanish coast. Eventually, advantages and disadvantages of this method are discussed.

National Geographic Institute of Spain has a strong background concerning technical aspects of geodetic VLBI. As a step forward in this field, a VLBI analysis team has been set up and tests with different software packages have been carried out. In this sense, two VLBI software packages have been used for experimentation activities in order to compare and validate IGE capability to produce accurate and consistent geodetic products, specifically Earth Orientation Parameters, station coordinates and troposphere delays. The purpose of this contribution is to present the results of these analyses, including some tests to use GNSS-based troposphere delay in VLBI processing and the study of gravitational deformation in Yebes radiotelescope.