Accurate time synchronization across space geodetic techniques is essential for realizing a consistent global reference frame and for advancing chronometric geodesy. At the Geodetic Observatory Wettzell, delay-stabilized optical links have been developed to provide traceable and temperature-stable clock connections between co-located space geodetic systems. These stabilized links form the backbone for calibration signals that enhance the time coherence among geodetic techniques such as Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), and Global Navigation Satellite System (GNSS). GNSS is the only continuously operating geodetic system that can perform global clock comparisons with an accuracy level of 10⁻¹⁷ and beyond, which enables applications such as chronometric leveling. However, its full potential is restricted by internal delay instabilities, primarily caused by temperature variations in the receiver chains. This contribution discusses the development and initial results of a GNSS calibration system designed to reduce instabilities and enhance time consistency between different measurement techniques. We propose using a ground-based GNSS pseudolite system that is synchronized with a delay-drift-free timing system. By utilizing a software-defined radio, we successfully tracked an E1B Galileo signal replica with geodetic receivers. The pseudolite system features a feedback tone calibration that stabilizes transmission epochs and calibrates both the phase and frequency of the internal L-band upconverter, along with its internal delays. Our ultimate goal is to achieve clock parameter stability that exceeds current VLBI solutions. This improvement will facilitate the use of calibrated GNSS clocks in VLBI clock modeling and ultimately enhance the consistency of multi-technique geodetic solutions.     «

Accurate time synchronization across space geodetic techniques is essential for realizing a consistent global reference frame and for advancing chronometric geodesy. At the Geodetic Observatory Wettzell, delay-stabilized optical links have been developed to provide traceable and temperature-stable clock connections between co-located space geodetic systems. These stabilized links form the backbone for calibration signals that enhance the time coherence among geodetic techniques such as Very...     »