Testing of geodetic and geophysical parameters on potential sites for space geodesy observatory

The techniques used in space geodesy are Very Long Baseline Interferometry (VLBI), Global Positioning System<br>(GPS), Satellite Laser Ranging (SLR) and Lunar Laser Ranging (LLR). VLBI uses the precise timing of radio<br>signals from distant quasars arriving at different points on earth. SLR and LLR are based on the round-trip time<br>required by light from ground-based laser stations to bounce off satellites or the moon (in the case of LLR) and<br>return to the station. GPS methods measure the travel time of radio signals between satellites and receivers on the<br>ground.