February 22, 2011: Observing Earth's surface displacements: The Point-Techniques. Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), Lunar Laser Ranging (LLR), Global Navigation Satellite Systems (GNSS) and Doppler Orbitography and Radiopositioning Integrated by Satellites (DORIS): observing point motion and maintaining global geodetic reference frames.