What is Geodesy and Global Positioning Systems (GPS)?
Geodesy is concerned with the study of the size and shape of the Earth and its gravity field, together with their variation over time. Today, many of the fundamentals of geodesy are accomplished using advanced space techniques such as the Global Positioning System (GPS), Satellite Laser Ranging (SLR) and Very Long Baseline Interferometry (VLBI). These techniques are capable of measuring distances up to thousands of kilometres with an accuracy of just a few millimetres. Areas of study that require Geodesy cover global problems such as monitoring vertical and horizontal movements of the Earth (tectonic plate motion, for example), measuring change in sea level due to global warming and measuring variations in the rotation axis and rate of rotation of the Earth. Geodesy is also applied to more local problems such as monitoring volcanoes, measuring the movements of bridges, and the real-time alignment of roads and railway tracks. Map showing global tectonic plate motion. The Global Position
