Earth-Observation Applications of Navigation Satellites

Introduction The development of Earth-observation techniques based on the use of navigation signals can be traced back to the use of GPS in geodetic applications to provide astonishing precision, such as the determination to within a few centimetres of the relative positions of points on the Earth’s surface separated by several thousand kilometres. This ultra-precise positioning of fixed GPS receivers is now routinely used as a tool for studying the dynamics of the Earth’s crust (e.g. plate tectonics).