GPS Surveying & Drone Mapping for Public Works and Cadaster Departments
Background Historically local governments in many countries used optical survey instruments to map their cadastre and public works projects. Many municipalities establish a baseline using a survey control benchmark in the square near their municipal offices to establish a baseline to measure their surveys from. In the Philippines the U.S. Army Corps of Engineers originally established the geographic coordinates of these control monuments using celestial observations. These coordinates have been updated with the launching of the GPS satellites by the U.S. Department of Defence in 1978. Since then Europe, China, Russia and others have added their own constellations of satellites to augment positional accuracy and to decrease the reliance on one nation for that service. They are referred to the Global Navigation Satellite System (GNSS) as a whole for precise geo-spatial positioning, navigation and timing (PNT) services. They are named respectively Galileo, BeiDou, Glonas...