Twenty-year Successful Operation of GEONET

Abstract

The Geospatial Information Authority of Japan (GSI) started installing permanent Global Positioning System (GPS) stations in 1994. The initial number was 210, which increased to 610 in 1996 and 1,200 in 2003. As of April 1, 2017, a total of 1,318 Continuously Operating Reference Stations (CORS) had been installed by the GSI. The receiving and analysis systems were upgraded in 2010 to expand the function to receive other Global Navigation Satellite System (GNSS) signals. This network is now called GEONET (GNSS Earth Observation NETwork system), and is one of the largest CORS networks in the world. It is not only a tool for precise surveying, detection of crustal deformation, and research on earthquakes and volcanoes, but is also an infrastructure for precise positioning of automated vehicles, weather forecasting, and more. We report on the history of GEONET and the results obtained during its 20 years of successful operation.