Although multiple GNSS constellations such as GPS, GLONASS, and Galileo are now being realized, there are few analysis software for precise surveying that can handle multi-GNSS data including Japanese Quasi Zenith Satellite System (QZSS). The Geospatial Information Authority of Japan (GSI) launched a 4-year project from 2011 to develop and standardize a precise positioning technique that can fully utilize the potential of multi-GNSS data including QZSS for surveys in urban canyons or rapid detection of crustal deformation after large earthquakes. After a brief review of general GNSS software packages, this paper focuses on the status and findings of GSI's multi-GNSS project.
