The Use of Multiple GNSS Constellations with Strict Quality Constraints for Achieving High Accuracy in Urban Environments

摘要

The availability of Global Navigation Satellite System (GNSS) applications is anticipated to improve over the next few years because of the introduction of new positioning satellites, forming what is called "multi-GNSS". Asia in particular will be able to benefit from multi-GNSS using the U.S. Global Positioning System (GPS), the Russian GLONASS, the European Galileo, the Chinese Navigation Satellite System (BeiDou), and the Japanese Quasi-Zenith Satellite System (QZSS). The combined multi-GNSS signals are capable of improving satellite availability for both standalone and differential positioning. At present, the potential for high-accuracy automobile navigation using GNSS is constrained by severe multipath and poor satellite geometry, especially in "urban canyons" in large cities. With differential GNSS positioning, inconvenient system time differences can be removed by reference-station processing, allowing user receiver position to be calculated with integrity from four or more visible satellite signals. Therefore, in the future, we can tightly screen the quality of the numerous multi-GNSS measurements to enhance positioning performance in urban environments.