Multi-GNSS processing, positioning and applications.

In the past few decades the Global Positioning System (GPS) has been the number one positioning tool in a range of Geodesy and Geophysics applications. GPS modernisation from dual-frequency to triple-frequency signals has lately also been complemented by global GLObal' naya NAvigatsionnaya Sputnikovaya Sistema (GLONASS), Galileo and BeiDou Navigation Satellite System (BDS), as well as the regional Quasi-Zenith Satellite system (QZSS) and Navigation with Indian Constellation (NavIC). Single-frequency receivers, in particular, need ionospheric models to be able to precisely determine positions, and by making use of ionospheric models one can also speed up the parameter convergence for dual- and multi-frequency GNSS applications. [Extracted from the article]