GNSS stands for Global Navigation Satellite System, and is the
standard generic term for satellite navigation systems that provide
autonomous geo-spatial positioning with global coverage. This term
includes e.g. the GPS, GLONASS, Galileo, Beidou and other regional
systems. GNSS is a term used worldwide The advantage to having access
to multiple satellites is accuracy, redundancy and availability at all
To use GNSS you need a device that can support all the GNSS frequencies and software to capture your data for processing the signals.
An example (there are others) is a device called bad elf pro
Stationary high precision GNSS as low as 1m out of the box with PPP in
regions with SBAS coverage.
(*disclaimer have used this device in the field with good results in the sub $500 budget)