[crote]

Geostationary orbit wouldn't work for a GNSS: all satellites would be in the same plane, so it would be impossible to distinguish between the northern and southern hemisphere. This would render it inconvenient in most countries and unusable anywhere near the equator.

[danw1979]

Related: an inclined geosynchronous orbit uses similar altitudes to GEO, allowing focussed coverage on specific longitudes, as seen with QZSS - https://en.m.wikipedia.org/wiki/Quasi-Zenith_Satellite_Syste...

(albeit these are slightly elliptical)