GPS and mobile connection with IMEI are two uncorrelated things. Precision for triangulation on a highway in countryside will not be precise enough to reliably know the speed.
I k ow they're different. That's what the navigation app does, uses gps, mobile and wi-fi networks. It puts the together.
Modern GPS has a resolution of ~1m. It can very accurately determine speed.
I was talking about triangulation from cell towers not GPS.