How many satelites are tracked by a typical android phone? 4? Or more? Can it track both GPS and other systems like glonass at the same time?
Each satellite adds another constraint, which helps, and with more satellites to choose from, you can drop the weakest or worst measurements.
[0] https://developer.android.com/reference/android/location/Gns...()
> The current Android platform supports GPS, SBAS, GLONASS, QZSS, BEIDOU, GALILEO, and IRNSS[0].
But it depends (and varies wildly) on the hardware of said Android. I buy 3 to 5 cheap (sub 100 euro/US$) Androids per year and it always surprises me which device supports which GNSS is supported and how accurate or not they are.
PS I use them to Wigle (https://wigle.net) mainly, and the WiFi reception is exactly as diverse as the GNSS.