I tried out the gps on my 3 Xiaomi phones, and the gps works fine on all 3, with the network position however off from 200 meters up to several kilometers at times, but it would after a time (10-20 minutes?) correct back to only a few hundred meters off from the GPS.
However I could not get the LTE Discovery app to do a GPS fix at all in my Mix1, but in Google maps it worked fine.