Doing inertial navigation with the sensors only is not going to work well. In this invention they seem to augment the sensors with external information and deduce the most probable location that way - the article is rather scant on details though.
AFAIK you can be located using cell towers both on the device side and the cell network side.
You can be located with WIFI too: if you have WIFI enabled and communicate the access point names to Google/Apple, your location can be discovered. WIFI AP locations collected beforehand (by something like the Google car or the phone itself) are matched with their known accurate position and the measured AP signal strengths.
And Bluetooth beacons can also be used for location. What else... the pictures you take with the camera and upload to a cloud storage can be used to locate you.
Having a functioning inertial navigation would be very useful for many purposes. For example, offline navigation without GPS (=longer battery life).
