I've been trying to use my phone as a GPS system (an LG Escape 2) but the GPS signal is unreliable and intermittent. My use is strictly in the USA. The android apps I.m using are RideWithGPS (
https://ridewithgps.com/), good for planning, navigation and recording; there's also Offline Maps & Navigation (
https://play.google.com/store/apps/details?id=com.navigation.offlinemaps.gps) which has downloadable offline maps of just about everywhere; I also use some topo maps, but these are north america which won't help you out in Russia.
I was looking at the Garmin GLO, which is a GPS receiver that will communicate with a navigation devise, like a phone or tablet, via bluetooth. The attraction is that the screen on the LG phone is about 3x the size of the eTrex 20x.
Anyone have experience using the GLO with a phone?