Lock screen but keep Google Maps turn-by-turn navigation and GPS active I've a Sony Xperia Z with Android 4.2.2 and need to lock my screen but keep the (voice/turn-byturn) navigation active. How can I achieve that?

As it's currently, as soon as I lock the screen, GPS seems to be disabled instantely (at least when I unlock the phone, it needs to reaquire a GPS fix) and turn-by-turn navigation in Google Maps is instantly disabled.

How can I keep both things activated?

Background: I want to travel by bike without needing to look at my smartphone every few crossroads. Since I don't have a handlebar mount for my smartphone I've to keep it in one of the pockets of my pants. For some reason (I guess the fabric is too thin) the phone registers touches all the time, leading to 'butt-dials' and similiar things.
Power saving mode will disable the gps when the screen is locked. Disable power saving mode in settings.