... application keeps last acquired position from gps and uses it if new one is not available atm. when application goes foreground - gps starts working again(as it has been switched off), and it takes some time to warm up. actually it does. If you press any button("places","feed" so on) again, even if you are on that page already - content is reloaded from 4sq. It's just take some time to warm up gps, you can speed up it by setting supl a-gps server to "supl.google.com". Gps lock time will be about 2-3 secs.