Try this : first of all install Hardware tests from the Store.
1. Shut down your phone and remove the SIM and restart it (in this way the phone can't get the position from the GSM-3G network)
2. Disable the WiFi (the phone can't get the position from the Wi-Fi network)
3. Open Hardware tests, go outdoor or near a window with your phone and start the Gps test.
4. Wait a little bit and you will get your position. The last line of the Gps test screen must say Position source : Satellite.
5. Now open Maps or Here drive+ to check if also the apps can get the right position.
6. If all went right you can reinsert your Sim and use the phone as usual.