A phone is not at all rugged enough for hiking. Yes, most phones have a GPS receiver but they are only designed to navigate you to the store and back.
Get yourself a good GPS unit. And even a basic unit that pinpoints your location so that you can look it up on a map.
Give me an Accurate Chart, a Compass and a Stop Watch and I will fly the Swiss Alps with the Windows Covered.
If you Cannot Navigate the Old Fashioned way, without Fancy Electronics, you Can Not Navigate At ALL!!