From what I've seen, most modern phones either use wifi triangulation or GPS for location. They use towers as well, but it's much less precise than using wifi. Wifi triangulation has been around since 2007 or so, my brother worked for Skyhook Wireless, the company that really kicked that off. If you go into your phone settings (at least for Android), there is usually a setting to select how your phone gets it location. Using wifi and towers is often labeled "battery saving" as the GPS does use more power.
Any somewhat recent Android tablet should do well. But, the Amazon Fire tablets do not have a GPS chip... a real shame since they're cheap. I have a decent 10" tablet (ZTE K92, sold as the "AT&T Primetime") in my Jeep for offroad navigation and watching shows when babysitting a major MVC scene for hours. If you don't need topo or satellite maps, Google Maps offline maps is a nice option. For topo and/or satellite maps, I like using Backcountry Navigator, it can operate using data or you can download sections for offline use, too. It works great on phones, too... used it hiking last year in Utah.