I am not clear at all about this stuff about apps. If my Samsung already enables me to find a satellite (which is why I think it tells me to work under open skies to find location), doesn't that mean that it already contains an app? Or, is there a further thing that indeed has to be downloaded? As I say, it does show me a spot on its map where it thinks I am, badly, and does tell me to use a bigger power source.
The cellphone works via my home contract for Internet, not any local WiFi into which I have to tune; so, I assume that when it gives me a reading for location, it is taking that reading off a combination of local cellphone signal transmitters and also satellite, or why the need for open skies? Wouldn't it just work perfectly well without sky access if it depended only on relay transmitters?
The worst problem is not accuracy, but battery depletion if used without access to bigger power units.
Rob
Maybe you do already have an app installed.
Just having a GPS unit in the phone is not enough.
Without the phone having some graphical way of showing YOU where it is the fact that the phone itself knows where it is becomes a complete non sequitur - hence the need for an app.
Also, as I mentioned in an earlier post: a smartphone will either use triangulation from local microwave towers or it will use its GPS unit. It does not use a combination of the two. My suggestion is to not waste data (money) and to make sure that one uses the GPS when one needs to find one's way around precisely because it does not cost data (money) and the GPS unit is MUCH more accurate.
As for power requirements particularly when driving - just use the 9V option in your vehicle (the cigarette lighter) to keep the phone charged.
I kept my smartphone charged for five weeks in just this way when travelling in Africa in 2015 while using it as a GPS.
Never made one phone call during that time.
In addition one can buy (relatively cheaply) what I call USB batteries that one charges via USB cable and then one can draw power, again via a USB cable to the phone that will keep it charged for several days.
I own a couple of these batteries and took them to Africa as well, as an emergency back-up in case all the camera batteries were drained and I did not have another charging option. As it turned out that was never the case and I did not actually need to use them.
In Australia the Nissan Patrol that I use for photographic expeditions has 12 9V sockets that continually run or charge a multitude of devices including fridges, GPS units, Smartphones, two laptops, charging for satellite phones, and charging batteries for a combination of five still and video cameras. The vehicle has two extra deep cycle batteries to deal with this and what is called a step-up charger that keeps these batteries in tip-top condition.
I also have a large solar blanket to keep these large deep-cycle batteries charged if the vehicle is not moving for any length of time. When on photography expeditions I will often be far away from 240 V mains power for days to weeks at a time.
The point I am making is that it is actually pretty simple to get around the limitations of the battery that is built-in to a smartphone. Consider that current Samsung phones just use a simple USB cable for charging rather than more complicated options of earlier generation phones. Nothing more than a USB cable (it comes with the phone) and a simple 9V plug that has a USB port is all that is required for what would essentially be infinite power while driving. Any general electronics store stocks items such as these and they are cheap.
Tony Jay