Kind of a throw back idea, but what if the Chart and GPS had each own benefits?
GPS
So currently in U3 the GPS is basically a Satellite photographic map, really isn’t much more use than the Chart and mainly just for looks.
Heres my idea:
Battery life: The GPS is (obviously) an electronic device, so this would allow use at night time (being having an illuminating screen), this mean then GPS’s would need to charge somehow with the use of generators and maybe a makeshift charger? Currently in U3 you can use both a Chart and GPS at night with out any difference to day time, but I think that should effect how we use these. A GPS would be great for use at night time, say for a raid, you could easily pin point out on the GPS markers and other players in your group would be able to see those markers on their GPS as well.
However
Those with a Chart will not be able to see markers, unless manually placed by the player themself.
But you’re now thinking, well a Chart isn’t really useful then for groups, I’m getting to that.
Charts
Charts would be more reliable than a GPS, without the need for a battery they would have practically infinite use, now going back to the point with the markers, if for example I were in a group with 2 other players, and we’re in a roughly 2 meter radius of each other in the game world itself, and I placed a marker on my Chart, then on my friends charts that same marker would show up for them, being in theory I would have showed them where to place it somewhat on their Charts. (Bit of a stretched idea, other way is the player would be able to turn their chart around to show the markers on their map)
As well as having reliableness on a Chart we would be able to draw on it, sort of like Arma 3, On a chart we could use a pencil item we’d have to find and have the ability to draw on the charts making raid planning quiet smoother than in U3 where we’d have to use voice or text ingame how the plan would go to raid a base.
Raiding a larger base with a drawn plan sounds a lot cooler too. 
As well as charts the GPS would also have the ability to draw, but maybe would then need signal to other towers for those said drawings to be receive from a team mate who would maybe be a fair distance away (Say a local radio tower that would need a generator to get running to receive and send out signal). But if two players in the same group are close enough the GPS themselves could send signal to each other.
Possibly maybe have makeshift radio towers? 
This was all kinda thought out on the loo but plenty of space for suggestions.
