Hasn't this already been done?
Or am I missing something...
I recall a system still under development that used a separate GPS receiver and laptop with built in maps that was built for the purposes of "touristy" information,. and perhaps to automate and streamline the new student orientation at the university.
This was well before hand-helds existed let alone had the power to numbercrunch this.
The prototype was quite large, and was a huge backpack that consisted of a laptop and associated equipment along with the battery packs, and used a virtual-reality headset with built in camera to augment the video.
Mind you, that hasn't stopped apple from patenting as its own, even if they had to steal it.