As long as it's in the phone, couldn't you tether it to Google Glass to generate a real-time HUD based on where you were? (and perhaps also capture images to attach to the 3D model)
That was the first thing I thought about - actual augmented reality down to the inch would be quite something.
With future versions of Google Glass perhaps. The current version does not have a display that can provide a HUD in the way that it seems you are thinking.
You don't have to tie it to google glass. You can make the phone itself serve as 'window' onto the "down to the inch" augmented reality.
It relies on some hardware sensors which are in the phone.
The first thing I imagined is a wearable with a clicker for the blind. You say navigate me to ___, and the clicker gives you hot and cold signals (lots of feedback vs. less) as well as maybe a buzzing feedback if you're approaching a hazard.
You could apply current directly to your head to provide necessary signals, similar to how tDCS works. No buzzing required.