An example of how that worked in the military sense, the eye piece would put a targeting diamond over a target while you were looking at it and would be either clear, or light up a single pixel on the edge of the screen where you would have to look to see the diamond(s).
On fighter yets the hud is fixed over the cockpit 'dash' and doesn't move relative to your head, so when you look out of the cockpit it isn't in front of your eyes.
The conclusions NASA came to was that locating stuff and anchoring it in space around the pilot was essential in keeping the pilot from losing situational awareness and instead looking at the display on the glass.
In the Russian helmet, they would need some way to combine your GPS location, and head orientation, to perhaps put virtual cones in the road in front of you showing you where to go.
Ideally, this should be tested.
ATS HUD: http://www.youtube.com/watch?v=tpXYwoZ6zWw
For a while they even had a radar overlay so you could see deer in the road on your HUD before your eyes could in the dark.
http://cdn0.mos.techradar.futurecdn.net//art/car%20tech/Head...