One of the techs they wanted to explore was a HUD for Navy firefighters. Apparently shipboard fires can be really nasty because the smoke in the confined compartments reduces visibility to absolute zero. The Navy wanted to project VR data on the inside of a fireman's breathing apparatus faceplate. The idea was that the fireman would see a wireframe of the compartment he was in superimposed over his view of the real world so he wouldn't get lost. Tracking data gathered from other sailors would be integrated so he could find them if they needed to be rescued.
Ships are big hunks of metal which hoses GPS and traditional magnetic tracking.
This is very interesting stuff. Finding your way out often depends on following the hose back out of the compartment. The visibility is so bad that determining the source of the fire is often difficult and this is why the Thermal Cameras are used to locate hot spots.