A navigation system for navigating in low visibility environments includes
a portable detection unit which uses position and orientation sensors
and/or wireless location to track the position of the portable detection
unit relative to some reference location, such as a fire truck. The
relative position of the portable detection unit, and thus its user, is
then output to a visual display for viewing by the user so that the user
may see his/her position in a dark or smoky environment. The system may
also include portable beacons which may be left at landmarks so that the
relative positions of the landmarks may be seen on the visual display.