1.   Another is a hand-held navigation unit that uses a global positioning system to keep firefighters from getting lost.

2.   According to boat dealers, the hottest marine accessories this year are hand-held GPS navigation units.

3.   It also makes a range of avionics equipment, including Apollo navigation units for small aircraft.

4.   Now, several companies are trying to bring the air drop into the digital age, combining advances in parachute technology with satellite-based navigation units.

5.   Several companies are trying to bring the air drop into the digital age, combining advances in parachute technology with satellite-based navigation units.

6.   Discovery was supposed to fly Thursday, but NASA delayed liftoff to replace a failed navigation unit.

7.   It had been delayed one day because a navigation unit needed to be replaced.

8.   NASA, meanwhile, has yet to determine why one of three critical navigation units malfunctioned Thursday aboard Endeavour.

9.   The flight had been delayed one day so NASA could replace a failed navigation unit.

10.   The jammed hatch and the failure of a navigation unit were other factors in the decision.