What airplane pilots want to know when they cannot see the ground is exactly where they are. They can get this information by various combinations of electronic direction-finding and distance-measuring, as with the U.S. VOR (Very High Frequency Omnirange) and DME
(Distance Measuring Equipment), by cross-bearings on radio compasses, etc. But such operations take a little time and a little room for position-plotting, and the pilot may not have enough of either. Recently the Decca Navigator Co. Ltd. of Britain* demonstrated over Germany a system that tells the pilot where he is all the time) with no effort on his part.
The Decca...