Hyperbolic Systems


The British Royal Air Force and the U.S. Eighth Air Force relied extensively on the GEE hyperbolic system in their bombing campaigns over Europe, where it was essential in the overcast skies. Late in the war, GEE combined with a system of radar beacons (known as GEE-H) allowed the bomber crews to attack their targets without seeing them.
The APN-4 was the first LORAN set for aircraft to enter service. It had a separate receiver and display unit. The navigator had a leather hood to put over the oscilloscope’s cathode ray tube so he could clearly see it in daylight. LORAN was most valuable when the skies couldn’t be seen for celestial navigation and when coastlines couldn’t be picked up by radar. It did require a skilled operator.