Science: Shoran in Korea

Unlike the radar bombsight, which has to "see" its target by means of radar waves, Shoran (Short Range Air Navigation) can put bombs on a target that has not been seen at all. It needs nothing but an accurate map with the target marked. Last week the Air Force announced that it has begun to use Shoran in Korea.

A bomber equipped to use Shoran carries a radio transmitter that sends out short pulses of ultra high frequency (above 300 megacycles) waves. Two ground stations at well-separated points behind friendly lines pick up the airplane's pulses and echo them back greatly amplified. Apparatus on the plane measures the time it took for the pulses to make round trips to each of the stations. This gives a continuous picture of the airplane's distance from the two stations—and therefore its position on the map. The system is accurate enough to show the position of the plane within 50 feet.

In darkness or clouds, the crew figures out how the Shoran instruments should read when the airplane reaches the bomb release point just short of the target. They set some dials. A computing mechanism that takes account of wind drift, altitude, etc. helps them reach the selected point. A red light flashes, and the bombardier drops the bombs.

Shoran was used toward the end of World War II. The Air Force has more advanced systems that are still secret, but figures that Shoran works efficiently enough for its Korean operations.