An illustration of the Oboe navigation system. IWM catalogue number E(MOS) 1439.
<p>Oboe was a radio navigation system used by RAF Bomber Command during World War II, especially during the Battle of the Rhur. Transponders on an Oboe-equipped aircraft re-broadcast signals being sent to them from two stations in the UK, code-named Cat and Mouse. The signals were received back at the station and the distance to the aircraft measured on large CRTs, similar in fashion to traditional radar but using the stronger return signals of the transponder.
</p>
Measuring distance can be accomplished quickly, but turning two such measurements into a single location in space can be timing consuming. To address this, Oboe measured the distance from the Cat station to the target, and then directed the aircraft to turn left or right as needed to stay at that range. The same distance from Mouse was also measured, and when the aircraft was seen approaching that range the Mouse operator would tell the pilot to drop the bombs.
RAF Bomber Command
<a rel="nofollow" class="external free" href="https://media.iwm.org.uk/ciim5/176/425/large_000000.jpg">https://media.iwm.org.uk/ciim5/176/425/large_000000.jpg</a>