Oboe (navigation)

Oboe (navigation)

Oboe was a British aerial blind bombing targeting system in World War II, based on radio transponder technology. Prior to a mission, a circle was drawn around one of the Oboe transmitters so that it passed over the selected target. The bombers, one at a time, would then attempt to fly along this path towards the target. The Oboe operator in England would use the equipment to see if the bomber strayed from the path, and give the pilot instructions on how to regain it. The path was only 35 yards wide, allowing for much greater accuracy than competing systems like Gee. The curved path was quite evident to German radar operators, who came to call the system "Boomerang" after the arc segment left on their displays as the aircraft appeared and disappeared out of range.

The system was first used in December 1941, about the same time as H2S radar was introduced and a few months after the first use of Gee. As it could only guide a single aircraft at a time, Oboe was used to guide the pathfinder bombers to drop their target indicators for the initial stages of the raid; following bombers would use the markers as a reference for conventional bombsights. Individual aircraft were also used to bomb point targets. Gee, a passive system that could be used by an unlimited number of aircraft, remained in use for local guidance over the UK even after Oboe became widely used for bombing.

Oboe's limitation of one aircraft at a time led to several new systems. Among these were the Gee-H system, which used the existing Gee equipment with Oboe-like transmitters. Gee-H could guide about 80 aircraft at the same time. In the US, SHORAN was similar, with a limitation of about 20 aircraft at once.