Radar, Anti-Aircraft No. 3 Mk. 7, also widely referred to by its development rainbow code Blue Cedar, was a mobile anti-aircraft gun control radar designed by British Thomson-Houston (BTH) in the mid 1940s. It was significantly smaller and more portable than the World War II-era SCR-584 and GL Mk. III radars it replaced. It was used extensively by the British Army and was exported to countries such as Holland and Sweden. In British service it was used with the 5.25 inch and QF 3.7 inch AA guns, as well as the Brakemine missile. The unit was housed in an air conditioned trailer towed by an AEC Matador artillery tractor unit.