Reminds me of the RAF Vulcan Bomber story practicing precision bombing on a featureless desert in the US using airborne RADAR during the early sixties. The USAF were amazed that they hit their impossible RADAR target they were given, thinking that the RAF had a secret technology way ahead of the USA at the time.

Apparently the RAF aircrew wifes had gone for a picnic out in the desert at a predetermined location, then at a specific time they all opened and closed their car boot doors which gave a blinking RADAR return to the Vulcan bombers enough to pinpoint their ground target using with the car boot RADAR location as a offset geographical reference.