Decoys

Decoys are used to confuse an enemy into diverting resources into reporting or attacking false, or 'dummy', targets. If the enemy mistakenly identifies a decoy as a real target, it is hoped that they will be less inclined to search for the actual, hidden target nearby.
 
To achieve this goal, a decoy must be placed in the correct location for that target type so that its discovery is realistic. It must be of high-quality construction and scale so that it convinces the enemy they have found the real target. If the decoy is recognised as such, however, the enemy is likely to look even harder for the real target, as decoys are generally deployed close by.
 
During the Second World War decoys were used by all sides to simulate many types of high-value assets; the most common were decoy factories, oil plants, airfields and cities. They rarely fooled bomber crews during the day but at night, with realistic lighting and fire-making devices, they could divert bombers away from their intended targets. Photographic interpreters in Q-Section of the Allied Central Interpretation Unit, RAF Medmenham, were tasked with identifying and locating such sites so that bomber crews could be briefed on their positions before future missions.