Abstract: An acoustic countermeasure system comprises a plurality of individual countermeasure devices which act in concert to emulate a target with spatial extent. The individual countermeasure devices may be programmed to navigate into predetermined positions within a preset pattern with spatial characteristics similar to that of a target of interest, e.g., a submarine. The individual countermeasure devices are programmed to produce acoustic signals, such as in response to a ping or pulse by an incoming torpedo that collectively appears to be an echo similar to that which would come from a target having spatial extent.