Early during World War II, German U-boats operating in the North Atlantic decimated allied shipping until a Dayton engineer helped design a fleet of computing machines that deciphered coded Nazi communications faster than the U-boat commanders could themselves. Today, the U.S. and its allies face a similar challenge from an enemy that often strikes from the shadows at a time and place of its choosing, said Dr. David Jerome, director of the Air Force Research Laboratory Sensors Directorate. "To unravel their networks and defeat this enemy we must watch over entire cities, day and night, in all weather conditions," Dr. Jerome said. The Gotcha radar is being developed by AFRL engineers to meet that challenge and to provide future joint…