A Breakthrough Beneath the Waves The U.S. Navy is preparing to launch one of the most advanced detection systems in its history — a new passive sonar technology. Unlike active sonar, which sends out signals that can be tracked, passive sonar works in total silence. It listens to natural sounds in the ocean, processing them … Continue reading It’s over, and it’s grim news for Russian submarines: according to the U.S. Navy, the new-generation passive sonar installed on Arleigh Burke destroyers can detect up to 150 km.