В Гибралтаре - обычный радар.
Magnetic anomaly detectors were first employed to detect submarines during World War II. MAD gear was used by both Japanese and U.S. anti-submarine forces, either towed by ship or mounted in aircraft to detect shallow submerged enemy submarines. The Japanese called the technology "jikitanchiki". After the war, the U.S. Navy continued to develop MAD gear as a parallel development with sonar detection technologies.