It is an acronym for Sound Navigation & Ranging (SONAR) Sonar is the technology of making use of sound waves to navigate, communicate and detect objects which are used for monitoring a particular area 24/7. It detects objects within 180 degrees and up to 8 meters. The word "sonar" comes from the first letters of "sound navigation ranging." Sonar can detect and locate objects under the sea by echoes, much as porpoises and other marine animals navigate using their natural sonar systems. In 1906, American naval architect Lewis Nixon invented the first sonar-like listening device to detect icebergs. During World War I (1914-18), a need to detect submarines increased interest in sonar. French physicist Paul Langévin constructed the first sonar set to detect submarines in 1915. At first, these sonar sets could only "listen" to returning signals. By 1918, Britain and the United States had built sonar sets that could send out, as well as receive, sound ...