It was nature itself that invented "sonic radar," or sonar, well before humans did. For example, bats fly in the dark with poor sight without hitting obstacles and locate prey by means of sound pulses humans cannot hear.
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 signals. The U.S. military began using the term "sonar" during World War II. As with radar, new military applications for sonar are constantly being developed. For example, in the early 2000's, the U.S. Navy introduced a sonar system to help clear military mines.