The art and science of navigation date back to antiquity. Beginning with procedures one step removed from black magic, navigation has progressed through the refined skill of the celestial navigator, the explosive development of electronic systems after the Second World War, to the artificial celestial system NAVSTAR GPS. Celestial navigation is certainly the most historic form, metaphysically speaking, and woe be to the mariner who proceeds to sea without a knowledge of it. This review will, however, concentrate on man‐made systems, which can operate automatically, that is, the position derived from man‐made signals propagating over finite distances can and usually are processed with man‐made systems. Usually one thinks of electromagnetic radio signals as exclusively fonning this set of signals, but underwater acoustic positioning systems are mathematically very similar and differ only in realization. Our review will highlight the state‐of‐the‐art in these positioning systems, commenting on the needs of users which spawned their development, and the major measures of the systems’ performance.