Ferry boat navigation in reduced visibility conditions - utilises ultrasonic signals emitted by radio from ferry boat
Реферат: The ferry boats travelling between two fixed landing areas are given navigation information in reduced visibility conditions by ultrasonic and radiofrequency signalling. The ferry boat (V) carries two hydrophones (B, C) spaced from longitudinal axis and symmetric to it. These receive ultrasonic signals, from beacons (A, D) connected by cables to controllers. High frequency short duration ultrasonic pulses are transmitted when radio signal is received by the controller from the ferry. Detector circuits measure propagation time of signals transmitted to the hydrophones. Distances are determined from beacons and distance from linear trajectory determined.
Method and apparatus for error reduction when measuring movement in space of test points by means of ultrasonic signals
Номер патента: US4939701A. Автор: Wolfgang Brunner,Ludwig Von Zech. Владелец: Zech Ludwig Von. Дата публикации: 1990-07-03.