Method and device for the measurement of the heights, the distances and the direction of a target by means of the sound vibrations and noise ultra -

摘要

790,934. Echo distancemeasuring. KONINKLIJKE LUCHTVAART MAATSCHAPPIJ N.V., DERKSEN, J. W., and KIPS, E. J. E. Aug. 3, 1955 [Aug. 4, 1954], No. 22329/55. Drawings to Specification. Class 118 (2). Apparatus for determining the height or the distance to a reflecting surface by measuring the time interval between the transmission of an acoustic sonic or ultrasonic vibration and the reception of such vibration after reflection from the reflecting surface is characterized in that for transmitting the vibration use is made of a source of sound, the transmitted energy of which is in its entirety concentrated on one adjustable frequency, and wherein at the beginning of the transmission a predetermined constant amplitude is obtained substantially without building- up time and at the end of the transmission the amplitude becomes zero substantially without decaying time. An embodiment, illustrated by means of a block diagram, utilizes as transmitter an ionophone as described in Specification 659,796, [Group XL (a)], and a special receiver having a very high selectivity responsive to only one predetermined frequency and harmonics thereof. Extraneous noises, for example on an aircraft, are thus largely eliminated from the apparatus. The transmitter and receiver are directional and are controlled by a gyroscopic system whereby measurements are independent of the rolling of the aircraft or other vessel carrying the apparatus. Range is measured by means of low-frequency timing pulses which are passed to an electronic counter and indicator by a switching device which is gated on by the transmission pulse and gated off by the echo pulse. The number of pulses passed during this interval are proportional to range and the frequency of the timing pulse generator may be varied to give the indication in any desired units. U.S.A. Specification 2,574,596 also is referred to.