Showing papers on "Obstacle avoidance published in 1967"
Patent•
22 Mar 1967
TL;DR: In this article, a single narrow-beam radar is used to guide an aircraft over ground obstacles by a pulse radar mounted in the nose of the aircraft, and the rate of climbing is increased upon further intrusion of the obstacle by an integration term in the control loop.
Abstract: 1,062,981. Pulse radar. SPERRY GYROSCOPE CO. Ltd. March 16, 1962 [Dec. 16, 1960], No. 43355/60. Heading H4D. An aircraft is guided over ground obstacles by a pulse radar mounted in the nose. Signals are generated at the radar receiver when obstacles lying forward of the craft intrude within a predetermined threshold range. The signals activate the elevators to cause climbing. The rate of climbing is increased upon further intrusion of the obstacle by an integration term in the control loop. The radar antenna transmits and receives during alternate periods. The transmission is effected by a single narrow beam which scans in a vertical plane which includes the craft line of flight. During reception the directivity characteristic of the antenna is in the form of two overlapping, narrow, lobes in the scanning plane, and which produce two signals so as to provide an equi-signal plane perpendicular to the plane of the lobes. The received lobe signals form sum and difference signals, and the latter are either in-phase or anti-phase with the sum signals, which form a reference, according as the obstacle is below or above the equi-signal plane. Only those obstacle signals within a specified range are used to control the aircraft climb and this range is increased at scan angles above the equi-signal plane. Similarly, only anti-phase difference signals, corresponding to obstacles above the equi-signal surface are used.
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