Accession Number : ADD007191

Title :   Angle Sensing System.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Lewis,Bernard L

Report Date : 18 Mar 1980

Pagination or Media Count : 7

Abstract : A system for measuring, in conjunction with a GCA radar, the crab angle of an aircraft which is making its landing approach above a runway. A loop antenna mounted on the craft transmit an audio-frequency electromagnetic wave to two sets of crossed receiving loops, each set mounted at one side of the runway. A line joining the centers of the loops makes a 45 deg angle with the plane of each loop. The outputs of the loops in each set are subtracted from each other, amplified, detected and rectified and then differentiated to provide a pulse output indicating the zero point of the subtraction, i.e., the time when the H-field vector is at an angle of 45 deg to the plane of each of the loops in the set providing the zero-indicating pulse output. The zero-indicating pulse outputs are fed to a time interval counter which determines the time interval between them. With this information plus the ground speed of the craft (as determined by the GCA radar) and the distance between the receiving-loop sets, the crab angle of the aircraft can be calculated. (Author)

Descriptors :   *Patents, *Ground controlled approach radar, *Aircraft landings, Glide slope, Loop antennas, Aircraft antennas, Angles, Ground speed, Time interval counters

Subject Categories : Air Navigation and Guidance
      Active & Passive Radar Detection & Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE