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Method and apparatus for implementing automatic tilt control of a radar antenna on an aircraft

  • US 6,236,351 B1
  • Filed: 07/06/1999
  • Issued: 05/22/2001
  • Est. Priority Date: 07/06/1998
  • Status: Expired due to Term
First Claim
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1. A method, performed on an aircraft, for automatically adjusting the tilt angle of a radar antenna to limit ground clutter to acceptable levels, with the radar antenna scanning a forward field of view within a specified range, said method comprising the steps of:

  • storing a terrain database including terrain cells identified by latitude and longitude intersections indexed by ilat and ilng values, with each terrain cell including a terrain elevation value;

    determining current location co-ordinate indices of the aircraft;

    for co-ordinates within the field of view and range, and based on the current location co-ordinate indices, determine minimum and maximum latitude and longitude index values;

    setting ilat equal to the minimum latitude index and setting ilng equal to the minimum longitude index;

    (a) retrieving the terrain elevation at the co-ordinates specified by ilat and ilng from the terrain database;

    (b) based on the terrain elevation and distance between the current location co-ordinates and the point (ilat, ilng) calculating an elevation angle between a horizontal along the flight path of the aircraft and the terrain elevation point;

    (c) storing the calculated elevation angle;

    if ilng is less than the maximum longitude co-ordinate incrementing ilng else;

    if ilng is equal to the maximum longitude co-ordinate and ilat is less than the maximum latitude co-ordinate incrementing ilat and repeating steps (a), (b), and (c) else;

    adjusting the antenna to have a tilt angle equal to the elevation angle.

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