초록 ▼

A method and apparatus for automatically controlling the tilt of a radar antenna to avoid ground clutter returns while scanning the weather formations of most interest. In one embodiment a terrain database is utilized to determine tilt angles for different terrain cells. The tilt angle is determined

A method and apparatus for automatically controlling the tilt of a radar antenna to avoid ground clutter returns while scanning the weather formations of most interest. In one embodiment a terrain database is utilized to determine tilt angles for different terrain cells. The tilt angle is determined starting at the aircraft position and working out to the radar range. If a tilt angle for a more distant cell is less than for a nearer cell it is ignored taking shadowing into account. In another embodiment the weighted tilt angle frequencies are entered into a histogram and the histogram is scanned to obtain a tilt angle resulting in an acceptable amount of ground clutter.

대표청구항 ▼

[ What is claimed is:] [1.]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

[ What is claimed is:] [1.]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 andsetting 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.