Obstacle and terrain avoidance sensor
OwnerHaim Nivinventor
Life of this patent
Estimating the term…
Abstract
A method and apparatus for terrain mapping and/or obstacle detection for aircraft, including (a) transmitting a non-scanning beam that illuminates the terrain and/or obstacles; (b) receiving a Doppler shifted signal that is Doppler frequency shifted by an amount dependent on an angle between a line of flight of the aircraft and scatterers that reflect the transmitted beam; (c) determining the angle from the Doppler frequency; (d) determining the range of at least some of said scatterers; and (e) determining the azimuth and elevation of the scatterers.
Claims63
A method of terrain mapping and/or obstacle detection for aircraft, comprising:
- (a) transmitting a non-scanning beam that illuminates the terrain and/or obstacles;
- (b) receiving a Doppler shifted signal that is Doppler frequency shifted by an amount dependent on an angle between a line of flight of the aircraft and scatterers that reflect the transmitted beam;
- (c) determining the angle from the Doppler frequency;
- (d) determining the range of at least some of said scatterers;
- and
- (e) determining the azimuth and elevation of the scatterers,
- wherein a backscatter Doppler signal from a terrain cell or object, located on the opposite side of the aircraft's line of flight from a range cell or object of interest and falls within the same range cell and same Doppler filter is suppressed by a null, common to both sum and difference patterns of an antenna receiving said Doppler shifted signal.
A method of terrain mapping and/or obstacle detection for aircraft, comprising:
- (a) transmitting a non-scanning beam that illuminates the terrain and/or obstacles;
- (b) receiving a Doppler shifted signal that is Doppler frequency shifted by an amount dependent on an angle between a line of flight of the aircraft and scatterers that reflect the transmitted beam;
- (c) determining the angle from the Doppler frequency;
- (d) determining the range of at least some of said scatterers;
- and
- (e) determining the azimuth and elevation of the scatterers;
- and
- (f) resolving elevation ambiguity by:
- determining skyline contours, possibly containing tall, discrete obstacles, from said elevation, range and azimuth, said skyline contours including an upper contour and a lower contour, only one of which is real;
- if the area between the contours is substantially empty of measured scatterers, then the lower contour is chosen as the real contour;
- and
- if the area between the contours contains a substantial number of scatterers, then the upper contour is chosen as the real contour.
A method of terrain mapping and/or obstacle detection for aircraft, comprising:
- (a) transmitting a non-scanning beam that illuminates the terrain and/or obstacles;
- (b) receiving a Doppler shifted signal that is Doppler shifted by an amount dependent on an angle between a line of flight of the aircraft and scatterers that reflect the transmitted beam;
- (c) determining the angle of an object or terrain cell nearest to the line of flight at a certain range;
- and
- (d) displaying a distorted contour in the form of a half circle around the line of flight, whose radius represents the angular distance of this object from the line of flight.
Dependencies are inferred from the claim text.