| US 7,522,089 B2 | ||
| Airborne look-down doppler radar tracking of hovering helicopters using rotor features | ||
| Bernard Radza, Tucson, Ariz. (US); Joseph Henning, Tucson, Ariz. (US); Sunny Ali, Tucson, Ariz. (US); John Mincer, Tucson, Ariz. (US); and Randal Walters, Green Valley, Ariz. (US) | ||
| Assigned to Raytheon Company, Waltham, Mass. (US) | ||
| Filed on Jun. 12, 2006, as Appl. No. 11/423,590. | ||
| Prior Publication US 2007/0285303 A1, Dec. 13, 2007 | ||
| Int. Cl. G01S 7/41 (2006.01); G01S 13/72 (2006.01); F41G 7/20 (2006.01) | ||
| U.S. Cl. 342—62 [342/90; 342/91; 342/93; 342/95; 342/159; 342/160; 342/162] | 29 Claims |
| 1. A method of missile radar tracking helicopters, comprising:
receiving on-board missile radar samples having an amplitude and Doppler shift that define a Doppler map including ground
clutter, body and extended rotor returns;
detecting a potential target in the Doppler map;
defining at least one search window that excludes ground clutter and body returns and includes at least a portion of the extended
rotor return;
setting a threshold above a constant false-alarm rate (CFAR) threshold;
comparing the samples within said at least one search window to the threshold to identify rotor samples;
extracting rotor features from the rotor samples; and
classifying the potential target as a helicopter or other based on the extracted rotor features and known attributes of a
helicopter rotor assembly.
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