| 摘要 |
A stand alone collision avoidance system is disclosed for mounting to a large passenger jet especially to avoid the collision problem common to such large jets colliding with small propeller driven aircraft. A bistatic radar antenna system is disclosed having a frequency in the range of 40 Giga Hertz (hereafter GHz). Paired bistatic antennas are used with each couplet of bistatic transmitting and receiving antennas searching one quadrant of a total forward hemisphere of search in the direction of plane travel. Paired transmitter antennas, one for each quadrant, are typically located above and below the nose located weather radar and are mechanically scanned side to side in the typical "beaver tail" scan with the beaver tail occupying 100 DEG of elevation and 0.71 DEG of beam width. Paired receiving antennas, again one for each quadrant, are located with one such antenna on the leading edge of the vertical stabilizer or tail and the other antenna on a special mast lowered in a position where landing gear shadow does not obscure forward view. Each receiving antenna is mechanically scanned side to side synchronously with its transmitter antenna and consists of a phased array with a vertical scan generated from about 500 discrete linearly disposed receiving elements for vertical resolution of up to 0.21 DEG . The antenna is responsive only to radar return signals approaching the antenna in a narrow vertical angular range, at some desired, and variable, vertical angle.
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