Communications: radio wave antennas – Antennas – Balanced doublet - centerfed
Patent
1979-10-12
1981-06-23
Tubbesing, T. H.
Communications: radio wave antennas
Antennas
Balanced doublet - centerfed
343 5HE, 343 171PF, G01S 1302
Patent
active
042753961
ABSTRACT:
An airborne pulse doppler radar set generally includes a moving target indicator (MTI) system for detecting moving aircraft within its scanning purview. To avoid processing undesirable clutter, the MTI system includes a clutter cancelling type filter for rejecting doppler shift frequency signals reflected from objects moving at velocities below a predetermined minimum velocity value. Unfortunately, the doppler shift frequencies representative of the body velocity of most helicopters fall within this clutter repetition band and may go undetected by the MTI system. To detect these helicopters, a helicopter detection system which operates on the specular flash energy of the doppler shift frequency signals reflected from the rotating blades of a helicopter is provided. The helicopter detection system passes substantially the received reflected radar signals that have doppler shift frequencies representative of the helicopter rotating blade velocities, derives a threshold value based on the values of the passed signals, and generates detection signals at times corresponding to the passed signal values which are at least that of the derived threshold value. In addition, the helicopter detection system is capable of inhibiting the generation of the detection signals at time corresponding to the reception of interference type radar signals by the radar set. Furthermore, an unambiguous range of each detected helicopter may be computed. Moreover, the helicopter detection system has the capability of distinguishing between detected targets having even and odd numbers rotating blades.
REFERENCES:
patent: 1981884 (1934-11-01), Taylor et al.
patent: 3733603 (1973-05-01), Johnston
patent: 3858209 (1974-12-01), Zulch
patent: 3983558 (1976-09-01), Rittenbach
patent: 4038656 (1977-07-01), Webb, Jr. et al.
patent: 4101890 (1978-07-01), Goyard
patent: 4106019 (1978-08-01), Alexander et al.
patent: 4143373 (1979-03-01), Chernick
LandOfFree
Helicopter rotating blade detection system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Helicopter rotating blade detection system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Helicopter rotating blade detection system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2210868