Monopulse, fan-beam, search-radar system with improved height and azimuth determination
First Claim
1. A monopulse, fan beam, search-radar system in which multipath signals are received only when a target is in a multipath region located at low elevation angles, which comprises:
- transmitter means for producing pulses of electromagnetic wave energy;
antenna means for radiating said pulses and receiving target return signals, said antenna means forming a narrow-azimuth fan beam whose center line is aimed at the horizon and whose central plane is tilted at an angle of from 30°
to 60°
from the vertical plane, said antenna means including a sum receiving channel and an elevation-difference receiving channel for providing a sum signal and an elevation difference signal, respectively, from the target return signals; and
monopulse-receiver means coupled to said antenna means for receiving said sum signals and said elevation-difference signals, said monopulse-receiver means providing an elevation angle signal and a range signal corresponding to the elevation angle and range of the target.
0 Assignments
0 Petitions
Accused Products
Abstract
Multipath signals are eliminated at all but the lowest elevation angles awing monopulse techniques to be used to determine target height and azimuth in a two-dimensional, fan-beam, search-radar system. A narrow-azimuth fan beam is oriented at an angle to the vertical plane and has its boresight centered approximately on the horizon so that a V-beam is formed by the direct beam and the portion of the direct beam reflected from the surface (i.e., the portion that is below the horizon). The reflected beam does not interfere with the direct beam except in a multipath region near the reflecting surface. Frequency diversity or a receive-only beam in the vertical plane may be used to determine if a target is in the multipath region.
18 Citations
8 Claims
-
1. A monopulse, fan beam, search-radar system in which multipath signals are received only when a target is in a multipath region located at low elevation angles, which comprises:
-
transmitter means for producing pulses of electromagnetic wave energy; antenna means for radiating said pulses and receiving target return signals, said antenna means forming a narrow-azimuth fan beam whose center line is aimed at the horizon and whose central plane is tilted at an angle of from 30°
to 60°
from the vertical plane, said antenna means including a sum receiving channel and an elevation-difference receiving channel for providing a sum signal and an elevation difference signal, respectively, from the target return signals; andmonopulse-receiver means coupled to said antenna means for receiving said sum signals and said elevation-difference signals, said monopulse-receiver means providing an elevation angle signal and a range signal corresponding to the elevation angle and range of the target. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. In a monopulse search radar having a transmitter for producing pulses of electromagnetic energy and monopulse-receiver means for producing signals providing the elevation angle, azimuth angle, and range of a detected target, the improvement comprising:
-
antenna means for radiating said pulses and receiving target return signals, said antenna means forming a narrow-azimuth fan beam whose center line is aimed at the horizon and whose central plane is tilted at an angle of from 30°
to 60°
from the vertical plane,said antenna means including a sum receiving channel and an elevation-difference receiving channel for providing a sum signal and an elevation-difference signal, respectively, from the target return signals, whereby multipath return signals are minimized. - View Dependent Claims (8)
-
Specification