Airborne metal detecting radar
First Claim
1. A radar system for detecting a metal target which may be camouflaged or concealed by natural foliage from an airborne flying vehicle and comprising:
- an antenna carried by a flying vehicle for transmitting an electromagnetic signal,first receiving antenna means carried by the flying vehicle for receiving the transmitted electromagnetic signal selected from the terrain and the target,second receiving antenna means carried by the flying vehicle and arranged orthogonally to the first antenna means for receiving the transmitted electromagnetic signal reflected from the target, andmeans coupled to the first and second receiving antenna means for processing the received signals to provide information as to the presence of a metal target.
6 Assignments
0 Petitions
Accused Products
Abstract
Method and arrangement for an airborne radar system particularly adapted to detect large metal targets that are concealed from the air by camouflage or natural foliage. The arrangement includes an antenna that transmits a continuous wave electromagnetic signal having a selectable frequency that preferably has a wave length generally twice the length of an anticipated target and which is carried by a flying vehicle. The frequency of the transmitted signal is chosen to provide maximum penetration of the camouflage or natural foliage and maximum re-radiation from a metal target. Receivers connected to an in-line receiving antenna and to a crossed receiving antenna carried by a flying vehicle detect the radiation that is reflected from the terrain and a target with the same polarization as that transmitted. The co-linear antenna and receiver respond to the reflected radiation while the cross-polarized antenna does not detect this reflected radiation. However, a metal object on the ground re-radiates cross polarized electromagnetic waves in proportion to their angular orientation and lateral distance to the transmitting antenna so that a metal target is detected by observing the output differences for the two receivers.
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Citations
22 Claims
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1. A radar system for detecting a metal target which may be camouflaged or concealed by natural foliage from an airborne flying vehicle and comprising:
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an antenna carried by a flying vehicle for transmitting an electromagnetic signal, first receiving antenna means carried by the flying vehicle for receiving the transmitted electromagnetic signal selected from the terrain and the target, second receiving antenna means carried by the flying vehicle and arranged orthogonally to the first antenna means for receiving the transmitted electromagnetic signal reflected from the target, and means coupled to the first and second receiving antenna means for processing the received signals to provide information as to the presence of a metal target. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method to detect a metal target that is camouflaged or concealed by natural foliage which comprises the steps of:
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illuminating a metal target and surrounding terrain with an electromagnetic signal having a frequency in the band of 2 to 30 MHz and transmitted by an antenna carried by a flying vehicle, receiving the transmitted signal re-radiated from the metal target with an antenna also carried by the flying vehicle and oriented orthogonally to the in-line antenna, and processing the re-radiated signals received from the metal target and the terrain by the antennas to develop data indicative of the presence of a metal target. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A method to detect a metal target that is camouflaged or concealed by natural foliage which comprises the steps of:
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illuminating a metal target and surrounding terrain with an electromagnetic signal transmitted by a transmitting antenna carried by a flying vehicle, receiving the transmitted signal re-radiated from the metal target with a first antenna carried by the flying vehicle, and a second antenna carried by the flying vehicle and oriented orthogonally to the first antenna, and processing the re-radiated signals received from the metal target and the terrain by the first and second antennas to develop data indicative of the presence of a metal target. - View Dependent Claims (20, 21, 22)
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Specification