Window-passage detection system of an airplane
First Claim
1. A window-passage detecting system of an airplane having at least one ground system each comprising:
- a first course generator for generating a horizontal DDM (Differential Depth of Modulation) pattern for defining a horizontal width of a virtual window frame through which a precision approach landing course of an airplane is set, by emitting a first carrier signal and a first side-band signal at the same time upwards toward the virtual window frame from a pair of first transmission antennae provided under the virtual window frame and arranged horizontally and line-symmetrically to a center line of a runway to generate a polarization plane parallel to a horizontal direction of the virtual window frame,said first carrier signal being obtained by amplitude-modulating a first base signal of a first frequency with a first and second modulation signal synchronized with each other,said first side-band signal being obtained by balanced-modulating the first base signal with the first modulation signal whereof phase is inverted and the second modulation signal,one of said first transmission antennae being supplied with the first side-band signal and the first carrier signal, andthe other of said first transmission antennae being supplied with the first side-band signal whereof phase is inverted and the first carrier signal;
a second course generator for generating a vertical DDM pattern for defining a vertical width of the virtual window frame, by emitting a second carrier signal and a second side-band signal at the same time in the horizontal direction toward the virtual window frame from a pair of second transmission antennae provided sideways of the virtual window frame and arranged vertically and line-symmetrically to a horizontal line orthogonal to the center line and crossing with the precision approach landing course to generate a polarization plane parallel to a vertical direction of the virtual window frame,said second carrier signal being obtained by amplitude-modulating a second base signal of a second frequency which is a little shifted from the first frequency with the first and the second modulation signal,said second side-band signal being obtained by balanced-modulating the second base signal with the first modulation signal whereof a phase is inverted and the second modulation signal,one of said second transmission antennae being supplied with the second side-band signal and the second carrier signal, andthe other of said second transmission antennae being supplied with the second side-band signal whereof a phase is inverted and the second carrier signal; and
a third course generator for generating a longitudinal DDM pattern for defining a longitudinal position of the virtual window frame, by emitting a third carrier signal and a third side-band signal at the same time in the horizontal direction toward the virtual window frame from a pair of third transmission antennae provided sideways of the virtual window frame and arranged horizontally and line-symmetrically to the horizontal line orthogonal to the center line and crossing with the precision approach landing course to generate a polarization plane parallel to a normal direction of the virtual window frame,said third carrier signal being obtained by amplitude-modulating a third base signal of a third frequency which is a little shifted from both of the first and the second frequency with the first and the second modulation signal,said third side-band signal being obtained by balanced-modulating the third base signal with the first modulation signal whereof a phase is inverted and the second modulation signal,one of said third transmission antennae being supplied with the third side-band signal and the third carrier signal, andthe other of said third transmission antennae being supplied with the third side-band signal whereof a phase is inverted and the third carrier signal.
1 Assignment
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Accused Products
Abstract
A window-passage detection system has a ground system comprising: a first course generator (3) for generating a horizontal DDM (Differential Depth of Modulation) pattern for defining a horizontal width (25) of a virtual window frame by emitting a first carrier signal and a first side-band signal from a pair of first transmission antennae (6a and 6b), a second course generator (4) for generating a vertical DDM pattern for defining a vertical width (26) of the virtual window frame by emitting a second carrier signal and a second side-band signal from a pair of second transmission antennae (7a and 7b), and a third course generator (5) for generating a longitudinal DDM pattern for defining a longitudinal position (27) of the virtual window frame by emitting a third carrier signal and a third side-band signal from a pair of third transmission antenna (8a and 8b). Pairs of the first to the third transmission antennae (6a to 8b) generate three orthogonal polarization planes. With each pair of antenna, each carrier signal is emitted with the same phase and each side-band signal is emitted with inverted phase. Each carrier signal is amplitude-modulated with addition of a first and a second modulation signal, and each side-band signal is balanced-modulated with differential of the first and the second modulation signal.
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Citations
6 Claims
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1. A window-passage detecting system of an airplane having at least one ground system each comprising:
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a first course generator for generating a horizontal DDM (Differential Depth of Modulation) pattern for defining a horizontal width of a virtual window frame through which a precision approach landing course of an airplane is set, by emitting a first carrier signal and a first side-band signal at the same time upwards toward the virtual window frame from a pair of first transmission antennae provided under the virtual window frame and arranged horizontally and line-symmetrically to a center line of a runway to generate a polarization plane parallel to a horizontal direction of the virtual window frame, said first carrier signal being obtained by amplitude-modulating a first base signal of a first frequency with a first and second modulation signal synchronized with each other, said first side-band signal being obtained by balanced-modulating the first base signal with the first modulation signal whereof phase is inverted and the second modulation signal, one of said first transmission antennae being supplied with the first side-band signal and the first carrier signal, and the other of said first transmission antennae being supplied with the first side-band signal whereof phase is inverted and the first carrier signal; a second course generator for generating a vertical DDM pattern for defining a vertical width of the virtual window frame, by emitting a second carrier signal and a second side-band signal at the same time in the horizontal direction toward the virtual window frame from a pair of second transmission antennae provided sideways of the virtual window frame and arranged vertically and line-symmetrically to a horizontal line orthogonal to the center line and crossing with the precision approach landing course to generate a polarization plane parallel to a vertical direction of the virtual window frame, said second carrier signal being obtained by amplitude-modulating a second base signal of a second frequency which is a little shifted from the first frequency with the first and the second modulation signal, said second side-band signal being obtained by balanced-modulating the second base signal with the first modulation signal whereof a phase is inverted and the second modulation signal, one of said second transmission antennae being supplied with the second side-band signal and the second carrier signal, and the other of said second transmission antennae being supplied with the second side-band signal whereof a phase is inverted and the second carrier signal; and a third course generator for generating a longitudinal DDM pattern for defining a longitudinal position of the virtual window frame, by emitting a third carrier signal and a third side-band signal at the same time in the horizontal direction toward the virtual window frame from a pair of third transmission antennae provided sideways of the virtual window frame and arranged horizontally and line-symmetrically to the horizontal line orthogonal to the center line and crossing with the precision approach landing course to generate a polarization plane parallel to a normal direction of the virtual window frame, said third carrier signal being obtained by amplitude-modulating a third base signal of a third frequency which is a little shifted from both of the first and the second frequency with the first and the second modulation signal, said third side-band signal being obtained by balanced-modulating the third base signal with the first modulation signal whereof a phase is inverted and the second modulation signal, one of said third transmission antennae being supplied with the third side-band signal and the third carrier signal, and the other of said third transmission antennae being supplied with the third side-band signal whereof a phase is inverted and the third carrier signal. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification