Millimeter-wave aircraft landing and taxing system

Claim 1

An aircraft landing or taxiing aid, comprising: a multiple beam antenna system installed in an aircraft and having overlapping receive beams aligned in different directions to provide coverage of a selected field of view from the aircraft; and signal processing means, for processing signals received by the multiple beam antenna system, the signal processing means including signal analysis means, for separating signals from each receive beam into components having amplitudes corresponding to the strengths of signals received from a plurality of emitters installed at known locations on the ground, at least some of the emitters being located to define the outline of a runway, and angle determination means, for determining the apparent angular location of each detected emitter, whereby the determined angular directions can be used in instruments providing a visual indication of the location and course of the aircraft with respect to the runway; wherein each emitter is modulated at a different selected frequency, and the signal analysis means includes a fast Fourier transform (FFT) module, to separate the signals from each receive beam into frequency components, thereby uniquely identifying signal contributions from each emitter on the ground, said fast Fourier transform module generating a set of amplitudes for each of the identified emitters, wherein the angle determination means uses the generated amplitudes to determine the angular direction of each emitter.

Claim 18

A method for providing navigational data to a pilot of an aircraft during landing or taxiing operations, the method comprising the steps of: emitting a plurality of radio-frequency (rf) signals from beacons at selected locations on the ground, at least some of the beacons being located to define the outline of a runway; modulating the rf signals transmitted by the beacons, such that each beacon is modulated at a different selected frequency and is uniquely identifiable from an aircraft; receiving rf signals in the aircraft, using an array of rf antennas having overlapping receive beams aligned in different directions to provide coverage of a selected field of view from the aircraft; amplifying any received rf signals and converting them to digital form, in which they may be conveniently processed; and processing the converted signals, the signal processing step including separating converted signals from each rf module into components having amplitudes corresponding to the strengths of signal detected from individual beacons, and determining azimuth and elevation angles of the apparent direction of each detected beacon, whereby the determined azimuth and elevation angles can be used in instruments providing a visual indication of the location and course of the aircraft with respect to the runway; wherein the step of separating converted signals into components includes performing a fast Fourier transformation (FFT) on the converted signals, to separate them into frequency components, thereby uniquely identifying signal contributions from each beacon on the ground, the step of performing a fast Fourier transform including generating a set of amplitudes for each of the emitters, wherein the step of determining azimuth and elevation angles includes using the generated amplitudes to determine the angular direction of each emitter.

Claim 19

A method for providing navigational data to a pilot of an aircraft during landing or taxiing operations, the method comprising the steps of: emitting a plurality of radio-frequency (rf) signals from beacons at selected locations on the ground, at least some of the beacons being located to define the outline of a runway; modulating the rf signals transmitted by the beacons, such that each beacon is modulated at a different selected frequency and is uniquely identifiable from an aircraft; receiving rf signals in the aircraft, using an array of rf antennas having overlapping receive beams aligned in different directions to provide coverage of a selected field of view from the aircraft; amplifying any received rf signals and converting them to digital form, in which they may be conveniently processed; and processing the converted signals, the signal processing step including separating converted signals from each rf module into components having amplitudes corresponding to the strengths of signal detected from individual beacons, and determining azimuth and elevation angles of the apparent direction of each detected beacon, whereby the determined azimuth and elevation angles can be used in instruments providing a visual indication of the location and course of the aircraft with respect to the runway; wherein the step of separating converted signals into components includes performing a fast Fourier transformation (FFT) on the converted signals, to separate them into frequency components, thereby uniquely identifying signal contributions from each beacon on the ground, the step of performing a fast Fourier transform including generating a set of amplitudes for each of the emitters, wherein the step of determining azimuth and elevation angles includes using the generated amplitudes to determine the angular direction of each emitter.