Patent US3798646A successfully refreshed from Google Patents.
US3798646A
Expired / Lapsed
US
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Continuous-wave, multiple beam airplane landing system
Assignee: Boeing Co
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Filing: 1971-09-07
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Granted: 1974-03-19
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Expires: 1991-09-07
Abstract
Abstract A microwave landing system for airplanes is disclosed in which continuous wave energy from a common source is radiated in overlapping beams which are modulated at respectively different audio frequencies detectable by an airplane receiver which detects the separate modulations and indicates relative offset from the overlap axis of the beams by relative levels of the demodulated signals. Modulation of the beams is effected by solid state semi-conductor devices placed in resonant cavities in wave guide system branches in the radiator element feeds. Radiator elements forming the beams comprise rectangular wave guide endings serving as highly compact closely spaced horns directed against a common paraboloidal reflector, with the narrow walls of the wave guides terminating in a common transverse plane and the broad walls terminating in flared triangular extensions beyond such plane. Monitoring of the transmitted beams for the presence and relative energy levels of the modulated beams is achieved by a microwave aperture located at the apex of the paraboloidal reflector and feeding a modulation detector and associated alarm indicator or control means.
Inventors
- 👤 W Buehler
- 👤 C Lunden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 01:26
CPC Classifications
G; G01; G01S; G01S1/00; G01S1/02
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
217 words
A microwave guidance system for landing of air-planes comprising a ground based microwave energy transmitter for producing substantially similar directional beams diverging mutually from and overlapping at corresponding partial power points along an intermediate directional axis which defines a desired landing path, the CW energy in each of said beams being modulated by signals of respectively different relatively low frequencies and of substantially equal amplitude, and an airplane based microwave receiver including means for demodulating the received beam energy signals, discriminating by frequency between the demodulated signals, and indicating by amplitude of such demodulated signals the relative beam energy levels being received, and thereby relative positional offset of the airplane from the landing path, said transmitter comprising a CW microwave energy source, directional antenna means including separate beamforming radiator elements therein, and means dividing energy from said source and feeding the energy at substantially equal levels to each of said radiator elements, said dividing and feeding means including separate wave guide means each having a variable impedance element arranged therein to modulate the level of microwave source energy being fed thereby to the associated radiator element in accordance with impedance variations of such variable impedance element, and means applying to such variable impedance elements impedance-varying signals of respectively difference relatively low frequencies and of substantially equal amplitudes.
Claim 2
Dependent Claim
217 words
A microwave guidance system for landing of air-planes comprising a ground based microwave energy transmitter for producing substantially similar directional beams diverging mutually from and overlapping at corresponding partial power points along an intermediate directional axis which defines a desired landing path, the CW energy in each of said beams being modulated by signals of respectively different relatively low frequencies and of substantially equal amplitude, and an airplane based microwave receiver including means for demodulating the received beam energy signals, discriminating by frequency between the demodulated signals, and indicating by amplitude of such demodulated signals the relative beam energy levels being received, and thereby relative positional offset of the airplane from the landing path, said transmitter comprising a CW microwave energy source, directional antenna means including separate beamforming radiator elements therein, and means dividing energy from said source and feeding the energy at substantially equal levels to each of said radiator elements, said dividing and feeding means including separate wave guide means each having a variable impedance element arranged therein to modulate the level of microwave source energy being fed thereby to the associated radiator element in accordance with impedance variations of such variable impedance element, and means applying to such variable impedance elements impedance-varying signals of respectively difference relatively low frequencies and of substantially equal amplitudes.
Claim 3
Dependent Claim
105 words
The guidance system defined in claim 1, wherein the antenna means comprises a concave paraboloidal reflector and associated beam-forming radiator elements directed against the reflector from respective locations grouped symmetrically about the axis of said reflector adjacent its focal point so as to produce the respective directional beams thereby, and means to monitor the beams including a microwave energy transfer element positioned at the apex of the reflector to extract energy in substantially equal proportions from the emissions of said radiator elements, and means connected with said energy transfer element for demodulating the energy received therefrom and indicating the relative amplitudes of modulation signals therein.
Claim 4
Dependent Claim
23 words
The guidance system defined in claim 2, wherein the microwave energy transfer element comprises a slot formed in the apex of the reFlector.
Claim 5
Dependent Claim
81 words
The guidance system defined in claim 1, wherein the antenna means comprises a concave paraboloidal reflector and associated beam-forming radiator elements directed against the reflector from respective locations grouped symmetrically about the axis of said reflector adjacent its focal point so as to produce the respective directional beams thereby, said radiator elements comprising rectangular wave guide endings with narrow walls coterminal in a common transverse plane and with their broad walls extending substantially equally beyond said plane in symmetrically convergent form.
Claim 6
Dependent Claim
24 words
The guidance system defined in claim 4, wherein the extended broad walls of the wave guide endings are relatively flared beyond the said plane.
Claim 7
Dependent Claim
64 words
The guidance system defined in claim 1, wherein the separate wave guide means each branch to the associated energy radiator element and to the variable impedance element, the branch containing the variable impedance element terminating in a resonant cavity wherein is mounted the variable impedance element effectively at a location substantially a whole number of electrical half wavelengths from the wave guide branch junction.
Claim 8
Dependent Claim
48 words
The guidance system defined in claim 6, wherein the variable impedance element comprises a solid state semiconductor device having electrical connections by which to pass electrical current through said device in order to vary the electrical current through said device in order to vary the electrical impedance thereof.
Claim 9
Dependent Claim
100 words
In an airplane instrument guidance system using overlapping antenna pattern directional beams, means for forming of such beams comprising a common source of microwave CW energy, a pair of radiators connected to be energized at substantially equal energy levels from said source, beam pattern forming means associated with said radiators, means including separate varible impedance elements in the respective connections between said source and radiators, and means to apply impedance-changing modulation signals of different relatively low frequencies to said elements of substantially equal amplitudes thereby to vary the CW energy envelopes at the respective modulation frequencies emitted from said radiators.
Claim 10
Dependent Claim
100 words
In an airplane instrument guidance system using overlapping antenna pattern directional beams, means for forming of such beams comprising a common source of microwave CW energy, a pair of radiators connected to be energized at substantially equal energy levels from said source, beam pattern forming means associated with said radiators, means including separate varible impedance elements in the respective connections between said source and radiators, and means to apply impedance-changing modulation signals of different relatively low frequencies to said elements of substantially equal amplitudes thereby to vary the CW energy envelopes at the respective modulation frequencies emitted from said radiators.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |