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Patent US3683281A successfully refreshed from Google Patents.
US3683281A
Expired / Lapsed
US
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Crab angle sensing system
Assignee: Scanwell Laboratories Inc
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Filing: 1969-10-13
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Granted: 1972-08-08
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Expires: 1989-10-13
Abstract
Abstract A six-sided antenna of substantially rectangular cross-section made up of a thin metal foil firmly attached to a base of insulating material on four of the six sides. One side of the base not covered by foil is attached to the airframe of an aircraft at approximately the plane of symmetry of the upper and lower halves of the airframe, while the other uncovered side is faced forward toward the nose. A second antenna is similarly constructed and positioned so that the two antennas may each receive signals from a ground source in order to determine crab angle. A second source, airborne, supplies equal signals to the respective antennas in order to provide a check on the accuracy of the reading from the ground source. Signal processing circuitry, including plural modulating and demodulating elements, are employed for determining crab angle, and for verifying system operability.
Inventors
- 👤 Chester B Watts Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:15
CPC Classifications
H; H01; H01Q; H01Q13/00; H01Q13/10; H01Q13/106; G; G01; G01S; G01S1/00; G01S1/02; G01S3/00; G01S3/02; G01S3/14; G01S3/46; H01Q9/00; H01Q9/04; H01Q9/0407; H01Q9/0421
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
268 words
A crab angle determining signal processing circuit employing circuit operability verification means, said circuit being operable in conjunction with an incoming source signal, comprising first and second separate antennas for receiving the incoming signals, a first modulator, signal producing means for providing a modulating signal of frequency F3 connected to said first modulator, means coupling the output of said first modulator to each of said two separate antennas for providing each antenna with an identical signal, second and third modulating means, a source of signal of frequency F1, a source of signal of frequency F2, means connecting said first antenna to said second modulating means wherein the composite received signal comprising the output of said first modulator and the received incoming signal is modulated by the signal of frequency F1 generated by said source thereof, means connecting said second antenna to said third modulating means wherein the composite received signal comprising the output of said first modulator and the received incoming signal is modulated by a signal of frequency F2 generated by said source thereof, a first filter circuit, first detecting means connecting said second and third modulating means to said first filter circuit wherein the frequency F3 with its attendant modulation at frequency F1 and F2 is recovered, second detector means connected to said first filter circuit for recovering said signals of frequencies F1 and F2, and indicating means connected to said second detecting means for monitoring said F1 and F2 signals and for signaling the difference therebetween, whereby an indication of improper circuit operation is given whenever said indicating means indicates that the signals are unequal.
Claim 2
Dependent Claim
268 words
A crab angle determining signal processing circuit employing circuit operability verification means, said circuit being operable in conjunction with an incoming source signal, comprising first and second separate antennas for receiving the incoming signals, a first modulator, signal producing means for providing a modulating signal of frequency F3 connected to said first modulator, means coupling the output of said first modulator to each of said two separate antennas for providing each antenna with an identical signal, second and third modulating means, a source of signal of frequency F1, a source of signal of frequency F2, means connecting said first antenna to said second modulating means wherein the composite received signal comprising the output of said first modulator and the received incoming signal is modulated by the signal of frequency F1 generated by said source thereof, means connecting said second antenna to said third modulating means wherein the composite received signal comprising the output of said first modulator and the received incoming signal is modulated by a signal of frequency F2 generated by said source thereof, a first filter circuit, first detecting means connecting said second and third modulating means to said first filter circuit wherein the frequency F3 with its attendant modulation at frequency F1 and F2 is recovered, second detector means connected to said first filter circuit for recovering said signals of frequencies F1 and F2, and indicating means connected to said second detecting means for monitoring said F1 and F2 signals and for signaling the difference therebetween, whereby an indication of improper circuit operation is given whenever said indicating means indicates that the signals are unequal.
Claim 3
Dependent Claim
50 words
The circuit of claim 1 wherein said first modulator coupling means comprise two auxiliary probes, said two antennas each being coupled to a respective one of said auxiliary probes, said antennas each including a main antenna probe each connected to a different one of said second and third modulating means.
Claim 4
Dependent Claim
63 words
A combination as in claim 1 further comprising additional fIlter means connected to said first detecting means for separately recovering the modulation products of frequency F1 and F2 impressed on the source signal by said second and third modulating means, and indicating means responsive to the difference in amplitude between said recovered signals of frequency F1 and F2, to thereby determine crab angle.
Claim 5
Dependent Claim
48 words
The circuit of claim 2 wherein the two said antennas are mounted upon opposite sides of the airframe of an aircraft so that said antennas are approximately centered about a plane above and below which the airframe has symmetry and substantially disposed at a plane of vertical symmetry.
Claim 6
Dependent Claim
75 words
The circuit of claim 4 wherein the said two antennas each comprise a thin layer of metal foil and a dielectric base, said base including plural sides, said foil surrounding said base on all but two sides thereof and firmly attached thereto, one side not covered by said foil being attached to said airframe, and the other side not covered by said foil being mounted on the airframe as the forward side of the antenna.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |