US3861220A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microwave gyro
Assignee: United States Department of the Navy
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Filing: 1973-10-26
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Granted: 1975-01-21
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Expires: 1993-10-26
Abstract
Abstract A system for measuring angular velocity by comparing the frequencies of oppositely-directed microwave signals. In one embodiment, a gyro is disclosed in which a circular waveguide loop is used and oppositely directed signals are read out separately for comparison of their frequencies and phases. Angular velocity of the gyro about an axis perpendicular to the plane of the loop results in a difference in frequency between the two output signals. The difference in phase between these signals, being proportional to the time integral of the frequency difference, is thus proportional to the angular position of the gyro.
Inventors
- 👤 Jr Harry D Felsenthal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:25
CPC Classifications
G; G01; G01C; G01C19/00; G01C19/58; G01C19/64; G01P; G01P3/00; G01P3/42; G01P3/44
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
280 words
Microwave gyro apparatus for accurately determining angular position, comprising: a. at least one waveguide loop which lies in a plane perpendicular to the axis of rotation; b. a plurality of amplifier means each connected to respective waveguide terminations for generating and maintaining different continuous wave signals of which at least one of said signals travels in an opposite direction to at least one another signal around said at least one waveguide loop, each said amplifier means having suitable bandwidth for selecting a desired integral number of wavelengths in the waveguide loop; c. the exact frequency of said continuous wave signals in each direction also being controlled by waveguide loop effective length; d. directional couplers coupling said waveguide terminations with said amplifier means, said continuous wave signals in both directions being isolated from each other by said directional couplers together with said amplifier means; e. attenuation means connected to the output of each said amplifier means for absorbing unwanted oppositely directed signals to prevent backscatter and frequency locking, and to increase amplifier gains; f. frequency reduction means for lowering the frequencies of said continuous wave signals prior to phase comparison, respective continuous wave signals from the waveguide being fed to said frequency reduction means via said directional couplers; g. phase comparison means coNnected to two respective outputs of said frequency reduction means for determining the gyro angular position, angular velocity of the gyro apparatus about the axis of rotation resulting in a difference in frequency between two output signals, the difference between the two output signals being proportional to the time integral of the frequency difference and thus proportional to the angular position of the gyro relative to a reference position.
Claim 2
Dependent Claim
280 words
Microwave gyro apparatus for accurately determining angular position, comprising: a. at least one waveguide loop which lies in a plane perpendicular to the axis of rotation; b. a plurality of amplifier means each connected to respective waveguide terminations for generating and maintaining different continuous wave signals of which at least one of said signals travels in an opposite direction to at least one another signal around said at least one waveguide loop, each said amplifier means having suitable bandwidth for selecting a desired integral number of wavelengths in the waveguide loop; c. the exact frequency of said continuous wave signals in each direction also being controlled by waveguide loop effective length; d. directional couplers coupling said waveguide terminations with said amplifier means, said continuous wave signals in both directions being isolated from each other by said directional couplers together with said amplifier means; e. attenuation means connected to the output of each said amplifier means for absorbing unwanted oppositely directed signals to prevent backscatter and frequency locking, and to increase amplifier gains; f. frequency reduction means for lowering the frequencies of said continuous wave signals prior to phase comparison, respective continuous wave signals from the waveguide being fed to said frequency reduction means via said directional couplers; g. phase comparison means coNnected to two respective outputs of said frequency reduction means for determining the gyro angular position, angular velocity of the gyro apparatus about the axis of rotation resulting in a difference in frequency between two output signals, the difference between the two output signals being proportional to the time integral of the frequency difference and thus proportional to the angular position of the gyro relative to a reference position.
Claim 3
Dependent Claim
14 words
Apparatus as in claim 1 wherein said amplifier means are unidirectional narrow-band RF amplifiers.
Claim 4
Dependent Claim
14 words
Apparatus as in claim 1 wherein matched waveguide terminations are used to minimize reflections.
Claim 5
Dependent Claim
23 words
Apparatus as in claim 1 wherein the clockwise and counterclockwise path lengths in the waveguide loop are exactly equalized at zero angular rate.
Claim 6
Dependent Claim
14 words
Apparatus as in claim 1 wherein said at least one waveguide loop is circular.
Claim 7
Dependent Claim
14 words
Apparatus as in claim 1 wherein said at least one waveguide loop is rectangular.
Claim 8
Dependent Claim
19 words
Apparatus as in claim 1 wherein the sensitivity of the gyro increases by increasing the size of the loop.
Claim 9
Dependent Claim
102 words
Apparatus as in claim 1 wherein: a. two waveguide loops are used; b. the first waveguide loop having the higher frequency signal of its opposing continuous wave signals travelling in a clockwise direction, and the second waveguide loop having its higher frequency signal travelling in a counterclockwise direction; c. first and second mixer means for combining the two output frequencies from each of said first and second loops, respectively, to produce two difference frequencies which differ slightly from each other when the apparatus is rotating; d. said two difference frequencies then being fed to said frequency reduction means prior to phase comparison.
Claim 10
Dependent Claim
18 words
Apparatus as in claim 8 wherein said two waveguide loops are formed from low expansion dimensionally stable material.
Claim 11
Dependent Claim
113 words
Apparatus as in claim 1 wherein: a. a single waveguide loop is used; b. three different continuous wave signal frequencies being circulated in said single loop by respective amplifiers; c. the highest and lowest of said three continuous wave frequencies being circulated in one direction, and the center frequency being circulated in the opposite direction; d. first and second mixer means for combining said highest and center output frequencies, and said lowest and center output frequencies, respectively, from said waveguide loop to produce two difference frequencies which differ from each other when the apparatus is rotated; e. said two difference frequencies then being fed to said frequency reduction means prior to phase comparison.
Claim 12
Dependent Claim
199 words
A microwave gyro apparatus for accurately determining angular position, comprising: a. at least one waveguide loop which lies in a plane perpendicular to the axis of rotation; b. a plurality of amplifier means connected to respective waveguide terminations for generating and maintaining a carrier frequency and an amplitude modulation frequency on said carrier frequency travelling in one direction around said at least one waveguide loop; c. said amplifier means having suitable bandwidth whereby a desired number of wavelengths in the waveguide loop are selected, the exact frequency of said carrier and modulated signals also being controlled by the waveguide loop effective length; d. a demodulator included in said amplifier means for recovering only the amplitude modulation output frequency from the carrier; e. phase comparison means to which respective carrier and amplitude modulation output frequencies from the said waveguide are fed for determining the gyro angular position, angular velocity of the gyro apparatus about the axis of rotation resulting in a difference in frequency between two output signals, the difference between the two output signals being proportional to the time integral of the frequency difference and thus proportional to the angular position of the gyro relative to a reference pOsition.
Claim 13
Dependent Claim
199 words
A microwave gyro apparatus for accurately determining angular position, comprising: a. at least one waveguide loop which lies in a plane perpendicular to the axis of rotation; b. a plurality of amplifier means connected to respective waveguide terminations for generating and maintaining a carrier frequency and an amplitude modulation frequency on said carrier frequency travelling in one direction around said at least one waveguide loop; c. said amplifier means having suitable bandwidth whereby a desired number of wavelengths in the waveguide loop are selected, the exact frequency of said carrier and modulated signals also being controlled by the waveguide loop effective length; d. a demodulator included in said amplifier means for recovering only the amplitude modulation output frequency from the carrier; e. phase comparison means to which respective carrier and amplitude modulation output frequencies from the said waveguide are fed for determining the gyro angular position, angular velocity of the gyro apparatus about the axis of rotation resulting in a difference in frequency between two output signals, the difference between the two output signals being proportional to the time integral of the frequency difference and thus proportional to the angular position of the gyro relative to a reference pOsition.
Claim 14
Dependent Claim
66 words
Apparatus as in claim 11 whereby the amplifier means for generating the carrier frequency has broad bandwidth to accommodate sidebands and also includes narrow band filter means whereby only the desired oscillation mode of said carrier frequency is maintained in the loop; an integral number of half-cycles of modulation and carrier oscillation being maintained in the waveguide by controlling the effective length of the waveguide loop.
Claim 15
Dependent Claim
17 words
Apparatus in claim 11 whereby said amplifier means also includes means for amplifying the amplitude modulated frequency.
Claim 16
Dependent Claim
23 words
Gyro apparatus as in claim 11 wherein frequency multiplier means is provided to raise the amplitude modulation output frequency by a desired factor.
Claim 17
Dependent Claim
31 words
Gyro apparatus as in claim 11 wherein frequency reduction means is provided for lowering the respective carrier and amplitude modulation output frequencies prior to being fed to said phase comparison means.
Claim 18
Dependent Claim
95 words
Gyro apparatus as in claim 11 wherein: a. two waveguide loops are used; b. the modulation signals traversing the two loops are in opposite directions; c. a first mixer means provided for combining the first loop carrier output frequency and the second loop amplitude modulation output frequency, and a second mixer means for combining the second loop carrier output frequency and the first loop amplitude modulation output frequency, to produce two difference frequencies which differ from each other when the apparatus is rotating; d. said two difference frequencies being fed to said phase comparison means.
Claim 19
Dependent Claim
28 words
Gyro apparatus wherein two apparatuses as in claim 11 are used and the outputs of the two phase comparison means are compared in a third phase comparison means.
Claim 20
Dependent Claim
26 words
Gyro apparatus as in claim 11 wherein a plurality of waveguide loops are used and wherein said plurality of loops have their lengths substantially in common.
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) | 1978-01-20 | 1978-07-22 | 1979-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-20 | 1982-07-22 | 1983-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-20 | 1986-07-22 | 1987-01-21 | $7700.00 | Window Closed / Lapsed |