US4641970A
Expired / Lapsed
US
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Ring laser lock-in correction apparatus
Assignee: Honeywell Inc
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Filing: 1982-09-20
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Granted: 1987-02-10
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Expires: 2002-09-20
Abstract
Abstract In the present application, an apparatus is provided for altering a ring laser angular rate sensor in such a way that the phase difference between the propagating waves therein includes lock-in error compensation. The apparatus of the present invention obtains a compensation output signal derived from the intensity of one or both of the propagating waves related to sensor lock-in error which can be utilized to alter the behavior of the ring laser so as to alter the behavior of the phase difference between the counter-propagating waves so that lock-in error contained therein is corrected.
Inventors
- 👤 Harry A. Gustafson
- 👤 Wah L. Lim
- 👤 Francis H. Zeman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:31
CPC Classifications
G; G01; G01C; G01C19/00; G01C19/58; G01C19/64; G01C19/66; G01C19/68
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
208 words
A lock-in error correction apparatus for an angular rate sensor of the class wherein two waves propagate in opposite directions along a closed-loop path, each of said waves having an intensity associated therewith which includes intensity variations related to the coupling of energy of each of said waves into the other along said closed-loop path, wherein the frequency of each of said waves and corresponding phase rate related to the phase difference between said waves is a function of the rate of rotation of said closed-loop path, and wherein associated with said sensor is a phase rate error related to said coupling of energy, the apparatus comprising: phase rate biasing means having output means coupled to said sensor for altering said phase rate to provide a phase rate bias in response to at least a first compensation signal; and phase rate error detection means having input means responsive to at least one of said waves for providing a first compensation signal related to, at least in part, said phase rate error so as to direct said phase rate biasing means to produce said phase rate bias so as to have magnitude and sign which is substantially equal in magnitude, but opposite in sign, of said phase rate error.
Claim 2
Dependent Claim
208 words
A lock-in error correction apparatus for an angular rate sensor of the class wherein two waves propagate in opposite directions along a closed-loop path, each of said waves having an intensity associated therewith which includes intensity variations related to the coupling of energy of each of said waves into the other along said closed-loop path, wherein the frequency of each of said waves and corresponding phase rate related to the phase difference between said waves is a function of the rate of rotation of said closed-loop path, and wherein associated with said sensor is a phase rate error related to said coupling of energy, the apparatus comprising: phase rate biasing means having output means coupled to said sensor for altering said phase rate to provide a phase rate bias in response to at least a first compensation signal; and phase rate error detection means having input means responsive to at least one of said waves for providing a first compensation signal related to, at least in part, said phase rate error so as to direct said phase rate biasing means to produce said phase rate bias so as to have magnitude and sign which is substantially equal in magnitude, but opposite in sign, of said phase rate error.
Claim 3
Dependent Claim
36 words
The apparatus of claim 1 wherein said phase rate error detection means includes means responsive to said intensity variations of at least one of said waves for providing said at least a first compensation output signal.
Claim 4
Dependent Claim
46 words
The apparatus of claim 2 wherein said phase rate error detection means includes means for providing a signal being a function of the first derivative of said at least one wave intensity, said at least a first compensation signal being a function of said first derivative.
Claim 5
Dependent Claim
106 words
The apparatus of claim 1 wherein said phase rate error detection means includes signal means responsive to each of said wave intensities for providing a first output signal being a function of the first derivative with respect to time of the intensity of one of said waves and for providing a second output signal being a function of the first derivative with respect to time of the intensity of the other one of said waves, and providing said at least a first compensation signal being a function of said first output signal and a second compensation output signal being a function of said second output signal.
Claim 6
Dependent Claim
51 words
The apparatus of claim 4 wherein: said sensor includes first and second electrical currents for generating said waves; and said phase rate biasing means includes transducing means responsive to said first and second compensation signals for modulating said first and second electrical currents respectively and thereby produce said phase rate bias.
Claim 7
Dependent Claim
59 words
The apparatus of claim 4 wherein said signal means includes: a first photodetection means coupled to said input means for providing an intensity signal related to the intensity of one of said waves; and a second photodetection means coupled to said input means for providing an intensity signal related to the intensity of the other one of said waves.
Claim 8
Dependent Claim
57 words
The apparatus of claim 1 wherein: said phase rate biasing means further comprises means interposed in a signal path between said input means and said output means for providing phase adjustment and gain adjustment so that said phase rate bias is substantially equal in magnitude and in phase with said phase rate error but with opposite sign.
Claim 9
Dependent Claim
62 words
The apparatus of claim 1 wherein said phase rate error detection means input means is responsive to each of said waves and includes: combining means for combining a portion of each of said waves for providing a phase rate signal indicative of said phase rate; and means responsive to said phase rate signal for providing said at least a first compensation signal.
Claim 10
Dependent Claim
38 words
The apparatus of claim 8 wherein said combining means includes: means for heterodyning a portion of each of said waves for providing an interference pattern; photodetection means responsive to said interference pattern for providing said phase rate signal.
Claim 11
Dependent Claim
35 words
The apparatus of claim 1 wherein said phase rate biasing means includes means interposed in the path of said waves responsive to said at least a first compensation signal for providing said phase rate bias.
Claim 12
Dependent Claim
65 words
The apparatus of claim 1 wherein: said closed-loop path includes at least one wave reflecting means so as to define, at least in part, said closed-loop path; and said phase rate biasing means includes means for altering the position of said at least one wave reflecting means in response to said at least a first compensation signal so as to provide said phase rate bias.
Claim 13
Dependent Claim
55 words
The apparatus of claim 1 wherein said angular rate sensor includes: means for rotationally oscillating said sensor in a rotational mode, back and forth; and said phase rate biasing means includes means for modulating said rotational oscillations in response to said at least a first compensation signal so as to provide said phase rate bias.
Claim 14
Independent Claim
48 words
The apparatus of claims 4, 5, 8, 9, or 10 wherein said sensor includes a biasing means for introducing a frequency bias in at least one of said waves for preventing said waves from locking in to a common frequency for at least a majority of the time.
Claim 15
Dependent Claim
27 words
The apparatus of claim 13 wherein said biasing means includes means for oscillating said sensor in a rotational mode, back and forth for introducing said frequency bias.
Claim 16
Dependent Claim
34 words
The apparatus of claim 1 wherein said phase rate error detection means includes photodetection means coupled to said input means for providing an intensity signal related to the intensity of one of said waves.
Claim 17
Dependent Claim
15 words
The apparatus of claim 1 wherein said waves are in the form of laser beams.
Claim 18
Dependent Claim
16 words
The apparatus of claim 1 wherein said closed-loop path is in the shape of a triangle.
Claim 19
Dependent Claim
47 words
The apparatus of claim 3 wherein said phase rate error detecting means includes means for providing said at least one compensation signal having the form I 1 /I 1 where I 1 is said first derivative of the intensity of one of said waves I 1 .
Claim 20
Dependent Claim
61 words
The apparatus of claim 4 wherein said signal means further includes means for providing said at least a first compensation signal having the form of I 1 /I 1 and providing said second compensation signal having the form I 2 /I 2 where I 1 and I 2 are said first derivatives of wave intensities I 1 and I 2 respectively.
Claim 21
Independent Claim
60 words
The apparatus of claims 10, 11, or 12 wherein: said phase rate biasing means further comprises means interposed in a signal path between said input means and said output means for providing phase adjustment and gain adjustment so that said phase rate bias is substantially equal in magnitude and in phase with said phase rate error but with opposite sign.
Claim 22
Dependent Claim
36 words
The apparatus of claim 20 wherein said phase rate error detection means includes means responsive to said intensity variations of at least one of said waves for providing said at least a first compensation output signal.
Claim 23
Dependent Claim
64 words
The apparatus of claim 20 wherein said phase rate error detection means input means is responsive to each of said waves and includes: combining means for combining a portion of each of said waves for providing a phase rate signal indicative of said phase rate; and signal processing means responsive to said phase rate signal for providing said at least a first compensation signal.
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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) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |