Determining and compensating for modulator dynamics in interferometric fiber-optic gyroscopes

• US 7,872,758 B2
• Filed: 01/22/2008
• Issued: 01/18/2011
• Est. Priority Date: 01/22/2007
• Status: Active Grant

• Current Assignee: Charles Stark Draper Laboratory Incorporated
• Original Assignee: Charles Stark Draper Laboratory Incorporated
• Inventors: Soucy, Matthew, Smith, Stephen P., Ward, Paul A., Zarinetchi, Farhad, Kishinevsky, Michael
• Primary Examiner(s): LEE, HWA S
• Application Number:
  US12/018,016
• Publication Number:
  US 20090201510A1
• Time in Patent Office: 1,092 Days
• Field of Search: 356459-476
• US Class Current: 356/460
• CPC Class Codes: G01C 19/726 Phase nulling gyrometers, i.e. compensating the Sagnac phase shift in a closed loop system

Abstract

Determining linear modulator dynamics in an interferometric fiber-optic gyroscope may be accomplished by applying a stimulus at a point within the gyroscope, observing a response in an output of the gyroscope, and determining, from the observed response, the linear modulator dynamics.

Claims

1. A method for determining, in-situ, linear modulator dynamics in an interferometric fiber-optic gyroscope, comprising:

applying a first signal to a phase modulator located within an interferometric fiber-optic gyroscope;

observing a response in an output of the interferometric fiber-optic gyroscope to the first signal; and

determining, from the observed response, linear modulator dynamics introduced by the phase modulator,

wherein determining the linear modulator dynamics comprises determining at least one of (i) one pole or (ii) one zero of the phase modulator.

2. The method of claim 1, wherein determining the linear modulator dynamics further comprises determining a high frequency gain of the phase modulator.

3. The method of claim 1 further comprising compensating for the linear modulator dynamics.

4. The method of claim 3, wherein the linear modulator dynamics are compensated by pre-filtering a drive signal before it drives the phase modulator.

5. The method of claim 4, wherein the drive signal is multiplied by an inverse of a transfer function for the phase modulator.

6. The method of claim 3, wherein the compensation of the linear modulator dynamics occurs while the interferometric fiber-optic gyroscope is also performing functions unrelated to the compensation.

7. The method of claim 1, wherein the first signal applied to the phase modulator comprises a step.

8. A method for determining, in-situ, linear modulator dynamics in an interferometric fiber-optic gyroscope, comprising:

applying a stimulus at a point within an interferometric fiber-optic gyroscope;

observing a response in an output of the interferometric fiber-optic gyroscope to the stimulus; and

determining, from the observed response, linear modulator dynamics present in the interferometric fiber-optic gyroscope,

wherein determining the linear modulator dynamics comprises determining at least one of (i) one pole or (ii) one zero of a phase modulator in the interferometric fiber-optic gyroscope.

9. The method of claim 8, wherein determining the linear modulator dynamics further comprises determining a high frequency gain of the phase modulator in the interferometric fiber-optic gyroscope.

10. The method of claim 8 further comprising compensating for the linear modulator dynamics.

11. The method of claim 10, wherein the linear modulator dynamics are compensated by pre-filtering a drive signal before it drives the phase modulator in the interferometric fiber-optic gyroscope.

12. The method of claim 11, wherein the drive signal is multiplied by an inverse of transfer function for the phase modulator.

13. The method of claim 10, wherein the compensation of the linear modulator dynamics occurs while the interferometric fiber-optic gyroscope is also performing functions unrelated to the compensation.