CLOSED LOOP ATOMIC INERTIAL SENSOR

• US 20140022534A1
• Filed: 02/04/2013
• Published: 01/23/2014
• Est. Priority Date: 06/27/2012
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Strabley, Jennifer S., Salit, Kenneth, Salit, Mary K., Nelson, Karl D., Compton, Robert
• Granted Patent: US 9,030,655 B2
• Time in Patent Office: Days
• US Class Current: 356/72
• CPC Class Codes: G01C 19/58 Turn-sensitive devices without moving masses
• CPC Class Codes: G01C 21/166 Mechanical, construction or arrangement details of inertial navigation systems
• CPC Class Codes: G01C 21/183 Compensation of inertial measurements, e.g. for temperature effects
• CPC Class Codes: G01P 15/08 with conversion into electric or magnetic values
• CPC Class Codes: G01P 15/093 by photoelectric pick-up
• CPC Class Codes: G01P 21/00 Testing or calibrating of apparatus or devices covered by the preceding groups

Abstract

An apparatus for inertial sensing is provided. The apparatus comprises at least one atomic inertial sensor, and one or more micro-electrical-mechanical systems (MEMS) inertial sensors operatively coupled to the atomic inertial sensor. The atomic inertial sensor and the MEMS inertial sensors operatively communicate with each other in a closed feedback loop.

Claims

1. An apparatus for inertial sensing, the apparatus comprising:

at least one atomic inertial sensor; and

one or more micro-electrical-mechanical systems (MEMS) inertial sensors operatively coupled to the atomic inertial sensor;

wherein the atomic inertial sensor and the MEMS inertial sensors operatively communicate with each other in a closed feedback loop.

2. The apparatus of claim 1, wherein the atomic inertial sensor comprises an atomic interferometer.

3. The apparatus of claim 1, wherein the MEMS inertial sensors comprise at least one MEMS gyroscope and at least one MEMS accelerometer.

4. The apparatus of claim 3, further comprising a plurality of laser devices in optical communication with the atomic inertial sensor.

5. The apparatus of claim 4, wherein the laser devices comprise distributed Bragg reflector laser diodes or vertical-cavity surface-emitting lasers.

6. The apparatus of claim 4, wherein the laser devices comprise:

a master laser that emits a first beam and a second beam;

a first slave laser that emits a first beam and a second beam; and

a second slave laser that emits a first beam and a second beam.

7. The apparatus of claim 6, further comprising one or more optical components that direct the first beam from the master laser and the first beam from the first slave laser to interfere with one another and generate a first radio frequency signal at a first photodetector.

8. The apparatus of claim 7, further comprising one or more optical components that direct the second beam from the master laser and the first beam from the second slave laser to interfere with one another and generate a second radio frequency signal at a second photodetector.

9. The apparatus of claim 8, wherein the MEMS gyroscope and the MEMS accelerometer are each operatively coupled to a calibration unit that corrects for MEMS bias and scale factor errors based on a comparison of atomic data from the atomic inertial sensor.

10. The apparatus of claim 9, wherein the calibration unit converts a rotation rate signal received from the MEMS gyroscope into a first frequency offset, and converts an acceleration signal received from the MEMS accelerometer into a second frequency offset.

11. The apparatus of claim 10, further comprising a frequency sweep generator that receives the first and second frequency offsets from the calibration unit.

12. The apparatus of claim 11, further comprising a first mixer that receives a first frequency sweep signal from the frequency sweep generator and receives the first radio frequency signal from the first photodetector, wherein the first mixer compares the first frequency sweep signal to the first radio frequency signal and generates a frequency offset lock signal that is sent to a first low pass filter.

13. The apparatus of claim 12, wherein the first low pass filter sends a filtered signal to the first slave laser to adjust its frequency such that the second beam emitted by the first slave laser is at an adjusted frequency and is directed to a first input of the atomic inertial sensor.

14. The apparatus of claim 13, further comprising a second mixer that receives a second frequency sweep signal from the frequency sweep generator and receives the second radio frequency signal from the second photodetector, wherein the second mixer compares the second frequency sweep signal to the second radio frequency signal and generates a frequency offset lock signal that is sent to a second low pass filter.

15. The apparatus of claim 14, wherein the second low pass filter sends a filtered signal to the second slave laser to adjust its frequency such that the second beam emitted by the second slave laser is at an adjusted frequency and is directed to a second input of the atomic inertial sensor.

16. A method for inertial sensing, the method comprising:

providing an inertial sensing apparatus comprising;

at least one atomic inertial sensor; and

a plurality of micro-electrical-mechanical systems (MEMS) inertial sensors in operative communication with the atomic inertial sensor, wherein the MEMS inertial sensors comprise at least one MEMS gyroscope and at least one MEMS accelerometer; and

wherein the atomic inertial sensor and the MEMS inertial sensors operatively communicate with each other in a closed feedback loop;

directing a first beam from a master laser and a first beam from a first slave laser to interfere with one another and generate a first radio frequency signal;

directing a second beam from the master laser and a first beam from a second slave laser to interfere with one another and generate a second radio frequency signal;

converting a rotation rate signal received from the MEMS gyroscope into a first frequency offset;

converting an acceleration signal received from the MEMS accelerometer into a second frequency offset;

generating a frequency sweep signal from the first and second frequency offsets;

comparing the frequency sweep signal to the first radio frequency signal to generate a first frequency offset lock signal;

comparing the frequency sweep signal to the second radio frequency signal to generate a second frequency offset lock signal;

sending the first frequency offset lock signal to the first slave laser to adjust its frequency such that the first slave laser emits a second beam at an adjusted frequency that is directed to the atomic inertial sensor; and

sending the second frequency offset lock signal to the second slave laser to adjust its frequency such that the second slave laser emits a second beam at an adjusted frequency that is directed to the atomic inertial sensor.

17. The method of claim 16, wherein the atomic inertial sensor comprises an atomic interferometer.

18. The method of claim 16, further comprising correcting outputs of the MEMS gyroscope and MEMS accelerometer for MEMS bias and scale factor errors based on a comparison of atomic data from the atomic inertial sensor.

19. An inertial sensing apparatus comprising:

at least one atomic inertial sensor comprising an atomic interferometer;

a plurality of micro-electrical-mechanical systems (MEMS) inertial sensors in operative communication with the atomic inertial sensor, wherein the MEMS inertial sensors comprise at least one MEMS gyroscope and at least one MEMS accelerometer; and

a plurality of laser devices in optical communication with the atomic inertial sensor;

wherein the atomic inertial sensor and the MEMS inertial sensors operatively communicate with each other in a closed feedback loop.

20. The apparatus of claim 19, further comprising a calibration unit operatively coupled to the MEMS gyroscope and the MEMS accelerometer, the calibration unit configured to correct for MEMS bias and scale factor errors based on a comparison of atomic data from the atomic inertial sensor.