Systems and methods for angular rate and position measurement

• US 7,938,004 B1
• Filed: 03/21/2008
• Issued: 05/10/2011
• Est. Priority Date: 03/21/2008
• Status: Expired due to Fees

• Current Assignee: David A. Bittle, Gary T. Jimmerson, James P. Brunsch Jr, Julian L. Cothran, Russell S. Garner
• Original Assignee: David A. Bittle, Gary T. Jimmerson, James P. Brunsch Jr, Julian L. Cothran, Russell S. Garner
• Inventors: Garner, Russell S., Brunsch, James P. Jr., Bittle, David A., Cothran, Julian L., Jimmerson, Gary T.
• Primary Examiner(s): NOLAND, THOMAS
• Application Number:
  US12/053,402
• Time in Patent Office: 1,145 Days
• Field of Search: 73495-497, 7350403-50404, 735/041.2, 73509-511, 735/26, 73 137- 138, 701/4, 701/7, 701/10, 701/13, 702 92- 96, 702/141, 702144-145, 702150-153
• US Class Current: 73/509
• CPC Class Codes: G01C 21/166 Mechanical, construction or arrangement details of inertial navigation systems
• CPC Class Codes: G01C 21/188 for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems

Abstract

Disclosed herein are systems and methods of angular rate and position measurement that combine a small footprint with hardening and isolation technologies that allow it to function in acceleration, angular rate, noise and vibration environments that cause other gyroscopes to either fail or to produce erroneous outputs. An example embodiment contains a triad of accelerometers, a triad of gyroscopes, analog and digital ancillary electronics and a processor housed within a housing which is also filled with vibration reducing encapsulating compound. The disclosed systems and methods of angular rate and position measurement are capable of measuring and correcting internal errors and perturbations caused by the longitudinal and angular accelerations and temperature excursions of aerospace vehicles, isolating the gyroscope elements from the effects of acoustic noise and vibration, and accurately measuring the relatively small pitch and yaw oscillations of the vehicle in its flight path trajectory.

Claims

1. A system comprising:

a plurality of micro electro mechanical system (MEMS) gyroscopes;

a plurality of MEMS accelerometers;

at least one environmental sensor;

a processor communicatively coupled to the plurality of MEMS gyroscopes and the plurality of MEMS accelerometers;

an enclosure configured to enclose the plurality of MEMS gyroscopes, the plurality of MEMS accelerometers, and the at least one environmental sensor; and

mechanical isolators positioned at least one mounting location of the enclosure;

the mechanical isolators comprising elastomeric grommet isolators; and

encapsulent potting for filling the enclosure,

wherein the processor

calculates a correction value using outputs from the plurality of MEMS gyroscopes, the plurality of MEMS accelerometers, and the at least one environmental sensor; and

applies the correction value to an output of the system.

2. The system of claim 1, wherein the correction value is calculated using at least one of

measured sensitivities of at least one of the plurality of MEMS gyroscopes;

and

measured environmental values from the at least one environmental sensor.

3. The system of claim 1, wherein the enclosure is attached to a movable object.

4. The system of claim 3, wherein the movable object is an aerospace vehicle.

5. The system of claim 3, wherein the plurality of MEMS gyroscopes comprises at least three MEMS gyroscopes each aligned parallel with a plane normal to a rotational axis of the movable object.

6. The system of claim 1, wherein the plurality of MEMS accelerometers comprises at least three MEMS accelerometers aligned mutually orthogonally.

7. A system comprising:

a plurality of micro electro mechanical system (MEMS) gyroscopes;

a plurality of MEMS accelerometers;

at least one environmental sensor;

a processor communicatively coupled to the plurality of MEMS gyroscopes and the plurality of MEMS accelerometers;

an acoustic foam enclosure configured to enclose the plurality of MEMS gyroscopes, the plurality of MEMS accelerometers, and the at least one environmental sensor; and

encapsulent potting for filling the acoustic foam enclosure,

wherein the processor

calculates a correction value using outputs from the plurality of MEMS gyroscopes, the plurality of MEMS accelerometers, and the at least one environmental sensor; and

applies the correction value to an output of the system.

8. A system comprising:

an aerospace vehicle; and

a system for measuring angular rate of motion comprising;

a plurality of micro electro mechanical system (MEMS) gyroscopes;

a plurality of MEMS accelerometers;

at least one environmental sensor;

a processor communicatively coupled to the MEMS gyroscope and MEMS accelerometers;

an acoustic foam enclosure configured to enclose the plurality of gyroscopes, the plurality of accelerometers, and the at least one temperature sensor; and

encapsulent potting filling the enclosure,

wherein the processor

calculates a correction value using outputs from the plurality of MEMS gyroscopes, the plurality of MEMS accelerometers, and the at least one environmental sensor; and

applies the correction value to an output of the system.

9. The system of claim 8, wherein the correction value is calculated using at least one of

a measured sensitivity of at least one of the plurality of MEMS gyroscopes;

a measured sensitivity of at least one of the plurality of MEMS accelerometers; and

a measured environmental value from the at least one environmental sensor.

10. The system of claim 8, further comprising mechanical isolators positioned at least one mounting location of the enclosure.

11. The system of claim 8, wherein the plurality of MEMS accelerometers comprises at least three MEMS accelerometers aligned mutually orthogonally.

12. The system of claim 8, wherein the plurality of MEMS gyroscopes comprises at least three MEMS gyroscopes each aligned parallel with a plane that contains a rotational axis of the vehicle.

13. The system of claim 8, wherein the processor is a digital signal processor.