Miniaturized inertial measurement and navigation sensor device and associated methods

• US 8,887,566 B1
• Filed: 05/31/2011
• Issued: 11/18/2014
• Est. Priority Date: 05/28/2010
• Status: Expired due to Fees

• Current Assignee: Tanenhaus and Associates, Inc.
• Original Assignee: Tanenhaus and Associates, Inc.
• Inventors: Tanenhaus, Martin E.
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US13/149,124
• Time in Patent Office: 1,267 Days
• Field of Search: 735/044, 702/151, 702/145
• US Class Current: 73/504.04
• CPC Class Codes: G01C 19/02 Rotary gyroscopes
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01K 13/00 Thermometers specially adapted for specific purposes
• CPC Class Codes: G01P 15/14 by making use of gyroscopes gyroscopes per se G01C19/00

Abstract

A miniaturized inertial measurement and navigation sensor device and a flexible, simplified GUI operating in real time are provided to create an optimum IMU/INS. The IMU includes multiple angle rate sensors, accelerometers, and temperature sensors to provide stability device. A navigation GUI tests algorithms prior to embedding them in real-time IMU hardware. MATLAB code is converted to C++ code tailored for real-time operation. Any point in the algorithm suite structure can be brought out as a data channel to investigate the pattern of operation. The data channels permit zooming in on the algorithm'"'"'s operation for the open-loop angle, velocity and position drift measurements for bias-compensated channels. The GUI can be used to verify results of an extended Kalman filter solution as well as the implementation of the real-time attitude and heading reference system. When the code has been verified, it is compiled and downloaded into a target processor.

Claims

1. An inertial measurement unit comprising:

a base;

three assemblies mounted in orthogonal fashion to the base in axial planar alignment, each assembly comprising;

eight angle rate sensors mounted to be aligned with each other in the assembly;

eight temperature sensors mounted in the assembly, each sensor for sensing a temperature of a corresponding angle rate sensor; and

eight accelerometers mounted in the assembly;

a signal processor mounted on the base, the signal processor adapted for signal communication with the eight angle rate sensors, the eight temperature sensors, and the eight accelerometers; and

an application resident on the signal processor for;

improving a precision of the signals from the eight angle rate sensors in each assembly with the use of signals from the respective eight temperature sensors;

fusing the improved-precision signals from the eight angle rate sensors in each assembly to provide three respective virtual gyro data channels; and

fusing signals from the eight accelerometers in each assembly to provide three respective virtual accelerometer data channels.

2. The inertial measurement unit recited in claim 1, further comprising:

an exoskeleton having an interior in which are positioned the base and signal outputting means; and

potting material sufficient to substantially fill spaces in the exoskeleton interior not occupied by the base and the signal outputting means.

3. The inertial measurement unit recited in claim 1, further comprising three assembly cases, in an interior of each of which is positioned one assembly, the assembly cases orthogonally mountable to the base.

4. The inertial measurement unit recited in claim 3, further comprising potting material sufficient to substantially fill spaces in the assembly case interiors not occupied by the assembly positioned therewithin.

5. The inertial measurement unit recited in claim 4, further comprising:

an exoskeleton having an interior in which are positioned the assembly cases and the base; and

potting material sufficient to substantially fill spaces in the exoskeleton interior not occupied by the assembly cases, the base, and the signal outputting means.

6. The inertial measurement unit recited in claim 1, further comprising a denoising filter resident on the signal processor for substantially eliminating high-frequency spikes in the three virtual gyro data channels and the three virtual accelerometer data channels to provide three denoised virtual gyro data channels and three denoised virtual accelerometer data channels.

7. The inertial measurement unit recited in claim 6, further comprising a Kalman-filtered bias compensation algorithm resident on the signal processor for substantially removing gyro bias from the three denoised virtual gyro data channels.

8. The inertial measurement unit recited in claim 1, wherein each assembly comprises a unitary, substantially planar assembly base comprising four sectors, each sector having mounted thereon two of the eight angle rate sensors, two of the eight temperature sensors, and two of the eight accelerometers, the sectors foldable relative to each other to form an approximately cubic assembly.

9. The inertial measurement unit recited in claim 8, wherein the sectors are substantially linearly arrayed, and the sectors are foldable in accordion fashion.

10. The inertial measurement unit recited in claim 8, further comprising three assembly cases, in an interior of each of which is positioned one assembly, the assembly cases orthogonally mountable to the base, and wherein the base comprises a unitary, substantially planar processor base foldable about the assembly cases.

11. A method for making an inertial measurement unit comprising:

mounting to a base three assemblies in orthogonal fashion to the base in axial planar alignment, each assembly comprising;

eight angle rate sensors mounted to be aligned with each other in the assembly;

eight temperature sensors mounted in the assembly, each sensor for sensing a temperature of a corresponding angle rate sensor; and

eight accelerometers mounted in the assembly;

mounting a signal processor on the base, the signal processor adapted for signal communication with the eight angle rate sensors, the eight temperature sensors, and the eight accelerometers;

installing an application on the signal processor for;

improving a precision of the signals from the eight angle rate sensors in each assembly with the use of signals from the respective eight temperature sensors;

fusing the improved-precision signals from the eight angle rate sensors in each assembly to provide three respective virtual gyro data channels; and

fusing signals from the eight accelerometers in each assembly to provide three respective virtual accelerometer data channels; and

mounting a signal output device on the base, for outputting signals from the signal processor to a remote processor for providing data enabling a calculation of at least one of a change in attitude, a change in position, a change in angular rate, a change in velocity, and a change in acceleration of the unit over a plurality of finite time increments.

12. The method recited in claim 11, further comprising:

positioning the base and the signal output device within an interior of an exoskeleton; and

substantially filling spaces in the exoskeleton interior not occupied by the base and the signal output device with potting material.

13. The method recited in claim 11, further comprising positioning one assembly in each of three assembly cases, the assembly cases orthogonally mountable to the base.

14. The method recited in claim 13, further comprising substantially filling spaces in the assembly cases interiors not occupied by the respective assembly positioned therewithin with potting material.

15. The method recited in claim 14, further comprising:

positioning the assembly cases and the base within an interior of an exoskeleton; and

substantially filling spaces in the exoskeleton interior not occupied by the assembly cases, the base, and the signal outputting means with potting material.

16. The method recited in claim 11, further comprising installing a denoising filter on the signal processor for substantially eliminating high-frequency spikes in the three virtual gyro data channels and the three virtual accelerometer data channels to provide three denoised virtual gyro data channels and three denoised virtual accelerometer data channels.

17. The method recited in claim 16, further comprising installing a Kalman-filtered bias compensation algorithm on the signal processor for substantially removing gyro bias from the three denoised virtual gyro data channels.

18. The method recited in claim 11, wherein the assembly mounting comprises:

providing for each assembly a unitary, substantially planar assembly base comprising four sectors;

mounting on each sector two of the eight angle rate sensors, two of the eight temperature sensors, and two of the eight accelerometers; and

folding the sectors relative to each other to form an approximately cubic assembly.

19. The method recited in claim 18, wherein the sectors are substantially linearly arrayed, and the folding comprises folding the sectors in accordion fashion.

20. The method recited in claim 18, wherein the assembly mounting comprises:

positioning each of the three assemblies in an interior of a respective assembly case;

mounting the assembly cases orthogonally to the base; and

folding the about the assembly cases.

21. A method for providing a inertial measurement data on a substrate comprising:

receiving a signal from each of three assemblies positioned in orthogonal fashion in axial planar alignment, each assembly comprising;

eight angle rate sensors mounted to be aligned with each other in the assembly;

eight temperature sensors mounted in the assembly, each sensor for sensing a temperature of a corresponding angle rate sensor; and

eight accelerometers mounted in the assembly;

improving a precision of the signals from the eight angle rate sensors in each assembly with the use of signals from the respective eight temperature sensors;

fusing the improved-precision signals from the eight angle rate sensors in each assembly to provide three respective virtual gyro data channels;

fusing signals from the eight accelerometers in each assembly to provide three respective virtual accelerometer data channels; and

transmitting the fused signals from the three virtual gyro data channels, the three virtual accelerometer data channels, and the signal processor to a remote processor for providing data enabling a calculation of at least one of a change in attitude, a change in position, a change in angular rate, a change in velocity, and a change in acceleration of the unit over a plurality of finite time increments.

22. The method recited in claim 21, further comprising denoising the three virtual gyro data channels and the three virtual accelerometer data channels, for substantially eliminating high-frequency spikes, to provide three denoised virtual gyro data channels and three denoised virtual accelerometer data channels.

23. The method recited in claim 22, further comprising applying a Kalman-filtered bias compensation algorithm to the three denoised virtual gyro data channels, for substantially removing gyro bias therefrom.