Inertial Measurement Unit for Aircraft

• US 20080154495A1
• Filed: 01/28/2008
• Published: 06/26/2008
• Est. Priority Date: 10/22/1997
• Status: Active Grant

• Current Assignee: American Vehicular Sciences LLC (Acacia Research Corporation)
• Original Assignee: Intelligent Technologies International, Inc.
• Inventors: Breed, David S.
• Granted Patent: US 7,962,285 B2
• Time in Patent Office: Days
• US Class Current: 701/208
• CPC Class Codes: G01C 21/12 executed aboard the object being navigated; Dead reckoning
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence

Abstract

System for determining position of a vehicle includes an integral inertial measurement unit (IMU) including accelerometers and gyroscopes for providing raw data about movement of the vehicle and a correction unit coupled to the IMU and arranged to receive and/or derive positional corrections and the raw data from the IMU and generate accurate positional information about the vehicle based on the raw data and positional corrections. A navigation system is coupled to the correction unit and receives and acts upon the positional information of the vehicle provided by the correction unit. The IMU may be a MEMS-packaged IMU and integrated with the correction unit in combination with one another. A map database may be coupled to the navigation system which would receive information about a travel lane the vehicle is travelling on and could guide an operator of the vehicle based on the accurate positional information and travel lane information.

Claims

1. A system for determining position of a vehicle, comprising:

an integral inertial measurement unit (IMU) including a plurality of accelerometers and gyroscopes for providing raw data about movement of the vehicle;

a correction unit coupled to said IMU and arranged to receive or derive positional corrections and the raw data from said IMU and generate accurate positional information about the vehicle based on the raw data and positional corrections; and

a navigation system coupled to said correction unit for receiving and acting upon the accurate positional information of the vehicle provided by said correction unit.

2. The system of claim 1, wherein said IMU and said correction unit are integrated in combination with one another.

3. The system of claim 1, further comprising a map database coupled to said navigation system, said navigation system being arranged to receive information about a travel lane the vehicle is travelling on and guiding an operator of the vehicle based on the accurate positional information and travel lane information.

4. The system of claim 1, wherein said correction unit is arranged to communicate with satellites to receive positional corrections therefrom.

5. The system of claim 1, wherein said correction unit is arranged to communicate with ground base stations to receive positional corrections therefrom.

6. The system of claim 1, wherein the vehicle is an airplane.

7. The system of claim 1, wherein said correction unit includes at least one of a GPS receiver for receiving GPS signals and a DGPS receiver for receiving differential correction signals.

8. The system of claim 1, wherein said IMU is a MEMS packaged IMU.

9. The system of claim 8, further error correction determining means for negating real-time influences of physical characteristics on said accelerometers and said gyroscopes after installation of said IMU on the vehicle.

10. The system of claim 9, wherein said error correction determining means comprise a processor arranged to apply a Kalman filer to the raw data, said Kalman filter being arranged to function based on input from said correction unit.

11. The system of claim 10, further comprising at least one of a device for measuring at least one of the downward direction of the earth'"'"'s magnetic field, a flux gage compass, a magnetic compass, a gravity sensor, a speedometer, an odometer, an anti-lock brake sensor, and a wheel speed sensor for providing input to said Kalman filter.

12. The system of claim 10, wherein said Kalman filter is arranged to determine and apply a correction for each of said accelerometers and said gyroscopes.

13. The system of claim 1, wherein said IMU comprises three accelerometers and three gyroscopes.

14. A system for determining position of an aircraft, comprising:

a single integrated unit including a MEMS-packaged integral inertial measurement unit (IMU) and a correction unit coupled to said IMU, said IMU including a plurality of accelerometers and gyroscopes for providing raw data about movement of the vehicle, said correction unit being arranged to receive or derive positional corrections and the raw data from said IMU and generate accurate positional information about the vehicle based on the raw data and positional corrections; and

a navigation system coupled to said correction unit for receiving and acting upon the accurate positional information of the vehicle provided by said correction unit.

15. The system of claim 14, further comprising a map database coupled to said navigation system, said navigation system being arranged to receive information about a travel lane the vehicle is travelling on and guiding an operator of the vehicle based on the accurate positional information and travel lane information.

16. The system of claim 14, wherein said correction unit is arranged to communicate with satellites to receive positional corrections therefrom and/or communicate with ground base stations to receive positional corrections therefrom.

17. The system of claim 14, wherein said correction unit includes at least one of a GPS receiver for receiving GPS signals and a DGPS receiver for receiving differential correction signals.

18. The system of claim 17, further error correction determining means for negating real-time influences of physical characteristics on said accelerometers and said gyroscopes after installation of said IMU on the vehicle, said error correction determining means comprising a processor arranged to apply a Kalman filer to the raw data, said Kalman filter being arranged to function based on input from said correction unit.

19. The system of claim 18, further comprising at least one of a device for measuring at least one of the downward direction of the earth'"'"'s magnetic field, a flux gage compass, a magnetic compass, a gravity sensor, a speedometer, an odometer, an anti-lock brake sensor, and a wheel speed sensor for providing input to said Kalman filter.

20. The system of claim 18, wherein said Kalman filter is arranged to determine and apply a correction for each of said accelerometers and said gyroscopes.