INTEGRATED INERTIAL MEASUREMENT SYSTEM AND METHODS OF CONSTRUCTING THE SAME

• US 20090308157A1
• Filed: 06/12/2008
• Published: 12/17/2009
• Est. Priority Date: 06/12/2008
• Status: Active Grant

• Current Assignee: Rosemount Aerospace, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Rosemount Aerospace, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Eriksen, Odd Harald Steen, Stuelke, Robert William
• Granted Patent: US 8,037,754 B2
• Time in Patent Office: Days
• US Class Current: 73/504.40
• CPC Class Codes: G01C 21/166 Mechanical, construction or arrangement details of inertial navigation systems

Abstract

An inertial measurement system having a triangular cupola shaped base structure with three mutually orthogonal sides and a bottom surface surrounding a hollow core. The bottom surface includes an aperture providing access to the hollow core. An inertial module is mounted on each of the sides and includes a gyroscopic rotational rate sensor and a linear accelerometer connected to a circuit board. The inertial measurement system also includes a motherboard and a plurality of metallization elements. The metallization elements extend from the bottom surface to the sides of the base structure and conductively connect the inertial module to the motherboard. The inertial measurement system may also include a non-conductive adhesive underfill positioned between the inertial module and the base structure.

Claims

1. A method of constructing an integrated inertial measurement unit, the method comprising the steps of:

a) forming a base structure having three mutually orthogonal planar surfaces and a bottom surface, the bottom surface having a central aperture, each of the planar surfaces forming a junction with the bottom surface;

b) bridging each of the junctions with a metallization layer; and

c) surface mounting an inertial module on each of the planar surfaces, the inertial module interfacing with at least a portion of the metallization layer.

2. The method according to claim 1, wherein the step of surface mounting the inertial module includes flip-chip bonding the inertial module to the base structure.

3. The method of claim 2, wherein the step of surface mounting the inertial module includes underfilling the inertial module with a non-conductive material to securely attach the inertial module to the base structure.

4. The method of claim 3, wherein underfilling the inertial module with a non-conductive material includes underfilling the inertial module with a non-conductive adhesive.

5. The method of claim 1, wherein the step of surface mounting an inertial module on each of the planar surfaces includes connecting a plurality of microelectromechanical devices to a circuit board to form the inertial module.

6. The method of claim 5, wherein the step of connecting a plurality of microelectromechanical devices includes connecting a plurality of non-planar microelectromechanical devices.

7. The method of claim 5, wherein the step of connecting a plurality of microelectromechanical devices to a circuit board includes connecting a linear accelerometer and a gyroscopic rotational rate sensor to the circuit board.

8. The method of claim 5, wherein the step of connecting a plurality of microelectromechanical devices to a circuit board includes connecting the microelectromechanical devices to a circuit board made of a ceramic material.

9. The method of claim 8, wherein the step of connecting a plurality of microelectromechanical devices to a circuit board includes connecting the microelectromechanical devices to a circuit board made of a multi-layer co-fired ceramic material.

10. The method of claim 5, further comprising flip-chip bonding the microelectromechanical devices to the circuit board.

11. The method of claim 1, wherein the step of bridging the junctions with a metallization layer includes forming a plurality of discrete metallization elements across each of the junctions.

12. The method of claim 1, wherein base structure is formed from a ceramic substrate.

13. The method of claim 1, wherein the shape of the base structure is a triangular cupola.

14. The method of claim 1, wherein the step of forming the base structure includes pressing ceramic powder to form the base structure, firing the base structure, and machining the base structure.

15. The method of claim 1, wherein the step of forming the base structure includes injection molding the base structure.

16. An inertial measurement system comprising:

a) a base structure with three mutually orthogonal sides and a bottom surface surrounding a hollow core, the bottom surface having an aperture providing access to the hollow core;

b) an inertial module mounted on each side, the inertial module including a gyroscopic rotational rate sensor and a linear accelerometer connected to a circuit board;

c) a plurality of metallization elements extending from the bottom surface to the sides of the base structure for conductively connecting the inertial module to a motherboard.

17. The inertial measurement system of claim 16, further comprising a motherboard, the metallization elements conductively connecting the inertial module to the motherboard.

18. The inertial measurement system of claim 16, further comprising a recessed portion formed in each of the three mutually orthogonal sides for accommodating electrical components.

19. The inertial measurement system of claims 17, further comprising a non-conductive adhesive positioned within the recessed portion to securely fasten the inertial module to the base structure.

20. The inertial measurement system of claim 16, further comprising a non-conductive adhesive underfill positioned between at least a portion of the inertial module and the base structure to securely fasten the inertial module to the base structure.

21. The inertial measurement system of claim 16, further comprising a sensing structure mounted within the hollow core of the base structure and connected to the motherboard.

22. The inertial measurement system of claim 16, wherein the shape of the base structure is a triangular cupola.

23. The inertial measurement system of claim 16, wherein the base structure is made of a ceramic material.

24. The inertial measurement system of claim 16, wherein in the inertial module is surface mounted to the planar surface on the base structure.

25. The inertial measurement system of claim 16, wherein the inertial module is flip-chip bonded to the planar surface on the base structure.

26. An inertial measurement system comprising:

a) a base structure with three mutually orthogonal sides and a bottom surface surrounding a hollow core, the bottom surface having an aperture providing access to the hollow core;

b) a circuit card assembly mounted on each side, the circuit card assembly including a plurality of microelectromechanical components mounted directly to the circuit card assembly;

c) a plurality of metallization elements extending from the bottom surface to the sides of the bases structure for conductively connecting the circuit card assembly to a motherboard.