Piezoelectric rate sensor system and method

• US 6,853,315 B2
• Filed: 01/23/2002
• Issued: 02/08/2005
• Est. Priority Date: 01/23/2002
• Status: Expired due to Fees

• Current Assignee: Triad Sensors Incorporated
• Original Assignee: Triad Sensors Incorporated
• Inventors: Johnson, Barron, Moncur, Timothy R., Schiller, Peter J.
• Primary Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US10/055,186
• Publication Number:
  US 20030137433A1
• Time in Patent Office: 1,112 Days
• Field of Search: 340/973, 340/974, 340/971, 340/975, 340/979, 340/967, 701/14, 731/78.R, 735/033, 735/040.8, 735/143.4, 735/041.4, 735/041.2, 735/041.3, 333/28, 333/20, 333/61, 333/55.R, 333/66
• US Class Current: 340/974
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01C 23/00 Combined instruments indicating more than one navigational value, e.g. for aircraft; Combined measuring devices for measuring two or more variables of movement, e.g. distance, speed or acceleration

Abstract

A compact, lightweight, cost effective, self-contained standby electronic navigation system with high signal-to-noise ratio and good dynamic stability is provided. The system includes a first sensor module for providing a plurality of rotational rate signals, a second sensor module for providing a plurality of compensation signals, and a microcontroller module for processing the rotational rate signals and the compensation signals and sending the signals to a display for displaying attitude information, directional information, and turn coordinate information on a single screen simultaneously. In one embodiment, the first sensor module includes a plurality of rotational sensors made of piezoelectric elements. The piezoelectric elements are made from a single sheet of piezoelectric material so that the elements possess uniform characteristics, and are arranged to reduce systematic drift and random noise normally present in a rotational rate sensor. The sensors can be configured on a single multi-sensor chip.

Claims

1. A gyroscopic navigation system, comprising:

a first sensor module, having a plurality of electrical rotational rate sensors, for providing a plurality of rotational rate signals;

a second sensor module, having a plurality of electrical compensation sensors, for providing a plurality of compensation signals;

a microcontroller module, coupled to the first and second sensor modules, for processing the rotational rate signals and the compensation signals and generating attitude information, directional information, and turn coordinate information;

a display, coupled to the microcontroller module, for displaying the attitude information, the directional information, and the turn coordinate information simultaneously;

wherein the rotational rate sensors are made of piezoelectric elements, the piezoelectric elements are made from a single sheet of piezoelectric material;

wherein one of the rotational sensors is a directional gyro, and another rotational sensor is an attitude gyro;

wherein each of the directional and the attitude gyros is a three-dimensional solid-state gyro which comprises;

a substrate having a proof-mass;

a membrane, the proof-mass being suspended on the membrane;

a single common electrode layer being disposed on the membrane;

the single sheet of piezoelectric material being disposed on the single common electrode layer; and

a plurality of electrodes being disposed on the single sheet of piezoelectric material in a thin-film format, the rotational rate signals being outputted through the electrodes, wherein each of the electrodes, the piezoelectric material, and the single common electrode layer form a plurality of piezoelectric elements; and

wherein the compensation sensors provide acceleration, magnetic field, and temperature compensation signals to reduce correlated noise caused by acceleration, magnetic field, and temperature.

2. The system of claim 1, wherein the piezoelectric elements are arranged and configured in a circular shape with a plurality of pairs of piezoelectric elements, one element in a pair is disposed on an inner ring of the circular shape, and the other element in the pair is disposed on an outer ring of the circular shape.

3. The system of claim 1, wherein the two elements of the pair have equal area.

4. The system of claim 3, wherein each pair of piezoelectric elements has a mirror image pair of piezoelectric elements disposed on opposite side of an axis passing through a center of the proof-mass.

5. The system of claim 1, wherein the piezoelectric elements are arranged and configured in an oval shape with a plurality of pairs of piezoelectric elements, one element in a pair is disposed on an inner ring of the oval shape, and the other element in the pair is disposed on an outer ring of the oval shape.

6. The system of claim 5, wherein the two elements of the pair have equal area.

7. The system of claim 6, wherein each pair of piezoelectric elements has a mirror image pair of piezoelectric elements disposed on opposite side of an axis passing through a center of the proof-mass.

8. An aircraft instrument system, comprising:

a plurality of aircraft primary instruments including a mechanical attitude gyro, a mechanical directional gyro, a mechanical-electrical turn coordinator/slip-skid indicator;

a standby gyroscopic navigation system connected independently of the primary instruments;

electrical power having a primary power source and a battery power source, the primary power source supplying power to the primary instruments and the standby gyroscopic navigation system, the standby battery power source supplying power to the standby gyroscopic navigation system to provide attitude information, directional information, and turn coordination information when the primary power source fails;

wherein standby gyroscopic navigation system includes;

a first sensor module, having a plurality of electrical rotational rate sensors, for providing a plurality of rotational rate signals;

a second sensor module, having a plurality of electrical compensation sensors, for providing a plurality of compensation signals;

a microcontroller module, coupled to the first and second sensor modules, for processing the rotational rate signals and the compensation signals; and

a display, coupled to the microcontroller module, for displaying attitude information, directional information, and turn coordinate information simultaneously;

wherein the rotational rate sensors are made of piezoelectric elements, the piezoelectric elements are made from a single sheet of piezoelectric material;

wherein one of the rotational sensors is a directional gyro, and another rotational sensor is an attitude gyro; and

wherein each of the directional and the attitude gyros is a three-dimensional solid-state gyro which comprises;

a substrate having a proof-mass;

a membrane, the proof-mass being suspended on the membrane;

a single common electrode layer being disposed on the membrane;

the single sheet of piezoelectric material being disposed on the single common electrode layer; and

a plurality of electrodes being disposed on the single sheet of piezoelectric material in a thin-film format, the rotational rate signals being outputted through the electrodes, wherein each of the electrodes, the piezoelectric material, and the single common electrode layer form a plurality of piezoelectric elements; and

wherein the compensation sensors provide acceleration, magnetic field, and temperature compensation signals to reduce correlated noise caused by acceleration, magnetic field, and temperature.

9. The system of claim 8, wherein the piezoelectric elements are arranged and configured in a circular shape with a plurality of pairs of piezoelectric elements, one element in a pair is disposed on an inner ring of the circular shape, and the other element in the pair is disposed on an outer ring of the circular shape.

10. The system of claim 9, wherein the two elements of the pair have equal area.

11. The system of claim 10, wherein each pair of piezoelectric elements has a mirror image pair of piezoelectric elements disposed on opposite side of an axis passing through a center of the proof-mass.

12. The system of claim 8, wherein the piezoelectric elements are arranged and configured in an oval shape with a plurality of pairs of piezoelectric elements, one element in a pair is disposed on an inner ring of the oval shape, and the other element in the pair is disposed on an outer ring of the oval shape.

13. The system of claim 12, wherein the two elements of the pair have equal area.

14. The system of claim 13, wherein each pair of piezoelectric elements has a mirror image pair of piezoelectric elements disposed on opposite side of an axis passing through a center of the proof-mass.