Identifying a directional reference using rate gyros oriented along different axes

• US 7,845,085 B2
• Filed: 07/12/2007
• Issued: 12/07/2010
• Est. Priority Date: 07/12/2007
• Status: Active Grant

• Current Assignee: Textron Systems Corporation (Textron Inc)
• Original Assignee: Textron Systems Corporation (Textron Inc)
• Inventors: Pruszenski, Anthony S.
• Primary Examiner(s): BENNETT, GEORGE B
• Application Number:
  US11/777,072
• Publication Number:
  US 20100024230A1
• Time in Patent Office: 1,244 Days
• Field of Search: 333/16, 333/18, 333/20, 333/21, 333/24, 333/25
• US Class Current: 33/325
• CPC Class Codes: G01C 19/00 Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
• CPC Class Codes: G01C 19/34 for indicating a direction in the horizontal plane, e.g. directional gyroscopes
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G08C 21/00 Systems for transmitting the position of an object with respect to a predetermined reference system, e.g. tele-autographic system

Abstract

A deployable stationary device includes a device support, rate gyros supported by the device support, the rate gyros being oriented along different axes, and a controller supported by the device support. The controller is arranged to receive rate gyro signals from the rate gyros. Each rate gyro signal indicates a rate of rotation about a respective axis associated with a particular rate gyro. The controller is further arranged to perform a vector sum operation based on the rate gyro signals, and generate a direction signal which identifies a direction resulting from performance of the vector summing operation. Such a deployable stationary device is capable of operating as one of a network of such devices in a surveillance system to enable detection and precise location of suspicious activity.

Claims

1. A surveillance system, comprising:

a set of deployable stationary devices, each deployable stationary device including (i) a device support, (ii) rate gyros supported by the device support, the rate gyros being oriented along different axes, and (iii) a controller supported by the device support, the controller being arranged to;

receive rate gyro signals from the rate gyros, each rate gyro signal indicating a rate of rotation about a respective axis associated with a particular rate gyro, perform a vector sum operation based on the rate gyro signals, and

generate a direction signal which identifies a direction resulting from performance of the vector sum operation; and

a base station arranged to (i) acquire, from each deployable stationary device, a device signal which includes the direction signal generated by the controller of that deployable stationary device, and (ii) identify a location of interest based on the device signal from each deployable stationary device.

2. A surveillance system as in claim 1 wherein the different axes include an X-axis, a Y-axis, and a Z-axis;

wherein the X-axis, the Y-axis, and the Z-axis are substantially orthogonal to each other; and

wherein the controller of each deployable stationary device, when receiving the rate gyro signals from the rate gyros, is arranged to obtain (i) an X-axis signal indicating a rate of rotation about the X-axis, (ii) a Y-axis signal indicating a rate of rotation about the Y-axis, and (iii) a Z-axis signal indicating a rate of rotation about the Z-axis.

3. A surveillance system as in claim 2 wherein the controller of each deployable stationary device, when generating the direction signal which identifies the direction resulting from performance of the vector summing operation, is arranged to:

provide a True North vector signal which identifies a direction of the North-South earth axis relative to that deployable stationary device.

4. A surveillance system as in claim 3 wherein, for each deployable stationary device:

that deployable stationary device further includes a sensor supported by the device support of that deployable stationary device, the sensor being arranged to output a sensor signal; and

the controller of that deployable stationary device is further arranged to output a respective device signal based on (i) the direction signal identifying the direction resulting from performance of the vector summing operation and (ii) the sensor signal.

5. A surveillance system as in claim 4 wherein the device signal outputted by the controller of each deployable stationary device identifies a bearing of a particular location of interest, the bearing being an angular displacement between the particular location of interest and the North-South earth axis.

6. A surveillance system as in claim 5 wherein the device signal outputted by the controller of each deployable stationary device further identifies a location of the deployable stationary device identified via a Global Positioning System (GPS).

7. A surveillance system as in claim 5 wherein the base station is arranged to communicate wirelessly with a first deployable stationary device when the first deployable stationary device resides at a first ground location and a second deployable stationary device when the second deployable stationary device resides at a second ground location which is distal from the first ground location.

8. A surveillance system as in claim 5 wherein each rate gyro is a Microelectromechanical Systems (MEMS) technology angular rate sensor.

9. A surveillance system as in claim 5 wherein each rate gyro is a fiber optic technology angular rate sensor.

10. A deployable stationary device, comprising:

a device support;

rate gyros supported by the device support, the rate gyros being oriented along different axes; and

a controller supported by the device support, the controller being arranged to;

receive rate gyro signals from the rate gyros, each rate gyro signal indicating a rate of rotation about a respective axis associated with a particular rate gyro,

perform a vector sum operation based on the rate gyro signals, and

generate a direction signal which identifies a direction resulting from performance of the vector sum operation.

11. A deployable stationary device as in claim 10 wherein the different axes include an X-axis, a Y-axis, and a Z-axis;

wherein the X-axis, the Y-axis, and the Z-axis are substantially orthogonal to each other; and

wherein the controller, when receiving the rate gyro signals from the rate gyros, is arranged to obtain (i) an X-axis signal indicating a rate of rotation about the X-axis, (ii) a Y-axis signal indicating a rate of rotation about the Y-axis, and (iii) a Z-axis signal indicating a rate of rotation about the Z-axis.

12. A deployable stationary device as in claim 11 wherein the controller, when generating the direction signal which identifies the direction resulting from performance of the vector summing operation, is arranged to:

provide a True North vector signal which identifies a direction of the North-South earth axis relative to the deployable stationary device.

13. A deployable stationary device as in claim 12, further comprising a sensor supported by the device support, the sensor being arranged to output a sensor signal;

and

wherein the controller is further arranged to output a device signal based on (i) the direction signal identifying the direction resulting from performance of the vector summing operation and (ii) the sensor signal.

14. A deployable stationary device as in claim 13 wherein the device signal identifies a bearing of a particular location of interest, the bearing being an angular displacement between the particular location of interest and the North-South earth axis.

15. A deployable stationary device as in claim 14 wherein the device signal further identifies a location of the deployable stationary device identified via a Global Positioning System (GPS).

16. A deployable stationary device as in claim 14 wherein each rate gyro is a Microelectromechanical Systems (MEMS) technology angular rate sensor.

17. A deployable stationary device as in claim 14 wherein each rate gyro is a fiber optic technology angular rate sensor.

18. In a deployable stationary device having rate gyros oriented along different axes, a method of identifying a directional reference, the method comprising:

receiving rate gyro signals from the rate gyros, each rate gyro signal indicating a rate of rotation about a respective axis associated with a particular rate gyro;

performing a vector sum operation based on the rate gyro signals; and

providing a direction signal which identifies a direction resulting from performance of the vector sum operation.

19. A method as in claim 18 wherein the different axes include an X-axis, a Y-axis, and a Z-axis;

wherein the X-axis, the Y-axis, and the Z-axis are substantially orthogonal to each other; and

wherein receiving the rate gyro signals from the rate gyros includes obtaining (i) an X-axis signal indicating a rate of rotation about the X-axis, (ii) a Y-axis signal indicating a rate of rotation about the Y-axis, and (iii) a Z-axis signal indicating a rate of rotation about the Z-axis.

20. A method as in claim 19 wherein providing the direction signal which identifies the direction resulting from performance of the vector summing operation includes:

generating a True North vector signal which identifies a direction of the North-South earth axis relative to the deployable stationary device.