Monitoring a location of a mobile computing device

• US 7,769,542 B2
• Filed: 01/18/2007
• Issued: 08/03/2010
• Est. Priority Date: 01/18/2007
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Wulff, Thomas, Calvarese, Russell
• Primary Examiner(s): NGUYEN, TAN QUANG
• Application Number:
  US11/624,327
• Publication Number:
  US 20080174445A1
• Time in Patent Office: 1,293 Days
• Field of Search: 701/211, 701/207, 701/26, 701/28, 701/210, 701/216, 701/300, 342/357.01, 342/357.07, 342/357.08, 340/995.25, 340/995.28, 340/686.1, 455/456.1
• US Class Current: 701/211
• CPC Class Codes: G01C 21/16 by integrating acceleration or speed, i.e. inertial navigation
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence

Abstract

A memory for storing constraint data describing a constrained area, a location sensor, and a processor operationally coupled to the memory and location sensor for location tracking. In operation, the device acquires real-time location information from the location sensor and calculates a location within the constrained area utilizing the constraint data and the acquired real-time location information. The location sensor may include an accelerometer that produces signals corresponding to a change in speed and a gyroscope that produces signals corresponding to a direction traveled. The processor may calculate a distance traveled over time utilizing the signals from the accelerometer and calculate the location utilizing the calculated distance traveled over time and the direction traveled.

Claims

1. A location tracking device comprising:

a memory configured to store constraint data describing a constrained area;

a location sensor; and

a processor operationally coupled to the memory and location sensor, wherein the processor is configured to acquire real-time location information from the location sensor, and is configured to calculate a location within the constrained area utilizing the constraint data and the acquired real-time location information, wherein the processor is configured to utilize the constraint data to correct the acquired real-time location information to calculate the location.

2. The device of claim 1, wherein the location sensor comprises:

an accelerometer configured to produce electrical signals corresponding to a change in speed; and

a gyroscope configured to produce electrical signals corresponding to a direction traveled, wherein the processor is configured to calculate a distance traveled over time utilizing the electrical signals from the accelerometer, and is configured to calculate the location utilizing the calculated distance traveled over time and the direction traveled.

3. The device of claim 1, wherein the location sensor comprises:

an accelerometer configured to produce electrical signals corresponding to a change in speed allowing for a calculation of distance traveled over time; and

an electronic compass configured to produce electrical signals corresponding to a direction traveled, wherein the processor is configured to utilize the electrical signals from the electronic compass and the gyroscope to calculate the location.

4. The device of claim 1, wherein the constrained area is a grid of areas accessible to the device surrounding areas inaccessible to the device.

5. The device of claim 1, wherein the constrained area is a collection of areas accessible to the device surrounding areas inaccessible to the device.

6. The device of claim 1, wherein the location sensor comprises a location correction device configured to produce electrical signals corresponding to location correction data for correcting the calculated location.

7. The device of claim 6, wherein the location correction device is a Radio Frequency Identification Device (RFID) tag that operates to identify when the device approaches an identified location, and wherein the processor is configured to correct a calculated location based on an indication that the device has approached the identified location.

8. The device of claim 6, wherein the location correction device is a camera that operates to identify a location of the device, and wherein the processor is configured to correct a calculated location based on the identified location.

9. The device of claim 6, wherein the location correction device is a plurality of access points that operate to identify a location of the device, and wherein the processor is configured to correct a calculated location based on the identified location.

10. The device of claim 1, wherein the processor is configured to correct the calculated location as a straight line between a previous known location and the current calculated location.

11. An application embodied on a computer readable medium configured to aid in tracking a device within a constrained area, the application comprising:

a portion configured to store constraint data describing the constrained area;

a portion configured to acquire real-time location information; and

a portion configured to calculate a location within the constrained area utilizing the constraint data and the acquired real-time location information, wherein the portion configured to calculate the location is configured to utilize the constraint data to correct the acquired real-time location information.

12. The application of claim 11, comprising:

a portion configured to receive signals corresponding to a change in speed;

a portion configured to calculate a distance traveled over time from the change in speed;

a portion configured to receive signals corresponding to a direction traveled; and

a portion configured to utilize the calculated distance traveled over time and the received signals corresponding to the direction traveled to calculate the location.

13. The application of claim 11, wherein the constrained area is a grid of accessible areas surrounding inaccessible areas.

14. The application of claim 11, wherein the constrained area is a collection of accessible areas surrounding inaccessible areas.

15. The application of claim 11, comprising:

a portion configured to receive electrical signals corresponding to location correction data; and

a portion configured to correct the calculated location utilizing the location correction data.

16. A method of tracking a device within a constrained area, the method comprising acts of:

storing constraint data describing the constrained area;

acquiring real-time location information; and

calculating a location within the constrained area utilizing the constraint data and the acquired real-time location information, wherein the act of calculating the location comprises an act of utilizing the constraint data to correct the acquired real-time location information.

17. The method of claim 16, comprising acts of:

receiving signals corresponding to a change in speed;

calculating a distance traveled over time from the change in speed;

receiving signals corresponding to a direction traveled; and

calculating the location utilizing the calculated distance traveled over time and the received signals corresponding to the direction traveled.

18. The method of claim 16, wherein the constrained area is a grid of accessible areas surrounding inaccessible areas.

19. The method of claim 16, wherein the constrained area is a collection of accessible areas surrounding inaccessible areas.

20. The method of claim 16, comprising the acts of:

receiving electrical signals corresponding to location correction data; and

correcting the calculated location utilizing the location correction data.