Dead reckoning pedometer

• US 6,549,845 B2
• Filed: 01/10/2001
• Issued: 04/15/2003
• Est. Priority Date: 01/10/2001
• Status: Expired due to Fees

• Current Assignee: Savannah River Nuclear Solutions LLS
• Original Assignee: Westinghouse Savannah River Company
• Inventors: Hofstetter, Kenneth J., Eakle, Robert F. Jr.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Marc-Coleman, Marthe Y.
• Application Number:
  US09/757,560
• Publication Number:
  US 20020091482A1
• Time in Patent Office: 825 Days
• Field of Search: 701/200, 701/207, 701/208, 701/216, 701/217, 600/595, 600/587
• US Class Current: 701/207
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 22/006 Pedometers

Abstract

A system to determine the location of a person within a structure utilizes a magnetometer, magnets, pressure sensors and a CPU to calculate the length and direction of each step. The data may be displayed to the wearer, preferably on a map or floorplan and may be broadcast to persons outside the structure.

Claims

1. A dead reckoning pedometer comprising:

a) a foot pressure sensor attached to each front;

b) a magnetic point source attached at or near each foot;

c) a magnetometer attached at or near each foot;

d) a signal conditioning unit to process signals from each sensor and each magnetometer;

e) a computer analysis and data storage unit;

f) means for displaying the results from said computer analysis.

2. A dead reckoning pedometer according to claim 1 further comprising a database containing floorplans.

3. A dead reckoning pedometer according to claim 1 further comprising a radio frequency transmitter.

4. A dead reckoning pedometer according to claim 1 wherein said means for displaying said result is a liquid crystal screen.

5. A dead reckoning pedometer according to claim 1 wherein said means for displaying said result is a heads-up display.

6. A method for determining the location of a person using a dead reckoning pedometer comprising:

a) means for determining when each foot is in contact with a supporting surface;

b) means for determining the position of permanent magnets;

c) means to calculate the position of said permanent magnets relative to a previous position.

7. A method according to claim 6 wherein said means for determining when each foot is in contact with a supporting surface is a pressure sensor.

8. A method according to claim 6 wherein said means for determining the position of permanent magnets is a magnetometer.

9. A method according to claim 6 wherein said means for calculating is a signal conditioning unit and a CPU.

10. A method according to claim 9 further comprising displaying the results from said calculating on a map.