Local area positioning system

• US 20040263348A1
• Filed: 09/16/2003
• Published: 12/30/2004
• Est. Priority Date: 11/03/2000
• Status: Active Grant

• Current Assignee: L.A.P.S., LLC
• Original Assignee: WCR Company
• Inventors: Watson, Mitchell L.
• Granted Patent: US 7,049,957 B2
• Time in Patent Office: Days
• US Class Current: 340/8.1
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/02216 Timing or synchronisation of the receivers
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence

Abstract

A positioning system includes a command signal generator, a subject module, a plurality of sensor modules, and a plurality of counters. A comparator compares the plurality of increments and generate a plurality of counter differential values; and a correlator correlates the plurality of counter differential values to determine a subject location in the defined space.

A method for locating a subject includes transmitting a signal to a subject unit; transmitting a signal to slave units located within the defined three-dimensional space, such that each slave unit starts a 1 GHz counter; transmitting a subject signal from the subject unit; stopping said counters; determining net counter values; comparing the net counter values to determine counter difference values; and correlating said counter difference values to determine a subject unit location in the three-dimensional space.

Claims

1. A positioning system, comprising:

a command signal generator structured to transmit a command signal;

a subject module structured to receive the command signal and emit a subject signal responsive thereto;

a plurality of sensor modules arrayed in a defined three-dimensional space and structured to detect the subject signal;

a plurality of counters corresponding to the plurality of sensors, each of said counters configured to count an increment relating to reception of the subject signal by the corresponding sensor module;

a comparator configured to compare the plurality of increments and generate a plurality of counter differential values; and

a correlator configured to correlate the plurality of counter differential values to determine a subject location in the defined space.

2. The system of claim 1, further comprising:

a calibration module disposed in a predetermined location in the defined three-dimensional space relative to the plurality of sensor modules and structured to transmit a calibration signal.

3. The system of claim 1 wherein the counter has an increment of about 10⁻

7 seconds.

4. The system of claim 1 wherein the counter has an increment of about 10⁻

8 seconds.

5. The system of claim 1 wherein the counter has an increment of about 10⁻

9 seconds.

6. The system of claim 1, further comprising:

a plurality of subject modules, each of said subject modules having a unique transmission identity.

7. The system of claim 1 wherein the subject module further includes a memory.

8. The system of claim 1 wherein the correlator is configured to determine a subject location in the defined space in real time.

9. A method for locating a subject, comprising:

transmitting a signal to a subject unit located within a defined three-dimensional space;

transmitting a signal to slave units located within the defined three-dimensional space, each slave unit configured to start a 1 GHz counter from a counter start value;

transmitting a subject signal from the subject unit located within a defined three-dimensional space;

stopping said counters of said slave units to define counter stop values;

determining net counter values for each slave unit;

comparing the net counter values to determine counter difference values; and

correlating said counter difference values to determine a subject unit location in the three-dimensional space.

10. The method of claim 9 wherein correlating comprises correlating said counter difference values to determine a subject unit location in three dimensions.

11. The method of claim 9 wherein correlating comprises correlating said counter difference values to determine a subject unit location to within three feet.

12. The method of claim 9 wherein correlating comprises correlating said counter difference values to determine a subject unit location to within one foot.

13. The method of claim 9 wherein correlating comprises said correlating counter difference values to determine a subject unit location in the three-dimensional space in real time.

14. The method of claim 9, further comprising:

receiving data from said subject unit.

15. The method of claim 9, further comprising:

transmitting a calibration signal to the slave units from a calibration unit located at a preselected position within the defined three-dimensional space;

stopping said counters of said slave units to define calibration counter stop values;

determining net calibration counter values for each slave unit;

comparing the net calibration counter values to determine calibration difference values;

correlating said counter difference values to determine the calibration unit location in the three-dimensional space; and

comparing the determined calibration unit location to a reference value for the preselected position of the calibration unit.