Sub-room-level indoor location system using power line positioning

• US 20080091345A1
• Filed: 06/28/2007
• Published: 04/17/2008
• Est. Priority Date: 06/28/2006
• Status: Active Grant

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Reynolds, Matthew, Patel, Shwetak, Truong, Khai, Robertson, Thomas, Abowd, Gregory
• Granted Patent: US 8,392,107 B2
• Time in Patent Office: Days
• US Class Current: 701/208
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01S 5/02521 using a radio-map

Abstract

Disclosed is an indoor location system that uses an electrical power line, power line signal injection devices, and portable position receivers (tags) to generate location data relating to positions of the tags in a structure such as a residence or business. The indoor location system fingerprinting of multiple signals transmitted along the power line to achieve sub-room-level localization of the positioning receivers. Details regarding power line positioning are described along with how it compares favorably to other fingerprinting techniques.

Claims

1. Indoor location apparatus comprising:

an electrical power line infrastructure disposed in a structure;

at least two transmitting devices connected to the electrical power line infrastructure at different points within the electrical power line infrastructure, each of the transmitting devices injecting a respective signal into the electrical power line infrastructure;

at least one positioning tag disposed to receive the signals emanating from the electrical power line infrastructure and caused by the least two transmitting devices.

2. The apparatus recited in claim 1 in which the at least one positioning tag generates a signal fingerprint based upon the signals of each of the at least two transmitting devices.

3. The apparatus recited in claim 2 in which the positioning tag locally stores and processes the signal fingerprint.

4. The apparatus recited in claim 2 in which the positioning tag wirelessly transmits the signal fingerprint to a base station.

5. The apparatus recited in claim 2 in which the signal fingerprint is processed to generate an estimate of the location of the at least one positioning tag.

6. The apparatus recited in claim 2 wherein the signal fingerprint is associated with at least one estimated location based on a predetermined location map.

7. The apparatus recited in claim 2 wherein the fingerprint is processed using k-Nearest Neighbor (KNN) classification to determine the at least one estimated location.

8. The apparatus recited in claim 2 wherein the fingerprint comprises at least the signal strength of the signals emanating from the electrical power line infrastructure.

9. The apparatus recited in claim 2 wherein the fingerprint comprises at least the relative phase difference between at least two signals emanating from the electrical power line infrastructure.

10. The apparatus recited in claim 2 wherein the fingerprint comprises at least the phase shift between successive signals emanating from the electrical power line infrastructure.

11. A method comprising:

generating a plurality of electromagnetic signals that are transmitted over an electrical power line infrastructure disposed in a structure;

wirelessly detecting each of the plurality of electromagnetic signals using at least one positioning tag;

processing the plurality of electromagnetic signals in the positioning tag to generate a signal fingerprint that is associated with the location of the positioning tag;

locally storing the signal fingerprint for subsequent remote processing, or wirelessly transmitting the signal fingerprint to a wireless base station in real time for processing;

processing the signal fingerprint from the at least one positioning tags at the base station to identify an associated location of each of the at least one positioning tags in the structure.

12. The method recited in claim 11 further comprising:

calibrating the base station by;

generating a plurality of electromagnetic signals that are transmitted over an electrical power line infrastructure disposed in the structure;

successively locating a positioning tag at a plurality of predetermined locations in the in the structure;

processing each of the plurality of electromagnetic signals to generate a signal fingerprint that is associated with the spatial location of the positioning tag at each of the plurality of predetermined locations; and

generating a location map associating each signal fingerprint with at least one position.

13. The method recited in claim 12 wherein a wireless base station processes the fingerprint and maps the signal signature to an associated location based on a predetermined location map.

14. The method recited in claim 12 wherein the positioning tag processes the electromagnetic signals using k-Nearest Neighbor (KNN) classification to determine a location of the positioning tag.

15. The method recited in claim 12 wherein the fingerprint comprises at least the signal strength of the signals emanating from the electrical power line infrastructure.

16. The method recited in claim 12 wherein the fingerprint comprises at least the relative phase difference between detected signals emanating from the electrical power line infrastructure.

17. The method recited in claim 12 wherein the fingerprint comprises at least the phase shift between successive detected signals emanating from the electrical power line infrastructure.