Method and system for calibrating a location system

• US 6,784,842 B2
• Filed: 01/22/2003
• Issued: 08/31/2004
• Est. Priority Date: 01/22/2003
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Vesuna, Sarosh
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US10/349,631
• Publication Number:
  US 20040140931A1
• Time in Patent Office: 587 Days
• Field of Search: 342/465, 342/463
• US Class Current: 342/463
• CPC Class Codes: G01S 5/02525 Gathering the radio frequency fingerprints
• 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

The present invention is useful in connection with calibration of a wireless location system based on RF signals within a facility. Identification devices are provided at fixed locations which are selected within the facility. The RF environment is sampled at selected locations and data representing the sampled RF environment and the corresponding selected location is provided to a computer which maintains a database corrolating the RF environment data and the selected locations to be used with calibrating a location system.

Claims

1. A method for calibrating a location system based on RF signals at a facility, comprising:

placing one or more identification devices at selected locations in said facility;

reading information from said one or more identification devices, said reading performed by a portable device;

sampling the RF environment at a plurality of said selected locations in said facility, said sampling step performed by said portable device;

signaling data representing said sampled RF environment and corresponding selected location in said facility to a computer;

maintaining a database in said computer correlating said RF environment data and said information and said selected locations; and

using said database to calibrate said location system.

2. A method as specified in claim 1 wherein said one or more identification devices includes an RF communication device for communicating with one or more fixed communications devices in said facility, and wherein sampling said RF environment comprises sampling transmissions received from said RF communications device on said one or more identification devices.

3. A method as specified in claim 1 wherein said one or more identification devices comprise RFID tags encoding data representing said selected location, and wherein said sampling includes reading said RFID tag data with a portable RFID tag reading device, and wherein said signaling comprises sending said RFID tag data and said sampled RF environment data from said portable RFID tag reading device by RF data communication.

4. A method as specified in claim 1 wherein said one or more identification devices includes an RF communication device for communicating with one or more fixed communications devices in said facility, and wherein sampling said RF environment comprises sampling transmissions received by said RF communications device on said identification device.

5. A method as specified in claim 4 wherein said signaling comprises sending data representing said sampled RF environment using said RF communications device on said one or more identification devices.

6. A system for calibrating a location system based on RF signals at a facility, comprising:

one or more identification devices at selected locations in said facility;

one or more portable devices for reading information from said one or more identification devices;

a receiver for sampling the RF environment at a plurality of said selected locations in said facility; and

a computer for receiving data representing said sampled RF environment and corresponding selected location in said facility;

wherein said computer is programmed to maintain a database correlating said RF environment data and said selected locations, and calibrate said location system using said database.

7. A system as specified in claim 6 wherein said one or more identification devices comprise RFID tags encoding said selected location, and wherein said receiver is provided on a portable RFID tag reader, and wherein said portable RFID tag reader includes an RF data communications radio and is arranged to send data representing said RFID tag location data and said RF environment data to said computer by RF data communication.

8. A system as specified in claim 6 wherein said one or more identification devices comprise RF communication devices for communicating with one or more fixed communications devices in said facility, and wherein sampling said RF environment comprises sampling transmissions received by said one or more identification devices from said fixed communications devices.

9. A system as specified in claim 8 wherein said one or more identification devices are arranged to send data representing said sampled RF environment using said RF communications devices.

10. A system as specified in claim 6 wherein said one or more identification devices include one or more RF communication devices for communicating with one or more fixed communications devices in said facility, and wherein said RF communication devices are arranged to sample transmissions received from said one or more identification devices.

11. A system as specified in claim 10 wherein said one or more identification devices are arranged to send data representing said sampled RF environment using said RF communications devices.

12. A method for calibrating a location system based on RF signals at a facility, comprising:

placing one or more identification devices at selected locations in said facility;

sampling the RF environment at a plurality of said selected locations in said facility;

signaling data representing said sampled RF environment and corresponding selected location in said facility to a computer;

maintaining a database in said computer correlating said RF environment data and said selected locations; and

using said database to calibrate said location system;

wherein said one or more identification devices comprise bar code labels encoding data representing said selected location, and wherein said sampling includes reading data from said bar code labels with a portable bar code reader, and wherein said signaling comprises sending said bar code data and said sampled RF environment data from said portable bar code reader by RF data communication.

13. A system for calibrating a location system based on RF signals at a facility, comprising:

one or more identification devices at selected locations in said facility;

a receiver for sampling the RF environment at a plurality of said selected locations in said facility; and

a computer for receiving data representing said sampled RF environment and corresponding selected location in said facility;

wherein said computer is programmed to maintain a database correlating said RF environment data and said selected locations and calibrate said location system using said database, and further wherein said one or more identification devices comprise bar code labels encoding said selected location, wherein said receiver is provided on a portable bar code reader, and wherein said portable bar code reader includes an RF data communications radio and is arranged to send data representing said bar code location data and said RF environment data to said computer by RF data communication.