Methods and Apparatus for Localizing a Source of a Set of Radio Signals

• US 20160283756A1
• Filed: 06/25/2015
• Published: 09/29/2016
• Est. Priority Date: 03/25/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Lenchner, Jonathan, Nelson, John C., Santala, Timo Juhani
• Granted Patent: US 10,761,179 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01S 5/02524 Creating or updating the radio-map
• CPC Class Codes: G01S 5/04 Position of source determined by a plurality of spaced direction-finders
• CPC Class Codes: G06K 7/10128 the step consisting of detection of the presence of one or more record carriers in the vicinity of the interrogation device

Abstract

Methods and apparatus are provided for localizing a source of a set of radio signals, such as radio signals received from an RFID tag at various locations. A source of a set of radio signals (such as radio signals received from an RFID tag at various locations) is localized by obtaining a plurality of radio signals in the set from a different location in an environment; determining a magnitude and received location for each of the plurality of radio signals; determining a direction for each of the plurality of radio signals by comparing each given radio signal to other radio signals in the set; and determining a location of the source of the set of radio signals by determining an intersection of the direction for each of the plurality of radio signals. The direction for each of the plurality of radio signals optionally comprises a net directional vector determined using a weighted circular mean.

Claims

1. A method for localizing a source of a set of radio signals, the method comprising the steps of:

obtaining a plurality of radio signals in said set from a different location in an environment, wherein each of said plurality of radio signals is transmitted by said source;

determining a magnitude and received location for each of said plurality of radio signals;

determining a direction for each of said plurality of radio signals by comparing each given radio signal to other radio signals in said set; and

determining a location of said source of said set of radio signals by determining an intersection of said direction for each of said plurality of radio signals, wherein at least one of said steps are performed by at least one hardware device.

2. The method of claim 1, wherein said set of radio signals comprises radio signals received from an RFID tag at various locations.

3. The method of claim 1, wherein said magnitude of each given radio signal in said set is proportional to a received signal strength at said corresponding received location of said environment.

4. The method of claim 1, wherein said magnitude of each of said plurality of radio signals in said set is proportional to a function of a received signal strength at said corresponding received location of said environment.

5. The method of claim 1, wherein said direction for each of said plurality of radio signals comprises a net directional vector.

6. The method of claim 5, wherein said net directional vector is determined using a weighted circular mean.

7. The method of claim 5, wherein said step of determining said location of said source of said set of radio signals identifies an intersection of said net directional vector for each of said plurality of radio signals.

8. The method of claim 7, wherein said intersection is identified by creating one or more arcs and employing a flood-fill technique.

9. The method of claim 8, wherein said intersection is identified by determining a location contained in a largest number of arcs.