Method and system for personal area networks

• US 8,023,959 B2
• Filed: 06/28/2006
• Issued: 09/20/2011
• Est. Priority Date: 06/28/2006
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Inventors: Eaton, Eric T., Bhuta, Mahesh B., Perdomo, Jorge L.
• Primary Examiner(s): Negron; Daniell L
• Assistant Examiner(s): Nguyen; Huy D
• Application Number:
  US11/427,262
• Publication Number:
  US 20080004036A1
• Time in Patent Office: 1,910 Days
• Field of Search: 455/456.1, 455/456.2, 455/456.3, 455/456.5, 455/456.6
• US Class Current: 455/456.1
• CPC Class Codes: G01S 19/48 by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
• CPC Class Codes: G01S 5/02527 Detecting or resolving anomalies in the radio frequency fingerprints of the radio-map
• CPC Class Codes: G01S 5/0263 by combining or switching between positions derived from two or more separate positioning systems
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination

Abstract

A system (160) and method (400) is provided for validating a location of a tracking device. The method can include monitoring (902) a set of signal strengths (600) to one or more personal area networks (104) and one or more cellular towers (110), generating (906) a Radio Frequency Time Profile RFTP (700) from the set of signal strengths, comparing (908) the RFTP o coverage variation limits (720) of one or more pre-calibrated paths, and signaling (910) an alert if the set of signal strengths are not within the coverage variation limit of the one or more pre-calibrated paths. The RFTP is a time series of the signal strengths between the tracking device and the one or more PANs resulting from a change in location of the tracking device.

Claims

1. A tracking system for validating a location suitable for use with location Positioning Systems, comprising:

a tracking device that generates a Radio Frequency Profile (RFTP);

one or more personal area network units (PANs) communicatively coupled to the tracking device; and

a processor operable to;

receive GPS data reporting an immediate location of the tracking device;

project a path of the tracking device based on a history of the RFTP;

predict a location of the tracking device along the path;

determine whether the location is within a region of a last received GPS reading;

raise an alert if the location is outside a coverage variation limit of a pre-calibrated path; and

wherein the RFTP is a signature of communication patterns recorded between the tracking device, the PAN, and, if present, one or more external communications systems, and the tracking system validates a location of the tracking device based on the RFTP.

2. The tracking system of claim 1, wherein the tracking system monitors the RFTP for communication pattern transitions, and signals an alert if the communication pattern transitions are outside a coverage variation limit of a monitored location.

3. The tracking system of claim 1, wherein the tracking system validates the immediate location reported by the GPS in view of the path.

4. The tracking system of claim 3, wherein the tracking system

predicts the location of the tracking device along the path when GPS data for reporting a location of the tracking device is unavailable.

5. The tracking system of claim 3, wherein the tracking device tracks and stores one or more network readings including GPS data, cellular signals, RF signal strengths, and PAN coverage, for creating the RFTP.

6. The tracking system of claim 5, wherein the tracking system determines changes in a time and location sequence of the tracking device from the network readings for characterizing a safe zone.

7. The tracking system of claim 1, wherein the RFTP includes a first set of signal strength indicators measured between the tracking device and the one or more cellular towers, and a second set of signal strength indicators measured between the tracking device and the one or more PANs,

wherein the tracking device monitors a first variation in the first set of signal strength indicators and a second variation in the second set of signal strengths over a time window for determining whether the variations are within a coverage variation limit of a monitored location.

8. The tracking system of claim 1, wherein the tracking system updates the RFTP based on one or more false alarms.

9. The tracking system of claim 1, wherein the PAN includes a positional detector for determining whether the PAN has moved from a pre-specified location.

10. The tracking system of claim 1, wherein the tracking device and the PAN communicate over a non-network assisted communication protocol including at least one from the group comprising:

BlueTooth, ZigBee, IEEE 802.11, and two-way radio.

11. The tracking system of claim 1, wherein the tracking device further comprises:

a modem for acquiring a coverage pattern from one or more cellular towers and at least one personal area network unit; and

a processor for determining whether a variation in the coverage pattern is within a monitored location,

wherein the processor captures one or more RF signals from the modem, determines a signal strength of the one or more RF signals, and compares the coverage pattern with a coverage variation limit of a monitored location.

12. The tracking system of claim 1, wherein the personal area network unit further comprises:

a first modem for establishing communication with one or more cellular towers or other PANs;

a second modem for establishing non-network assisted communication with the tracking device; and

a monitoring unit for comparing the RTFP with one or more communication patterns from the one or more cellular towers or other PANs.