Positioning with wireless local area networks and WLAN-aided global positioning systems

• US 7,899,472 B1
• Filed: 07/31/2006
• Issued: 03/01/2011
• Est. Priority Date: 02/14/2003
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Atheros Communications Incorporated (Qualcomm, Inc.)
• Inventors: Wang, Yi-Hsiu
• Primary Examiner(s): Le; Danh C
• Application Number:
  US11/461,335
• Time in Patent Office: 1,674 Days
• Field of Search: 455/456.5, 455/456.1, 455/456.6, 342/450
• US Class Current: 455/456.5
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• CPC Class Codes: G01S 19/252 Employing an initial estimate of location in generating assistance data
• CPC Class Codes: G01S 19/28 Satellite selection
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• 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 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04B 7/1851 Systems using a satellite or space-based relay H04B7/18508, H04B7/18521 take precedence; providing specific services H04B7/18523 - H04B7/18576
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Accurate position capability can be quickly provided using a Wireless Local Area Network (WLAN). When associated with a WLAN, a wireless device can quickly determine its relative and/or coordinate position based on information provided by an access point in the WLAN. Before a wireless device disassociates with the access point, the WLAN can periodically provide time, location, and decoded GPS data to the wireless device. In this manner, the wireless device can significantly reduce the time to acquire the necessary GPS satellite data (i.e. on the order of seconds instead of minutes) to determine its coordinate position.

Claims

1. A method of determining a position of a wireless device, the method including:

identifying a first access point having a first known location and a predetermined radio propagation range of r, wherein the position of the wireless device is the first known location with an uncertainty of r;

determining a first radio signal strength indicator (RSSI) of the first access point;

correlating the first RSSI to a first stored distance, wherein the first stored distance represents a first relative distance from the first access point to the wireless device;

identifying a second access point and a third access point having a second known location and a third known location, respectively;

determining a second RSSI and a third RSSI of the second access point and the third access point, respectively;

correlating the second RSSI and the third RSSI to a second stored distance and a third stored distance, respectively, wherein the second stored distance represents a second relative distance from the second access point to the wireless device, and wherein the third stored distance represents a third relative distance from the third access point to the wireless device;

determining weighting factors based on the first, second, and third relative distances; and

computing a coordinate position of the wireless device using the first, second, and third known positions and the weighting factors.

2. A method of determining a position of a device having wireless networking capability, the method including:

identifying a fixed position of an access point accessible by the device;

computing the position of the device using short radio wave propagation between the access point and the device, wherein computing the position includes;

determining a radio signal strength indicator (RSSI) of the access point;

correlating the RSSI to a stored distance, wherein the stored distance represents a relative distance from the access point to the device;

identifying fixed positions of multiple access points accessible by the device;

determining RSSIs of the multiple access points;

correlating the RSSIs to stored distances, wherein the stored distances represent relative distances from the multiple access points to the device;

determining weighting factors based on the relative distances; and

computing a coordinate position of the device using the fixed positions and the weighting factors.