Continuous data optimization of moved access points in positioning systems

• US 20070004428A1
• Filed: 02/22/2006
• Published: 01/04/2007
• Est. Priority Date: 02/22/2005
• Status: Active Grant

• Current Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Original Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Inventors: Alizadeh-Shabdiz, Farshid, Jones, Russel, Shean, Michael, Morgan, Edward
• Granted Patent: US 8,244,272 B2
• Time in Patent Office: Days
• US Class Current: 455/456.100
• CPC Class Codes: G01S 5/0205 Details
• CPC Class Codes: H04W 12/122 Counter-measures against attacks; Protection against rogue devices
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 4/20 Services signaling; Auxiliary data signalling, i.e. transmitting data via a non-traffic channel
• 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 64/003 locating network equipment
• CPC Class Codes: H04W 84/10 Small scale networks; Flat hierarchical networks
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Methods and systems of continuously optimizing data in WiFi positioning systems. A location-based services system uses WiFi-enabled devices to monitor WiFi access points in a target area to indicate whether a WiFi access point has moved relative to its previously recorded location. A WiFi-enabled device communicates with WiFi access points within range of the WiFi-enabled device so that observed WiFi access points identify themselves; A reference database is accessed to obtain information specifying a recorded location for each observed WiFi access point in the target area. The recorded location information is used for each of the observed WiFi access points in conjunction with predefined rules to infer whether an observed WiFi access point has moved relative to its recorded location. The reference database is informed of the identity of any observed WiFi access point that is inferred to have moved.

Claims

1. In a location-based services system, a method of utilizing WiFi-enabled devices to monitor WiFi access points in a target area to indicate whether a WiFi access point has moved relative to its previously recorded location, the method comprising the acts of:

a) a WiFi-enabled device communicating with WiFi access points within range of the WiFi-enabled device so that observed WiFi access points identify themselves;

b) accessing a reference database to obtain information specifying a recorded location for each observed WiFi access point in the target area;

c) using the recorded location information for each of the observed WiFi access points in conjunction with predefined rules to infer whether an observed WiFi access point has moved relative to its recorded location;

d) informing the reference database of the identity of any observed WiFi access point that is inferred to have moved.

2. The method of claim 1 wherein the predefined rules include (i) rules to identify clusters of observed WiFi access points, (ii) rules to determine the cluster with the largest number of WiFi access points, (iii) rules to calculate a reference point location from the average of the recorded locations for the observed WiFi access points within the largest cluster;

and (iv) rules to infer as moved any observed WiFi access point whose recorded location stored in the reference database is more than a threshold distance from the reference point.

3. The method of claim 1 wherein the predefined rules include (i) rules to calculate a median location of the observed WiFi access points, and (ii) rules to identify as suspect any observed WiFi access point whose position stored in the reference database is more than a threshold distance from the median location.

4. The method of claim 1 wherein the predefined rules include (i) rules to store a recent position of the WiFi-enabled device as a reference point, and (ii) rules to identify as suspect any observed WiFi access point whose position stored in the reference database is more than a threshold distance from the median location.

5. The method of claim 4 wherein the method further determines the velocity of WiFi-enabled device and wherein the threshold distance is selected based on the velocity of the WiFi-enabled device.

6. The method of claim 1 wherein the reference database is located remotely relative to the WiFi-enabled device.

7. The method of claim 1 wherein Wi-Fi access points identified as suspect are marked in the reference database immediately.

8. The method of claim 1 wherein WiFi access points identified as suspect in the WiFi-enabled device and marked in the reference database at a later time.

9. The method of claim 1 wherein the reference database is part of a location-based services system with a large plurality of subscribers each having WiFi-enabled devices with logic to determine the geographical position of the WiFi-enabled device of the respective user and wherein acts (a) through (d) are repeatedly performed by the large plurality of WiFi-enabled devices using the system.