LOCATION AGENT GEOFENCE

• US 20130231137A1
• Filed: 03/04/2013
• Published: 09/05/2013
• Est. Priority Date: 03/02/2012
• Status: Abandoned Application

• Current Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Original Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Inventors: Hugie, Rick, Lau, Josiah, Phalke, Seema, Ferguson, Ed
• Application Number:
  US13/783,725
• Publication Number:
  US 20130231137A1
• Time in Patent Office: Days
• US Class Current: 455/456.3
• 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 2205/01 specially adapted for specific applications
• CPC Class Codes: G01S 5/0278 involving statistical or probabilistic considerations G01S5/0252, G01S5/0294 take precedence
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 4/021 Services related to particular areas, e.g. point of interest [POI] services, venue services or geofences

Abstract

A least squares geofence method that introduces inventive geofence steps and modifies existing geofence steps to minimize trigger misfires caused by data variability and location blunders and to minimize delayed/missed entry triggers generated under urban and/or indoor conditions. The least squares geofence method periodically retrieves sample locations for a target wireless device to determine that device'"'"'s geographic location and to evaluate a corresponding side condition. Sample locations retrieved with accuracies greater than 1 km are filtered. If a potential change in side condition is detected for a given device, the least squares geofence method retrieves five fast location fixes for that device and evaluates a weighted least squares (LS) location estimate based on sample locations retrieved. A LS location estimate is then filtered according to an anticipated trigger event and the least squares geofence method evaluates a final geofence side condition based on the LS location estimate previously computed.

Claims

1. A least squares geofence method that supports improved geofencing, comprising:

a get trigger side fast step;

a filter locations step;

a calculate least squares location step; and

an entering or exiting filter step.

2. The least squares geofence method that supports improved geofencing according to claim 1, wherein:

said least squares geofence method uses a least squares model to compute a location estimate for a target device.

3. The least squares geofence method that supports improved geofencing according to claim 1, wherein:

said get trigger side fast step uses a point in circle algorithm to alert said least squares geofence method to a potential change in geofence side condition for a specified target device.

4. The least squares geofence method that supports improved geofencing according to claim 1, wherein:

said filter locations step filters sample location points retrieved for a target device to minimize the effect of coarse locates on location estimates computed for said target device.

5. The least squares geofence method that supports improved geofencing according to claim 4, wherein said filter locations step filters said sample location points retrieved for said target device:

with accuracies greater than 1 km.

6. The least squares geofence method that supports improved geofencing according to claim 1, wherein:

said calculate least squares location step uses a weighted least squares model to compute a least squares fit of sample location points retrieved for a target device.

7. The least squares geofence method that supports improved geofencing according to claim 1, wherein:

said entering or exiting filter step filters a least squares location estimate computed for a target device.

8. The least squares geofence method that supports improved geofencing according to claim 7, wherein said entering or exiting filter step:

uses a 500 m loose exiting filter to filter a least squares location estimate computed for a device potentially exiting a geofence.

9. The least squares geofence method that supports improved geofencing according to claim 7, wherein:

said entering or exiting filter uses a 100 m tighter exiting filter to filter a least squares location estimate computed for a device potentially entering a geofence.

10. A least squares geofence method that supports improved geofencing according to claim 1, wherein:

existing geofence step wait until next fix time is modified to only take location position in to account.

11. A least squares geofence method that supports improved geofencing according to claim 1, wherein:

existing step enter slow fix time is modified to switch back to a fast fix mode from a slow fix mode after attempting to get 4 additional fast fixes for a target wireless device.

12. A least squares geofence method that supports improved geofencing according to claim 1, wherein:

existing step get location is modified to use a 15 second GPS timeout in a fast fix cycle.

13. A method of implementing a least squares geofence method, comprising:

determining a time and technique to gather sample location points for a target wireless device;

determining a location estimate for said target wireless device based on said gathered sample location points;

filtering said determined location estimate based on a current state of said target wireless device; and

determining if an event has been triggered.