Probabilistic reverse geocoding

• US 20100088019A1
• Filed: 10/06/2009
• Published: 04/08/2010
• Est. Priority Date: 10/06/2008
• Status: Active Grant

• Current Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Original Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Inventors: Hahn, John, Barcklay, Bob, Tsurutome, Kevin
• Granted Patent: US 8,396,658 B2
• Time in Patent Office: Days
• US Class Current: 701/201
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G01C 21/34 Route searching; Route guidance
• CPC Class Codes: G01C 21/3415 Dynamic re-routing, e.g. recalculating the route when the user deviates from calculated route or after detecting real-time traffic data or accidents

Abstract

The accuracy of a reverse geocode for a GPS fix in a mobile phone navigation device is improved significantly by considering together the user'"'"'s last known location on an original route, the elapsed time between the last known location on the original route and the latest GPS fix, and the likelihood that the user could have traveled from the last known location on the original route to one of numerous candidate locations (generated from the reverse geocode) in the elapsed time. The navigation server relies only on a GPS fix, timestamps, and a back-end routing database to provide improved or superior accuracy of reverse geocoding a GPS fix (selection of a point on a road) when a relevant user has deviated from the intended route. The reverse geocoding allows for accurate and functional re-routing capabilities.

Claims

1. A method of providing an accurate location to a portable navigation device in a congested area when in an off-route condition, comprising:

obtaining a latest location fix of said user'"'"'s wireless navigation device, said latest location fix being off-route;

obtaining a last known on-route location of a user'"'"'s wireless navigation device;

determining an elapsed time between said last known on-route location and said latest location fix;

performing a reverse geocode on said latest location fix resulting in a plurality of potential location candidates;

determining an estimated time of travel from said last known on-route location to each of said potential location candidates; and

mapping as a current location of said user'"'"'s wireless navigation device a one of said plurality of potential location candidates having a travel time closest to said elapsed time.

2. The method of providing an accurate location to a portable navigation device in a congested area when in an off-route condition according to claim 1, wherein:

said latest location fix is a global positioning system (GPS) fix.

3. The method of providing an accurate location to a portable navigation device in a congested area when in an off-route condition according to claim 1, further comprising:

calculating a new route from said current location to an original destination.

4. The method of providing an accurate location to a portable navigation device in a congested area when in an off-route condition according to claim 1, wherein:

said navigation device is portable.

5. The method of providing an accurate location to a portable navigation device in a congested area when in an off-route condition according to claim 1, wherein:

said navigation device is a wireless phone.

6. A method of providing navigation server-based support for a wireless navigation device, comprising:

considering together a user wireless device'"'"'s last known on-route location, a latest GPS fix of said user'"'"'s wireless device, and an elapsed time between said last known location on said original route and said latest GPS fix; and

determining a likelihood that said user'"'"'s wireless device could have traveled from said last known on-route location on said original route to one of a plurality of candidate locations generated from a reverse geocode, in said elapsed time;

determining an estimated time of travel from said last known on-route location to each of said plurality of candidate locations; and

providing mapping information based on a current location of said user'"'"'s wireless navigation device being determined as being a one of said plurality of potential location candidates having an estimated time of travel closest to said elapsed time.

7. The method of providing navigation server-based support for a wireless navigation device according to claim 6, further comprising:

calculating a new route from said current location to an original destination.

8. The method of providing navigation server-based support for a wireless navigation device according to claim 6, wherein:

said wireless navigation device is portable.

9. The method of providing navigation server-based support for a wireless navigation device according to claim 6, wherein:

said navigation device is a wireless phone.