Probabilistic Reverse Geocoding

摘要

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 travelled 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.

主权项

1. A method of providing an accurate location to a portable navigation device in a congested area when 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.