Patent ID: 7418339

Claim:
A method for navigation guidance in a distributed navigation guidance system comprising a portable navigation device having a first navigation operating mode for requesting and receiving routelet data and navigation route data and operating in accordance with the routelet data and a second navigation operating mode for operating in accordance with the navigation route data, the method comprising the steps of: in the first navigation operating mode, transmitting a navigation route request comprising first location data and a destination location, the first location data determined in response to a present location of the portable navigation device when the navigation route request is transmitted and transmitting a routelet request comprising second location data, speed data and direction data, wherein the second location data and the speed and direction data are determined in response to a present location, a present speed and a present direction of travel, respectively, of the portable navigation device when the routelet request is transmitted; receiving routelet data; and operating in accordance with the received routelet data, wherein operating in accordance with the received routelet data includes switching operation of the portable navigation device from the first navigation operating mode to the second navigation operating mode in response to the received routelet data intersecting a main route, the main route defined by received navigation route data comprising routing data describing the main route from a route start location determined in response to the first location data to the destination location.