US Patent 7389179 Real-time navigation system for mobile environment

A system and method for providing navigational information to a user connected in real-time, such as through a wireless telephone, PDA, or other device. The system provides navigational information to the user in the form most useful to the user, such as according to landmarks, or the number of blocks until the next action. The system also provides directions to points of interest along the user's route. Further, the system allows the user to suspend and resume a session. Also, the system varies the sampling rate at which the user's location is examined, to enhance efficiency and convenience.