Navigation system for guiding a vehicle along a precomputed optimal route

A vehicle navigation system, which comprises:

• means for storing and retrieving map data;
• first means for detecting a present location of a vehicle;
• means for computing from said map data an original optimal route for said vehicle from a starting point to a destination;
• second means for detecting a deviation of said vehicle from said original optimal route;
• means, responsive to said second means for detecting, for displaying an indication that said vehicle is off said original optimal route;
• means for sending a command signal manually;
• first means, responsive to said command signal, for selecting a plurality of possible new starting points by searching said map data;
• each of said new starting points being located on a different road;
• each of said new starting points being located at a distance greater than a specified distance from said present location of said vehicle;
• said means for computing including means for making a first computation of a plurality of new optimal routes from each of said possible new starting points to said destination;
• second means for selecting a single new optimal route from among said plurality of new optimal routes;
• and
• said second means for selecting including means for selecting said single new optimal route when said second means for detecting detects that said vehicle is off said original optimal route.

A vehicle navigation system, which comprises:

• a CD ROM for storing and retrieving map data;
• a shaft sensor;
• a terrestrial magnetism sensor;
• said shaft sensor and said terrestrial magnetism sensor sending signals that determine a present location of a vehicle;
• a microcomputer for computing from said map data an original optimal route for said vehicle from a starting point to a destination;
• said signals from said shaft sensor and said terrestrial magnetism sensor permitting said microcomputer to detect a deviation of said vehicle from said original optimal route;
• said microcomputer including means for selecting a plurality of possible new starting points by searching said map data;
• each of said new starting points being located on a different road;
• each of said new starting points being located at a distance greater than a specified distance from said present location of said vehicle;
• said microcomputer including means for computing a plurality of new optimal routes from each of said possible new starting points to said destination;
• said microcomputer including means for selecting a single new optimal route from among said plurality of new optimal routes;
• and
• said microcomputer including means for selecting said single new optimal route when said shaft sensor, said terrestrial magnetism sensor, and said microcomputer cooperate to detect that said vehicle is off said original optimal route.

A vehicle navigation system, which comprises:

• a CD ROM for storing and retrieving map data;
• a shaft sensor;
• a terrestrial magnetism sensor;
• said shaft sensor and said terrestrial magnetism sensor sending signals that determine a present location of a vehicle;
• a microcomputer for computing from said map data an original optimal route for said vehicle from a starting point to a destination;
• said signals from said shaft sensor and said terrestrial magnetism sensor permitting said microcomputer to detect a deviation of said vehicle from said original optimal route;
• said microcomputer including means for signalling said deviation;
• a CRT display for displaying information;
• said CRT including means for indicating that said vehicle is off said original optimal route when said microcomputer signals said deviation;
• a manually operated switch for sending a command signal;
• said microcomputer including means for selecting a plurality of possible new starting points by searching said map data;
• each of said new starting points being located on a different road;
• each of said new starting points being located at a distance greater than a specified distance from said present location of said vehicle;
• said microcomputer being responsive to said command signal;
• said microcomputer including means for computing a plurality of new optimal routes from each of said possible new starting points to said destination;
• said microcomputer including means for selecting a single new optimal route from among said plurality of new optimal routes;
• and
• said microcomputer including means for selecting said single new optimal route when said shaft sensor, said terrestrial magnetism sensor, and said microcomputer cooperate to detect that said vehicle is off said original optimal route.