Navigation system and navigation equipment

Navigation equipment comprising:

• a communicating unit for communicating bi-directionally with a navigation server over a radio communication network;
• a positioning unit for determining a self-location;
• a control unit for transmitting position information delivered by said positioning unit to said navigation server through said communicating unit, and for acquiring, from said communicating unit, map information for display indicative of a map of a surrounding area including the self-location provided by said position information sent back from said navigation server, to perform map matching between road information included in said acquired map information for display and the position information determined by said positioning unit, thereby determining a current position of a mobile unit on a road;
• and
• a display unit for displaying a map in the form of an image in accordance with said map information for display and for displaying said current position determined by said control unit on said map displayed in the form of an image,
• wherein said control unit transmits the position information delivered by said positioning unit and information with regard to a destination to said navigation server, and acquires route information indicative of an optimal route and formed of only road information with regard to a road to said destination from the self-location provided by the position information sent back from said navigation server, to perform map matching between the route information sent back from said navigation server and the position information determined by said positioning unit, instead of performing map matching between the road information included in said map information for display and the position information determined by said positioning unit, thereby determining a current position to be displayed on said display unit.

A navigation system, comprising:

• a mobile unit capable of communicating with a navigation server over a radio communication network,
• wherein said mobile unit comprises:
• a communication device that communicates bi-directionally with said navigation server over said radio communication network;
• a positioning device that determines a self-location of the mobile unit;
• a controller that transmits position information determined by said positioning device to said navigation server through said communication device, and that receives map information from said navigation server through said communication device,
• wherein said map information represents a map of a surrounding area including said self-location,
• wherein said controller performs map matching between road information included in said map information and said position information determined by said positioning device to determine a current position of said mobile unit on a road represented by said road information,
• wherein said navigation server uses road information to produce optimum route information, and
• wherein the road information included in the map information for display is formed by data having a smaller capacity than the road information which is for use in producing the optimum route information by the navigation server.

A method of navigating a vehicle with a navigation system, the method comprising:

• determining a self-location of the vehicle;
• sending first transmission data to a navigation server over a communication network;
• receiving second transmission data from said navigation server over said communication network,
• wherein said second transmission data includes map data including a predetermined minimal amount of data for displaying line segments, which represent roads, on a displaying device,
• wherein said navigation server uses road information to produce optimum route information, and
• wherein said map data includes road information which is formed by data having a smaller capacity than another road information which is for use in producing the optimum route information by the navigation server.