Electronic navigation system and method

Abstract

The invention provides a method and system for providing route guidance and other information from a base unit to a remote unit in response to a request from the remote unit. A query is formatted at the remote unit, the query including the request, and is transmitted from the remote unit to the base unit. Requested route guidance information is calculated at the base unit in response to the query, using a large up-to-date database located at the base unit. A response to the query is formatted at the base unit, the response including route guidance information. The response is then transmitted from the base unit to the remote unit for display. The transmission is made in a compact form through the use of maneuver arms and combined maneuver arms and through the use of tokenized forms. A maneuver arm represents a road at an intersection, for depiction on a display, by one or two endpoint coordinates. The tokenized forms are expanded at the remote unit into textual driving instructions for each of one or more languages. In addition, the amount of information available at a remote unit can be increased by providing the remote unit with information from the base unit which is not adequately covered by any databases on-board the remote unit.

What is claimed is:  
     
         1 . A method of transmitting route directions in a compact form, comprising the steps of: 
 (a) generating a first set of maneuver arms to depict a first intersection on a display, each maneuver arm of the first set of maneuver arms being represented by at least one endpoint;    (b) generating a second set of maneuver arms to depict a second intersection on a display, each maneuver arm of the second set of maneuver arms being represented by at least one endpoint;    (c) comparing the proximity of the first intersection and the second intersection and, if the first intersection and the second intersection are within a predetermined range of each other, combining the first set of maneuver arms with the second set of maneuver arms to produce a combined set of endpoints to depict the first set of maneuver arms and the second set of maneuver arms on a common display; and    (d) transmitting the combined set of endpoints to a remote unit in electromagnetic form.    
     
     
         2 . A method of efficiently transmitting routing directions, comprising the steps of: 
 (a) generating a routing direction for a user;    (b) expressing the routing direction in at least one of a plurality of tokenized forms, each of said plurality of tokenized forms representing a pre-defined routing direction in compact form;    (c) electromagnetically transmitting said at least one of said plurality of tokenized forms to a remote unit;    (d) receiving said at least one of said plurality of tokenized forms at said remote unit; and    (e) at said remote unit, expanding said at least one of said plurality of tokenized forms received in step (d) into a textual driving instruction for display to a user at said remote unit.    
     
     
         3 . A method as set forth in  claim 2 , further comprising the steps of: 
 (f) receiving instructions from said user specifying that textual driving instructions be displayed in one or more languages; and    (g) at said remote unit, expanding said at least one of said plurality of tokenized forms, received in step (d), into a textual driving instruction for each of said one or more languages specified in step (f).    
     
     
         4 . A method as set forth in  claim 2 , further comprising the steps of: 
 (f) in step (c), transmitting a road name to said remote unit along with said one of said plurality of tokenized forms; and    (g) in step (e), inserting the road name transmitted in step (f) into expanded text corresponding to said at least one of said plurality of tokenized forms received in step (d).    
     
     
         5 . A method of expanding the amount of information available to a remote unit in a routing. system having a base unit and a remote unit, comprising the steps of: 
 (a) electromagnetically transmitting a route request from the remote unit to the base unit;    (b) electromagnetically transmitting a route from the base unit to the remote unit in response to the route request of step (a);    (c) receiving in the remote unit the route transmitted in step (b);    (d) in the remote unit, comparing the route received in step (c) with a coverage of any databases on-board the remote unit;    (e) if the route received in step (c) is not adequately covered by any databases on-board the remote unit, electromagnetically transmitting from the remote unit to the base unit a request for the base unit to provide information which is not adequately covered by any databases on-board the remote unit; and    (f) receiving in the remote unit said information which is not adequately covered by any databases on-board the remote unit in response to the request of step (e).    
     
     
         6 . A method as set forth in  claim 5 , wherein step (f) includes receiving in the remote unit map information which is not adequately covered by any databases on-board the remote unit in response to the request of step (e).  
     
     
         7 . A system for generating and transmitting route directions in a compact form, comprising: 
 (a) a base unit which 
 (i) generates a first set of maneuver arms to depict a first intersection on a display, each maneuver arm of the first set of maneuver arms being represented by at least one endpoint,  
 (ii) generates a second set of maneuver arms to depict a second intersection on a display, each maneuver arm of the second set of maneuver arms being represented by at least one endpoint, and  
 (iii) compares the proximity of the first intersection and the second intersection and, if the first intersection and the second intersection are within a predetermined range of each other, combines the first set of maneuver arms with the second set of maneuver arms to produce a combined set of endpoints to depict the first set of maneuver arms and the second set of maneuver arms on a common display; and  
   (b) a communications link to transmit the combined set of endpoints to a remote unit in electromagnetic form.    
     
     
         8 . A system for generating and transmitting routing directions efficiently, comprising: 
 (a) a base unit which 
 (i) generates a routing direction for a user, and  
 (ii) expresses the routing direction in at least one of a plurality of tokenized forms, each of said plurality of tokenized forms representing a pre-defined routing direction in compact form;  
   (b) a communications link to electromagnetically transmit said at least one of said plurality of tokenized forms; and    (c) a remote unit which 
 (i) receives said at least one of said plurality of tokenized forms from the communications link, and  
 (ii) expands said at least one of said plurality of tokenized forms into a textual driving instruction for communication to a user at said remote unit.  
   
     
     
         9 . A system as set forth in  claim 8 , wherein: 
 the remote unit receives instructions from the user specifying that textual driving instructions be displayed in one or more languages; and    the remote unit expands said at least one of said plurality of tokenized forms into a textual driving instruction for each of said one or more languages specified by the user.    
     
     
         10 . A system as set forth in  claim 8 , wherein: 
 the communications link transmits a road name to said remote unit along with said one of said plurality of tokenized forms; and    the remote unit inserts the road name transmitted by the communications link into expanded text corresponding to said at least one of said plurality of tokenized forms.    
     
     
         11 . A system as set forth in  claim 8 , wherein the remote unit includes a display for said communication to said user at said remote unit.  
     
     
         12 . A system as set forth in  claim 8 , wherein the remote unit includes an annunciator for said communication to said user at said remote unit.  
     
     
         13 . A routing system which makes a large amount of information available to a remote unit, the system comprising: 
 (a) a base unit;    (b) a remote unit; and    (c) a communications link to electromagnetically transmit a route request from the remote unit to the base unit and to electromagnetically transmit a route from the base unit to the remote unit in response to the route request;    wherein the remote unit 
 (i) receives the route transmitted by the communications link,  
 (ii) compares the route received with a coverage of any databases on-board the remote unit, and  
 (iii) if the route received is not adequately covered by any databases on-board the remote unit, electromagnetically transmits from the remote unit to the base unit, via the communications link, an additional request for the base unit to provide information which not adequately covered by any databases on-board the remote unit.  
   
     
     
         14 . A routing system as set forth in  claim 13 , wherein the remote unit receives map information which is not adequately covered by any databases on-board the remote unit in response to said additional request.  
     
     
         15 . A method of efficiently transmitting routing directions, comprising the steps of: 
 (a) generating a routing direction for a user;    (b) expressing the routing direction in at least one of a plurality of tokenized forms, each of said plurality of tokenized forms representing a pre-defined routing direction in compact form;    (c) electromagnetically transmitting said at least one of said plurality of tokenized forms to a remote unit;    (d) receiving said at least one of said plurality of tokenized forms at said remote unit; and    (e) at said remote unit, expanding said at least lone of said plurality of tokenized forms received in step (d) into a textual driving instruction for annunciation to a user at said remote unit.