Abstract:
The vehicle routing and guidance system includes a vehicle-based navigation system ( 35 ) located in a vehicle, which includes an input device ( 38 ) for entry of one or more destinations (B) to which the vehicle is to travel and a self-locating device for determining location of the vehicle, a superordinate server system ( 12 ) for making navigational information available to the navigation system, for determining a route ( 16 ) to the destination or destinations (B) provided to the navigation system and for dividing the route ( 16 ) piecewise into route sections ( 34 ), and transmitter and receiver devices for at least temporarily establishing communication between the server system ( 12 ) and the navigation system ( 35 ) to transmit the route sections ( 34 ) separately to the navigation system ( 35 ) so that the route ( 16 ) is transmitted in a piecewise manner to the navigation system ( 35 ).

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a vehicle routing and guidance system and, more particularly, to a vehicle routing and guidance comprising a navigation system that includes a self-locating means for the vehicle and a superordinate server system for making of navigational information available to the navigation system, whereby the navigational system communicates with the server system at least temporarily by means of transmitter and receiver devices.  
           [0003]    2. Prior Art  
           [0004]    Vehicle-based navigation systems are known for guidance of vehicles. These systems use map information required for navigation in the vehicle in order to guide the vehicle to a destination point predetermined by the operator of the vehicle. All information required for the entire route is supplied in the vehicle. It is disadvantageous however that a correspondingly large memory capacity is required for the memory used in the navigation system for a number of different destinations over a comparatively large region or territory. Furthermore it is also disadvantageous that information effecting the destination of the vehicle, for example detours, road blockages and so on, is not considered.  
           [0005]    Furthermore superordinate server systems for preparation of navigational data are known, by means of which routes corresponding to a destination predetermined by the operator of the vehicle are transmitted to the vehicle-based navigation system. The entire navigational information for the chosen destination is transmitted. It is disadvantageous therefore that a comparatively large amount of information is to be transmitted and changes during travel over the route can no longer be considered.  
           [0006]    By “route” a section of a digital chart or map with at least one destination, which is useable in a vehicle-based navigation system, is to be understood. For guidance to the destination the vehicle must be located on the digital chart, which means the route.  
           [0007]    Furthermore vehicle routing and guidance systems are known that include traffic guidance devices arranged at fixed locations along a path of travel of the vehicle, by means of which navigational information corresponding to the selected route is transmitted from those traffic guidance devices that the vehicle passes during its travel.  
         SUMMARY OF THE INVENTION  
         [0008]    It is an object of the present invention to provide an improved vehicle routing and guidance system that does not have the above-described disadvantages.  
           [0009]    These objects, and others which will be made more apparent hereinafter, are attained in a vehicle routing and guidance system comprising a vehicle-based navigation system that includes a self-locating means for the vehicle and a superordinate server system for making navigational information available to the navigation system, whereby the navigation system communicates with the superordinate server system at least temporarily by means of transmitter and receiver devices.  
           [0010]    According to the invention, the navigation system includes an input device by which at least one destination is input thereto, the server system includes means for determining a route for the vehicle from the at least one destination and means for transmitting the route determined from the at least one destination piecewise to the navigation system.  
           [0011]    The vehicle routing and guidance system according to the invention has the advantage that it provides an efficient dynamic guidance to a destination, which means that actual changes by means of additional further transmissions of navigational information are possible during travel of the vehicle over the route, by determining the position of the vehicle by means of a comparatively simple built-in vehicle-based navigational system, for example a GPS, and by an exchange of comparatively little information for route guidance with the server system communicating with the navigational system. It is advantageously possible to provide the required memory capacity needed for the route section prepared by the server system in the memory of the vehicle-based navigation system because the navigation system includes an input device by which at least one destination is input thereto, the server system includes means for determining a route for the vehicle from the at least one destination and means for transmitting the route determined from the at least one destination piecewise to the navigation system. The term ‘piecewise transmission’ means that each route section is transmitted to the vehicle-based navigation system only when the previous route section has been traversed. By piecewise transmission of the entire route in route sections prior to reaching the destination, changes can be considered in sections or parts of the route over which the vehicle has not traveled during its travel over the route and can be transmitted to the navigation system. Thus dynamic navigational information of significant events which are comparatively far removed from the actual position of the vehicle can be made available to the navigation system over the entire route, without adding memory capacity in the vehicle-based navigation system and additional data transmission capacity for communication between the navigation system and the central server system. When an actual position of the vehicle transmitted to the server system is just in the next route section, the actual route section already prepared by the central server is then transmitted to the navigation system of the vehicle.  
           [0012]    In another embodiment the vehicle routing and guidance system according to the invention comprises a vehicle-based navigation system located in a vehicle, a superordinate server system for making navigational information available to the navigation system including means for establishing a communications link between the navigation system and the server system prior to start of travel of the vehicle for transmission of a most updated route for vehicle travel from a predetermined destination from the server system to the navigation system and transmitter and receiver means for at least temporarily establishing communication between the server system and the navigation system. This embodiment provides the advantage that the vehicle-based navigation system can be loaded with an updated or actual route according to the destination selected immediately prior to start. Since the navigation system is connected with the server system prior to the start of travel so that the updated route derived from the predetermined destination by the server system is read into the navigation system, it is advantageously possible to take into account all traffic information since the beginning of travel in preparing the travel route. The vehicle-based navigation system needs no large memory capacity to set up routes to all eventually possible destinations since only the actual route associated with the particular actual destination is copied into the navigation system and needs to be stored in it. Furthermore travel or traffic information, for example, street blockages, current traffic density, traffic predictions and the like, can be taken into account in preparing the route in a timely manner up to the start of travel. It is preferable when the navigation system is connected with the server system by means of a telecommunications server, for example a wired or wireless telecommunications network, for copying of the route information.  
           [0013]    In another preferred embodiment of the invention certain selectable, for example repeatedly used routes, are stored in the navigation system. The route corresponding to the actually selected route is updated by the server system via the communications link before travel starts. Thus dynamic navigational information is made available in the vehicle results, which means taking updated traffic information into consideration.  
           [0014]    Additional advantageous embodiments of the invention result from other features claimed in the appended dependent claims.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0015]    The objects, features and advantages of the invention will now be illustrated in more detail with the aid of the following description of the preferred embodiments, with reference to the accompanying figures in which:  
         [0016]    [0016]FIGS. 1 a  and  1   b  are, respectively, a simplified block diagram of a central server for a vehicle routing and guidance system according to the invention and a portion of a map showing a starting point and destination used by the vehicle routing and guidance system according to the invention; and  
         [0017]    [0017]FIG. 2 is a simplified block diagram of a vehicle routing and guidance system according to the invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    A map  10  is shown schematically in FIG. 1 b , with the aid of which the vehicle routing and guidance system according to the invention is explained in more detail. The present example is based on an unshown motor vehicle traveling from a starting point A on the map to a destination B. The driver of the vehicle enters the destination B into his vehicle-based navigation system  53  at the starting point A. The navigation system  53  sets up a wireless communications link  14  with the central server  12  as shown in FIG. 1 a . The communications link  14  can be made, for example, by cellular telephone. The vehicle and also the central server have receiver and transmitter devices  13 .  
         [0019]    The server system  12  conducts the information, namely the aforementioned destination B, to a processor  17 , which computes an optimum route  16  for reaching the destination with the aid of a detailed map of the entire area stored in the processor  17 . This route  16  is produced from the stored map  10  and additional actual external traffic information  18 , with which the central server is continuously provided. The traffic information  18  can include, for example, information regarding blocked streets, traffic congestion, unfavorable weather conditions and the like.  
         [0020]    The route  16  is transmitted to the vehicle piecewise by means of the communications link  14  considering the traffic information  18  and the map  10 . The individual sections of the route  16  are transmitted to the vehicle according to a previously established division of the map  10 . The map  10  is divided into certain region, of which here, for example, the region  20 , region  22 , region  24 , region  26 , region  28  and region  30  are named. The division of the regions  20  to  30  and also other unshown region can be according to geographic conditions, administrative organizations (districts, municipalities, townships and so forth) or other freely selectable criteria. The individual regions  20  to  30  border each other at respective transmission points  32 (For simplicity of illustration only one transmission point  32  is shown in FIG. 1, but they exist between all regions of the map  10 ). The division of the regions with the aid of travel-specific border conditions is advantageous. A partial route or route section can be, for example, limited to one region on the highway during a long-distance journey on the highway and cover a comparatively large distance. The route covers all streets during a city trip and covers a comparatively small distance.  
         [0021]    The best route  16  for the vehicle is determined in the central server  12 , separately acquired and stored in the central server according to the requirements of the vehicle that travels from starting point A to destination B. For example, the route  16  passes through the regions  20 ,  22 ,  24 ,  26 ,  28  and  30 . First a first section  34  of the route  16 , which is associated with the section or portion of the route  16  in the region  20 , is copied to the navigation system of the vehicle. A detailed digital map exclusively for the region  20  is transmitted to the navigation system of the vehicle. Since the navigation system of the vehicle does not detect and store the entire detailed map  10 , but only the region  20 , a correspondingly small memory capacity is provided in the navigation system. Next the transmission point  32  between the regions  20  and  22  is provided as an intermediate destination for the navigation system of the vehicle. This means that the driver of the vehicle obtains no information from this intermediate goal regarding when he will arrive at the destination B. The autonomous intermediate destination at the transmission point  32  between the regions  20  and  22  is however the apparent destination for the navigation system of the vehicle.  
         [0022]    The navigation system of the vehicle can provide the driver or operator with the required information in different ways, for example by display of a suitable map on a display device, by a digital speech synthesizer or other digital or analog devices for guiding the vehicle.  
         [0023]    The server system  12  detects an approach of the vehicle to the transmission point  32  between the regions  20  and  22  by means of the navigation system in the vehicle. The next section of the route  16 , which, in the indicated example, is in region  22 , is copied to the navigation system of the vehicle by means of the receiver and transmitter devices  13  when the vehicle reaches the transmission point  32  or shortly prior to reaching the transmission point  32 . Since the region  20  has already been traversed, the navigational information for it can be erased. Thus no additional memory capacity is required.  
         [0024]    When the portion of the route  16  in the region  22  is first copied to the navigation system on reaching the transmission point  32 , traffic information  18  generated since the start of the journey from the starting point A can be processed by the processor  17  and considered in set up the actual or updated route  16  to be traveled. The internal route that is set up by the central server  12  can change during the actual travel over the route  16  without the driver&#39;s knowledge. The copying of the next section of the route on reaching the next transmission point between the regions  22  and  24  occurs in an analogous manner, which means in this case copying the section of the route in the region  24  from the central server  12  to the navigation system of the vehicle. This process is continued until the destination B is reached.  
         [0025]    As a whole the vehicle routing and guidance system advantageously divides the work required for navigation of the vehicle between internal navigation system in the vehicle and the central server  12 . The powerful processor  17  of the central server  12  performs the comparatively difficult calculation of the route  16  and its continuous updating, even after the start of the journey from the starting point A. Thus a dynamic guidance of the vehicle is possible, since updated traffic information  18  is considered during set up or change of the route  16 . The autonomous navigation system of the vehicle only needs to have a small memory capacity, since the route is only stored piecewise with respect to regions  20  to  30 . The navigation system only detects the autonomous intermediate destinations at the transmission points, that are not known to the operator, since they are subordinated to the reaching of the final destination B.  
         [0026]    A deviation of the vehicle from the predetermined route  16  is detected by the server system  12  by means of a self-location of the vehicle, so that immediate influences can be immediately taken into consideration for an eventual change of route  16  during preparation of the navigational information. Either the information that the original predetermined route  16  was abandoned is transmitted to the operator of the vehicle or a new route  16  is prepared internally, which means not known to the operator of the vehicle and copied to the navigation system. Changes in the subsequent regions  20  to  30  resulting from the changes of the route  16  are then considered internally by the server system  12 , when the sections of the route  16  passing through the respective regions  20  to  30  to be later traversed are transmitted on reaching the respective transmission points.  
         [0027]    An additional embodiment of the vehicle routing and guidance system according to the invention is shown schematically in FIG. 2. The same parts as in FIG. 1 are provided with the same reference number in FIG. 1 and are not explained in further detail.  
         [0028]    According to the embodiment shown in FIG. 2 the autonomous navigation system  35  of the vehicle is connected with the central server  12  by a communications link  14  before the start of the trip. The communications link  14  can be a line connection, such as a telephone line, a broad band cable or similar connection, in this case. Furthermore the radio link illustration in FIG. 1 to the central server  12  can also occur. The navigation system  35  has an interface  36 , by which communication with the central sever  12  is possible. The destination B is transmitted to the central server  12  by means of an input device  38 . The optimum route  16  is determined by the processor  17  of the central sever and transmitted to the navigation system  35 . The navigation system  35  has a memory unit  38 , in which the navigational information transmitted according to the route  16  can be stored. Since a loading of the route  16  in the memory can occur shortly prior to the start of the trip or journey, the updated traffic information  18  from the processor  17  can be considered in planning the optimum route  16 .  
         [0029]    In practice either the memory  38  of the navigation system  35  is portable, for example in the form of a diskette or CD-ROM or DVD, which is insertable in a suitable data processing unit for storing the actual route  16  or the navigation system  35  is coupled directly with the communications link  14  via the interface  36 . Since only the actual route  16  is stored in the memory  38 , the memory capacity can be reduced to a required minimum, since the entire map  10  (FIG. 1) with all the eventual possible destinations does not need to be stored in it.  
         [0030]    If necessary the memory  38  can store several routes usually used as standard routes by the vehicle. By connection to the central server  12  shortly prior to the start of the trip an update of the route  16  can take place, whereby the actual traffic information currently available in the central server  12  is considered in planing the route  16 . Also the advantage that the entire road network with all its destinations does not need to be made available or stored in the navigation system  35  results.  
         [0031]    A combination of the embodiments of FIGS. 1 and 2 for the vehicle routing and guidance system is possible. Thus prior to the start of the journey a route  16  corresponding to a selected destination B can be loaded into the navigation system  35 , by means of an line-type communications link  14 , for example by means of an ISDN. The actual position of the vehicle is monitored by the central server  12  by means of a self-location performed by the vehicle during its travel over the route  16  from the starting point A to the destination B. Only when changes in the route  16  in individual regions  20  to  30  through which the route  16  passes occur in the intervening time, which means after loading the route  16 , an appropriate data exchange and correction of the route  16  occurs in the navigation system  35  by means of updated traffic information  18 . The data exchange is kept to a minimum during travel because the data exchange only concerns the eventually required changes in the route  16 .  
         [0032]    The present invention is not limited to the above-described embodiments. For example, it is also possible to input several destinations, instead of a single destination B, with the help of knowledge from a customer service representative, or with commercial carriers, whereby the central server  12  determines an optimum route  16  for travel to several destinations.  
         [0033]    The disclosure in German Patent Application 197 37 256.2-32 of Aug. 27, 1997 is incorporated here by reference. This German Patent Application, at least in part, describes the invention described hereinabove and claimed in the claims appended hereininbelow and provides the basis for a claim of priority for the instant invention under 35 U.S.C. 119.  
         [0034]    While the invention has been illustrated and described as embodied in a vehicle routing and guidance system, it is not intended to be limited to the details shown, since various modifications and changes may be made without departing in any way from the spirit of the present invention.  
         [0035]    Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.  
         [0036]    What is claimed is new and is set forth in the following appended claims.