Abstract:
A method of controlling a navigation system. Navigation systems which are capable of gathering historical information concerning routes taken by a number of individual vehicles are known. Such systems rely on a central database to analyse and store the historical information of all the participating vehicles. The central database can therefore suggest an improved route to a vehicle based on the analysis of the information gathered from the participating vehicles. However, as the central database analyses historical information received from a number of different types of vehicles (e.g. delivery trucks, taxis, motorbikes etc.), the routes suggested by the system are often inappropriate for a specific type of vehicle. For example, a route which is appropriate for a motorbike is often not appropriate for a truck, and vice versa. A method of controlling a navigation system is provided which builds up historical information of routes taken by a vehicle and uses this information to provide an appropriate route for the vehicle based upon deviations from suggested routes stored upon a mobile computer unit of the navigation system of the vehicle.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to the information technology field. More specifically, the invention relates to navigation systems. 
       BACKGROUND ART 
       [0002]    Navigation systems have become increasingly popular in recent years. A navigation system consists of a small electronic device that aids a driver of a vehicle to reach a desired destination. Navigation systems are particularly useful for people visiting areas they are not familiar with. 
         [0003]    Navigation systems operate by knowing where the navigation unit is positioned by using Global Positioning Satellites (GPS) and by applying that position to a context provided by a map and by a desired destination. The navigation system can then suggest how the driver of a vehicle (for example) should act (e.g. turn right in 500 metres) to get to the desired destination according to possible route alternatives (defined in the map) and personal preferences (e.g. avoiding motorways). 
         [0004]    The context can be augmented using additional information such as broadcasts of traffic information (traffic jams on certain routes). U.S. Pat. No. 5,610,821 discloses a system for determining optimal vehicle routes using current traffic flow information. The system receives current traffic flow information from a number of individual vehicles and uses this information to identify when a traffic flow problem exists. Once the system has identified that a traffic problem exists, it re-calculates a new route based on the information received from the vehicles. The system therefore continuously monitors the traffic flow of a road network and provides alternative routes when traffic flow problems are identified. 
         [0005]    The system of U.S. Pat. No. 5,610,821 relies upon receiving dynamic feedback traffic flow information from the individual vehicles, but often local knowledge is the only way to choose one route over another in terms of efficiency. Local knowledge, for example, could be that cars often double-park on a particular street, reducing its effective width, road conditions, such as potholes, and so on. 
         [0006]    Navigation systems exist which are capable of gathering historical information concerning routes taken by a number of individual vehicles. Such systems rely on a central database to analyse and store the historical information of all the participating vehicles. The central database can therefore suggest an improved route to a vehicle based on the analysis of the information gathered from the participating vehicles. However, such systems are often troublesome and costly to administrate. Furthermore, as the central database analyses historical information received from a number of different types of vehicles (e.g. delivery trucks, taxis, motorbikes etc.), the routes suggested by the system are often inappropriate for a specific type of vehicle. For example, a route which is appropriate for a motorbike is often not appropriate for a truck, and vice versa. 
         [0007]    Navigation systems, such as those discussed above, are therefore limited in that they are expensive to administrate and often cannot suggest the optimal route to the driver of a specific type vehicle. 
       SUMMARY OF THE INVENTION 
       [0008]    According to the present invention there is provided a method of controlling a navigation system. The method including the steps of: inputting an indication of a destination location to a mobile computer unit; monitoring the current location of the mobile computer unit; outputting a suggested route for reaching the destination location from the current location along a route selected on a predefined map, wherein the suggested route is determined by the mobile computer unit and takes into consideration traffic data stored on the mobile computer unit; monitoring deviations from the suggested route; and using the monitored deviations to improve the traffic data stored on the mobile computer unit. 
         [0009]    Another aspect of the present invention provides a computer program for performing the above-described method. 
         [0010]    A still further aspect of the present invention provides a system including means for performing the steps of the above-described method. 
         [0011]    A still further aspect of the present invention provides mobile computer unit for a navigation system, the mobile computer unit comprising: means for inputting an indication of a destination location to the mobile computer unit; means for storing traffic data; means for calculating a suggested route for reaching the destination location from a current location along a route selected on a predefined map, wherein the suggested route is calculated by the mobile computer unit and takes into consideration traffic data stored on the mobile computer unit; means for outputting the suggested route; means for monitoring deviations from the suggested route; means for improving the traffic data using the monitored deviations. 
         [0012]    Further embodiments of the invention are provided in the appended dependent claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The invention itself, as well as further features and the advantages thereof, will be best understood with reference to the following detailed description, given purely by way of a non-restrictive indication, to be read in conjunction with the accompanying drawings, in which: 
           [0014]      FIG. 1  is a schematic block diagram of a data processing system in which the method of the invention is applicable; 
           [0015]      FIG. 2  shows the functional blocks of a generic computer system; 
           [0016]      FIG. 3  shows a system suitable for implementing the present invention; 
           [0017]      FIG. 4  shows exemplary applications of the solution according to an embodiment of the invention; and 
           [0018]      FIG. 5  shows a diagram describing the flow of activities relating to an illustrative implementation of the method. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    With reference in particular to  FIG. 1 , a data processing system  100  with distributed architecture implementing a Navigation System, is depicted. The system  100  includes multiple endpoints  105 , which are grouped into different sets. The endpoints  105  can be mobile units, vehicle units and more generally any kind of data processing system capable of receiving signal from the Central Navigation Server. The endpoints  105  are connected to the Central Navigation Server  115  through wireless networks  110 - 120  (for example, a GPS or GSM networks). The Central Navigation Server  115  maintains a repository where traffic data maps and routes are collected and managed. 
         [0020]    As shown in  FIG. 2 , a generic computer of the system (e.g. mobile computer unit, central server, router, transmitter) is denoted with  150 . The computer  150  is formed by several units that are connected in parallel to a system bus  153 . In detail, one or more microprocessors (mP)  156  control operation of the computer  150 ; a RAM  159  is directly used as a working memory by the microprocessors  156 , and a ROM  162  stores basic code for a bootstrap of the computer  150 . Peripheral units are clustered around a local bus  165  (by means of respective interfaces). Particularly, a mass memory consists of a hard-disk  168  and a drive  171  for reading CD-ROMs  174 . Moreover, the computer  150  includes input devices  177  (for example, a keyboard and a mouse), and output devices  180  (for example, a monitor and a printer). A Network Interface Card (NIC)  183  is used to connect the computer  150  to the network. A bridge unit  186  interfaces the system bus  153  with the local bus  165 . Each microprocessor  156  and the bridge unit  186  can operate as master agents requesting an access to the system bus  153  for transmitting information. An arbiter  189  manages the granting of the access with mutual exclusion to the system bus  153 . 
         [0021]    Similar considerations apply if the system has a different topology, or it is based on other networks. Alternatively, the computers have a different structure, include equivalent units, or consist of other data processing entities (such as PDAs, mobile phones, and the like). In any case, the solution of the invention is also suitable to be used in a system wherein the control of the workstations is decentralized, or even in a stand-alone computer. For example, in a in-vehicle satellite navigation system or a hand-held satellite navigation system. 
         [0022]      FIG. 3  shows a system suitable for implementing the present invention. As shown in  FIG. 3 , there is provided a constellation of navigation satellites  311 ,  312  and  313  belonging for example to the GPS or Galileo systems. There is further provided a vehicle  400  carrying a navigation system  416 . The navigation system includes a mobile computer unit  416   a  which includes a user interface unit  416   b , a satellite positioning receiver  331  and cellular communication device  341 . The satellite positioning receiver  331  receives timing data transmitted by the navigation satellites  311 ,  312  and  313  and thereby determines the instantaneous position of the vehicle  400  in which it is located. There is further provided a cellular telephone network  360 , which is capable of bi-directional communication with the cellular communication device  341 . There is further provided a navigation processor  370 , connected to the cellular telephone network  360  as well as a map database  381  and a journey database  382 . 
         [0023]    The system typically works by a user in the vehicle  400  entering a request for navigation information to a particular destination into the vehicle&#39;s mobile computer unit  416   a . The satellite positioning receiver  331  processes signals received from the navigation satellites  311 ,  312  and  313  so as to determine the position of the vehicle  400 . The cellular communication device  341  is used to transmit the request data from the mobile computer unit  416   a  and the position data from the satellite positioning receiver  331  to the navigation processor  370  by means of the cellular telephone network  360 . On receiving at least a present position and destination information, the navigation processor  370  implements a routing algorithm with reference to the map database  381  so as to determine a preferred route between the present position of the vehicle  400  and the destination. This route may be added to a central journey database  382 . 
         [0024]    When a large number of vehicles of different types submit similar journey information to a navigation system having a central database, the improved route suggested the system is often inappropriate for a specific type of vehicle. For example, if the journey information submitted to the system comes mainly from motorbikes, then the improved route suggested by the system may not be appropriate for trucks. 
         [0025]    Thus according to the present invention, a method of controlling a navigation system is provided which provides optimal route suggestions to specific vehicles. 
         [0026]    In the following example a journey is described between one node and another, by convention the journey starts at the first node mentioned and terminates at the second. Obviously, the journey as described may form parts of larger journeys. 
         [0027]      FIG. 4  exemplifies an embodiment of the invention. In  FIG. 4  there is shown a road network within which the vehicle  400  is travelling. The network comprises a starting node  410 , a finishing node  412  and a plurality of roads  414   a - 414   d . The starting node  410  defines the starting point of the journey and the finishing node  412  defines the finishing point of the journey. 
         [0028]    As illustrated in  FIG. 4 , the vehicle  400  has requested navigation information from the starting node  410  to the finishing node  412 . The computer unit  416   a  performs a calculation in order to determine the optimal route for the vehicle  400 . The computer unit  416   a  typically tries to determine the quickest route from starting node  410  to finishing node  412  and suggests this as the optimal route for the vehicle  400 . However, the computer unit  416   a  is also adapted to take into consideration predetermined user preferences when determining the optimal route for the vehicle  400 , e.g. avoid motorways etc. 
         [0029]    As illustrated in  FIG. 4 , the computer unit  416   a  has suggested that the vehicle  400  takes roads  414   a  then  414   b  and then  414   c  as the optimal route to get from starting node  410  to finishing node  412 . 
         [0030]    During the journey, the computer unit  416   a  continuously monitors the location of the vehicle  400  and records any deviations which the vehicle  400  takes from the suggested route. For example, in the present example illustrated in  FIG. 4 , although the computer unit  416   a  has suggested taking roads  414   a ,  414   b  and  414   c , the computer unit  416   a  notes that the vehicle actually takes roads  414   a ,  414   d  and  414   c  in order to get from starting node  410  to finish node  412 . The noted deviation is stored on the mobile computer unit  416   a.    
         [0031]    The vehicle  400  may deviate from the suggested route because the driver has a local knowledge of the area. Local knowledge could be that cars often double-park on a particular street thus reducing its width, road conditions such as potholes etc. Also, depending on the type of vehicle being driven, e.g. motorbike, truck etc., the driver may exercise this local knowledge to avoid certain roads. 
         [0032]    For each repeated journey, i.e. each time the vehicle  400  requests navigation information from starting node  410  to finishing node  412 , the computer unit  416   a  notes any deviations from the suggested route and stores them in its internal memory. In this way the mobile computer unit  416   a  gathers historical information on the actual route taken by the vehicle  400  instead of the originally suggested route. 
         [0033]    Once the computer unit  416   a  builds up a sufficient body of historical information about the journey from starting node  410  to finish node  412 , it then begins to take into consideration the deviations from the suggested route when determining the suggested route. 
         [0034]    For example, the computer unit  416   a  compares the number or times a deviation from the suggested route was taken with the number of times the suggested route was taken. If the number of times a deviation from the suggested route is at least 85% then the computer unit  416   a  can give an option of taking the originally suggested route, or taking the deviation from this route. In this way the vehicle  400  knows that there is an alternative option to the originally suggested route. The computer unit  416   a  may present the alternative route to the user of the vehicle  400  as a route which has been taken more commonly than the original suggested route. 
         [0035]    Alternatively, once the computer unit  416   a  has determined that the ratio between the number of times a deviation from the suggested route is taken and the number of times the suggested route was taken satisfies a predetermined criteria, the computer  416   a  may consider this deviated route to be the optimal route and modify the originally suggested route to match the newly determined optimal route. In this way, the computer unit  416   a  always presents the optimal route as the suggested route for the vehicle  400 . 
         [0036]    In this way the computer unit  416   a  can determine an optimal route based on local knowledge of the area. It should be appreciated that the computer unit  416   a  can continuously compare any deviations from suggested routes and present alternative routes for the vehicle  400  or modify original routes to match newly determined routes. 
         [0037]    With reference to  FIG. 5 , the logic flow of controlling the navigation system according to an embodiment of the invention is illustrated with a method  500 . The method begins at the black start circle  510 . Continuing to block  512  an indication of a destination location is input to the mobile computer unit  416   a . At step  514  the current location of the mobile computer unit  416   a  is monitored. At step  516  the computer unit  416   a  determines a suggested route for reaching the destination location from the current location along a route selected on a predefined map. At step  518  the computer unit  416   a  checks to see if there are any recorded deviations from this previously suggested route. If there are no recorded deviations from this previously suggested route, the method moves on to step  520  where the computer unit  416   a  outputs the suggested route. At step  522  the computer unit  416   a  monitors the vehicle along the suggested route and records any deviations from the suggested route. The mobile computer unit  416   a  stores any deviations from the suggested route thereon for future use. If there are recorded deviations from this previously suggested route, the method moves on to step  524  where the computer  416   a  considers whether the suggested route should be modified to match a previously deviated route. If the computer unit  416   a  considers that the suggested route should not be modified the method moves to step  520 . If the computer unit  416   a  considers that the suggested route should be modified the method moves to step  526  where the computer unit  416   a  outputs the modified suggested route. At step  528  the computer unit  416   a  monitors the vehicle along the modified suggested route and records any deviations from the modified suggested route. The mobile computer unit  416   a  stores any deviations from the modified suggested route thereon for future use. 
         [0038]    Although only one particular journey has been illustrated and described here, it should be appreciated that the mobile computer unit  416   a  can monitor deviations from a plurality of repeated journeys and determine optimal routes for each one based on gathered local knowledge. 
         [0039]    The navigation system  416  of the present invention is intended to build up historical information of optimal routes of individual vehicles based on deviations from originally suggested routes. The navigation system  416  is intended to gather local knowledge of the optimal routes for the particular vehicle and to provide these optimal routes as alternatives to the user of the vehicle, or to modify original routes based on the recorded deviations. As the optimal routes are particular the vehicle in which the navigation system  416  is fitted, the problem of getting an inappropriate route is avoided. 
         [0040]    The navigation system  416  is particularly suited for use in commercial vehicles such as delivery trucks, taxis etc. where the vehicle is often a local vehicle but the driver is not familiar with the area. In this instance the navigation system  416  is able to provide the driver of the vehicle with optimal routes for journeys around the area. 
         [0041]    The navigation system  416  is a relatively inexpensive item which can be easily installed and maintained in a large number of vehicles. 
         [0042]    It should also be appreciated that the mobile computer unit  416   a  may store a number of deviations from the suggested route, i.e. a number of fragments of a complete route. In this manner the complete route taken need not be stored, but rather only any deviations from the suggested route. 
         [0043]    Furthermore, the decision the mobile computer unit  416   a  makes concerning when to modify the originally suggested route is based on a ‘policy’ defined within the system/user preferences. For example, if the same deviation is noted in over 25% of route fragment navigation, or if the same deviation is noted in five successive journeys, the mobile computer unit  416   a  will modify the originally suggested route to incorporate the previously recorded deviations therein. 
         [0044]    Although the navigation system  416  has been described above as being used in a vehicle  400 , it should be appreciated that the navigation system  416  could be a hand-held unit. 
         [0045]    Although the threshold for considering a deviated route to be the optimal route has been described above as approximately 85%, it should be appreciated that the navigation system  416  can be completely customisable set any desired threshold value. Also, instead of the threshold for considering a deviated route to be an optimal route being a ratio between deviated routes and suggested routed, the navigation system  416  may be configured to consider a deviated route to be the optimal route once the number of times the deviated route has been taken has reached a predetermined value. 
         [0046]    While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood that various changes in form and detail may be made therein without departing from the spirit, and scope of the invention.