Abstract:
A navigation apparatus displays a trend of house number increase or house number decrease when a vehicle is traveling on a street from one intersection to another intersection. By displaying the trend of the house number increase or the house number decrease as a clue of currently traveling position of the vehicle, the navigation apparatus makes it possible for a driver of the vehicle to easily understand where the driver is going and/or where the driver is traveling.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based on and claims the benefit of priority of Japanese Patent Application No. 2006-331951 filed on Dec. 8, 2006, the disclosure of which is incorporated herein by reference. 
       FIELD OF THE DISCLOSURE 
       [0002]    The present disclosure generally relates to an apparatus and a program for vehicle navigation. 
       BACKGROUND INFORMATION 
       [0003]    Conventionally, a navigation apparatus is used for displaying a map of current vehicle position on a display unit with a vehicle position icon superposed thereon. When a user is navigated by the navigation system, the user is not always aware of a navigation route he/she is actually traveling only with a recognition of a final destination. In that case, the user may feel uncomfortable even with the current vehicle position displayed on top of the map of vicinity. For example, the uncertainty of a position currently approached, the uncertainty of a road currently traveling and/or whether the currently traveling road is the one that is notified in advance may cause uncomfortableness to the user. Japanese patent document JP-A-H09-222329 discloses and proposes a technique that displays a location name in a currently traveling direction together with the current vehicle position for enabling the user to overcome the uncomfortableness. Further, Japanese patent document JP-A-H08-35850 discloses and proposes a technique that displays a name of the currently traveling road. 
         [0004]    However, even when the location name in the currently traveling direction and/or the currently traveling road name are displayed, there are cases that the user cannot grasp the direction of the traffic of the currently traveling road, that is, whether the vehicle is traveling up or down the street, whether the address number is increasing in the traveling direction or decreasing in the traveling direction or the like. More practically, even when the user has been told that he/she should travel a road A in a down direction, he/she does not have a clue to understand whether he/she is traveling in a correct direction on the road if he/she does not know the name of the location in the traveling direction (e.g., the location name displayed on the map). 
       SUMMARY OF THE DISCLOSURE 
       [0005]    In view of the above and other problems, the present disclosure provides a navigation apparatus that enables a user to grasp the direction of the traffic on a currently traveling road. 
         [0006]    The navigation apparatus in the disclosure includes a position determination information acquisition unit, a road information acquisition unit, a notification unit, and a control unit. More practically, the position determination information acquisition unit acquires position determination information required for determining a current position; the road information acquisition unit acquires road information required for determining a traffic direction of a road that has a distinction of traffic directions; the notification unit notifies various information; and the control unit determines, for notification of information on the traffic direction by the notification unit, the traffic direction of the road by determining a currently traveling road that is traveled by the vehicle based on the position determination information acquired by the position determination information acquisition unit and the road information acquired by the road information acquisition unit. 
         [0007]    By using the navigation apparatus described above, the user, or the driver of the vehicle, securely understands a traveling direction on the currently traveling road due to provision of the notification of the traveling direction of the currently traveling road. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which: 
           [0009]      FIG. 1  shows a block diagram of a navigation apparatus in a first embodiment of the present disclosure; 
           [0010]      FIG. 2  shows a flowchart of a house number display process  1 ; 
           [0011]      FIGS. 3A and 3B  show diagrams of link data in a table format and in a schematic format in the first and second embodiment of the present disclosure; 
           [0012]      FIGS. 4A and 4B  show illustrations of house number displays according to the house number display process  1 ; 
           [0013]      FIG. 5  shows a flowchart of a house number display process  2 ; 
           [0014]      FIGS. 6A to 6B  show illustrations of house number displays according to the house number display process  2 ; 
           [0015]      FIGS. 7A and 7B  show diagrams of link data in a table format and in a schematic format in a third embodiment of the present disclosure; and 
           [0016]      FIG. 8  shows a flowchart of a house number display process  3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    The embodiment which the present invention is applied to is described with reference to the drawing. 
         [0018]      FIG. 1  is a block diagram showing an outline configuration of a navigation apparatus  20  in a first embodiment of the present disclosure. 
         [0019]    The navigation apparatus  20  is installed on a vehicle, and includes various components as described in the following. That is, a vehicle position sensor  21  for detecting a current position of the vehicle, operation switch group  22  for inputting various instructions from a user, a remote control terminal (a remote controller hereinafter)  23   a  for inputting various instructions in the same manner as the switch group  22  and being provided as a separated part from the navigation apparatus  20 , a remote controller sensor  23   b  for detecting inputting a signal from the remote controller  23   a , an external communication unit  24  for conducting communication with external network by connecting to a packet communication network or the like, a map data input unit  25  for data input from map memory medium that stores map data, sound data and the like, a display unit  26  for displaying various information and maps, a sound output unit  27  for outputting various guide sound and the like, a microphone  28  for outputting an electrical signal based on the sound that is uttered by a user, a vehicle LAN communication unit  33  for communicating with various ECUs on a vehicle LAN and the like, and a control unit  29  for performing various processes and for controlling the external communication unit  24 , the display unit  26 , the sound output unit  27 , and the vehicle LAN communication unit  33  based on an input from the position sensor  21 , the operation switch group  22 , the remote controller sensor  23   b , the communication unit  24 , the map data input unit  25 , the microphone  28 , and the vehicle LAN communication unit  33  are included. 
         [0020]    The position sensor  21  includes the following parts as its components. That is, a GPS receiver  21   a  for receiving a radio signal from GPS satellites through the GPS antenna (not illustrated) and for outputting the signal, a gyroscope  21   b  for detecting a magnitude of rotary motion of the vehicle, and a distance sensor  21   c  for detecting a travel distance based on an acceleration in an anteroposterior direction of the vehicle and the like are included. Based on the output signal from each of these sensors  21   a - 21   c , the position, direction, speed and the like of the vehicle are calculated. In addition, the current position of the vehicle can be calculated by various methods based on the output signals from the GPS receiver. That is, the calculation method may be the point positioning method, or may be the relative positioning method. 
         [0021]    The operation switch group  22  consists of mechanical key switches around the display unit  26  as well as a touch panel that is integrally formed as a display surface of the display unit  26 . In addition, the touch panel and the display unit  26  is integrally layered, and the touch panel is activated by using any of the various methods such as a pressure sensing method, an electromagnetic induction method, a capacitance method or the combination of these methods for receiving inputs from the user. 
         [0022]    The remote controller  23   a  has plural buttons, and is configured to transfer, to the remote controller sensor  23   b , a signal according to the button type through the short distance wireless communication such as infrared rays. 
         [0023]    The remote controller sensor  23   b  receives a signal from the remote controller  23   a , and the received signal is output to the control unit  29 . The external communication unit  24  acquires, from VICS information center (traffic information service in JAPAN), accident information, traffic congestion information and the like through a light beacon or a radio beacon installed on the roadside. 
         [0024]    The map data input unit  25  is a device to input memorized various data from a map data memory medium such as, for example, a hard disk or a DVD-ROM (not illustrated). On the map data memory medium, map data (node data, link data, cost data, background data, road data, name data, mark data, crossing data, facility data and the like) as well as audio data for guidance, sound recognition data and the like are memorized. Instead of inputting these data from the map data memory medium, these data may be obtained through a communication network. 
         [0025]    The display unit  26  has a liquid crystal display, an organic electroluminescence display or the like as a display device, and displays, on a display screen, a present vehicle location mark based on a vehicle position detected by the position sensor  21  and the map data from the map data input unit  25  as well as the navigation course to the destination, names, landmarks, various facility marks and the like in a super-positioned manner. In addition, the guides of the facilities can also be displayed. 
         [0026]    The microphone  28  outputs an electrical signal (i.e., a voice signal) based on the input sound (i.e., utterance of the user) to the control unit  29 . The user can operate the navigation apparatus  20  by inputting various sounds into this microphone  28 . 
         [0027]    The vehicle LAN communication unit  33  performs communication with various ECUs (an engine ECU, an AT-ECU, a brake ECU and the like) and various sensors (a blinker sensor, a door opening and shutting sensor and the like) connected to the vehicle LAN. 
         [0028]    The control unit  29  consists substantially of a well-known type microcomputer having a CPU, a ROM, a RAM, an SRAM, an I/O and a bus line connecting these components together with other parts for performing various processes based on a program memorized in the ROM and the RAM. For example, the current position of the vehicle is calculated as a combination of coordinates and the travel direction based on each of the detecting signals from the position sensor  21 . Further, by the control unit  29 , a current location display process to display maps of current position neighborhood which is retrieved through the map data input unit  25  to the display unit  26 , a route calculation process which calculates a course from the current location to the destination according to the map data stored in the map data input unit  25  and according to the operation of the operation switch group  22  or the remote controller  23   a  and a route guidance process which guides the driver along the calculated course by displaying the calculated course on the display unit  26  or by outputting the guidance sound from the sound output unit  27  are respectively performed. 
         [0029]    A house number display process  1  that the control unit  29  carries out is described with reference to a flowchart in  FIG. 2  next. As for the house number display process  1 , an execution of the process is started when a map of the neighborhood of the current position is displayed on the display unit  26  in the present location display process, the route guidance process or the like. Description is omitted regarding the processes of the conventional navigation systems such as, for example, the current location display process, the route calculation process, the route guidance process and the like. 
         [0030]    When the control unit  29  starts execution of the house number display process  1 , a current link is identified (S 110 ). This step calculates a current position based on a signal from the position sensor  21 , and then identifies a link corresponding to the current vehicle position based on the map data that is input into from the map data memory medium through the map data input unit  25 . It goes without saying that a technology of map matching may be employed in this case. 
         [0031]    Then, whether the identified link has changed and whether the jurisdiction of the current position has changed are determined (S 120 ). Whether the link has changed is determined by examining whether the identified link in a previous execution of step S 110  is different from the link identified in the current execution of step S 110 . Whether the jurisdiction has changed is determined by examining whether the jurisdiction where the vehicle was existing in the previous execution of step S 110  is different from the jurisdiction where the vehicle is existing in the current execution of step S 110 . In this case, the “jurisdiction” means a country, a state, a province, a city, a town, a village or the like. When the link or the jurisdiction is determined to have changed (S 120 :Yes), the process proceeds to S 130 . When the link and the jurisdiction have not determined to have changed (S 120 :No), the process returns to S 110 . 
         [0032]    In S 130  that comes after the determination that the link or the jurisdiction has changed, a house number that is associated with the link identified in S 110  is acquired by referring to a link data table, and the acquired link is displayed on the display unit  26 . Then, the process returns to S 110 . 
         [0033]    The link data table is described with reference to  FIGS. 3A and 3B .  FIG. 3A  is a table layout illustration of the link data table, and  FIG. 3B  is an illustration which shows the relationship of each data constituting a record (link data) in the link data table. The link data table is a table memorized on the map data memory medium, and the link data (each record) of the link data table consists at least of a link number, a start node number, an end node number, a start house number, an end house number, and a road type. 
         [0034]    The link number is a number to uniquely identify the link. The start node number is a number of the node that exists on an upstream side of the travel direction among the nodes on both ends of a certain link. The end node number is a number of the node to be located on the downstream side of the travel direction among the nodes on both ends of a certain link. The start house number is a house number in a proximity of the link edge on the upstream side of the travel direction among link edges. The end house number is a house number in a proximity of the link edge on the downstream side of the travel direction among link edges. The road type is information representing the road type (a local road, an expressway and the like) of the road corresponding to the link. In the link data table used in the present embodiment, each travel direction has a dedicated link. That is, for example, the link with the link number L 10006  and the link with the link number L 10005  are respectively corresponding to two different roads (two roads having respectively different travel directions) that are separated from each other by a center line, a median or the like. 
         [0035]    Two examples are described with reference to  FIGS. 4A and 4B  next. The house number is preferably displayed by a display method according to the preference of the user. 
         [0036]      FIG. 4A  shows the first example of the house number display. In a situation that a subject vehicle  105  is traveling to a crossing  103  from a crossing  101 , the message regarding the road between the crossing  101  and the crossing  103  on the screen notifies that the house number is changing along the current travel direction. In this case, a road name (“AAA Street”) and a city name (“SAN FRANCISCO”) as well as a state name (“CA”) and the name of a country (“USA”) are also displayed. 
         [0037]      FIG. 4B  shows the second example of the house number display. In a situation that a subject vehicle  115  is traveling to a crossing  113  from a crossing  111 , the message regarding the road between the crossing  111  and the crossing  113  on the screen notifies that the house number is “down” (i.e., decreasing) along the current travel direction. In this case, too, the road name (“AAA Street”) and the city name (“SAN FRANCISCO”) as well as the state name (“CA”) and the name of the country (“USA”) are displayed. 
         [0038]    As shown in the above examples, the navigation apparatus  20  displays, on the display unit  26 , the increase and decrease of the house number (e.g., “down”) or the arrangement of the house number (e.g., “1800→1700”). Therefore, the driver of the vehicle can recognize the traffic direction of the currently traveling road by referring to the house number. 
         [0039]    Displaying the increase/decrease of the house number is especially advantageous for the driver who is traveling on the road that includes the destination of the travel. This is because the destination house number of, for example, 1250 which is known by the driver is considered to be easily reached by continuing the travel in the current direction when the driver is provided by information that the address number (the house number) is increasing along the traffic direction of the currently traveling road besides seeing a roadside sign that tells the house number of the current position is 1100. 
         [0040]    Further, when the arrangement of the house number is displayed, the driver can easily understand that the vehicle is approaching the destination house number even when the house number of the current position is not provided. 
         [0041]    A second embodiment is described in the following with a focus of explanation concentrated on differences from the first embodiment. 
         [0042]    The configuration of the second embodiment is similar to the one in the first embodiment. 
         [0043]    A house number display process  2  that the control unit  29  carries out is described in the following with a flowchart in the  FIG. 5 . When a map of the neighborhood of the current position is displayed on the display unit  26  in the current location display process or in the route guidance process, execution of the house number display process  2  is started. 
         [0044]    When the control unit  29  starts execution of the house number display process  2 , the traveling link is identified first (S 210 ). This step calculates a current position based on a signal from the position sensor  21 , and the link existing at the identified current position is determined based on the map data which is input from the map data memory medium through the map data input unit  25 . It goes without saying that the technique of the map matching may be employed in this case. 
         [0045]    Then, whether the identified link or jurisdiction has changed is determined by using the same method in the first embodiment (S 220 ). The process proceeds to S 230  when the link/jurisdiction has changed (S 220 :YES), or the process returns to S 210  when there is no change (S 220 :NO). 
         [0046]    In S 230  that comes after the link/jurisdiction change, the travel speed of the vehicle is acquired. The travel speed is acquired from a speed sensor (not illustrated) through the vehicle LAN communication unit  33 . 
         [0047]    Then, the display method of the house number set in conjunction with a link is determined (S 240 ). Determination of the display method of the house number indicates that determining information to change the interval of the house number to be displayed according to the traveling speed of the vehicle. More practically, determining the number of divisions between the starting house number and the ending house number is determined according to the traveling speed. For example, when the starting house number is 1800 and the ending house number is 1700 in the link that corresponds to the traveling road, the house number is displayed as “1800→1700” without divisions if the speed is equal to or greater than 40 km/h. On the other hand, if the speed is under 40 km/h, the number of divisions is determined as 2, the house numbers 1800-1700 is divided into two, and either of “1800-1750” or “1750-1700” is displayed depending on the position of the vehicle. The example of house number display screen is described later. 
         [0048]    When the display method (the number of divisions) is determined, the house number is displayed by the determined display method (by using the determined number of divisions) (S 250 ). More practically, the house numbers (the starting/ending house numbers) in association with the identified link in S 210  are acquired by referring to the link data table. Then, the range of the house numbers is determined by using the house number division number as described above, and the house numbers are displayed on the display unit  26 . Displaying which of the divided ranges is determined based on the information of the current position of the vehicle. Then, the process returns to S 210 . 
         [0049]    Two examples of the display method are described with reference to  FIGS. 6A and 6B . The display method of the house number is determined according to the travel speed of the vehicle (S 240 ).  FIG. 6A  shows the third example of the house number display. In the situation that the a subject vehicle  125  is traveling to a crossing  123  from a crossing  121 , the message on the screen indicates that the house number changes from 1800 to 1700 along the travel direction on the currently traveling road between the crossings  121  and  123 . The message also indicates that the road name (“AAA Street”), the city name (“SAN FRANCISCO”) and the state name (“CA”) as well as the name of the country (“USA”). In addition, the travel speed (“50 km/h”) is displayed under an icon of the subject vehicle  125 . 
         [0050]      FIG. 6B  shows the fourth example of the house number display. In the situation that a subject vehicle  135  travels from a crossing  133  from a crossing  131 , the message on the screen indicates that the house number changes from 1800 to 1750 along the travel direction on the currently traveling road between the crossings  131  and  133 . The message also indicates that the road name (“AAA Street”), the city name (“SAN FRANCISCO”) and the state name (“CA”) as well as the name of the country (“USA”). In addition, the travel speed (“30 km/h”) is displayed under an icon of the subject vehicle  135 . 
         [0051]    The house number to be displayed on the display unit  26  is configured to change according to the travel speed of the vehicle in the navigation apparatus  20  that executes the house number display process, 2. Therefore, the frequency of the change of the displayed house number operator can be reduced to a certain level, thereby allowing the driver to easily understand and the destination house number. 
         [0052]    A third embodiment is described in the following with a focus of explanation concentrated on differences from the first embodiment. 
         [0053]    The configuration of the third embodiment is similar to the one in the first embodiment. However, the setting method of the link data stored in the link data table is different from the first embodiment. That is, regardless of the difference of the travel directions, one common link is assigned to plural adjacent roads.  FIGS. 7A and 7B  are referred to for the explanation.  FIG. 7A  is a table layout illustration of the link data table, and the  FIG. 7B  is an illustration which shows the relationship of each data constituting a record (link data) in the link data table. The link data in the table has the same items as the first embodiment, that is, the items such as the link number, the start/end node number, the start/end house number, and the road type. 
         [0054]    The link number is a number to uniquely identify the link. The start node number is a node number of one of two nodes on both ends of a certain link. The end node number is a node number of one of two nodes on both ends of the certain link. The start house number is a house number in a proximity of the link edge that is associated to the start node number. The end house number is a house number in a proximity of the link edge that is associated to the end node number. The road type is information representing the road type (a local road, an expressway and the like) of the road corresponding to the link. In the link data table used in the present embodiment, the two adjacent roads has the same link associated thereto regardless of the difference of the travel directions. For example, the two roads with respectively different travel directions divided by a center line or a median have the same single link assigned thereto. The road that does not have the center line or the median (i.e., the road without regulated travel directions) has the single link setting. 
       [Explanation of the Operation] 
       [0055]    A house number display process  3  that the control unit  29  carries out next is described with a flowchart in  FIG. 8  next. As for the house number display process  3 , an execution of the process is started when a map of the neighborhood of the current position is displayed on the display unit  26  in the present location display process, the route guidance process or the like. 
         [0056]    When the control unit  29  starts execution of the house number display process  3 , a current link is identified (S 310 ). This step calculates a current position based on a signal from the position sensor  21 , and then identifies a link corresponding to the current vehicle position based on the map data that is input into from the map data memory medium through the map data input unit  25 . It goes without saying that a technology of map matching may be employed in this case. 
         [0057]    Then, whether the identified link has changed and whether the jurisdiction of the current position has changed are determined (S 320 ). Whether the link has changed is determined by examining whether the identified link in a previous execution of step S 310  is different from the link identified in the current execution of step S 310 . Whether the jurisdiction has changed is determined by examining whether the jurisdiction where the vehicle was existing in the previous execution of step S 310  is different from the jurisdiction where the vehicle is existing in the current execution of step S 310 . In this case, the “jurisdiction” means a country, a state, a province, a city, a town, a village or the like. When the link or the jurisdiction is determined to have changed (S 320 :Yes), the process proceeds to S 330 . When the link and the jurisdiction have not determined to have changed (S 320 :No), the process returns to S 310 . 
         [0058]    In S 330  that comes after the determination that the link or the jurisdiction has changed, whether the vehicle is traveling the link in a forward direction (i.e., a direction from the start node number toward the end node number) or in a backward direction (i.e., a direction from the end node number toward the start node number) is determined. The travel direction is determined based on the transition of the current vehicle position. 
         [0059]    Then, the travel speed is acquired in S 340  in the same manner as in S 230 , and the house number display method is determined in S 350  in the same manner as in S 240 . Then, the range of the house number is divided according to the travel speed in the same manner as described above. 
         [0060]    When the display method (the number of divisions) is determined, the house number is displayed by the determined display method (by using the determined number of divisions) (S 360 ). More practically, the house numbers (the starting/ending house numbers) in association with the identified link in S 310  are acquired by referring to the link data table. Then, the range of the house numbers is determined by using the house number division number as described above, and the house numbers are displayed on the display unit  26  according to the link direction identified in S 330 . The link direction considered in the course of displaying is that the house numbers are displayed in a progressive manner from the start house number to the end house number if the link is currently traveled in the forward direction, or the house numbers are displayed in a counter-progressive manner from the end house number to the start house number if the link is currently traveled in the backward direction. Because of the similarity to the example in the second embodiment, the display example on the display unit  26  is omitted. Then, the process returns to S 310 . 
         [0061]    The navigation apparatus  20  in the present embodiment has the same advantageous effect as the one in the second embodiment. In addition, the two adjacent roads have the same link regardless of the different travel directions, thereby making the number of records in the link data table smaller in comparison to the one in the second embodiment. 
         [0062]    Though the house number display method in the present embodiment changes according to the travel speed of the vehicle in the same manner as the second embodiment, the house number may be fixedly displayed on the display unit  26  as described in the first embodiment. 
         [0063]    Although the present invention has been fully described in connection with the preferred embodiment thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. 
         [0064]    (1) In each of the above embodiments, the house number is shown in a manner “1800→1700.” However, the house number may be displayed in a different manner. For example, the house number on both edges of the link together with the intermediate house number may be displayed as “1350, 1400, 1450,” or all house numbers may be displayed if there are only a few house numbers corresponding to the link concerned. Further, these display methods may preferably selected arbitrarily with an operation of the switch group  22  by the driver. 
         [0065]    (2) The house number may be output by voice from the speaker  27  instead of being displayed by an image on the display unit  26 . 
         [0066]    In this manner, the driver&#39;s attention is not distracted by watching the display unit  26  for recognizing the house number increase/decrease. 
         [0067]    (3) The address number described in the above embodiment may be the number that is different from the house numbers. That is, for example, the number may be a land number, a telephone pole number or any other number that is used to specifically identify the position of the vehicle. 
         [0068]    When such a number is used in substitution for the house number, the same effect derived from the navigation apparatus  20  stated above is achieved. 
         [0069]    (4) The display timing of the house number may be controlled by the user operation instead of the link/jurisdiction change as described in the above embodiments. In this manner, the user may confirm the current vehicle position with the travel direction and the address at an appropriate timing. 
         [0070]    Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims. 
         [0071]    Correspondence of terms mentioned in the specification to terms used in claims is specified in the following. The position sensor  21  is equivalent to a position determination information acquisition unit, and the map data input unit  25  is equivalent to a road information acquisition unit, and the display unit  26  and the sound output unit  27  are equivalent to a notification unit, and the vehicle LAN communication unit  33  is equivalent to a travel speed information acquisition unit.