JP4263058B2 - Navigation device and route search method thereof - Google Patents

Description

  The present invention relates to a navigation device, and more particularly to a technique for a recommended route search process for an in-vehicle navigation device.

  Patent Document 1 describes a navigation device that obtains, as a recommended route, a route that takes the shortest travel time from a departure place to a destination.

Japanese Patent Laid-Open No. 10-153447

  However, from the viewpoint that it is important for the user (driver) to travel more comfortably, the route with the shortest travel time or travel distance is not necessarily the recommended route. For example, the user feels stress when he / she has to travel at a speed of 30 km / h on a road having a regulated speed (speed limit) of 60 km / h. On the other hand, about driving at a speed of 30 km / h on a road with a regulated speed of 40 km / h, the user feels that he is running smoothly without feeling stress.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique for searching, as a recommended route, a route that can smoothly travel between a departure place and a destination.

The route searching method of the navigation device of the present invention is configured as follows. The navigation device has a storage device for storing information on the travel speed of each link constituting the road on the map, and sets the desired speed, and the cost obtained from the difference between the travel speed and the desired speed. A cost allocating step of allocating a link to each link, and a step of searching for a recommended route from a starting point to a destination using the cost of each link.

  Moreover, the information regarding the travel speed of each link stored in the storage device may be obtained by statistically processing traffic information collected in the past. Furthermore, the information regarding the travel speed of each link stored in the storage device is classified according to the collection condition of the traffic information, and the travel speed of each link used in the cost allocation step travels the link. You may make it use the travel speed of the collection conditions corresponding to the date and the situation.

  Further, the storage device stores link length information of each link and travel time information of each link, and a travel speed used in the cost allocation step is a travel obtained based on the link length and the travel time. Speed may be used.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which searches the path | route which can drive | work smoothly can be provided.

  An embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an in-vehicle navigation device 1000 according to an embodiment of the present invention. As shown in the figure, the in-vehicle navigation device 1000 of this embodiment includes an arithmetic processing unit 1, a display 2, a map / statistical traffic data storage device 3, a voice input / output device 4, an input device 5, and a wheel speed. The sensor 6 includes a geomagnetic sensor 7, a gyro sensor 8, a GPS (Global Positioning System) receiver 9, an in-vehicle LAN device 11, an FM multiplex broadcast receiver 12, and a beacon receiver 13.

  The arithmetic processing unit 1 is a central unit that performs various processes. For example, the present location is detected based on information output from the various sensors 6 to 8 and the GPS receiver 9, and map data necessary for display is obtained from the map / statistical traffic data storage device 3 based on the obtained current location information. read out. Further, the read map data is developed in graphics, and a mark indicating the current location is superimposed on the map data and displayed on the display 2. In addition, using the map data and statistical traffic data stored in the map / statistical traffic data storage device 3, an optimum route (recommended route) connecting the destination instructed by the user and the current location (departure point) is searched. The user is guided using the voice input / output device 4 and the display 2.

  The display 2 is a unit that displays graphics information generated by the arithmetic processing unit 1, and is configured by a CRT, a liquid crystal display, or the like. The signal S1 between the arithmetic processing unit 1 and the display 2 is generally connected by an RGB signal or an NTSC (National Television System Committee) signal.

  The map / statistical traffic data storage device 3 includes a storage medium such as a CD-ROM, DVD-ROM, HDD, or IC card. In this storage medium, map data and statistical traffic data are stored.

  FIG. 2 is a diagram illustrating a configuration example of map data stored in the map / statistical traffic data storage device 3. As shown in the figure, map data 310 is stored for each mesh region. The map data 310 includes a mesh area identification code (mesh ID) 311 and link data 312 of each link constituting a road included in the mesh area. The link data 312 includes a link identification code (link ID) 3121, coordinate information 3122 of two nodes (start node and end node) constituting the link, road type information 3123 including the link, and a link indicating the link length. Long information 3124, link restriction speed (limit speed) information 3125, link ID (connection link ID) 3126 of a link connected to each of the two nodes, and the like. Here, by distinguishing the start node and the end node for the two nodes constituting the link, the upward direction and the downward direction of the same road are managed as different links. The map data 310 also includes information (name, type, coordinate information, etc.) of map components other than roads included in the corresponding mesh area.

  FIG. 3 is a diagram illustrating a configuration example of statistical traffic data stored in the map / statistical traffic data storage device 3. As shown in the figure, statistical traffic data 320 is stored for each mesh region. The statistical traffic data 320 is management data for managing the mesh ID 321 of the mesh area and the traffic information statistical value (statistical value of the traffic information collected in the past) of each link constituting the road included in the mesh area. 322. The mesh ID 321 is the same as the mesh ID 311 of the map data 310. The management data 322 is composed of a plurality of tables 3221 to 3224 having a hierarchical structure.

  The table 3221 is a table for registering the day type. The type of day may be determined for each unit indicating a tendency of different traffic information statistics. Here, weekdays before holidays, “weekdays (before holidays)”, weekdays after holidays, “weekdays (after holidays)”, weekdays before special days such as Bon, New Year, etc. Weekdays of the day of the week “Weekdays (after singular days)”, Other weekdays “Weekdays (general)”, First days of singular days “Holidays (beginning of singular days)”, All day of singular days “Holidays (end of singular days)” The holiday “holiday (general)” is included.

  The table 3222 is a table for registering the weather type, and is provided for each day type registered in the table 3221. The type of weather may be determined for each unit indicating a tendency of different traffic information statistics. Here, “sunny / cloudy”, “rain”, “heavy rain”, “snow”, “heavy snow” are included as the types of weather.

  The table 3223 is a table for registering the link ID of each link constituting the road included in the mesh area registered by the mesh ID 321, and is provided for each type of weather registered in the table 3222. The same link ID as the link ID 3121 of the map data 310 is used.

  The table 3224 is a table for registering traffic information statistical values for each time zone, and is provided for each link ID registered in the table 3223. The traffic information statistical value for each time zone includes a link travel time (and / or travel speed (movement speed)) specified by a plurality of traffic information based on these. In addition, the traffic information statistics for each time zone are classified according to the traffic information collection conditions (the type of day and weather type when the basic traffic information is collected) and the target link. That is, the target link of the traffic information statistical value for each time zone registered in a certain table 3224 is a link specified by the link ID of the table 3223 associated with this table 3224. The traffic information that is the basis of these statistical values is the weather specified by the type of weather in the table 3222 associated with the table 3223 in which the link ID is registered, and It is the traffic information collected on the day specified by the day type of the table 3221 associated with the table 3222 in which the type is registered.

  The map / statistical traffic data storage device 3 stores a date conversion table that is a conversion table for specifying the type of day managed in the table 3221 from the date of the month.

  FIG. 4 is a diagram illustrating a configuration example of a date conversion table. As illustrated, a date 331 and a date type 332 corresponding to the date 331 are registered in association with each other. By using such a date conversion table, the type of day can be easily specified from the date.

  Returning to FIG. 1, the description will be continued. The voice input / output device 4 converts the message to the user generated by the arithmetic processing unit 1 into a voice signal and outputs it, and recognizes the voice uttered by the user and transfers the content to the arithmetic processing unit 1.

  The input device 5 is a unit that receives an instruction from a user, and includes a hardware switch such as a scroll key and a scale change key, a joystick, a touch panel pasted on a display, and the like.

  The sensors 6 to 8 and the GPS receiver 9 are used for detecting the current location (own vehicle position) by the vehicle-mounted navigation device. The wheel speed sensor 6 measures the distance from the product of the wheel circumference and the measured number of rotations of the wheel, and further measures the angle at which the moving body is bent from the difference in the number of rotations of the paired wheels. The geomagnetic sensor 7 detects the magnetic field held by the earth and detects the direction in which the moving body is facing. The gyro 8 is configured by an optical fiber gyro, a vibration gyro, or the like, and detects an angle at which the moving body rotates. The GPS receiver 9 receives a signal from a GPS satellite and measures the distance between the mobile body and the GPS satellite and the rate of change of the distance with respect to three or more satellites to thereby determine the current location, travel speed, and travel direction of the mobile body. Measure.

  The in-vehicle LAN device 11 receives various information of the vehicle on which the in-vehicle navigation device of the present embodiment is mounted, such as door opening / closing information, light lighting state information, engine status and failure diagnosis result.

  The FM multiplex broadcast receiver 12 receives the approximate current traffic data, traffic regulation information, and weather information sent from the FM multiplex broadcast station as FM multiplex broadcast signals.

  The beacon receiving device 13 receives current traffic data including the link travel time sent from the beacon.

  FIG. 5 is a diagram illustrating a hardware configuration example of the arithmetic processing unit 1.

  As illustrated, the arithmetic processing unit 1 has a configuration in which devices are connected by a bus 32. The arithmetic processing unit 1 includes a central processing unit (CPU) 21 that executes various processes such as numerical calculation and control of each device, and map data, statistical traffic data, and arithmetic data read from the map / statistical traffic data storage device 3. RAM (Random Access Memory) 22 for storing data, ROM (Read Only Memory) 23 for storing programs and data, and DMA (Direct Memory Access) for executing data transfer between the memories and between the memory and each device. 24, a drawing controller 25 that executes graphics drawing and performs display control, a video random access memory (VRAM) 26 that stores graphics image data, a color palette 27 that converts image data into RGB signals, and an analog signal A / D converter 28 that converts the signal into a digital signal and a parallel signal that synchronizes the serial signal with the bus It has a SCI (Serial Communication Interface) 29 for converting a PIO (Parallel Input / Output) 30 put on the bus to synchronize the parallel signals to the bus, a counter 31 for integrating a pulse signal, to the.

  FIG. 6 is a diagram illustrating a functional configuration of the arithmetic processing unit 1.

  As shown in the figure, the calculation processing unit 1 includes a user operation analysis unit 41, a route search unit 42, a route data storage unit 43, a route guidance unit 44, a map display processing unit 45, and a current position calculation unit 46. A map match processing unit 47, a data reading unit 48, a trajectory storage unit 49, a menu display processing unit 50, and a graphics processing unit 51.

  The current position calculation unit 46 uses distance data and angle data obtained as a result of integrating the distance pulse data S5 measured by the wheel speed sensor 6 and the angular acceleration data S7 measured by the gyro 8, respectively. The current position (X ′, Y ′), which is the position after the vehicle travels, is periodically calculated from the initial position (X, Y) and is output to the map match processing unit 47. . Here, in order to make the relationship between the rotation angle of the host vehicle and the traveling direction coincide, reference is made to the direction data S6 obtained from the geomagnetic sensor 7 and the angle data obtained by integrating the angular acceleration data S7 obtained from the gyro 8. Estimate the absolute direction of the direction in which the vehicle is traveling. In addition, since the error accumulates when the data of the wheel speed sensor 6 and the data of the gyro 8 are respectively integrated, the error accumulated based on the position data S8 obtained from the GPS receiver 9 in a certain time period is calculated. Processing for canceling is performed, and information on the current location is output to the map match processing unit 47.

  The map match processing unit 47 compares the map data around the current location read by the data reading unit 48 with the travel locus stored in the locus storage unit 49 described later, and the road (link) having the highest shape correlation. In addition, a map matching process is performed in which the current location periodically output from the current position calculation unit 46 is matched. Since the current position information obtained by the current position calculation unit 46 includes a sensor error, map matching processing is performed for the purpose of further improving the position accuracy. As a result, the current location often coincides with the traveling road.

  The trajectory storage unit 49 stores information on the current location on which the map match processing has been performed by the map match processing unit 47 as trajectory data every time the vehicle travels a predetermined distance. The trajectory data is used to draw a trajectory mark on the road on the map corresponding to the road that has been traveled so far.

  The user operation analysis unit 41 receives a request from the user input to the input device 5, analyzes the request content, and controls each unit of the arithmetic processing unit 1 so that processing corresponding to the request content is executed. To do. For example, when the user requests a search for a recommended route, the map display unit 45 is requested to display a map on the display 2 in order to set a destination, and further, from the current location (departure location) to the destination. Requests the route search unit 42 to calculate a route.

  The route search unit 42 uses a Dijkstra method or the like to search for a route connecting two designated points (current location, destination) using map data. The recommended route obtained as a result is stored in the route data storage unit 43. In the present embodiment, statistical traffic data stored in the map / statistical traffic data storage device 3 is used to calculate the cost of a route connecting two points. The route search unit 42 also performs processing for obtaining predicted travel time calculation / expected arrival time, smooth level display section, and smooth level of each section.

  The route guidance unit 44 compares the recommended route information stored in the route data storage unit 43 with the current location information output from the map match processing unit 47, and determines whether to proceed straight before passing the intersection or the like. The user is notified by voice using the voice input / output device 4 whether to turn left. Further, the route guiding unit 44 displays the direction to travel on the map displayed on the display 2 and notifies the user of the recommended route.

  Further, the route guiding unit 44 uses the statistical traffic data stored in the map / statistical traffic data storage device 3 to calculate the estimated travel time from the current location to the destination output from the map match processing unit 47. Then, by adding the calculated estimated travel time to the current time, an expected arrival time at the destination is calculated and notified to the user.

  Furthermore, the route guidance unit 44 measures the actual travel time required from the departure point of the recommended route to the current location output from the map match processing unit 47. Then, the travel time is compared with the cost of the section from the departure place to the current location among the costs used by the route search unit 42 to search for the recommended route, and the recommended route is determined according to the comparison result. Determine the need for re-search. If it is determined that there is a need for re-search, the route search unit 42 is requested to re-search for a recommended route with the current location output from the map match processing unit 47 as the departure location and the current time as the departure time.

  The data reading unit 48 displays map data and statistical traffic data in an area required to be displayed on the display 2 and an area required for route search (an area including a starting point and a destination) as map / statistics. It operates to prepare for reading from the traffic data storage device 3.

  The map display processing unit 45 receives the map data in the area where the display on the display 2 is requested from the map / statistical traffic data storage device 3, and the graphic processing unit 51 uses the designated scale and drawing method for the road, A map drawing command is generated so as to draw other map components and marks such as current location, destination, and an arrow for a guide route. In addition, in response to a command output from the user operation analysis unit 41, the statistical traffic data required to be displayed on the display 2 is received from the map / statistical traffic data storage device 3, and on the map being displayed on the display 2, A map drawing command is generated so that traffic information of each road is displayed in an overlapping manner.

  Upon receiving a command output from the user operation analysis unit 41, the menu display processing unit 50 generates a menu drawing command so that the graphic processing unit 51 draws various types of menus and graphs.

  The graphics processing unit 51 receives commands generated by the map display processing unit 45 and the menu display processing unit 50 and develops image data to be displayed on the display 2 on the VRAM 26.

  [Description of Operation] Next, the operation of the vehicle-mounted navigation device 1000 will be described. FIG. 7 is a flowchart showing an outline of operation centering on route search processing in the in-vehicle navigation device 1000 of the present embodiment.

  This flow is started when the user operation analysis unit 41 receives a request for searching for a recommended route or a calculation of an estimated travel time from the user via the voice input / output device 4 or the input device 5. Then, departure point setting, destination setting, departure time setting (S100), route search condition setting (S101), route search (S103), and recommended route display display (S105) are performed. Each process will be specifically described below.

  In the departure point, destination and departure time setting process (S100), the user operation analysis unit 41 sets the departure point, destination and departure time in the route search unit 42. Specifically, the current location output from the map match processing unit 47 when a search request for a recommended route is received is set as the departure location. When the current time is set as the departure time, the current time acquired when the recommended route search request is received is set as the departure time using a built-in timer (not shown). The destination is set based on a user instruction. For example, the user operation analysis unit 41 is registered in the display 2 through the menu display processing unit 50 and the graphics processing unit 51, and registered in the map data read from the map / statistical traffic data storage device 3 through the data reading unit 48. The information of the existing map constituent is displayed, and the user selects the destination from the information of the displayed map constituent via the voice input / output device 4 or the input device 5. Alternatively, information on a location (registration location) registered in advance in a storage device such as the RAM 22 is displayed by the user, and information on the registered location being displayed is displayed by the user via the voice input / output device 4 or the input device 5. Lets you select a destination from the inside. Furthermore, the user operation analysis unit 41 specifies the map data read from the map / statistical traffic data storage device 3 via the data reading unit 48 on the display 2 via the map display processing unit 45 and the graphics processing unit 51. The destination map is displayed, and a destination is selected by receiving designation of a point on the map from the user via the voice input / output device 4 or the input device 5.

  Next, the route search condition setting process (S101) will be described. Here, the conditions under which a route is searched for in the route search are set. At this time, the user operation analysis unit 41 displays a search condition setting screen 500 on the display 2 as shown in FIG. On the screen 500, as search conditions, a button 412 for setting a mode for searching for a route with priority on a toll road, a button 414 for setting a mode for searching for a route with priority for a general road, priority on a smooth road are given. Buttons 510 to 522 for setting a route search mode are displayed. When one of the modes is selected by the user via the input device 5, the selected content is sent to the route search unit 42 via the user operation analysis unit 41. The route search unit 42 performs a route search with the content of the selected mode. Here, a case will be described in which a route search mode is set with priority on smooth roads.

  The mode for setting a route search with priority on smooth roads includes a mode 512 for preferentially selecting a link having a large value X obtained by dividing the travel speed by the restriction speed, and a link for traveling at a user's desired speed. Mode 522 for preferential selection. In a mode 512 that preferentially selects a link having a large value X obtained by dividing the travel speed by the regulation speed, whether or not to consider the travel time can be set by the selection buttons 513 and 514.

  In a mode that preferentially selects a link that can travel at a user's desired travel speed, the travel speed is set to “high” (60 km to 100 km / h), “medium” (40 km to 60 km / h), and “low” (40 km / h to 40 km / h). 5 km) can be selected. It should be noted that the range of speeds assigned to the “high”, “medium”, and “low” levels may be selected according to the user's preference.

  When one of the modes is selected by the user while the screen 500 is displayed, the route search unit 42 sets the selected content as a route search condition.

  [Route Search Processing] Next, route search processing (S103) will be described. The following is an example of route search processing.

  FIG. 9 is a flowchart showing the flow of route search processing. First, the route search unit 42 specifies the mesh ID of each mesh region included in the region including the departure place and the destination from the coordinates of the current position. Then, each link data 312 registered in each map data 310 having the identified mesh ID is obtained from the map / statistical traffic data storage device 3 via the data reading unit 48. The route search unit 42 reads the date conversion table from the map / statistical traffic data storage device 3 through the data reading unit 48. Then, the type of departure date is specified using the date conversion table. If the date of departure is not registered in the date conversion table, the process of identifying the day type from the date by the calculation logic is executed by the software embedded in the in-vehicle navigation device, so that the departure date The type of day corresponding to can be specified. In this way, even when the date range registered in the date conversion table is exceeded, the process can be continuously executed (S10301).

  Next, the route search unit 42 uses each link data 312 obtained in S10301, and uses the link starting from the end node of the extracted link extracted from the heap table in S10309, which will be described later, as a candidate that constitutes a recommended route. Elect as a link. However, when the processing in S10309 is not performed, that is, in the initial stage in which no link is registered in the heap table, instead of selecting a link having the end node of the extracted link as a start node as a candidate link, the departure place Is selected as a candidate link (S10302).

  Next, the route search unit 42 calculates the estimated arrival time at the end node of the extracted link. This can be calculated by adding the total travel time of the extracted links registered in the heap table to the departure time. In addition, the route search unit 42 identifies the mesh ID of the mesh region where the end node is located from the coordinates of the end node of the extraction link. However, when the process in S10309 is not performed, that is, in the initial stage where the link is not registered in the heap table, the mesh ID of the mesh area where the departure point is located is specified. Then, the route search unit 42 has the identified mesh ID and a target time zone (referred to as an attention time zone) to which the estimated arrival time at the end node of the extraction link belongs via the FM multiplex broadcast receiving device 12. Weather information is obtained (S10303). Note that the weather may be determined from the wiper operation status information and the outside air temperature information received via the in-vehicle LAN device 11, and the determination result may be used as the weather information.

  Next, the route search unit 42 accesses the statistical traffic data 320 having the mesh ID specified in S10303 stored in the map / statistical traffic data storage device 3 via the data reading unit 48. Then, using the management data 322 of the statistical traffic data 320, for each candidate link, the traffic information statistical value of the attention time zone is specified by the type of day specified in S10301 and the weather information acquired in S10303. The traffic information statistical value associated with the type of weather to be obtained is obtained (S10304).

  Then, for each candidate link, the route search unit 42 obtains the cost of the candidate link using the traffic information statistical value obtained in S10304 (S10305).

  The cost of the candidate link differs depending on how the search condition is set in the search condition setting process (S101). Here, a description will be given of how to obtain the cost of a candidate link when the route search is set so that a smooth road is prioritized.

  When the mode 512 that preferentially selects a link having a large value obtained by dividing the travel speed by the regulation speed is set as the search condition, and the mode 513 that does not consider the travel time is set, the route search unit 42 Process. That is, as shown in the following formula 1, the reciprocal of the value obtained by dividing the travel speed by the restriction speed 3125 is set as the cost of the candidate link.

Cost = regulated speed / travel speed
In Equation 1 and Equations 2 and 3 to be described later, the travel speed obtained from the travel time included in the traffic information statistical value is used. Specifically, it is calculated by dividing the link length by the travel time. However, when the travel information is included in the traffic information statistics, the travel speed is used as it is. Further, when neither the travel speed nor the travel time is included, the cost cannot be obtained directly, but in such a case, it may be supplemented by assigning the cost of the surrounding links.

  If the cost is obtained by the above mathematical formula 1, a route constituted by links that can travel at a speed closer to the regulation speed can be searched.

  When the mode 512 for preferentially selecting a link having a large value obtained by dividing the travel speed by the restriction speed is set and the mode 516 is set in consideration of the travel time, the route search unit 42 calculates the following formula 2. As shown by, the cost of the candidate link is a value obtained by multiplying the travel time by the reciprocal of the value obtained by dividing the travel speed by the regulation speed.

Cost = travel time x (regulated speed / travel speed) ... Formula 2
If the cost is calculated by the above mathematical formula 2, a route that includes a link that can travel at a speed closer to the regulation speed and that has a short travel time is searched.

  In addition, when the mode 522 for preferentially selecting a link that can travel at a desired travel speed is set, the route search unit 42 calculates the absolute value of the difference between the travel speed and the desired speed, as shown in Equation 3 below. Is the cost of the candidate link.

Cost = | Travel speed-Desired speed |
Here, the desired speed differs depending on which level of “high”, “medium”, and “low” is selected on the setting screen shown in FIG. For example, an intermediate travel speed (80 km / h for “high”) within the travel speed range assigned to the selected level (eg, 60 km / h for “high”) can be assigned as the desired speed. .

  If the cost is calculated using Equation 3 above, a route having a link with a smaller difference between the travel speed and the desired speed as a constituent link is searched, so that the speed change during traveling is small and smooth. You can search for recommended routes that you can travel to. In particular, since a large change in travel speed can be suppressed, the fuel consumption of the vehicle can be suppressed.

  Returning to FIG. The route search unit 42 calculates the total cost from the departure point to the end node of the candidate link. Specifically, the cost of the candidate link calculated in S10305 is added to the total cost of the extracted link registered in the heap table, and the addition result is set as the total cost of the candidate link. However, at the initial stage where the extraction link is not registered in the heap table, the cost of the candidate link calculated in S10305 is set as the total cost of the candidate link. Then, the route search unit 42 adds the link data and the total cost of each candidate link to the heap table (S10307).

  Next, the route search unit 42 checks whether there is a destination link among the links newly added to the heap table in S10307 performed immediately before (S10308). If it is determined that there is no destination link (No in S10308), the route search unit 42 sorts the information on the links registered in the heap table in ascending order of the total cost, and extracts the first located link. Then, the candidate link with the minimum total cost is extracted from the heap table (S10309). Then, the process returns to S10302.

  On the other hand, when it is determined that there is a destination link (Yes in S10308), the route search unit 42 performs recommended route determination processing. Specifically, the heap table is searched for a link that has generated the destination link (a link having the start node of the destination link as the end node), and the detected link is determined as a constituent link that constitutes the recommended route. Next, it is checked whether or not the constituent link is a starting point link that exists or is close to the starting point. If it is not a starting point link, the link that generated this constituent link is searched and the detected link is detected. Is determined as a constituent link, and it is further examined whether or not it is a departure link. By repeating this process until it is determined that the configuration link is the departure link, each configuration link that constitutes the recommended route is determined. Then, the route search unit 42 stores the link data 312 and the traffic information statistical value obtained in S10304 in the route data storage unit 43 for each constituent link constituting the recommended route (S10310).

  According to the above flow, the route search unit 42 can search for a recommended route that satisfies the search condition set in the search condition setting process (S101).

  The route search processing has been described above, but the route search processing applicable to the present invention is not limited to the above. If the present invention can be implemented within the scope of the gist, other route search methods can be adopted. For example, a route search method that searches all routes from the starting point to the destination included in the assumed mesh area by the Dijkstra method and then searches for the route with the shortest cost among the routes. It may be adopted. Even in this case, for each link, the recommended route can be searched by using the value obtained by Formula 1, Formula 2 or Formula 3 as the link cost according to the set search condition.

  [Process for Obtaining Expected Travel Time / Estimated Arrival Time] In order to obtain the expected travel time, the route search unit 42 links data and traffic information statistics of each link constituting the recommended route registered in the route data storage unit 43. Is used to calculate the travel time of each component link. The total travel time of each link constituting the recommended route is set as the expected travel time of the recommended route. Further, a time obtained by adding the estimated travel time to the departure time (current time) is set as an estimated arrival time at the destination.

  [Process for Obtaining Smooth Level] Next, the process for obtaining the smooth level will be described.

  The route search unit 42 determines the smoothing level display section of the recommended route and the smoothing level of each display section. In the present embodiment, as shown in FIG. 10, the recommended route is divided into a plurality of sections (smooth level display sections), and the smooth level can be displayed on the display 2 in section units.

  This process is performed as follows, for example. First, for each link constituting the recommended route, a smooth level is assigned from a value X obtained by dividing the travel speed by the regulation speed. For example, the smooth level “high” is assigned to an X value of 0.7 or more, “medium” is assigned an X value of 0.4 to less than 0.7, and “low” is assigned an X value of less than 0.4. When adjacent links have the same smooth level, both links are assigned to the same smooth level display section. Then, the section is set to the same smooth level.

  In addition, about the link which does not have a traffic information statistical value, it handles as a smooth level display area of a smooth level unknown.

  Further, the route search unit 42 calculates the smoothness level of the entire recommended route. Specifically, first, the X value of each link constituting the recommended route is averaged by weighting the link length. A value obtained by averaging is assigned to a smooth level of “high”, “medium”, and “low” as described above.

  [Display Process] Next, the display process of the information obtained as described above will be described.

  As described above, when the estimated travel time / expected arrival time and smooth level display section / smooth level of each section are determined, the display 2 displays these pieces of information (S105). Specifically, the menu display processing unit 50 obtains such information from the route search unit 42. Then, a graph is displayed on the display 2 via the graphics processing unit 51 so that the estimated travel time / expected arrival time and the smooth level display section / smooth level of each section can be understood. In addition, the information source of the traffic information statistical value used for calculating these pieces of information is also displayed.

  FIG. 10 shows an example of displaying such information. In this example, an estimated travel time and the like when departing at the current time (9 o'clock) is displayed. The length of the bar graph 810 is proportional to the expected travel time 806. The graph 810 includes at least one smoothing level display section showing the smoothing level 812, and the length of the display section is also proportional to the travel time of the section. The user can determine the smoothness degree of the recommended route by confirming the ratio shown in the graph of the smoothness level display section having a high smoothness level.

  Furthermore, the smoothness level 815 of the whole route is also displayed. As a result, the user can determine the smoothness of the entire recommended route.

  Further, a traffic information statistical value information source 808 used to calculate the displayed information is displayed. The user can roughly determine the reliability such as the estimated travel time (expected arrival time) by referring to the information source 808.

  Further, as shown in FIG. 11, a map may be displayed. In FIG. 11, a recommended route 905 between the departure point 903 and the destination 904 is displayed on the map 909 so that the smooth level 906 in each smooth level display section can be identified. In FIG. 11, reference numeral 901 is a departure time, reference numeral 907 is an estimated travel time (expected arrival time) of the destination, and reference numeral 911 is a traffic information statistic used for calculating the expected travel time (expected arrival time) 907 and the like. A source of value. For each smooth level display section, an expected arrival time (estimated arrival time at the end node of the last link constituting the smooth level display section immediately before the smooth level display section) that reaches the smooth level display section is indicated. It may be displayed in accordance with the start position of the smooth level display section on the map.

  In addition, a recommended route when a search is performed with priority set to a link that can travel smoothly and a recommended route when another search condition is set may be displayed on the screen. In this way, the user can compare the recommended routes for each search condition.

  The embodiment to which the present invention is applied has been described above.

  In addition, this invention is not limited to said embodiment, A various deformation | transformation is possible within the range of the summary. For example, in the above embodiment, the link cost is obtained using the travel time and travel speed included in the statistical traffic information held by the map / statistical traffic data storage device 3. However, the present invention is not limited to this, travel time and the like may be obtained from the FM multiplex broadcast receiving device 12 and the beacon receiving device 13 and used for calculating the link cost. Alternatively, a traffic information distribution center that distributes traffic information via the Internet or the like may be accessed to obtain traffic information such as travel time.

  Moreover, although the example which applied this invention to the vehicle-mounted navigation apparatus was demonstrated, this invention is applicable also to navigation apparatuses other than vehicle-mounted.

FIG. 1 is a schematic configuration diagram of a navigation system to which an embodiment of the present invention is applied. FIG. 2 is a schematic configuration diagram of the in-vehicle navigation device 1000. FIG. 3 is a diagram illustrating a configuration example of map data stored in the map / statistical traffic data storage device 3. FIG. 4 is a diagram illustrating a configuration example of a date conversion table for specifying a day type from a date. FIG. 5 is a diagram illustrating a hardware configuration of the arithmetic processing unit 1. FIG. 6 is a diagram illustrating a functional configuration of the arithmetic processing unit 1. FIG. 7 is a flowchart showing an outline of the operation of the in-vehicle navigation device 1000. FIG. 8 is a diagram illustrating a display example of the search condition setting screen. FIG. 9 is a flowchart showing the flow of route search processing. FIG. 10 is a diagram illustrating a display example (bar graph) of the recommended route and the smooth level. FIG. 11 is a diagram illustrating a display example (map display) of the recommended route and the smooth level.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Arithmetic processing part, 2 ... Display, 3 ... Map / statistical traffic data storage device, 4 ... Voice input / output device, 5 ... Input device, 6 ... Wheel speed sensor, 7 ... Geomagnetic sensor, 8 ... Gyro, 9 ... GPS Receiver 10, network connection device 11, in-vehicle LAN device 12 FM multiplex broadcast reception device 13 beacon reception device 21 CPU 22 22 RAM 23 ROM 24 24 DMA controller 25 26 ... VRAM, 27 ... color palette, 28 ... A / D converter, 29 ... SCI, 30 ... PIO, 31 ... counter, 41 ... user operation analysis unit, 42 ... route search unit, 43 ... route data storage unit, 44 ... Route guidance unit, 45 ... Map display processing unit, 46 ... Current position calculation unit, 47 ... Map match processing unit, 48 ... Data reading unit, 49 ... Trajectory storage unit, 50 ... Menu display processing Part, 51 ... graphics processing part

Claims (5)

A storage device for storing information about the travel speed of each of the links that make up the road on the diagram earth,
A means to set the desired speed;
Means for assigning to each link a cost determined from the difference between the travel speed and the desired speed;
Means for searching for a recommended route from the starting point to the destination using the cost of each link;
A navigation device comprising: The navigation device according to claim 1,
Means for determining a smoothness level of each link constituting the recommended route based on a cost of each link;
Display means for displaying the smoothing level separately for each smoothing level;
Navigation apparatus and performs. The navigation device according to claim 2,
The display means includes
A navigation device, wherein the travel time of the recommended route is divided for each smooth level, and each smooth level is displayed in a bar graph with a length corresponding to the length of the divided section . The navigation device according to claim 2,
The display means includes
A navigation device, wherein the smoothness level of each link constituting the recommended route is displayed together with the recommended route displayed in a map . A navigation device route search method,
The navigation device includes:
A storage device for storing information on the travel speed of each link constituting the road on the map;
Setting the desired speed;
A cost allocation step of assigning a cost obtained from the difference between the travel speed and the desired speed to each link;
Searching for a recommended route from the starting point to the destination using the cost of each link;
A route search method for a navigation device, characterized in that: