JP2005292052A - On-vehicle navigation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exactly set the current position of a vehicle, without being operated by a user when the current position of the vehicle is displayed wrongly, when express way is close to a general road. <P>SOLUTION: Attention is focused on a point such that driving states on the express way and the general road are different significantly from each other, that is, a point that characteristic driving states appear on the express way and the general road, respectively. From this attention focused point, it is thought that the current position of the vehicle is on the general road, when a driving state is detected as characteristic of the general road, and that the current position of the vehicle is located on the express way, when a driving state is detected as characteristic of the express way. Thus, the current position of the vehicle can be set exactly and automatically, without the user having to operate, when the current position of the vehicle is being displayed wrongly, when the express way is close to the general road. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an in-vehicle navigation device.

Conventionally, when a general road and an expressway are running side by side, the in-vehicle navigation device may erroneously recognize the current position of the vehicle. In this case, even if an attempt is made to perform route guidance to a desired destination, in-vehicle navigation cannot correctly set the guide route because the current position is erroneously recognized. Therefore, as disclosed in, for example, Patent Document 1, there is known an apparatus that can accurately set a starting point of a route search on a desired road even when an expressway and a general road are close to each other. Yes. This device detects whether there is a highway near the current position of the vehicle, and if there is a highway nearby, displays a screen for confirming to the driver whether the vehicle is on the highway. . When it is confirmed that the vehicle is on the highway, the current position of the vehicle is set on the highway. When it is confirmed that the vehicle is not on the highway, the current position of the vehicle is set on the general road. Set to.
Japanese Patent Laid-Open No. 08-285624

  As described above, in order to accurately set the current position of the vehicle, the conventional device asks the driver to confirm whether the vehicle is on an expressway or a general road. At this time, the driver sees the confirmation screen and inputs information on which road he is on. That is, in addition to the driving operation, the driver is required to perform an operation for setting an accurate current position. While the driver is driving the vehicle, it is desirable to concentrate on driving operation. From this viewpoint, there is room for improvement in the prior art.

  The present invention has been made in view of the above-described points. When the highway and a general road are close to each other, the driver does not perform an operation when the current position of the vehicle is erroneously displayed. An object of the present invention is to provide an in-vehicle navigation device capable of accurately setting the current position of a vehicle.

In order to achieve the above object, an in-vehicle navigation device according to claim 1,
Driving state detection means for detecting the driving state of the vehicle;
Current position detecting means for detecting the current position of the vehicle;
Map data storage means for storing map data including road shapes;
Display control means for displaying a road map based on the map data and the current position of the vehicle on the display unit;
Determination means for determining whether the current position of the vehicle is on a general road or on a highway based on the driving state of the vehicle,
When the determination result of the determination means is different from the road type in which the current position of the vehicle is displayed, the display control means changes and displays the current position of the vehicle on the type of road determined by the determination means. It is characterized by that.

  In the in-vehicle navigation device according to the first aspect, attention is paid to the fact that the driving state of the vehicle is greatly different between the highway and the general road, that is, there is a specific driving state between the highway and the general road. From this point of view, when a driving condition peculiar to a general road is detected, the current position of the vehicle is on the general road, and when a driving condition peculiar to the highway is detected, the current position of the vehicle is on the highway. it is conceivable that. As a result, when the current position of the vehicle is displayed incorrectly when the expressway and the general road are close to each other, the current position of the vehicle is automatically set accurately without the driver's operation. can do.

  According to a second aspect of the present invention, there is provided a guide route searching means for searching for a guide route for guiding a vehicle to a destination using map data, and a route for performing route guidance according to the guide route searched by the guide route searching means. When the current position of the vehicle is changed based on the determination result during the route guidance by the guidance means and the route guidance means, the guidance route search means is searched to search for the guidance route from the current position after the change. The display control means can also display on the display section the current position after the change and the guide route searched by the instruction from the instruction means. As a result, when the current position of the vehicle is erroneously displayed during route guidance, the current position of the vehicle is automatically set accurately without any operation by the driver, and the accurate current position is You can search for a guide route from.

  According to a third aspect of the present invention, when the driving direction of the vehicle is detected, the traveling direction of the vehicle is detected, and when the determination unit determines that the vehicle has changed direction based on the detected change in the traveling direction, It is preferable to determine that the position is on a general road. It is unlikely that a vehicle will change direction on a highway, but it is possible to change direction on a general road. Thereby, when the vehicle changes its direction, it can be considered that the current position of the vehicle is on a general road.

  According to the fourth aspect of the present invention, the determination means determines that the current position is on a general road based on the change of direction of the vehicle because the distance from the current position of the vehicle to the interchange on the highway is predetermined. It may be limited to when it is longer than the distance. Even when the vehicle changes direction, the current position of the vehicle may be considered to be on the highway. For example, in order to travel on the opposite lane of the highway on which the vehicle is currently traveling, exit the interchange, change direction, enter the opposite lane interchange, and travel on the opposite lane of the highway. In this case, the vehicle may travel on a general road from the expressway. Therefore, when the vehicle changes direction, it is preferable to determine that the current position of the vehicle is on a general road only when the distance from the current position to the interchange is a predetermined distance or more.

  According to the fifth aspect of the present invention, the operating state of the engine is detected as the driving state of the vehicle, and the determination means is turned on again after the engine of the vehicle is turned off based on the detected operating state of the engine. It is preferable to determine that the current position is on a general road. It is unlikely that the vehicle is turned on again after the vehicle engine is turned off on the highway, but it is conceivable that the engine is turned off and turned on again on a general road. Thereby, when the engine of the vehicle is turned off and turned on again, it can be considered that the current position of the vehicle is on a general road.

  As described in claim 6, the determination means determines that the current position is on a general road based on whether the vehicle engine is on or off, from the current position of the vehicle to the service area attached to the highway. The distance may be limited to a predetermined distance or more. Even when the vehicle engine is turned off and then turned on again, the current position of the vehicle may be considered to be on the highway. For example, when the vehicle is parked in the service area, the engine is turned off and the engine is turned on again to start. Since the service area is attached to the expressway, the current position of the vehicle is considered to be on the expressway. Therefore, when the vehicle engine is turned off and then turned on again, it is preferable to determine that the current position of the vehicle is on a general road only when the distance from the current position to the service area is a predetermined distance or more. .

  According to a seventh aspect of the present invention, the vehicle includes a traffic jam information acquisition unit that acquires traffic jam information and a speed limit acquisition unit that acquires speed limit information of a road corresponding to the current position of the vehicle. Based on the detected traveling speed, the traffic congestion information acquired by the traffic jam information acquisition means, and the speed limit acquired by the speed limit acquisition means, the determination means determines whether the current position is on a general road. It is preferable to determine whether the vehicle is on the road. It is possible to determine whether or not the current position of the vehicle is on a general road by considering traffic jam information and speed limit information from the traveling speed of the vehicle.

  Specifically, as described in claim 8, the determination means calculates the average traveling speed by averaging the detected traveling speed, and the average traveling speed is used to determine the current position on the general road. It is preferable to determine whether the vehicle is on a highway. Basically, a vehicle often travels at a speed near the speed limit when the road is not congested. However, the instantaneous speed at each time may differ greatly from the speed limit depending on traffic conditions. On the other hand, since the fluctuation in the instantaneous speed is smoothed at the average traveling speed, the type of road on which the vehicle is traveling can be correctly determined from the average traveling speed.

  Further, as described in claim 9, the determination means sets a reference speed for determining which road is running based on at least the speed limit of each of the general road and the highway, By comparing the detected traveling speed with the reference speed, it can be determined whether the current position is on a general road or an expressway. By setting the reference speed from the speed limit of the general road and the expressway, it can be determined whether the current position of the vehicle is on the expressway or the general road depending on whether the vehicle traveling speed is faster than the reference speed or not. Can be determined.

  As described in claim 10, it is preferable to change the reference speed based on the acquired traffic jam information. This is because the traveling speed of the vehicle becomes slow according to traffic jams, and the current position of the vehicle cannot be accurately determined even if both speeds are compared unless the reference speed is changed.

  As described in claim 11, when the acquired traffic jam information is related to a highway, it is preferable that the determination means stop determining whether the current position is on a general road or on a highway. . When the expressway is congested, the difference between the travel speed of the vehicle traveling on the expressway and the travel speed of the vehicle traveling on the general road may be small. For this reason, even if the reference speed is changed, the current position of the vehicle cannot be accurately determined.

  According to a twelfth aspect of the present invention, the determination unit is configured such that the acquired traffic jam information relates to a general road, and a difference between the detected traveling speed and the acquired speed limit of the acquired highway is within a predetermined range. In this case, it can be determined that the current position is on the highway. This is because when the general road is congested and the vehicle traveling speed is close to the speed limit of the expressway, the current position is likely to be on the expressway.

(First embodiment)
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a schematic configuration of an in-vehicle navigation device 100 according to the present embodiment. Hereinafter, the in-vehicle navigation device according to the present embodiment will be described in detail.

  The navigation device 100 includes a position detector 10, a digital road map database 20, a computer 30, a display unit 40, an operation switch group 50, an audio output unit 60, an audio input unit 70, an external memory 80, and a VICS receiver 90. Yes.

  The computer 30 includes a known CPU, ROM, RAM, I / O, and a bus line for connecting these components. In the ROM, a program to be executed by the computer 30 is written, and a CPU or the like executes predetermined arithmetic processing according to this program. Further, the computer 30 is connected to an ignition SW 200 that outputs a signal for turning on and off the engine.

  The position detector 10 includes a GPS receiver 11 for a global positioning system (GPS) that measures the position of a vehicle based on radio waves from a satellite, a geomagnetic sensor 12 for detecting the absolute direction of the vehicle, and a relative direction of the vehicle. Has a steering sensor 13 for detecting. Further, the position detector 10 includes a vehicle speed sensor 14 for detecting a travel distance from the travel speed of the vehicle.

  As described above, the position detector 10 includes the GPS receiver 11 for vehicle position measurement by radio wave navigation, and the geomagnetic sensor 12, the steering sensor 13, and the vehicle speed sensor 14 for vehicle position estimation by self-contained navigation. ing. Further, the radio navigation is not limited to the GPS, but, for example, a VICS optical beacon may be used. Further, in order to detect the relative orientation of the vehicle in the self-contained navigation, a gyro sensor or wheel speed sensors provided on the left and right wheels of the vehicle may be used instead of the steering sensor 13.

  The digital road map database 20 is an apparatus for inputting digital map data including road data, background data, character data, speed limit information, and the like to the computer 30. The digital road map database 20 has an information storage medium 21 for storing digital map data. As the information storage medium 21, a CD-ROM or a DVD-ROM is generally used depending on the data amount. A card, a hard disk, or the like may be used.

  Here, the configuration of road data will be described. The road data is composed of data such as a link ID with a unique number for each road, link coordinate data, node coordinate data, road type data indicating a road type such as an expressway or a national road, and road width data. . The link in the road data is obtained by dividing each road on the map into a plurality of nodes by nodes indicating intersections, branching points, etc., and defining a link between the two nodes. The link coordinate data describes the start and end coordinates of this link. When a node is included in the middle of the link, the node coordinates are described in the node coordinate data. In addition to displaying a map, this road data is used to give the shape of a road when performing map matching processing, or used when searching for a guide route to a destination.

  The background data is data for displaying the facility shape, natural terrain, and the like to be displayed other than the road when the road map is displayed on the display unit 40. The character data is for displaying place names, facility names, road names, and the like on the road map, and is configured as data in which coordinates on the map corresponding to the display positions are associated. As for the facility, data such as a telephone number and an address are also stored in association with the facility name. The data regarding this facility may be stored in the external memory 80 described later.

  The display unit 40 is configured by, for example, a liquid crystal display, and the vehicle generated by the vehicle position mark corresponding to the current position of the vehicle on the screen of the display unit 40 and the map data input from the digital road map database 20. The surrounding road map can be displayed. When a destination is set, a guide route from the current position to the destination is displayed on the road map in an overlapping manner.

  The operation switch group 50 includes, for example, a touch panel switch integrated with the display unit 40 or a mechanical switch provided around the display unit 40, and is used for various inputs.

  The voice output unit 60 includes a speaker or the like, and outputs a guidance voice when route guidance is being performed, or outputs a guidance related to an input voice at the time of voice recognition. The voice input unit 70 is composed of a microphone or the like, and takes in a voice uttered by the user and inputs it to the computer 30. The computer 30 performs a process for recognizing the input voice, and executes various controls based on the recognition result.

  The external memory 80 is composed of a storage medium such as a memory card or a hard disk. The external memory 80 stores various data such as text data, image data, and audio data stored by the user.

  The VICS receiver 90 receives information such as road traffic information distributed from the VICS center via beacons laid on the road and FM broadcast stations in various places, and information from the vehicle side to the outside as necessary. It is a device that transmits. The received information is processed by the computer 30. For example, traffic jam information, speed limit information, and the like are superimposed on the road map displayed on the display unit 40.

  The ignition SW 200 is a switch for controlling start and stop of the engine, and normally has a four-stage switching position of off, accessory, on, and start. When switched to each position, an off signal, an accessory signal, an on signal, and a start signal corresponding to each position are output to the computer 30.

  In addition, when the position of the destination is input by the operation switch group 50 or voice recognition, the in-vehicle navigation device 100 according to the present embodiment automatically selects the optimum route from the current position to the destination and guides the route. A so-called route guidance function is also provided. As a method for automatically setting an optimum route, a known method such as the Dijkstra method is known. In addition, for example, a search function for searching for the position of a facility or the like from an address, a facility name, a telephone number or the like input by the user is also provided.

  These functions are executed mainly by the computer 30 performing various arithmetic processes. In other words, when the destination is input, the computer 30 calculates a route using the map data of the digital road map database 20, displays the route, and enlarges the road map and voices at a branch point or an intersection to turn left or right. Give guidance. In addition, the computer 30 displays the own vehicle position mark indicating the position of the vehicle and the surrounding road map on the display unit 40, or changes the scale of the road map.

  Next, in the above-described in-vehicle navigation device of the present embodiment, when the highway and the general road are close to each other, when the current position of the vehicle is displayed by mistake, the driver does not operate, Processing for correcting the current position of the vehicle to an accurate position will be described with reference to the flowcharts of FIGS. FIG. 2 is a flowchart showing a main routine of processing for correcting the current position of the vehicle to an accurate position, and FIG. 3 is a flowchart showing a routine of processing for determining the current position of the vehicle.

  First, in step S10 of FIG. 2, the current position of the vehicle is calculated based on the position data measured by each sensor of the position detector 10. At this time, the position data by the GPS receiver 11 is acquired in the same form as the coordinate data (latitude and longitude) of the road data described above. In addition, the geomagnetic sensor 12, the steering sensor 13, and the vehicle speed sensor 14 acquire data related to the traveling direction and travel distance of the host vehicle, and calculate the coordinate data of the current position based on the vehicle position calculated or determined in the past. Perform (calculation of coordinate data by self-contained navigation). The current position is basically obtained based on coordinate data calculated by self-contained navigation. However, when the position data by the GPS receiver 11 is acquired, the two are compared, and when the difference is equal to or greater than a predetermined distance, the position data by the GPS receiver 11 is adopted as the current position.

  In step S20, a map matching process is performed. For example, if a road within a predetermined distance from the current position calculated in step S10 or a road already matched on the road is identified as a road on which the vehicle may travel To do. Then, the travel locus is calculated by connecting the plurality of current positions calculated in the past in step S10 and the latest current position. The shape of the travel locus is compared with the shape of the road on which the vehicle may travel, and the road with the highest correlation is estimated as the road on which the vehicle is traveling. Thereby, the road which should display the present position acquired in Step S10 is determined.

  The calculation of the current position in step S10 and the calculation of the travel locus described above may be performed only from the position data of the GPS receiver 11, or may be performed only from the position data of the self-contained navigation.

  In step S30, it is determined whether the highway and the general road are close to each other around the current position of the vehicle. Specifically, for example, a highway and a general road are running side by side. If not, the process ends. On the other hand, if it is close, the process proceeds to step S40.

  In step S40, it is determined whether or not the current position is on the expressway. That is, it is determined whether or not the road determined in step S20 is a highway. If it is determined that the road is not an expressway, the process is terminated. On the other hand, if it is determined that the road is a highway, the process proceeds to step S50.

  In step S50, a current position determination process is executed. This current position determination process will be described with reference to the flowchart of FIG.

  In the flowchart of FIG. 3, first, in step S210, it is determined whether or not the traveling direction of the vehicle has changed by 170 ° or more based on the change in the traveling direction of the vehicle. That is, it is determined whether or not the vehicle has changed direction.

  Specifically, for example, the traveling direction of the vehicle detected by the geomagnetic sensor 12 at a certain time is set as the reference direction. If the difference between the reference azimuth and the traveling azimuth of the vehicle detected within a predetermined time is 170 ° or more, it is determined that the direction of the vehicle has been changed. On the other hand, if the difference between the traveling azimuths of all the vehicles detected within a predetermined time and the reference azimuth is smaller than 170 °, it is determined that the direction of the vehicle has not been changed. The reason why the predetermined time is set is that if the vehicle makes a plurality of right and left turns, it may be determined that the direction has been changed by mistake.

  In the above description, an example using a predetermined time has been described. However, a predetermined distance may be used instead of the predetermined time.

  Further, the direction change may be detected by using the steering sensor 13 that detects the relative direction. Specifically, the traveling direction of the vehicle detected by the steering sensor 13 at a certain point in time is set as the reference direction. The angle change between the reference azimuth and the traveling azimuth of the vehicle detected within a predetermined time is accumulated, and when the accumulated angle is 170 ° or more, it is determined that the direction of the vehicle has been changed. On the other hand, when the accumulated angle between the traveling azimuths of all the vehicles detected within a predetermined time and the reference azimuth is smaller than 170 °, it is determined that the direction of the vehicle has not been changed.

  In the above description, an example using the steering sensor 13 has been described. However, instead of the steering sensor 13, a gyro sensor or wheel speed sensors provided on the left and right wheels of the vehicle may be used.

  Furthermore, the direction change of the vehicle may be detected by using the traveling locus of the vehicle. More specifically, the detected travel locus of the vehicle is compared with a turning pattern stored in an internal memory (not shown) of the computer 30 to calculate a correlation coefficient indicating the degree of similarity between the two. If the calculated correlation coefficient is greater than or equal to a predetermined value, it is determined that the vehicle has changed direction.

  It is unlikely that a vehicle will change direction on a highway, but it is possible to change direction on a general road. Thereby, when a vehicle changes direction, it can determine with the present position of a vehicle being on a general road.

  If it is determined in step S210 that the vehicle has not changed direction, the process proceeds to step S240. In step S240, it is determined that the current position of the vehicle is on the highway. On the other hand, if it is determined that the vehicle has changed direction, the process proceeds to step S220.

  In step S220, it is determined whether the distance from the current position of the vehicle to the interchange is a predetermined distance or more. Specifically, the closest interchange from the current position of the vehicle is detected on the road where the current position of the vehicle is displayed from the digital road map database 20. In the digital road map database 20, the distance between the detected interchange and the current position of the vehicle is calculated.

  Even when the vehicle changes direction, the current position of the vehicle may be considered to be on the highway. That is, in order to travel on the opposite lane of the highway on which the vehicle is currently traveling, exit the interchange, change direction, enter the opposite lane interchange, and travel on the opposite lane of the highway. In this case, the vehicle may travel on a general road from the expressway. Therefore, when the vehicle changes direction, it is preferable to determine that the current position of the vehicle is on a general road only when the distance from the current position to the interchange is a predetermined distance or more.

  If it is determined in step S220 that the distance is equal to or greater than the predetermined distance, the process proceeds to step S230. In step S230, it is determined that the current position of the vehicle is on a general road. On the other hand, if it is determined that the distance is not greater than the predetermined distance, the process proceeds to step S240. In step S240, it is determined that the current position of the vehicle is on the highway.

  Returning to the flowchart of FIG. 2, the process proceeds to step S60. In step S60, it is determined whether the road types are the same. That is, it is determined whether or not the type of road displaying the current position determined in step S20 is different from the type of road on which the current position determined in step S50 is to be displayed. When it is determined that the road types are the same, the process proceeds to step S110. In step S110, it is determined whether route guidance is being performed. If it is determined that route guidance is not being performed, the process is terminated. On the other hand, if it is determined that route guidance is being performed, the process proceeds to step S120. In step S120, route guidance is continued.

  On the other hand, if it is determined in step S60 that the road type is different, the process proceeds to step S70. In step S70, the current position is changed based on the result determined in step S50. Specifically, in the display unit 40, the current position of the vehicle is changed on a general road with a different road type that is close to the expressway on which the current position of the vehicle is displayed. In step S80, it is determined whether route guidance is being performed. If it is determined that route guidance is not being performed, the process is terminated. On the other hand, if it is determined that route guidance is being performed, the process proceeds to step S90.

  In step S90, the guidance route is searched again. Specifically, the current position of the vehicle changed in step S70 is set as a new start point, and an optimum route from this start point to the destination is searched by a known method such as Dijkstra method. As a result, when the current position of the vehicle is erroneously displayed during route guidance, the current position of the vehicle is automatically set accurately without any operation by the driver, and the accurate current position is You can search for a guide route from.

  In step S100, route guidance is started based on the guidance route searched in step S90.

(Modification)
In the first embodiment described above, the example in which the direction change is determined when the traveling direction of the vehicle changes by 170 ° or more has been described. However, the angle for determining the direction change is not limited to 170 ° and can be set to an arbitrary angle.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. The in-vehicle navigation device according to the present embodiment has the same configuration as the in-vehicle navigation device 100 according to the first embodiment described above. In addition, regarding the main routine of the process for correcting the current position of the vehicle to an accurate position, the in-vehicle navigation device according to the second embodiment performs the same process as the in-vehicle navigation device 100 according to the first embodiment. Therefore, descriptions of these configurations and main routine processing will be omitted.

  The difference between the in-vehicle navigation device according to the first embodiment and the second embodiment is in the current position determination process. In the second embodiment, the determination is made based on the operating state of the engine rather than determining whether the current position is on a general road or an expressway based on the direction change of the vehicle.

  Hereinafter, the current position determination process in the second embodiment will be specifically described based on the flowchart of FIG. First, in step S310, it is determined based on the operating state of the engine whether the vehicle engine has been turned off and then turned on again. That is, it is determined whether or not the signal output from the ignition SW 200 to the computer 30 is changed from the off signal to the on signal after being changed from the on signal to the off signal.

  It is unlikely that the vehicle is turned on again after the vehicle engine is turned off on the highway, but it is conceivable that the engine is turned off and turned on again on a general road. Thereby, when the engine of the vehicle is turned off and turned on again, it can be considered that the current position of the vehicle is on a general road.

  If it is determined that the OFF signal has not been changed to the ON signal, the process proceeds to step S340. In step S340, it is determined that the current position of the vehicle is on the highway. On the other hand, if it is determined that the off signal is changed to the on signal, the process proceeds to step S320.

  In step S320, it is determined whether the distance from the current position of the vehicle to the service area is equal to or greater than a predetermined distance. Specifically, a service area closest to the current position of the vehicle is detected on the road where the current position of the vehicle is displayed from the digital road map database 20. In the digital road map database 20, the distance between the detected service area and the current position of the vehicle is calculated.

  On highways, the engine may be turned off to park the vehicle in the service area, and the engine may be turned on again to leave. In this case, since the service area is attached to the highway, it is considered that the current position of the vehicle is on the highway. Accordingly, when the vehicle engine is turned off and then turned on again, the vehicle's current position is considered to be on a general road only when the distance from the current position to the service area is equal to or greater than a predetermined distance.

  If it is determined in step S320 that the distance is not greater than the predetermined distance, the process proceeds to step S340. In step S340, it is determined that the current position of the vehicle is on the highway. On the other hand, if it is determined that the distance is equal to or greater than the predetermined distance, the process proceeds to step S330. In step S330, it is determined that the current position of the vehicle is on a general road.

(Third embodiment)
Next, a third embodiment of the present invention will be described. The in-vehicle navigation device according to the present embodiment has the same configuration as the in-vehicle navigation device 100 according to the first embodiment described above. In addition, regarding the main routine of the process for correcting the current position of the vehicle to an accurate position, the in-vehicle navigation device according to the third embodiment performs substantially the same processing as the in-vehicle navigation device 100 according to the first embodiment. Therefore, the description about the same process in these structures and main routine is abbreviate | omitted, The difference between the vehicle-mounted navigation apparatus by 1st Embodiment and 2nd Embodiment and 3rd Embodiment exists in the present position determination process. In the third embodiment, the average traveling speed of the vehicle is calculated, and based on the average traveling speed, it is determined whether the current position is on a general road or an expressway.

  In the first and second embodiments described above, if it cannot be determined that the vehicle is traveling on a general road, it is determined passively that the vehicle is traveling on a highway. On the other hand, in the third embodiment, based on the average traveling speed, whether each vehicle is traveling on a general road or an expressway is positively determined. For this reason, as shown in the main routine of FIG. 5, processing corresponding to step S40 of FIG. 2 is omitted.

  Hereinafter, the current position determination process in the third embodiment will be specifically described based on the flowchart of FIG.

  First, in step S610, the traveling speed of the vehicle is detected based on the signal from the vehicle speed sensor 14.

  In step S620, the average traveling speed is calculated by averaging the plurality of traveling speeds detected in the past in step S610 and the latest traveling speed. In step S630, traffic jam information is acquired. Specifically, the VICS receiver 90 receives traffic information distributed from the VICS center via beacons laid on the road and FM broadcast stations in various places. The traffic jam information includes a traffic jam location including a road type, a traffic jam degree, and the like. The degree of traffic jam is divided into four categories: “traffic jam”, “crowded”, “no traffic jam”, and “unknown”. The road types are classified into “highway”, “general road”, and “other”. The received traffic jam information is processed by the computer 30 and displayed superimposed on the road map displayed on the display unit 40.

  In step S640, it is determined whether or not the traffic jam information acquired in step S630 relates to a highway. If it is determined that the traffic information is related to the expressway, the process is terminated. When the expressway is congested, the difference between the travel speed of the vehicle traveling on the expressway and the travel speed of the vehicle traveling on the general road may be small. For this reason, the current position of the vehicle cannot be accurately determined based on the average travel speed calculated in step S620.

  On the other hand, if it is determined that the traffic jam information is not related to the expressway, the process proceeds to step S650. In step S650, speed limit information is acquired. Specifically, the speed limit information is acquired from the digital road map database 20. Alternatively, the VICS receiver 90 may receive the speed limit distributed from the VICS center via beacons laid on the road or FM broadcast stations in various places. The received speed limit information is processed by the computer 30.

  In step S660, whether or not the current position of the vehicle is on the general road is determined by comparing the average traveling speed in the section of the predetermined distance traveled in the past with the respective speed limits based on the current position of the vehicle. Determine. Basically, a vehicle often travels at a speed near the speed limit when the road is not congested. However, the instantaneous speed at each time may differ greatly from the speed limit depending on traffic conditions. On the other hand, since the fluctuation of the instantaneous speed is smoothed at the average traveling speed, it is possible to correctly determine the road on which the vehicle is traveling from the average traveling speed. Further, if there is a traffic jam based on the acquired traffic jam information, the vehicle cannot run at a running speed near the speed limit. Therefore, based on the acquired traffic jam information, the travel speed at the time of traffic congestion in which the vehicle can travel is calculated, the acquired speed limit is reduced to the calculated travel speed at the time of traffic jam, and the vehicle speed is the same as described above. The current position can be estimated. Thereby, it can be determined whether the current position of the vehicle is on the highway or the general road.

  A specific example will be described. From the speed limit information acquired in step S650, it is assumed that the speed limit of the highway is 100 km / h and the speed limit of the general road is 50 km / h. Further, based on the traffic jam information acquired in step S630, it is assumed that the average traveling speed calculated in step S620 is 43 km / h when no traffic jam has occurred. Then, the absolute value of the difference between the average travel speed and the speed limit of the highway and the general road is calculated. The absolute value of the difference from the speed limit of the expressway is | 43-100 | = | −57 | = 57 km / h. Further, the absolute value of the difference from the speed limit of a general road is | 43-50 | = | -7 | = 7 km / h. By comparing these two differences, it can be seen that the absolute value of 7 km / h of the difference from the speed limit of the general road is smaller. Thereby, it is determined that the vehicle is traveling at a traveling speed close to the speed limit of the general road, and the current position of the vehicle is on the general road.

  On the other hand, it is assumed that the average traveling speed calculated in step S620 is 97 km / h when traffic congestion occurs on a general road. Since traffic congestion has occurred, the speed limit for general roads is 50 km / h, but the traveling speed at the time of traffic congestion in which the vehicle can travel is calculated as 10 km / h, for example. Thereby, the speed limit of the acquired general road is reduced to 10 km / h. At this time, the absolute value of the difference between the average traveling speed of the vehicle of 97 km / h and the speed limit of the highway of 100 km / h is | 97-100 | = | −3 | = 3 km / h. Thereby, since the average traveling speed of the vehicle is close to the speed limit of the expressway, it can be considered that the current position is on the expressway. As a result, it is determined that the current position of the vehicle is on the highway.

  If it is determined in step S660 that the current position is on a general road, the process proceeds to step S670. In step S670, it is determined that the current position of the vehicle is on a general road. On the other hand, if it is determined that the current position is not on a general road, the process proceeds to step S680. In step S680, it is determined that the current position of the vehicle is on the highway.

(Modification)
In 3rd Embodiment mentioned above, when the traffic information regarding a general road was acquired, the example which changes the speed limit of a general road was demonstrated by considering this traffic information. However, when the acquired traffic information includes the average travel speed of the vehicle traveling on the road where the traffic jam occurs, this average travel speed may be used as the speed limit of the general road.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. The in-vehicle navigation device according to the present embodiment has the same configuration as the in-vehicle navigation device 100 according to the third embodiment described above. In addition, regarding the main routine of the process for correcting the current position of the vehicle to an accurate position, the in-vehicle navigation device according to the fourth embodiment performs the same process as the in-vehicle navigation device 100 according to the third embodiment. Therefore, descriptions of these configurations and main routine processing will be omitted.

  The vehicle-mounted navigation device according to the fourth embodiment performs a vehicle current position determination process based on the traveling speed of the vehicle as in the third embodiment. However, in the third embodiment, the determination is performed based on the average traveling speed of the vehicle. In the fourth embodiment, the reference speed is set, and the determination is performed based on the reference speed.

  Setting and changing the reference speed will be described. Specifically, for example, based on the acquired speed limit information, it is assumed that the speed limit of the highway is 80 km / h and the speed limit of the general road is 40 km / h. A reference speed is set from this speed limit. There are several methods for calculating the reference speed. In this embodiment, a method of averaging the speed limits of both roads is used. Therefore, the reference speed is calculated as (80 + 40) / 2 = 60 km / h.

  When a traffic jam occurs, the travel speed at the time of the traffic jam is used instead of the speed limit. For example, even if the speed limit of a general road is 40 km / h, if it is considered that the vehicle is traveling at a speed of about 10 km / h due to traffic congestion, the speed limit of the general road is reduced to 10 km / h. At this time, the reference speed is calculated as (80 + 10) / 2 = 45 km / h by averaging the speed limits of both roads. Thus, when a traffic jam occurs, the reference speed is changed from 60 km / h to 45 km / h. This is because the traveling speed of the vehicle becomes slow according to traffic jams, and the current position of the vehicle cannot be accurately determined even if both speeds are compared unless the reference speed is changed.

  Whether the current position of the vehicle is on the highway or the general road can be determined based on whether or not the traveling speed of the vehicle is faster than the set reference speed.

  A specific example will be described. It is assumed that the reference speed is 47.5 km / h and the vehicle traveling speed is 10 km / h. When this traveling speed is compared with the reference speed of 47.5 km / h, it can be considered that the current position is on a general road because the traveling speed is slower than the reference speed. As a result, it is determined that the current position of the vehicle is on a general road.

  As described above, according to the present embodiment, attention is paid to the point that the driving state of the vehicle is greatly different between the highway and the general road, that is, the driving state peculiar to the highway and the general road. From this point of view, when a driving condition peculiar to a general road is detected, the current position of the vehicle is on the general road, and when a driving condition peculiar to the highway is detected, the current position of the vehicle is on the highway. it is conceivable that. As a result, when the current position of the vehicle is displayed incorrectly when the expressway and the general road are close to each other, the current position of the vehicle is automatically set accurately without the driver's operation. can do.

It is a block diagram which shows schematic structure of the vehicle-mounted navigation apparatus 100 by 1st Embodiment. It is a flowchart which shows the main routine of the process which sets the present position of a vehicle to an exact position in 1st Embodiment. 5 is a flowchart illustrating a routine of processing for determining a current position of a vehicle in the first embodiment. In 2nd Embodiment, it is a flowchart which shows the routine of the process which determines the present position of a vehicle. It is a flowchart which shows the main routine of the process which sets the present position of a vehicle to an exact position in 3rd Embodiment. In 3rd Embodiment, it is a flowchart which shows the routine of the process which determines the present position of a vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Position detector 11 ... GPS receiver 12 ... Geomagnetic sensor 13 ... Steering sensor 14 ... Vehicle speed sensor 20 ... Digital road map database 21 ... Information recording medium 30 ... Computer 40 ... Display part 50 ... Operation switch group 60 ... Sound output part 70 ... Voice input unit 80 ... External memory 90 ... VICS receiver 200 ... Ignition SW

Claims (12)

Driving state detection means for detecting the driving state of the vehicle;
Current position detecting means for detecting the current position of the vehicle;
Map data storage means for storing map data including road shapes;
Display control means for displaying a road map based on the map data and the current position of the vehicle on a display unit;
Determination means for determining whether the current position of the vehicle is on a general road or on a highway based on the driving state of the vehicle;
The display control unit changes the current position of the vehicle on the road of the type determined by the determination unit when the determination result of the determination unit is different from the road type on which the current position of the vehicle is displayed. A vehicle-mounted navigation device characterized by being displayed. Guidance route search means for searching for a guidance route for guiding the vehicle to the destination using the map data;
Route guidance means for performing route guidance according to the guidance route searched by the guidance route search means;
When the current position of the vehicle is changed based on the determination result during the route guidance by the route guidance unit, the guidance route search unit is searched to search for a guidance route from the changed current position. And an instruction means for instructing
The in-vehicle navigation device according to claim 1, wherein the display control unit displays the current position after the change and a guide route searched by an instruction from the instruction unit on a display unit. As the driving state of the vehicle, the traveling direction of the vehicle is detected, and when the determination unit determines that the vehicle has changed direction based on the detected change in the traveling direction, the current position is on a general road. The in-vehicle navigation device according to claim 1, wherein the in-vehicle navigation device is determined to be in the vehicle. The determination means determines that the current position is on a general road based on the direction change of the vehicle only when the distance from the current position of the vehicle to the interchange on the expressway is a predetermined distance or more. The in-vehicle navigation device according to claim 3. If the operating state of the vehicle is detected as an operating state of the vehicle, and the determining means determines that the engine of the vehicle is turned on again after being turned off based on the detected operating state of the engine, The in-vehicle navigation device according to any one of claims 1 to 4, wherein the position is determined to be on a general road. The determination means determines that the current position is on a general road based on whether the engine of the vehicle is on or off because the distance from the current position of the vehicle to the service area attached to the expressway is a predetermined distance or more. The in-vehicle navigation device according to claim 5, which is limited to Traffic information acquisition means for acquiring traffic information,
Speed limit acquisition means for acquiring speed limit information on the road corresponding to the current position of the vehicle,
As the driving state of the vehicle, the traveling speed of the vehicle is detected, and the determination means sets the detected traveling speed, the traffic congestion information acquired by the traffic congestion information acquisition means, and the speed limit acquired by the speed limit acquisition means. The in-vehicle navigation device according to any one of claims 1 to 6, wherein a determination is made as to whether the current position is on a general road or an expressway. The determining means calculates the average traveling speed by averaging the detected traveling speeds, and determines whether the current position is on a general road or an expressway using the average traveling speed. The in-vehicle navigation device according to claim 7. The determination means sets a reference speed for determining which road is traveling based on at least the speed limit of each of the general road and the highway, and the detected traveling speed and the reference speed The vehicle-mounted navigation device according to claim 7, wherein whether the current position is on a general road or an expressway is determined based on the comparison. The in-vehicle navigation device according to claim 9, wherein the reference speed is changed based on the acquired traffic jam information. The said determination means stops the determination whether the present position is on a general road or on a highway when the acquired traffic congestion information is related to a highway. The in-vehicle navigation device according to any one of Items 10. The determination means determines that the current position is a highway when the acquired traffic jam information relates to a general road and the difference between the detected traveling speed and the acquired speed limit is within a predetermined range. The in-vehicle navigation device according to claim 7, wherein the on-vehicle navigation device is determined to be on.

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