JP3376578B2 - Car navigation system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted navigation device, and more particularly to a vehicle-mounted navigation device that calculates a recommended route based on a hierarchical map database.

[0002]

2. Description of the Related Art In a car navigation system, a user can designate an arbitrary point on an electronic map with a predetermined input device, and a vehicle position calculation processing device detects a vehicle position. Then, the road distance from the point designated by the user as the departure point or the vehicle position to the point designated by the user as the destination is the minimum,
Alternatively, the route having the minimum travel time according to the road type and the road distance is calculated as the recommended route by the well-known Dijkstra method, potential method, A * algorithm, or the like. Furthermore, in order to reduce the calculation time, the electronic map covers only high-grade roads such as highways and national roads, and a wide-area map network as high-level map information, and not only highways and national roads but also prefectural roads. Detailed map network as a lower level map information that covers roads and narrow roads, and a hierarchical map database that is layered into a detailed map network, and the detailed map network is used in both end ranges of the recommended route from the origin to the destination. On the other hand, the intermediate range of the recommended route is roughly calculated using the wide area map network. It should be noted that the wide area map network and the detailed map network do not each form one layer, but the inside is further layered, and the entire map database is usually layered in three or four layers.

7 to 9 show screens of a display device 38 in a conventional car navigation system. The same elements as those of the embodiment of the present invention described later are designated by the same reference numerals, detailed description thereof will be omitted, and only main points will be described.

FIG. 7 shows the screen of the display device 38 when the vehicle is traveling in the intermediate range of the recommended route 44 in the conventional car navigation system. The own vehicle position 42 is appropriately in front of the branch road of the prefectural road 41 from the recommended route 44,
In this case, the recommended route 44 is the shortcut route of the national highway 40.

FIG. 8 shows the screen of the display device 38 when the vehicle departs from the recommended route 44 and enters the prefectural road 41 in FIG. When the vehicle leaves the national highway 40 as the recommended route 44 to the prefectural road 41, a new recommended route 44 is calculated based on the detailed map network covering the vehicle position 42,
If the calculation is successful, it is displayed on the display device 38 as the recommended route 44.
Is displayed in.

FIG. 9 shows a screen of the display device 38 when the vehicle departs from the recommended route 44 to the dead end street 48 in the conventional car navigation system. The car navigation device cannot calculate the recommended route 44 and does not inform the user that the recommended route 44 cannot be calculated.

[0007]

The problems of the conventional car navigation system are listed below. (A) In FIG. 7, the intermediate range of the recommended route 44 is calculated by the wide area map network that does not cover the prefectural road 41 as the low grade road. Although there is the prefectural road 41 as the shortcut route of, the fact that the prefectural road 41 is the shortcut route is not presented. That is, as shown in FIG. 8, the vehicle is the first recommended route 44.
Unless the car navigation device 10 leaves the user, the information about the prefectural road 41 is not displayed on the display device 38, and the display of FIG. 8 is displayed not as the shortcut route but as the recommended route 44. is there. It should be noted that the user can search for the prefectural road 41 by himself by looking at the display of the display device 38 and the map book made of paper, and drive on the prefectural road 41. (B) In FIG. 9, when the recommended route 44 cannot be recalculated because it has departed from the recommended route 44 to the dead end narrow street 48 toward the destination, there is no response from the car navigation device to the user, and the user Feel distrust of car navigation systems.

An object of the present invention is to provide a vehicle-mounted navigation device that can overcome the above-mentioned problems.

[0009]

A vehicle-mounted navigation device (10) of the present invention has the following (a) to (d). (A) Hierarchical map database consisting of multiple layers of map information that covers roads with lower grades in the lower hierarchy than in the upper hierarchy (16) (b) Recommendations for connecting the departure point and destination Recommended route calculating means (c) for calculating the route (44) based on the map information of the hierarchy higher than both end ranges in the middle range, near the current position while the vehicle is traveling in the middle range of the recommended route (44) Then, the recommended route (44) is recalculated based on the map information of the lower hierarchy than the map information which is the basis of the calculation in the intermediate range of the recommended route (44) and the original recommended route (44)
If it is different from the shortcut route calculating means (d), the shortcut route (45) calculated by the shortcut route calculating means is displayed together with the display means (38).
(38)

[0010] A road has a high grade as it extends over a wide area in a region, and a low grade as a road extends only in a narrow region. Generally, highways and national roads have higher grades than prefectural roads, and prefectural roads have higher grades than municipal roads.

The hierarchical map database (16) is usually
Divided into an upper-layer wide-area map network that covers only wide-area roads such as expressways and national roads as map information, and a lower-level detailed map network that includes prefectural roads and narrow roads as map information in this wide-area map network. The wide-area map network and the detailed map network are further hierarchized from the upper level to the lower level, and have a hierarchical structure of 3 or 4 as a whole. The hierarchized map database (16) has a minimum of two hierarchies, but includes three or more hierarchies. In the case of three or more layers, the map information layers that are the basis for calculating the recommended route parts of both end ranges and intermediate ranges are not limited to the bottom layer and the top layer, respectively. The layers of map information that are the basis for calculating the recommended route portion in the edge range do not have to be the same.

The recommended route (44) is calculated by the recommended route calculating means by the well-known Dijkstra method, potential method,
Alternatively, the A * algorithm or the like is adopted. Calculation of the shortcut route (45) by the shortcut route calculation means,
Usually, it is performed based on the shortest distance according to the road distance, or travel time (static time based on road type, road width, etc.) is based on fixed data such as CD-ROM and is called static. It is performed based on the shortest time based on data that changes from moment to moment, etc.), but is calculated based on the shortest time based on travel time that takes into account dynamic data such as VICS information. May be done. This is because the travel time on the expressway is usually shorter, but the travel time on the general road may be shorter than that on the expressway depending on the VICS information.

In this way, in the intermediate range of the recommended route (44), the shortcut route (45) is calculated by the recommended route calculation based on the map information of the lower hierarchy, and as a result, the own vehicle is recommended by the recommended route calculation means. The middle range of route (44)
If the shortcut route (45) is present even if the user is traveling without departing from it, it is displayed to the user.

Vehicle-mounted navigation device (10) of the present invention
According to the above, the shortcut route calculating means calculates the shortcut route (45) only under a predetermined condition.

The predetermined condition is, for example, the recommended route (44).
Is congested and the traveling speed of the host vehicle is lower than the speed limit of the recommended route (44), or the user particularly instructs calculation of the shortcut route (45). By imposing such a condition, the load on the CPU can be reduced. On the contrary, when the traveling speed of the own vehicle is almost the speed limit of the recommended route (44), even if the load on the CPU is small, it may cause the user to be confused. Therefore, the shortcut route (45) should not be calculated or displayed. You should stop it.

Vehicle-mounted navigation device (10) of the present invention
Is the vehicle position (42) when the vehicle leaves the recommended route (44).
It has recalculation instructing means for instructing the recommended route calculation means to recalculate the recommended route (44) at least in the vicinity of the current position, starting from The shortcut route calculation means is
Recommendation that the recalculation instruction means forced the recalculation instruction means to recalculate the recommended route (44) even though the vehicle did not leave the recommended route (44) The shortcut route (45) is calculated based on the route (44).

Recalculation when the own vehicle departs from the recommended route (44), using the own vehicle position (42) as the starting point, and causing the recommended route calculation means to recalculate the recommended route (44) at least near the current position The instruction means is a known technique. Since this vehicle-mounted navigation device (10) uses this recalculation instruction means, it is possible to reduce the number of newly added parts for the recalculation instruction means and to simplify the entire vehicle-mounted navigation device (10). it can.

In-vehicle navigation device of the present invention (10)
If the vehicle departs from the recommended route (44) and it is judged that the recommended route calculation means is actually traveling on the dead end road (48) toward the destination, information on the dead end (52 )
It has a dead end information presenting means for presenting to the user.

The practical dead end is not limited to the case where the road (48) is a dead end, but the road width is temporarily extremely narrow even if the road (48) is not a dead end. Includes cases where the vehicle cannot pass.

When the vehicle departs from the recommended route (44) and travels toward the destination on the road (48) which is a substantially dead end, the known route uses the recommended route (44). The information (52) related to the dead end is presented to the user, whereas the user is left as it is without being able to recalculate, so that the user can accurately grasp the information placed by the user and deal with it.

Vehicle-mounted navigation device (10) of the present invention
Has the following (a) to (c). (A) Recommended route calculation means for calculating the recommended route (44) connecting the departure point and the destination (b) When the vehicle departs from the recommended route (44) The vehicle position (4)
Return route calculation means (c) for calculating the return route returning from 2) to the recommended route (44). The recommended route calculation means is substantially for the destination of the vehicle leaving the recommended route (44). Dead End Road (48)
When it is judged that the
Dead end information presenting means for presenting 2) to the user

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a car navigation device 10. 12 is a main controller including a microcomputer, 14 is a vehicle position processing device, 16 is a map database including a CD-ROM, etc., 18
Is a recording medium reading device such as a CD-ROM drive, 20 is a main storage memory such as RAM, 22 is an input device, 24 is a video processing device, and 26 is an audio output device (speaker).
Is. The vehicle position processing device 14 further includes an autonomous navigation sensor 28 including an angular velocity sensor that detects the rotational angular velocity of the vehicle and a distance sensor that detects the distance traveled by the vehicle, and the current position and current direction of the vehicle are determined by satellite navigation. It is equipped with a GPS receiver 30, and an own vehicle position calculation device 32 that calculates the own vehicle position based on inputs from the autonomous navigation sensor 28 and the GPS receiver 30. The recording medium reading device 18 reads the map data from the map database 16, and the main controller 12
Output to. The main controller 12 includes the unit data of the road network from the recording medium reading device 18, the current position data of the own vehicle from the own vehicle position processing device 14, and the user's input device 32 such as the departure place and the purpose of the own vehicle. The position data regarding the ground and the main memory 20 are stored.
The main controller 12 calculates recommended route guidance data and the like based on the data read from the main memory 20, and the recommended route guidance data, map data of a region including the own vehicle position, own vehicle position data, etc. Output to 24. Further, the main controller 12 sends data to the voice output device 26, and the voice output device 26 notifies the user of information by voice as appropriate. The image processing device 24 includes, in addition to the display device (display) 38, a graphics controller 34 and a video RAM 36. The recommended route guidance data stored in the video RAM 36 by the graphics controller 34 and read from the video RAM 36. Is output to the display device 38 and displayed.

FIG. 2 shows the screen of the display device 38 of the car navigation device 10 when the vehicle is traveling in the intermediate range of the recommended route 44. The own vehicle position 42 is appropriately in front of the branch road of the prefectural road 41 from the recommended route 44, and in this case, the distance is shorter than the portion of the national road 40 as the recommended route 44, and the recommended route 44 It has become a shortcut route 45 of. Therefore, on the display device 38, the national road 40 is displayed as the recommended route 44, and the prefectural road 41 is displayed as the shortcut route 45. Since the recommended route 44 and the shortcut route 45 are clearly distinguished on the display on the display device 38, for example, the recommended route 44 is displayed continuously and the shortcut route 45 is displayed in blinking. Recommended route 44 and shortcut route 45 in Figure 2
It is also possible to distinguish between and by making the colors different from each other. This allows the user to select the vehicle position 42 as the recommended route.
While traveling on 44, it will soon be known that there is a shortcut route 45 ahead.

FIG. 3 is a diagram showing a screen of the display device 38 when the recommended route 44 is not present during the period when the vehicle is traveling in the intermediate range of the recommended route 44. In front of the vehicle position 42, the narrow street 48,
There are 49 and 50, but only narrow street 49 intersects at the end of narrow street 48, both narrow streets 48 and 49 are blind alleys, and narrow street 50 can handle mini cars. However, it is not suitable for 3 number vehicles and large vehicles, or recommended route
It is a case where it does not lead to a reduction in time compared to passing 44 as it is. In such a case, the shortcut route 45 is not displayed on the display device 38. This is the same screen as the display device of the conventional car navigation device in which the shortcut route (45) is not calculated when the vehicle position 42 is on the national road 40.

FIG. 4 shows a screen of the display device 38 when the car has deviated from the recommended route 44 to the dead end narrow road 48 in the car navigation device 10. The car navigation device 10 has a recommended route 44 that replaces the original recommended route 44.
Although it cannot be recalculated, the dead end guide 52 such as "This is a dead end. U turn!" Is displayed on the display device 38 as it is, and appropriate information is notified to the user.

FIG. 5 shows a process in which the shortcut route 45 can be displayed on the display device 38 of the car navigation device 10 even when the vehicle is traveling in the middle range of the recommended route 44 without departing from the recommended route 44. Is a flowchart of In S60, the vehicle type of the own vehicle is input by the user. The vehicle type is, for example, a light vehicle, a standard vehicle, a large passenger vehicle such as a number 3 vehicle, a bus, a truck, etc., whereby the width, and in some cases, the length or height of the vehicle can be determined by the car navigation device 10. Is set. In S61, the recommended route 44 (= route) is calculated. The map database 16 of the car navigation device 10 includes a wide area map network as an upper layer that covers wide area roads such as national roads 40 and highways as map information, and further prefectural roads 41 as map information in this wide area map network. There are 2 layers, including the detailed map network as the lower layer, which includes up to 48 small streets, etc.
That is, both end ranges of the recommended route 44 are calculated based on the detailed map network, and the intermediate range as the rest is calculated based on the wide area map network. A well-known Dijkstra method, potential method, A * algorithm, or the like is adopted as this calculation method. Furthermore, in the calculation based on the detailed map network in both end ranges of the recommended route 44,
Considering the vehicle type information input in S60, roads that are impossible or difficult to pass due to the size of the vehicle are excluded as parts of the recommended route 44. In S62, the recommended route 44 calculated in S61 is displayed on the display device 38 to guide the user.
In S63, it is determined whether the own vehicle has arrived at the destination,
If the determination is YES, the routine ends, and if the determination is NO, the process proceeds to S64. In S64, it is determined whether or not the vehicle speed (traveling speed of the vehicle) is slower than a predetermined road speed that is considered to be slow driving, and if the determination is NO, S6
Returning to step 2, if YES, the process proceeds to step S65. In S65, reroute calculation (= recalculation of recommended route 44) is performed. The reroute calculation is almost the same as the calculation of the recommended route 44 in S61. However, in the reroute calculation, the own vehicle position 42 is only replaced with the departure place in the reroute calculation. In order to streamline the reroute calculation, the recommended route 44 near the vehicle position 42 may be calculated based on the detailed map network, and the remaining part may use the original recommended route 44 and omit the calculation. In S66, the reroute as the calculation result in S65 and the recommended route 44 are compared with each other, and if they are different routes (different portions are referred to as shortcut routes 45), the process proceeds to S67, and if they are the same route, Return to S62. In S67, the recommended route 44 and the shortcut route 45 are displayed on the display device 38 so that they can be identified.

FIG. 6 is a flow chart of a process for displaying an appropriate display on the display device 38 when the vehicle departs from the recommended route 44. Steps that are the same as those in FIG. 5 are given the same step numbers, and only the differences will be described. S70
Then, it is determined whether or not the vehicle has departed from the guide route in S62, that is, the recommended route 44. If the determination is NO, S62
If YES, the process proceeds to S65. In S71,
It is determined whether or not the reroute calculation in S65 has succeeded, that is, whether or not the reroute can be found.
If it is ES, proceed to S73 to reroute recommended route 44
Is displayed on the display device 38, and if NO, the process proceeds to S73 and the dead end guide 52 (FIG. 4) is displayed on the display device 38. After the process of S72 or S73, the process returns to S62.

[Brief description of drawings]

FIG. 1 is a block diagram of a car navigation device.

FIG. 2 shows a screen of a display device when a car is traveling in an intermediate range of a recommended route in a car navigation device.

FIG. 3 is a diagram showing a screen of the display device when there is no recommended route in a period in which the vehicle is traveling in an intermediate range of the recommended route.

FIG. 4 shows a screen of a display device when a car of a car navigation device departs from a recommended route to a dead end narrow street.

FIG. 5 is a flowchart of a process that enables a shortcut route to be displayed on the display device of the car navigation device even when the vehicle is traveling in the intermediate range of the recommended route without departing from the recommended route.

FIG. 6 is a flow chart of a process for enabling an appropriate display on the display device when the host vehicle departs from the recommended route.

FIG. 7 shows a screen of a display device when the own vehicle is traveling in the middle range of the recommended route in the conventional car navigation device.

FIG. 8 shows a screen of a display device when the vehicle departs from the recommended route and enters a prefectural road in FIG.

FIG. 9 shows a screen of a display device in a conventional car navigation device.

[Explanation of symbols]

10 car navigation device (vehicle-mounted navigation device) 16 map database (hierarchical map database) 38 display device (display means) 42 vehicle position 44 recommended route (recommended route) 45 shortcut route (shortcut route) 48 narrow street (dead end road) ) 52 Dead end guidance (information about dead end)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-189837 (JP, A) JP-A-8-128843 (JP, A) JP-A-8-159797 (JP, A) JP-A-8- 105754 (JP, A) JP-A-9-51314 (JP, A) JP-A-6-68389 (JP, A) JP-A-7-146154 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01C 21/00 G08G 1/0969

Claims (4)

(57) [Claims] 1. A hierarchical map database (16) comprising (a) a plurality of hierarchically divided map information so as to cover roads of a lower rank than roads of a lower rank than the upper hierarchy, and (b) a departure place. Recommended route calculating means for calculating the recommended route (44) connecting to the destination based on the map information of the hierarchy higher than both end ranges in the intermediate range, (c) the vehicle travels in the intermediate range of the recommended route (44) The recommended route (44) is recalculated based on the map information in the lower hierarchy than the map information that is the basis of the calculation in the intermediate range of the recommended route (44) near the current position during the period If it is different from (44), the shortcut route calculation means that uses the new recommended route (44) as the shortcut route (45),
And (d) a display unit (38) for displaying the shortcut route (45) calculated by the shortcut route calculation unit together with the display unit (38). 2. The vehicle-mounted navigation device according to claim 1, wherein the shortcut route calculation means calculates the shortcut route (45) only under a predetermined condition. 3. When the vehicle departs from the recommended route (44), the vehicle position (42) is used as a starting point to instruct the recommended route calculation means to recalculate the recommended route (44) at least near the current position. Recalculation instruction means, the shortcut route calculation means, the recalculation instruction means to the recommended route calculation means to re-establish the recommended route (44) even if the vehicle does not leave the recommended route (44). The vehicle-mounted system according to claim 1 or 2, characterized in that the shortcut route (45) is calculated based on the recommended route (44) recalculated by the recommended route calculation means by forcing a calculation instruction to be issued. Navigation device. 4. A dead end is determined when the vehicle departs from the recommended route (44) and the recommended route calculation means is actually traveling on the dead end road (48) toward the destination. The vehicle-mounted navigation device according to claim 3, further comprising dead end information presenting means for presenting information (52) to a user.