JP3237454B2 - In-vehicle route calculation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to, for example, an in-vehicle navigation device, receives the latest traffic information transmitted from an external communication device, and considers the traffic information to determine the current location and the destination. The present invention relates to an in-vehicle route calculation device that calculates a recommended route between the vehicles.

[0002]

2. Description of the Related Art Conventionally, in order to assist a vehicle traveling on an unfamiliar land, an in-vehicle navigation device that displays the current position of the vehicle together with a road map around the vehicle is used. Such an in-vehicle navigation device allows a driver or a passenger (hereinafter collectively referred to as a "driver") to set a destination, and a computer automatically sets a recommended route between the current position and the set destination. (See, for example, Japanese Patent Laid-Open No. 5-53)
No. 504).

In a vehicle-mounted navigation device to which this route calculation function is added, when a destination is set, road map data composed of links (hereinafter referred to as "navi links") connecting road intersections and the like is read out. Search the navigation link tree for the area including the current location and the destination. At this time,
The travel time (link cost) data of each navigation link included in the road map data is sequentially added, and the route that reaches the destination with the minimum link cost is set as the recommended route.

Incidentally, travel time data required for calculating a recommended route actually varies from moment to moment depending on traffic conditions such as road congestion, traffic restrictions due to road construction, and the presence or absence of an accident. On the other hand, it is impossible for the vehicle to prepare in advance travel time data that takes into account the ever-changing traffic conditions. Therefore, in the above-mentioned navigation device for a vehicle,
It is not possible to calculate a recommended route that reflects the ever-changing traffic conditions.

Therefore, in recent years, external communication devices have included travel time data associated with links connecting major intersections (hereinafter referred to as “traffic information links”), or have data on traffic congestion degree from which travel time data can be estimated. A system for providing the latest traffic information to vehicles, including, has been studied for practical use. For example, as a specific example of a system under consideration, a traffic information communication system (VICS: Vehicle Information) that transmits traffic information to a vehicle using a radio beacon, an optical beacon, or FM multiplex broadcasting is known.
and Communication System), and a traffic information service (ATIS: Advanced Traffic Information Form) that transmits traffic information to vehicles using an automobile / mobile phone network.
rvice).

[0006]

By the way, there are the following two types of methods for obtaining travel time data and the like in an external communication device for transmitting the traffic information to the vehicle. One is a method of knowing travel time data and the like from images obtained by vehicle sensors installed on various places on the road, helicopters navigating above the sky, or satellites. The other one is
The actual travel time value of the road currently traveling from the traffic information collection vehicle actually traveling on the road via the road beacon (for example, the time from when another road beacon arrives at the road beacon). It is a method of collecting and counting.

However, in any of the above methods, the collected travel time data or the like usually includes a measurement error having a deviation for each traffic information link. For example, as shown in FIG. 11, the collected travel time data and the like may be collected as a value that is always higher than the travel time actually required by a vehicle traveling using the on-vehicle navigation device. Such a deviation is caused by a different collection method of travel time data or the like, a limited number of collection means, or a personality of a driver. Therefore, even if a recommended route is calculated based on travel time data including the error, the recommended route cannot reflect the actual traffic condition.

[0008] From the above viewpoint, it is required that the above-mentioned on-vehicle navigation device can calculate a recommended route that more accurately reflects the current traffic situation. Also,
In an external communication device, a main arterial road is targeted as a road to be associated with travel time data or the like. Therefore, the travel time data and the like transmitted from the external communication device are the same as those of the road map shown in FIG.
As shown in the _figure , the traffic information links L _K1 , L _K2 , L _K3 , and L _K4 link the main intersections A, B, C, and D on the main arterial roads R ₁ , R ₂ , R ₃ , and R ₄ , respectively. It becomes relatively coarse information. Here, the reason why the network composed of traffic information links is rough is that there are restrictions on communication capacity, communication time, processing time, and the like.

On the other hand, as shown in FIG. 9 (c), the navigation links used for the route calculation on the vehicle side are all the main arterial roads R ₁ , R ₂ , R ₃ shown in FIG. 9 (a). , R ₄ , and links L _{N1 to} L _N20 connecting the main intersections A, B, C, D and the general intersections a, b, c on the main roads r ₁ , r ₂ other than the main roads, respectively. Therefore, even if the recommended route is calculated only based on the travel time data transmitted from the external communication device, it does not match the actual road situation.

More specifically, for example, even if only the navigation link L _N15 is actually congested, a relatively coarse traffic information link is regarded as a unit of traffic information to be transmitted from an external communication device. Traffic information link L _K4
Either travel time data or the like indicating that the (navigation links L _{N13 to} L _N16 ) are congested, or travel time data or the like indicating that the traffic information link L _K4 is not congested is transmitted.

Therefore, when calculating the recommended route, for example, the navigation link L between the main intersection A and the general intersection a
Even if a recommended route that can be guided to the destination c in the shortest time through _N13 and _LN14 can be calculated, as a result of considering the travel time data and the like, the relative route to the destination c that does not include the navigation links _LN13 and _LN14 is obtained. Is likely to be calculated as a recommended route.

[0012] In addition, since there is no traffic information link corresponding to the navigation link L _N18 ~L _N20, even if the navigation link L _N1 ~L _N17 that make up the other major road without traffic jam to the navigation link L _N18 ~L _N20 Even when traffic congestion occurs, when calculating the recommended route, the navigation links L _{N18 to} L _N20 are not the links to be calculated, so the navigation links L _{N18 to} L _N18
The recommended route including _N20 cannot be calculated.

[0013] As described above, in the above-described on-vehicle navigation device, since the traffic information link is coarser than the navigation link, it is required that a recommended route including a road other than the main arterial road can be calculated. Therefore, an object of the present invention is to solve the above technical problem and calculate a recommended route that more accurately reflects an actual traffic condition when acquiring traffic information including travel time data and the like from an external communication device. It is an object of the present invention to provide an in-vehicle route calculation device capable of performing the above.

[0014] Another object of the present invention is to provide a method in which a traffic information link and a navigation link do not correspond one-to-one, or even if there is a traffic information link that does not correspond to a navigation link. It is an object of the present invention to provide an in-vehicle route calculation device capable of calculating a recommended route including the route.

[0015]

According to a first aspect of the present invention, there is provided an on-board route calculating apparatus, comprising: a route calculating road map data associated with a link which is a constituent unit of a route network; Receiving the stored road map data storage means and traffic information including a travel time (hereinafter referred to as “link travel time”) associated with a link transmitted from an external communication device or capable of estimating the link travel time Receiving means for performing, when the traffic information is received by the receiving means, included in the traffic information,
Or the link travel time estimated from the traffic information,
An adoption value acquisition unit that converts the link travel time to a link travel time adoption value of the link by using a conversion coefficient associated with the link corresponding to the link travel time, and a link travel time adoption acquired by the adoption value acquisition unit; Route calculation means for calculating a recommended route based on the value and the road map data for route calculation stored in the road map data storage means, and travel time record which is the time the vehicle actually traveled on the road corresponding to the link. A measuring means for measuring the value when the vehicle travels on the link, and a conversion coefficient associated with the link corresponding to the road on which the vehicle traveled is updated so that the actual travel time value measured by the measuring means is reflected. Updating means,
The updating means performs smoothing in consideration of past conversion coefficients.
Is intended to update the transform coefficients Te, the adopted value acquisition means, by using the transform coefficients are updated in the update unit, the corresponding link travel time associated with the link to the transform coefficients, the link Is converted into a link travel time adoption value.

In this configuration, when the traffic information is received from the external communication device, the link travel time included in the traffic information or estimated from the traffic information is changed to the link corresponding to the link travel time. Using the associated conversion coefficient, the link is converted into a link travel time adoption value, and a recommended route is calculated based on the link travel time adoption value and the route calculation road map data.

Here, the link travel time included in the traffic information to be transmitted from the external communication device or can be estimated from the traffic information includes the travel time actually required when traveling on the road. Errors with deviations are usually included. Therefore, in this configuration, the actual travel time value, which is the time that the vehicle actually travels on the road corresponding to the link, is measured when traveling on the link, and the corresponding travel time value is reflected so that the actual travel time value is reflected. The conversion coefficient to be updated is updated, and the updated conversion coefficient is used for the conversion processing of the link from the next time. This makes it possible to obtain a travel time adoption value in which the deviation included in the link travel time corresponding to the link is corrected.

In the case where the conversion coefficient is updated based only on the actual travel time value measured during the travel, the updated conversion coefficient may vary greatly from one travel to another. was used at the same time, it is smoothing the conversion coefficient. According to this configuration, every time the vehicle travels on the same link, the actual travel time is accumulated and reflected in the conversion coefficient of the link, so that the conversion coefficient can be learned.

As described above, according to this configuration, the actual travel time is included in the link travel time obtained based on the traffic information transmitted from the external communication device using the conversion coefficient accumulated and reflected. The link travel time adoption value is obtained by correcting the deviation, and the recommended route is calculated using the link travel time adoption value. Therefore, the recommended route reflects the actual traffic information more accurately. It can be.

Further, the vehicle route calculation device according to the second aspect of the present invention is a road map data storage means for storing route calculation road map data associated with a navigation link which is a constituent unit of the first route network; Receiving means for receiving traffic information including a link travel time associated with a traffic information link which is a constituent unit of the second route network transmitted from an external communication device or capable of estimating the link travel time; When the traffic information is received by the receiving means, a storage means for storing the link travel time included in the traffic information or estimated from the traffic information in association with the traffic information link; A search for a traffic information link corresponding to the link is performed from traffic information links stored in the storage means and associated with the link travel time. And means, when the traffic information link corresponding to the route calculation object navigation link by this search means is searched, a link travel time corresponding to the traffic information links,
Using the conversion coefficient associated with the traffic information link corresponding to the link travel time, the traffic information link is converted into a link travel time adoption value, and the route calculation target navigation is performed based on the link travel time adoption value. An adoption value acquisition unit for acquiring a link travel time adoption value of a link, and a link travel time adoption value acquired by the adoption value acquisition unit and the route calculation road map data stored in the road map data storage unit. Route calculating means for calculating a recommended route, a measuring means for measuring a travel time actual value, which is a time when the vehicle actually travels on the road, at every predetermined timing, and a travel time actual value measured by the measuring means is reflected. Updating means for updating the conversion coefficient corresponding to the traffic information link including the road on which the vehicle actually traveled, Using the conversion coefficient updated by the updating unit, the link travel time associated with the traffic information link corresponding to the conversion coefficient is converted into a link travel time adoption value of the traffic information link. A link travel time adoption value of the route calculation target navigation link is acquired based on the adoption value.

Note that the predetermined timing may be, for example, when the vehicle travels on a road corresponding to a traffic information link or a navigation link. In this configuration, the traffic information link corresponding to the route calculation target navigation link is searched for from the stored traffic information links associated with the link travel time, and the traffic information link corresponding to the traffic information link is searched from the link travel time. The link travel time adoption value of the route calculation target navigation link is acquired based on the link travel time adoption value of the traffic information link obtained using the conversion coefficient corresponding to the information link.

Therefore, for example, even if one traffic information link includes a plurality of navigation links, each navigation link has a link travel time adoption value corresponding to the traffic information link obtained from the link travel time. Each can be given. Moreover, the link travel time adoption value given to each of the navigation links is determined based on the conversion coefficient updated to reflect the actual travel time value, as described in the configuration of the first aspect. Therefore, the deviation has been corrected. Therefore, for example, a navigation route without traffic congestion can be provided with a link travel time adoption value when traffic is not congested, and a recommended route that reflects the actual traffic situation more accurately is a navigation route finer than a traffic information link. It can be calculated in units.

[0023] Further, an on-vehicle route calculating device according to claim 3 is the on-vehicle route calculating device according to claim 2, wherein
When the traffic information link corresponding to the route calculation target navigation link does not exist, the adoption value obtaining unit may determine that the link travel time associated with one or more traffic information links closest to the route calculation target navigation link in terms of distance. Is converted to the link travel time adoption value of the traffic information link by the conversion coefficient corresponding to the traffic information link, and the route calculation target navigation link and the traffic information are added to the link travel time adoption value. The ratio according to the relationship with the link is multiplied, and the link travel time adoption value multiplied by the ratio is used as the link travel time adoption value of the route calculation target navigation link.

With this configuration, the link travel time adoption value of the route calculation target navigation link for which no corresponding traffic information link exists does not include the one or more traffic information links that are closest in distance to the route calculation target navigation link. The value obtained by multiplying the adopted link travel time adoption value by a ratio corresponding to the relationship between the navigation calculation target navigation link and the traffic information link.

For example, as shown in FIG. 10, a route calculation target navigation link L for which no corresponding traffic information link exists.
_When there is a traffic information link L _N2 having a parallel positional relationship with _N1, for example, it is unnatural to consider that only one of them is congested. In other words, it is natural to consider that the correlation between the traffic conditions is relatively strong between the links L _N1 and L _N2 that are close in distance. Further, each of the links L _N1 ,
The link travel time of L _N2 is, for example, each link L _N1 , L _N2
It can be inferred by the distance relationship between them. That is, at least initially, if one link is half the distance of the other link, the travel time could be considered half.

As described above, according to the above configuration, it is possible to provide a link travel time adoption value that more accurately reflects an actual traffic condition even for a route calculation target navigation link for which no corresponding traffic information link exists. Therefore, the route calculation target navigation link can also be a calculation target link. In the vehicle route calculation device according to any one of claims 1 to 3, the same effect can be obtained by using a link traveling speed associated with a link instead of the link travel time. Since the travel time and the travel speed have a relationship of (travel time) × (travel speed) = travel distance,
As long as the link distance is fixed, if one is determined, the other is automatically determined. Therefore, even if such replacement is performed, the content of the invention does not change.

[0027]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic diagram of a system for providing traffic information to an in-vehicle navigation device to which the in-vehicle route calculation device of the present invention is applied. This traffic information providing system includes a road beacon A installed on a road and an information center C connected to the road beacon A via a communication line (public line or dedicated line) B.

Instead of the road beacon A, for example, a communication (transmission) device used in an automobile / mobile phone network or an FM multiplex communication network may be applied. The aforementioned information center C, the link traffic information corresponding to the relatively coarse first path networks that link (the "traffic information link" referred) L _K a structural unit connecting the main intersections with each other are stored. This link traffic information can be obtained from, for example, a traffic information collection vehicle that is actually traveling on the road, or from time to time obtained based on images obtained by a vehicle detector, a helicopter navigating above, or a remote sensing satellite. latest traffic information is generated by being associated with the traffic information link L _K.

The link traffic information includes, for example, one or more of a travel time (link cost), which is a time required for the vehicle to travel on a road corresponding to the traffic information link L _K , a degree of congestion, and a congestion length. . For example, when a traffic jam occurs, the travel time or the length of the traffic jam is relatively long, and the degree of the traffic jam is relatively increased. When the traffic jam is resolved, the travel time or the length of the traffic jam is relatively short, and the degree of the traffic jam is relatively low. Is made smaller. In addition, when an accident or the like occurs and the vehicle becomes impassable, the travel time, the degree of congestion, or the length of congestion are made infinite. This link traffic information is provided to the roadside beacon A via the communication line B at regular intervals.

When the link traffic information is given via the communication line B, the road beacon A transmits the link traffic information to the vehicle. FIG. 2 is a block diagram showing an electric configuration of the vehicle-mounted navigation device mounted on the vehicle. The in-vehicle navigation device 1 includes an azimuth sensor 5 for detecting the amount of change in the azimuth of the vehicle and a distance sensor 6 for detecting the amount of movement of the vehicle. As the direction sensor 5, for example, a gyro such as an optical fiber gyro, a vibration gyro, a gas rate gyro, or a geomagnetic sensor can be applied. Further, as the distance sensor 6,
For example, a rotation speed sensor that detects the rotation speed of a tire wheel or a rotor is applicable. Each output of the direction sensor 5 and the distance sensor 6 is provided to a vehicle position detecting unit 14 in the vehicle-mounted navigation device body 1.

The vehicle position detector 14 determines the traveling direction of the vehicle based on the output of the direction sensor 5, and
The travel distance of the vehicle is obtained based on the output of the distance sensor 6. The vehicle position detecting section 14 is provided with accurate initial position data of the vehicle by the driver before the vehicle starts moving, for example. The current position of the vehicle is detected based on the traveling direction and the traveling distance of the vehicle.
The detection of the current position of the vehicle is performed at a constant cycle (for example,
Every second).

In addition, instead of the direction sensor 5, the distance sensor 6, and the vehicle position detecting unit 14, or together with the direction sensor 5, the distance sensor 6, and the vehicle position detecting unit 14,
GPS (Global Posioning S)
ystem) A GPS receiver that detects the current position of the vehicle based on the propagation delay time of the GPS radio wave transmitted from the satellite may be employed.

In the vehicle position detector 14, the detected current position of the vehicle is corrected by a so-called map matching process (for example, see Japanese Patent Application Laid-Open No. 63-148115). In other words, the traveling trajectory of the vehicle detected based on the outputs of the direction sensor 5 and the distance sensor 6 is compared with the road pattern stored in the in-vehicle dedicated map disk D, and according to the result, the vehicle travels. The traveling locus is corrected on the road pattern.

The current position data of the vehicle corrected by the map matching processing is given to the controller 16. The controller 16 is a control center of the vehicle-mounted navigation device main body 1 and includes a CPU 161, an SRAM 162, and a DRAM 163. Controller 1
6 receives the current location data of the vehicle from the vehicle position detector 14 and reads out display road map data from the on-vehicle map dedicated disk D via the memory controller 11 and the CD drive 2. The read display road map data and the current location data are supplied to the display control unit 12. When the display road map data and the current position data are given, the display control unit 12 superimposes a car mark indicating the current position of the vehicle on the road map and displays the display device 3 configured by a liquid crystal display element, a plasma display element, or a CRT. To be displayed.

The disk D dedicated to vehicle-mounted maps stores road map data for route calculation in addition to the road map data for display. The road map data for route calculation is divided into meshes of road maps (including highway national roads, motorways, other national roads, prefectural roads, city roads in government-designated cities, and other important living roads). A relatively fine second route network made up of a combination of a node corresponding to a road intersection or the like and a link (hereinafter referred to as a “navi link”) L _N for each mesh unit is used as a highway / national road map. The structure is divided into three layers of a general road correspondence map and a detailed map, and for each navigation link _LN , travel time (link cost), link length, coordinates of the start point and end point of the navigation link _LN , and the like. Are associated with each other.

The expressway / national road correspondence map mainly includes expressways (highway expressways and motorways) and other national roads, and the general road correspondence map includes expressways and other national roads as well as general roads. In. Detailed map,
This includes highways, other national roads, and general roads as well as important living roads. Due to the characteristics of the road map database, a closed network is formed nationwide for roads higher than national roads.

The map-dedicated disk D indicates the correspondence between the traffic information link L _K and the navigation link L _{N in} which the traffic information transmitted from the road beacon A is associated with the road map data. A first correspondence table and a second correspondence table representing a correspondence relationship with one or a plurality of traffic information links L _K closest to an arbitrary navigation link L _N in terms of distance are stored.

The correspondence between the traffic information link L _K and the navigation link L _N is such that the traffic information link L _K is the navigation link L
Since it is a structural unit of a route network that is generally coarser than _N , it can be classified as follows. FIG. 3A shows a case where the traffic information link L _K and the navigation link L _N correspond one-to-one. FIG. 3B shows a case where one traffic information link L _K includes a plurality of navigation links L _N1 , L _N2 ,..., L _Ni . This shows a case where there is a navigation link L _N (broken line portion in FIG. 3D) that does not correspond well to the information link L _K. Of these, the first correspondence table represents the correspondence in the case of FIGS. 3A and 3B, and FIG.
, (D) is a second correspondence table. FIGS. 4A and 4B show specific examples of the first correspondence table and the second correspondence table, respectively.

A remote controller key (hereinafter simply referred to as a “remote controller key”) 4 for inputting various calculation conditions such as a destination is connected to the controller 16 via an input control unit 13. The remote control key 4 includes, for example, a “joystick key” for scrolling a map, setting a position, and selecting a menu, a “map key” for displaying a road map screen centering on a car mark representing a current position, and a display scale for a road map. `` Scale key '' to scale up / down, `` rotation key '' to select whether to display the traveling direction of the vehicle at the top or north of the map at the top, and switch between displaying or not displaying the trajectory of the vehicle `` "Track key", "Route key" that allows you to input a route calculation instruction signal with one touch when you want to calculate the recommended route from the current location to the destination, "Return key" to return to the previous screen at the time of menu operation, "Purpose" Various keys (all not shown) such as a “menu key” for displaying a menu screen such as “land setting” and “route setting” are provided.

The controller 16 controls various calculation conditions such as destinations by the driver via the remote control key 4 (whether to give priority to toll roads, to give priority to ferry use, or to use transit points). , Etc.)
The input destination data and the like are stored in the DRAM 163, and the road map data for route calculation is read from the in-vehicle map dedicated disk D, and the navigation links L _N close to the destination and the current position detected by the vehicle position detection unit 14, respectively.
The recommended route between them is calculated using, for example, the Dijkstra method or the potential method. The calculated recommended route is superimposed on the road map displayed on the display device 3 by, for example, a broken line, and is output as sound from the microphone M via the voice control unit 18.

Here, the above-mentioned potential method is as follows. In other words, the navigation link L _N close to the starting point (which may be a destination) and the start of calculation link, the closest to the navigation link L _N to the destination (which may be a starting point) and the calculation end link, the navigation link that starts from the calculation start link Search all L _N. At this time, the process of sequentially adding the travel time data of each navigation link _LN included in the route calculation road map data, cutting off the route that is not the shortest route, and leaving only the route that realizes the shortest route is repeated. As a result, a tree of a path consisting of only the shortest path is finally obtained, and a recommended path can be obtained by following the path from the calculation end link to the calculation start link in reverse.

The controller 16 is also connected to the beacon receiver 7. When the vehicle enters the transmission area of the road beacon A and the link traffic information transmitted from the road beacon A is received by the beacon receiver 7, the CPU 161 gives the link traffic information to the DRAM 163 and causes the DRAM 163 to hold the link traffic information. When calculating the recommended route by the above method, if the link traffic information is held in the DRAM 163, the CPU 161 uses the link traffic information in addition to the link cost included in the road calculation road map data. Use it to calculate the recommended route.

FIG. 5, FIG. 6, FIG. 7, and FIG. 8 are flow charts for explaining a process of calculating a recommended route in the above-mentioned on-vehicle navigation device 1. When calculating the recommended route, the driver first inputs a destination and various calculation conditions from the remote control key 4, and then inputs a route calculation instruction signal. In response, the in-vehicle navigation device 1
Then, the recommended route from the current position to the destination is calculated by the above method.

Thereafter, during traveling, the on-vehicle navigation device 1 always determines whether or not link traffic information has been received from the road beacon A (step S1 in FIG. 5). If the link traffic information is not received from the road beacon A, it is determined whether or not the vehicle has reached a predetermined point for route guidance, for example, an intersection on the route, on the condition that the recommended route has been obtained. (Step S2; It is determined whether or not such a predetermined point has been reached.
This is performed based on the current location data output from the vehicle position detection unit 14. ), When it is determined that the predetermined point has been reached,
The driver is instructed on the shape of the intersection and the guidance direction by the display screen of the display 3 or by voice (step S3).

On the other hand, during traveling, the above-described step S1
When it is determined that the link traffic information has been received from the road beacon A, the link traffic information can be used by the on-vehicle navigation device 1 in consideration of the difference in the content of the link traffic information as shown in FIG. The process of converting into a travel time acquisition value A (t) (where t represents time) corresponding to the travel time data of the form is executed (steps S9 to S9).
S16).

More specifically, when the link traffic information represents the travel time data itself (YES in step S11), the travel time data becomes the travel time acquisition value A (t) as it is (step S11). S12). If the link traffic information indicates the traffic jam length (YES in step S13), the following information is obtained based on the traffic jam length.
The calculation of equation (1) is performed, and a travel time acquisition value A (t) is calculated (step S14). However, in the following equation (1), L ₁ is the congestion length, V ₁ is the average vehicle speed when congestion in the traffic information link L _K corresponding to the link traffic information,
L ₂ corresponds to the link traffic information traffic information link L
Link length of _K, and V ₂ represents the average vehicle speed at the time of non-congestion in the traffic information link L _K corresponding to the link traffic information. Incidentally, the average vehicle speed V _1, V ₂ is associated with the traffic information link L _K as each table stored in the map-only disc D.

A (t) = (L₁/ V₁) + ｛(L_Two-L₁) / V_Two｝ ‥‥ (1) In addition, the link traffic information
If neither the traffic congestion length nor
(NO in S13), the link traffic information indicates the degree of congestion.
Is considered (step S15), and based on the degree of congestion,
The calculation of the following equation (2) is performed, and the travel time acquisition value A (t) is calculated.
It is calculated (step S16). However, the following equation (2)
And V_ThreeIs the traffic information corresponding to the link traffic information
Link L _KThe average vehicle speed corresponding to the above-mentioned congestion degree in
The average vehicle speed V_ThreeIs the above average vehicle speed V₁, V_Two
Traffic information link L as a table_KMap to
And stored in the map dedicated disk D.

A (t) = L ₂ / V ₃ ‥‥ (2) Any of the above processes is performed on all traffic information links L _K transmitted from the road beacon A (step S10) The calculated travel time acquisition value A (t) is temporarily stored in the DRAM 163. By the way, as described above, the link traffic information transmitted from the road beacon A is traffic information obtained based on an image obtained by a vehicle sensor, a helicopter, or a remote sensing satellite, or traffic actually traveling. Although created based on the traffic information obtained by the information collecting vehicle, the link traffic information usually includes an error having a deviation from the actual travel time in any method. Therefore, in the in-vehicle navigation device 1 of this embodiment, as shown in FIG. 7, when the processes of the steps S9 to S16 are completed, the deviation included in the travel time acquisition value A (t) is corrected. A process for correcting the travel time acquisition value A (t) is performed (steps S17 to S25).

More specifically, step S
When the process of 9~S16 ends, the traffic information link L _K and with reference to the first correspondence table between the navigation link L _N, the traffic information links including any route calculation object navigation link L _N L
_It is searched whether or not there is _K (step S19). As a result, if there is traffic information links L _K including the route calculation object navigation link L _N is the (step S20 YE
S), traffic information link L _K and route calculation target navigation link L
_N is regarded as corresponding, and if so, a correction process is performed.

That is, the route calculation target navigation link L
_{When N} and the traffic information link L _K correspond one to one as shown in FIG. 3A, the travel time acquisition value A (t) corresponding to the traffic information link L _K is read from the DRAM 163. (Step S21) and the travel time acquisition value A
The conversion coefficient K (t) corresponding to the latest traffic information link L _K at that time, which will be described in detail later, necessary for correcting (t) is read from the non-volatile memory (not shown); The calculation of the following equation (3) is performed, and the travel time adoption value B (t) corresponding to the route calculation target navigation link _LN is calculated (step S22).

B (t) = K (t) × A (t) ‥‥ (3) As shown in FIG. 3B, the navigation link L _N is included as a part of the traffic information link L _K. If so,
After the travel time adoption value B (t) is calculated, the following equation (4) is calculated, and the travel time adoption value B '(t) corresponding to the route calculation target navigation link _LN is calculated. . However,
In the following equation (4), d _Ni represents the link length of the navigation link L _Ni , and d _K represents the link length of the traffic information link L _K.

B ′ (t) = (d _Ni / d _K ) × B (t) ‥‥ (4) Travel time adoption value B calculated by the above equation (3) or (4)
(t) or B '(t) is temporarily stored in the nonvolatile memory. On the other hand, as a result of the search in step S19, the traffic information link L _K including the route calculation target navigation link L _N is obtained.
If it is determined that there is no traffic information link (NO in step S20), one or a plurality of traffic information links L _{K that} are closest in distance to the route calculation target navigation link L _N are searched with reference to the second correspondence table ( Step S23).

As a result of this search, when a traffic information link L _K having a positional relationship as shown in FIG. 3C is searched, first, a travel time acquisition value A (t) corresponding to the traffic information link L _K.
Is read from the DRAM 163 (step S
24), the conversion coefficient K (t) associated with the traffic information link L _K is read out from the non-volatile memory, and the calculation of the above equation (3) is performed, and the travel time corresponding to the traffic information link L _K is calculated. The adoption value B (t) is calculated. Next, using the travel time adoption value B (t), the following equation (5) is calculated,
A travel time adoption value B '(t) corresponding to the route calculation target navigation link _LN is calculated (step S25). However, in the following equation (5), d _N represents the link length of the navigation link L _{N to be} calculated, and d _K represents the link length of the traffic information link L _K.

B ′ (t) = (d _N / d _K ) × B (t) ‥‥ (5) In the expression (5), the traffic condition of the navigation link L _N is the closest traffic information link in terms of distance. it is based on the presumption that is substantially the same as the traffic conditions of the L _K. Also, the above step S2
As a result of the search in FIG. 3, when the traffic information links L _K1 and L _K2 having the positional relationship as shown in FIG. _3D are searched, first, the travel time corresponding to each traffic information link L _K1 and L _K2 respectively. The acquired value A (t) is read from the DRAM 163 (step S24), and the conversion coefficient K (t) corresponding to each of the traffic information links L _K1 and L _K2 is read from the non-volatile memory. Is calculated, and each traffic information link L
Travel time adoption values B _L1 (t) and B _L2 (t) corresponding to _{K 1} and L _K2
Are calculated respectively. Then, using the travel time adoption values B _L1 (t) and B _L2 (t), the following equation (6) is used to calculate the travel time adoption value corresponding to the route calculation target navigation link L _N. B '(t) is calculated (step S25).
However, in the following equation (6), d _N indicates the link length of the navigation link L _{N to be} calculated, and d _K1 and d _K2 indicate the link lengths of the traffic information links L _K1 and L _K2 , respectively.

B ′ (t) = {d _N / (d _K1 + d _K2 )} × {B _L1 (t) + B _L2 (t)} (6) Calculated by the above equation (5) or (6). The travel time adoption value B '(t) is temporarily stored in the nonvolatile memory.
Thus, the corresponding traffic information link L in _K no navigation links L _N, travel time adopted values of the navigation link L _N correlation of traffic situation corresponds to a relatively strong points of the traffic information link L _K B (t ), The travel time adoption value B '(t) is obtained.

When the travel time adoption value B (t) or B '(t) is stored in the non-volatile memory as described above, the on-vehicle navigation device 1, as shown in FIG. The current position of the vehicle is recognized based on the current position data output from the CPU 14 (step S26), and the DRAM is used.
The recommended route between the set destination stored in 163 and the recognized current location is determined by using the travel time adoption value B (t) or B '(t) stored in the nonvolatile memory. (Step S27). Thereafter, the calculated recommended route is displayed on the display screen of the display 3 (step S28), and guidance instruction information corresponding to the recommended route is created (step S29). Then, the process proceeds to step S1.

By the way, considering the purpose of correcting the deviation included in the travel time acquisition value A (t) to correct the travel time acquisition value A (t), the conversion coefficient K (t) is considered as follows.
It is necessary to reflect the actual travel time. Therefore, in the on-vehicle navigation device 1 of this embodiment, the conversion factor K (t) is constantly updated to reflect the actual travel time. The process of updating the conversion coefficient K (t) is performed in steps S4 to S8 in FIG.

More specifically, step S
During the route guidance as in steps 1 to 3, the traffic information link L _K stored in the map-dedicated disk D
Based on a first correspondence table between the vehicle and the navigation link _LN, and the current position data output from the vehicle position detection unit 14.
Vehicle whether completed traveling on the road corresponding to the traffic information link L _K is determined (step S4). as a result,
If it is determined that the traveling is completed, the traffic information link L _K
The travel time (hereinafter referred to as "travel time actual value") C (t) required to travel from the start point to the end point of is calculated (step S5). As a result, the actual travel time of the traffic information link L _K at time t (link cost) is obtained.

Next, on condition that the calculated travel time actual value C (t) is within the allowable range (step S6),
The traffic information link L held in the nonvolatile memory
The travel time acquisition value A (t) of _K is read (step S).
7), the traffic information based on the travel time acquisition value A (t) and the travel time actual value C (t), which is updated when traveling on a road that corresponds to previously the traffic information link L _K The conversion coefficient K (t−Δt) corresponding to the link L _K is
The new conversion coefficient K (t) is updated as in the equation (7) (step S8). However, in the following equation (7), α
(0 <α <1) is a smoothing index, and k (t) is given by the following (8)
It is obtained by the equation, and is a ratio between the current travel time actual value C (t) and the travel time acquisition value A (t). Also,
The initial value of the conversion coefficient K (t) is, for example, 1.

K (t) = α × k (t) + (1−α) × K (t−Δt) ‥‥ (7) k (t) = C (t) / A (t) ‥‥ (8 As described above, the conversion coefficient K (t) is updated to reflect the actual travel time actual value C (t). In addition, since this update is smoothed in consideration of the past conversion coefficient K (t−Δt), the travel time actual value C (t) and the travel time acquisition value A
Extreme variations in the ratio with (t) can be absorbed.
Therefore, the more the vehicle travels on the same road corresponding to the same link, the more the actual travel time is accumulated and reflected in the conversion coefficient K (t), so that learning can be performed.

Therefore, for example, even if traffic information including an error having a deviation from the occurrence of a traffic congestion although there is almost no traffic congestion is always transmitted from the road beacon A, the deviation is corrected. The link travel time based on the traffic information is corrected with the conversion coefficient K (t) accumulated and reflected in the actual travel time to be used, and the travel time is used in the next and subsequent travels. , It is possible to obtain a recommended route reflecting actual traffic conditions.

For example, in FIG.
_FourNavigation link L in route A → D_N16Traffic jam only
In the case of frequent occurrences (the traffic congestion points are indicated by diagonal lines in Fig. 9 (a)).
Traditionally, due to deviations and link travel times
Relatively coarse traffic information link L _KGiven in units
Congestion has occurred on the entire route A → D, or
It is considered that there is no traffic congestion from A to D, and the destination
Route A → B → C → D → c
Or the route A → a → D → c is calculated as the recommended route.
There is it.

On the other hand, in this embodiment, each navigation
Link L_N13, L_N14, L_N15Anti-real travel time for each
Trip taking into account the link travel time reflected and the deviation corrected
The time adoption value B '(t) is given and the main road R₁~ R
_FourFine roads other than₁, R _TwoAbove, corresponding traffic information
Link L_KNavigation link L without_N18~ L_N20Against
The travel time adoption value B ′ (t) calculated by the above equation (5) is
Given, the route A → B → C → D → c or
Route A → a → D → c Less time consuming route than route A → a →
b → c can be calculated as the recommended route.

As described above, using the travel time adoption values B (t) and B ′ (t) in which the deviation included in the link travel time based on the traffic information given from the road beacon A is corrected, Moreover, since it calculates the recommended route in a fine navigation link L _N units relatively than the traffic information link L _K, can be made to reflect the actual traffic situation the recommended route. As a result, it is possible to obtain a more preferable recommended route such that the user can reach the destination in a short time.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the above embodiment, the actual travel time value C (t)
Is obtained when the vehicle travels along the traffic information link L _K. For example, each navigation link L _N
It may be the time when driving is completed. In this configuration, the conversion coefficient K (t) is updated as shown in the following equation (9). However, in the following equation (9), N at the lower right of each character indicates that the actual travel time value C (t) has been measured when the travel of each navigation link L _N has been completed, and k _N (t)
Is obtained as shown in the following equation (10).

K _N (t) = α × k _N (t) + (1−α) × K _N (t−Δt) ‥‥ (9) k _N (t) = C _N (t) / A _N ( t) ‥‥ (10) In addition, at the time of traveling after the traveling, the navigation link L
Using a conversion factor driving performance is reflected in the _N K _N (t), FIG. 3 (b), (c) and the navigation link shown in (d) L _N
Of the travel time adoption value B ′ (t) to the new travel time adoption value B ″
It can be modified to (t). More specifically, as shown in the following equations (11) and (12), each travel time adoption value B ′ (t) obtained by the above equations (4), (5) and (6) is further added. The above conversion coefficient K _N (t) is multiplied.

B ″ (t) = K _N (t) × B ′ (t) ‥‥ (11) B ″ (t) = K _N (t) × B ′ (t) ‥‥ (12) According to this, the travel time adoption value B ″ (t) of each navigation link L _N that does not correspond well to the traffic information link L _K
Since the actual traffic condition of the navigation link _LN can be more accurately reflected, a recommended route reflecting the actual traffic condition with higher accuracy can be calculated as compared with the above embodiment.

In the above embodiment, the travel time acquisition value A
(t) is converted to travel time adoption value B (t)
(3) The equation (B (t) = K (t) × A (t)) is adopted,
For example, the following equation (13) may be used as an equation for converting the travel time acquisition value A (t) into the travel time adoption value B (t). B (t) = K ₁ (t) × A (t) + K ₂ (t) ‥‥ (13) According to the equation (13), the conversion coefficients are K ₁ (t) and K _1
2 (t), so that each conversion coefficient K ₁ (t), K
_{If 2} (t) is updated every time
The accuracy can be improved as compared with the equation (3).

Various other design changes can be made within the scope of the present invention.

[0070]

As described above, according to the in-vehicle route calculating device according to the first aspect, each time the vehicle travels in the same place, the actual travel time value is associated with each link updated so as to be accumulated and reflected. The deviation included in the link travel time obtained based on the traffic information is corrected by the obtained conversion coefficient to obtain the travel time adoption value of the link, and the recommended route is calculated using the travel time adoption value. Therefore, the recommended route can more accurately reflect the actual traffic condition. Therefore, it is possible to obtain a more preferable recommended route such that the user can reach the destination in the shortest time.

Further, according to the vehicle-mounted route calculation device of the present invention, the travel time adoption value whose deviation has been corrected is used as the link travel time adoption value of the route calculation target navigation link. Even when the information link includes a plurality of navigation links, a link travel time adoption value with a corrected deviation can be given to each navigation link. Therefore, it is possible to calculate a recommended route on which the actual traffic condition is more accurately reflected in units of navigation links finer than the traffic information link.

In addition, according to the on-vehicle route calculating device of the present invention, the actual traffic condition whose deviation has been corrected is more accurately reflected even on a route calculation target navigation link having no corresponding traffic information link. Since the link travel time adoption value can be given, the route calculation target navigation link can also be a calculation target link. Therefore, it is possible to calculate a recommended route that also reflects traffic conditions on roads other than the main arterial roads that are not targets of the traffic information link.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a system for providing traffic information to an in-vehicle navigation device to which the in-vehicle route calculation device of the present invention is applied.

FIG. 2 is a block diagram showing an electrical configuration of the on-vehicle navigation device.

FIG. 3 shows a traffic information link which is a constituent unit of a route network prepared on the road beacon which constitutes a part of the traffic information providing system, and a constituent unit of a route network prepared by the on-vehicle navigation device. It is a figure for explaining a positional relationship with a navigation link.

FIG. 4 is a diagram showing a correspondence table representing a correspondence between a traffic information link and a navigation link. 4A is a first correspondence table representing a traffic information link corresponding to a navigation link, and FIG. 4B is a second correspondence table representing a traffic information link closest in distance to the navigation link.

FIG. 5 is a flowchart for explaining a process of calculating a recommended route in the in-vehicle navigation device.

FIG. 6 is a flowchart for explaining a process of calculating a recommended route in the in-vehicle navigation device.

FIG. 7 is a flowchart illustrating a process of calculating a recommended route in the in-vehicle navigation device.

FIG. 8 is a flowchart for explaining a process of calculating a recommended route in the in-vehicle navigation device.

FIG. 9 is a diagram for explaining a problem in the related art and an effect in the above-described in-vehicle navigation device.

FIG. 10 is a diagram for explaining that a traffic condition of a road near a target road can be predicted from a traffic condition of a target road.

FIG. 11 is a graph illustrating a deviation included in traffic information transmitted from an external communication device or included in travel time data and the like which can be estimated from the traffic information.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 In-vehicle navigation device 2 CD drive 7 Beacon receiver 11 Memory control part 16 Controller 161 CPU A Roadside beacon B Communication line C Information center D Map exclusive disk L _K Traffic information link L _N Navi link

Continuation of front page (58) Fields investigated (Int. Cl. ⁷ , DB name) G08G 1/0969 G01C 21/00 G06F 17/30 G09B 29/00

Claims (3)

(57) [Claims] 1. A road map data storage means for storing road map data for route calculation associated with a link which is a constituent unit of a route network, and a travel associated with a link transmitted from an external communication device. Receiving means for receiving traffic information including a time (hereinafter referred to as “link travel time”) or estimating the link travel time; when the traffic information is received by the receiving means, it is included in the traffic information; The link travel time estimated from the traffic information is converted to the link travel time adoption value of the link using a conversion coefficient associated with the link corresponding to the link travel time. Means, the link travel time adoption value acquired by the adoption value acquiring means, and the route calculation road map data stored in the road map data storage means. Route calculating means for calculating a recommended route based on the vehicle; measuring means for measuring a travel time actual value, which is a time when the vehicle actually travels on the road corresponding to the link, when the vehicle travels on the link; was as travel time actual value reflects that are, and a updating means for updating the transform coefficients associated with the link corresponding to the road on which the vehicle travels, said updating means, taking into account the past transform coefficients And smoothing
Is intended to update the transform coefficients Te, the adopted value acquisition means, by using the transform coefficients are updated in the update unit, the corresponding link travel time associated with the link to the transform coefficients, the link An in-vehicle route calculation device, which converts the value into a link travel time adoption value. 2. A road map data storage means storing road map data for route calculation associated with a navigation link which is a constituent unit of the first route network, and a second route network transmitted from an external communication device. Receiving means for receiving traffic information that includes a link travel time associated with the traffic information link that is a constituent unit of, or for estimating the link travel time, when the traffic information is received by the receiving means, A storage means for storing a link travel time included in or estimated from the traffic information in association with the traffic information link; and a traffic information link corresponding to the route calculation target navigation link,
A search means for searching from the traffic information links associated with the link travel times stored in the storage means, and a traffic information link corresponding to the route calculation target navigation link is searched by the search means. The link travel time corresponding to the traffic information link is calculated using a conversion coefficient associated with the traffic information link corresponding to the link travel time.
Converted to the link travel time adoption value of the traffic information link,
An adoption value acquisition unit that acquires a link travel time adoption value of the navigation calculation target navigation link based on the link travel time adoption value; and a link travel time adoption value acquired by the adoption value acquisition unit and the road map data storage. Route calculation means for calculating a recommended route based on the road map data for route calculation stored in the means, and measurement means for measuring a travel time actual value, which is the time the vehicle actually traveled on the road, at predetermined timings; Updating means for updating a conversion coefficient corresponding to a traffic information link including a road on which the vehicle actually travels, so that the actual travel time value measured by the measuring means is reflected. Using the conversion coefficient updated by the updating means, the link travel time associated with the traffic information link corresponding to the conversion coefficient is used to determine the link travel time. An in-vehicle route calculation device, which converts the link travel time adoption value of the link and acquires the link travel time adoption value of the route calculation target navigation link based on the link travel time adoption value. 3. When the traffic information link corresponding to the route calculation target navigation link does not exist, the adoption value acquiring means determines whether the traffic information link corresponding to the route calculation target navigation link is closest to the route calculation target navigation link.
Alternatively, on the condition that the link travel time associated with a plurality of traffic information links has already been converted to the link travel time adoption value of the traffic information link by the conversion coefficient corresponding to the traffic information link, The time adoption value is multiplied by a ratio according to the relationship between the route calculation target navigation link and the traffic information link, and the link travel time adoption value multiplied by the ratio is used as the link travel time adoption value of the route calculation target navigation link. 3. The in-vehicle route calculation device according to claim 2, wherein: