JPH08287393A - Traveling time providing device and route calculating device - Google Patents

Abstract

PURPOSE: To predict the traveling time that the future traffic status according to the route to be run from the time is predicted to some degrees based on the traffic status at a point of present time and to provide the traveling time. CONSTITUTION: When the traveling time is calculated according to a route to be run from the time, the link traveling time estimated value of each link L1 , L2 ,... Ln-1 on which the traffic status at a point of present time is reflected is used to reflect the traffic status as much as possible, the difference of the link traveling time estimated time obtained at present for each link L1 , L2 ,..., Ln-1 and a link traveling time statistic value is used, the link traveling time predicted values L1 , L2 ,..., Ln-1 corresponding to the future time of the links are obtained, and traveling time is calculated by these link traveling time predicted values.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to, for example, a vehicle-mounted navigation device, receives the latest traffic information transmitted from an external communication device, and takes the traffic information into consideration to determine the travel time of a predetermined route. The present invention relates to a travel time providing device that calculates and provides the driver with the travel time. Further, the present invention is applied to, for example, a vehicle-mounted navigation device, receives the latest traffic information transmitted from an external communication device, and takes the traffic information into consideration, and the shortest time route between the present location and the destination. The present invention relates to a route calculation device that calculates

[0002]

2. Description of the Related Art Conventionally, in-vehicle navigation devices that display the current location of a vehicle together with a road map around the vehicle have been used in order to support the traveling of the vehicle on an unfamiliar land. In such an in-vehicle navigation device, a driver or a passenger (hereinafter collectively referred to as “driver”) can set a destination, and a computer automatically determines the shortest time route between the current position and the set destination. There are things that can be obtained (for example, JP-A-5-53).
(See Publication No. 504).

When a destination is set in the vehicle-mounted navigation device to which the route calculation function is added, road map data composed of links connecting road intersections and the like is read, and the current position or the destination is used as a starting point. A tree of links of areas including the current location and the destination is searched. In this case, the travel time (link cost) data of each link included in the road map data is sequentially added, and the route with the longer travel time is deleted from the multiple routes that reach the same link. , Find a tree of routes that reach each link at the minimum link cost, and set the route along the tree between the current location and the destination as the shortest time route.

By the way, the travel time data required for calculating the shortest time route actually changes from moment to moment depending on traffic conditions such as road congestion, traffic restrictions due to road construction, and the presence or absence of accidents. On the other hand, it is impossible for the vehicle to prepare in advance travel time data that takes into account the traffic conditions that change from moment to moment. Therefore, the vehicle-mounted navigation device cannot calculate the shortest time route that reflects the traffic conditions that change from moment to moment.

Therefore, in recent years, a system for providing the latest traffic information to a vehicle from an external communication device has been studied for practical use. For example, as a specific example of a system currently under consideration, a road traffic information communication system (VICS) that transmits traffic information to a vehicle using a radio wave beacon, an optical beacon, or FM multiplex broadcasting
mmunication System) and traffic information service (ATIS: Advanced Traffic Information Service) that transmits traffic information to vehicles using the car / mobile phone network.
There is.

[0006]

By the way, there are the following two types of methods for obtaining the latest traffic information in an external communication device that should transmit the traffic information to the vehicle. One is a method of knowing traffic information by vehicle detectors installed in various places on the road or helicopters navigating above. The other one is the actual value of the travel time of the road currently traveling from the traffic information collection vehicle actually traveling on the road via the road beacon (from other road beacons until reaching the road beacon). Time) is collected and totaled.

However, in any of the above methods, it takes some time to collect and aggregate the traffic information and travel time information, and the traffic information is updated at intervals of several minutes to tens of minutes. As a result, the traffic information provided by the vehicle side is no longer real-time information in the strict sense. Moreover, the travel times collected vary greatly depending on the time of collection.

FIG. 10 shows a length of 3 k detected by the vehicle detector.
It is a graph which shows the time change of the travel time of the link of m.
The horizontal axis of the figure is divided every two hours from midnight, and the vertical axis represents the link travel time in seconds. According to this graph, it is understood that the link travel time fluctuates with 350 seconds as the lower limit value. In particular, during the rush hours from 8 am to 10 am, it fluctuates significantly from 350 seconds to 1000 seconds.

For this reason, the traffic information provided by the vehicle side cannot be said to accurately represent the time taken to pass through the link. Even if the shortest time route is calculated based on this inaccurate traffic information, the shortest time route does not reflect the actual traffic situation, and the route that is busy even though there is a free route The situation occurs such as recommending.

From the above viewpoints, it is required that the vehicle-mounted navigation device can calculate the shortest time route that reflects the current traffic condition with high accuracy. If the shortest time route is calculated and the travel time to the destination is shown to the driver, the travel time along the shortest time route to the destination currently requested will be added to determine the destination. As time elapses while the vehicle is traveling along the shortest route, it may happen that the vehicle actually does not fit.

For example, in the current rush hour,
When the travel time to the destination is calculated based on the link travel time at the current time, it will be a very large value, but as the road goes on, the road gradually becomes vacant and you can drive smoothly and reach the destination. I have arrived earlier than expected. Therefore, if the travel time is estimated using only the traffic information of the current time, the accuracy will deteriorate, so when showing the travel time to the destination to the driver, show the travel time to the accurate destination. There is a demand for a travel time providing device that can do this.

Therefore, the present invention is to provide a travel time providing device capable of calculating an accurate travel time along a route and informing a driver when traffic information is acquired from an external communication device. To aim. Another object of the present invention is to provide a route calculation device capable of calculating the shortest time route that reflects the actual traffic condition with high accuracy when acquiring traffic information from an external communication device.

[0013]

A travel time providing apparatus according to claim 1 for achieving the above object, is a link travel time under a plurality of conditions based on various road traffic conditions during a certain period in the past. Statistic storage means for measuring and storing as a link travel time statistical value for each time, receiving means for receiving traffic information including link travel time transmitted from an external communication device, and the receiving means. When the traffic information is received, the estimated value acquisition means for obtaining the link travel time estimated value of each link based on the traffic information and the difference between the currently obtained link travel time estimated value and the link travel time statistical value are calculated. Utilizing the statistical value correction means for correcting the link travel time statistical value corresponding to the future time to obtain the link travel time predicted value, and the link travel time estimated value along the predetermined route to the current time. And al addition, those and a travel time calculation means for calculating a traveling time using the link travel time prediction value corresponding to the summed time.

According to this structure, the link travel time is measured based on the past results and stored as the link travel time statistical value for each time. When the traffic information is received from the external communication device, the link travel time estimation value of each link is obtained based on the traffic information. This estimated link travel time value reflects the current traffic conditions.

On the other hand, when the travel time is calculated along the route to be traveled, since the traveling speed of the vehicle is finite, the travel time delay is taken into consideration in the travel time using the link travel time statistical value at the future time. You should calculate the time. In this case, it is desirable to reflect the traffic conditions in travel time as much as possible. Therefore, using the link travel time estimation value of each link reflecting the current traffic conditions, by utilizing the difference between the link travel time estimation value and the link travel time statistical value currently obtained for the link, The link travel time prediction value corresponding to the future time of the link is obtained, and the travel time is calculated using this link travel time prediction value.

This makes it possible to predict the future traffic situation along the travel route to some extent based on the current traffic situation, and calculate and provide the travel time in consideration of this prediction. Further, the travel time providing device according to claim 2,
The travel time providing device according to claim 1, wherein the travel time calculated by the travel time calculating means for the travel time when the vehicle actually travels on the road, and the route along the road traveled by the vehicle. A travel time for compensating the travel time calculated by the travel time calculation means for the route to be traveled, by using the comparison result of the comparison means for comparing the time with the travel time actually required for traveling, and the comparison result of the comparison means. A correction means is further provided.

The travel time provided by the travel time providing apparatus according to claim 1 is a travel time for all persons, which does not take into consideration the running performance of the vehicle and the tendency of the driver. It was decided to correct the travel time by taking into account the actual travel time required for traveling on past routes. As a result, a more accurate travel time that reflects the actual specific situation can be obtained and provided to the tribe.

The travel time providing device according to claim 3 is the travel time providing device according to claim 1, wherein the travel time measurement value, which is the time when the vehicle actually travels on the road corresponding to the link, travels on the link. And a calculating means for obtaining a ratio of the travel time measurement value measured by the measuring means and the link travel time prediction value calculated for the route along the road on which the vehicle has traveled in the past, The travel time calculation means calculates the route to be traveled from now on by using the ratio obtained by the calculation means and adding and averaging the ratios for each of the links forming the route along which the vehicle has traveled in the past. And travel time correction means for correcting the travel time.

According to this configuration, when the actual travel time required for traveling in the past route is taken into consideration, the ratio of the link travel time measured value and the link travel time predicted value is calculated for each link, and the average of these is calculated. Then, the averaged value is used to correct the travel time for the route to be traveled.
With this configuration as well, similar to the travel time providing device according to the second aspect, it is possible to obtain a more accurate travel time that reflects an actual specific situation and provide it to the tribe.

Further, the travel time providing device according to claim 4 is the travel time providing device according to claim 1, wherein the link travel time measurement value, which is the time when the vehicle actually travels on the road corresponding to the link, is linked. Obtain the ratio of the measuring means for measuring when traveling, the link travel time measurement value measured by the measuring means, and the link travel time predicted value of the link calculated for the route along the road on which the vehicle has traveled. , A calculation means for performing smoothing correction by using a ratio calculated for a route traveled by the vehicle before the relevant link and giving a relatively large weight to a link closer to the current location link, and the calculation means. Using the ratio,
And a travel time correction means for correcting the travel time calculated by the travel time calculation means for the route to be traveled from now on.

According to this configuration, when the actual travel time required for traveling on the past route is taken into consideration, the ratio of the link travel time measured value to the link travel time predicted value is calculated for each link, and this ratio is calculated as follows: Smoothing is performed based on past travels, and the smoothed travel is used to correct travel time for the route to be traveled. As a result, it is possible to give a relatively large weight to the travel record of the link that has traveled immediately before the current location link and correct the travel time for the route to be traveled. You can get accurate travel time.

According to a fifth aspect of the present invention, there is provided a route calculating device, which stores road map data storing means for storing route calculating road map data associated with a link which is a constituent unit of a route network, and various roads in a certain past period. A link travel time measured under a plurality of conditions based on traffic conditions, a statistical value storage means for storing as a link travel time statistical value,
Receiving means for receiving traffic information including link travel time transmitted from an external communication device, and when the traffic information is received by the receiving means, an estimated link travel time of each link based on the traffic information. The estimated value acquisition means for obtaining the link travel time estimated value obtained by this estimated value acquisition means, and the difference between the link travel time estimated value and the link travel time statistical value of the link calculated at the previous time. Estimated value correction means for obtaining a corrected link travel time estimated value by making a correction in consideration, and link travel time estimated value acquired by this estimated value correction means and routes stored in the road map data storage means. And a route calculating means for calculating a route based on the road map data for calculation.

In this configuration, the route calculation device stores the link travel time measured based on the past results as the link travel time statistical value. When the traffic information is received from the external communication device, the link travel time estimation value of each link is obtained based on the traffic information. This estimated link travel time value reflects the current traffic conditions.

If the route is calculated using only the link travel time estimated value acquired by the estimated value acquisition means, it is possible to show the shortest route in the case of actually traveling under the influence of momentary fluctuations. It may not be possible. on the other hand,
The link travel time statistical value is a value irrelevant to changes in traffic information. Therefore, correction is performed in consideration of the difference between the link travel time estimated value and the link travel time statistical value of the link calculated at the previous time, and the link travel time estimated value is corrected so as to be smoothed.

With this, it is possible to calculate the shortest route by using the link travel time estimation value in which the variation is suppressed in consideration of the past link travel time estimation values. In addition,
The travel time providing device according to any one of claims 1 to 4,
Alternatively, with the route calculating device according to the fifth aspect, the same operation and effect can be obtained by using the traveling speed instead of the travel time. Since the travel time and the traveling speed are in the relationship of (travel time) × (traveling speed) = distance traveled, the link distance is fixed, so that if one is obtained, the other is automatically obtained. . Therefore, even if such a replacement is performed, the content of the invention does not change.

[0026]

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

The road beacon A may be either a radio wave beacon or an optical beacon. Instead of the road beacon A, for example, a communication (transmission) device used for an automobile / cell phone network or an FM multiplex broadcasting network may be used. You may apply. The information center C stores link traffic information corresponding to a relatively coarse first route network having a link (hereinafter referred to as "traffic information link") that connects main intersections in the traffic information providing area as a constituent unit. ing. This link traffic information is, for example, a vehicle detector, a helicopter navigating over the sky, or the latest traffic information that changes from time to time acquired by a traffic information collection vehicle actually traveling on the road is associated with the traffic information link. It was created and created.

The link traffic information includes, for example, a travel time which is a time required for a vehicle to travel on a road corresponding to the traffic information link, a degree of congestion, or a length of congestion. For example, when a traffic jam occurs, the travel time or the traffic congestion length is relatively long, and the traffic congestion degree is relatively increased. Be made smaller. Also,
When an accident or the like makes the vehicle impassable, the travel time or the speed during traffic jam is set to infinity. This link traffic information is
It is given to the road beacon A via the communication line B at regular intervals (for example, 5 minutes).

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 electrical configuration of a vehicle-mounted navigation device mounted on a vehicle. The vehicle-mounted navigation device 1 is provided with an azimuth sensor 5 that detects the amount of change in the direction of the vehicle and a distance sensor 6 that detects the amount of movement of the vehicle. Direction sensor 5
For example, optical fiber gyro, vibration gyro,
A gyro such as 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 the tire wheel or the rotor can be applied. The outputs of the azimuth sensor 5 and the distance sensor 6 are given to the vehicle position detection unit 14 in the vehicle-mounted navigation device body 1.

In the vehicle position detector 14, the traveling direction of the vehicle is obtained based on the output of the direction sensor 5, and
The traveling distance of the vehicle is obtained based on the output of the distance sensor 6. Accurate initial position data of the vehicle is given to the vehicle position detection unit 14 by the driver, for example, before the vehicle starts, and the vehicle position detection unit 14 receives the previously given initial position data and the vehicle. 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 location of the vehicle is performed at regular intervals (for example, 1.2 seconds).

Instead of the direction sensor 5, the distance sensor 6 and the vehicle position detector 14, or the direction sensor 5,
Along with the distance sensor 6 and the vehicle position detector 14, a GPS (Global Posioning System) that navigates in an orbit around the earth.
) A GPS receiver that detects the current position of the vehicle based on the propagation delay time of GPS radio waves transmitted from the satellite may be adopted.

The vehicle position detector 14 also corrects the detected current position of the vehicle by so-called map matching processing (see, for example, Japanese Patent Laid-Open No. 63-148115). That is, the traveling locus of the vehicle detected based on the outputs of the azimuth sensor 5 and the distance sensor 6 is compared with the road pattern stored in the vehicle-mounted map dedicated disk D, and the vehicle pattern is checked according to the result. The traveling locus is corrected on the road pattern.

The current vehicle position data corrected by the map matching process is given to the controller 16. The controller 16 is a control center of the vehicle-mounted navigation device body 1, and includes a CPU 161, an SRAM 162, and a DRAM 163. Controller 16
When the current position data of the vehicle is given from the vehicle position detection unit 14, reads out the road map data for display from the vehicle-mounted map dedicated disk D via the memory control unit 11 and the CD drive 2. The read road map data for display and the present location data thus read are given to the display controller 12. When the display road map data and the current position data are given, the display control unit 12 superimposes a car mark representing the current position of the vehicle on the road map to display a liquid crystal display device, a plasma display device or C.
It is displayed on the display 3 configured by RT.

The on-vehicle map dedicated disk D stores route calculation road map data in addition to the display road map data. The road map data for route calculation divides the road map (including highway national roads, motorways, other national roads, prefectural roads, city roads of ordinance-designated cities, and other living roads) into meshes, and each mesh A relatively fine second route network consisting of a combination of nodes that correspond to road intersections and links that link each link (hereinafter referred to as "Navilink") is a highway / national road map and general road map It is a structure that is stored by dividing it into three layers of a detailed map and a travel time, a fixed travel time value, a travel time statistical value T _S (t), a link length for each navilink, and the coordinates of the start and end points of that navilink. Etc. are associated with each other.

The travel time statistical value T _S (t) is the traffic information of the traffic information link for each provision time provided in the traffic information provision area during the past certain period through the road beacon, the season, month, It is a value which is averaged and stored for each one or a plurality of combinations such as day of the week, weekday / holiday, etc., and written in the on-vehicle map dedicated disk D. The travel time statistical value T _S (t) is acquired by a terrestrial system such as the information center C and provided to each user.

In the map-dedicated disk D, the first correspondence indicating the correspondence relationship between the navigation map and the traffic information link associated with the traffic information transmitted from the road beacon A in addition to the road map data. A table is stored (see FIG. 4). The correspondence relationship between the traffic information link and the navigation link can be classified as follows because the traffic information link is generally a coarser unit of the route network than the navigation link. FIG. 3A shows a case where the traffic information link L _Ka and the navigation link L _Na have a one-to-one correspondence. Figure 3 (b)
Is one traffic information link L _Kb and multiple navigation links L _Nb
1 , L _Nb2 , ..., L _Nbi are included in FIG.
(c) shows a case where there is a navigation link L _N that does not correspond well to the traffic information link L _K. Of these, Figure 3 (a),
The first correspondence table represents the correspondence relationship in the case of (b), and FIG. 4 shows specific examples of the first correspondence table.
Since there is no direct correspondence in the case of FIG. 3C, the description of the correspondence table is omitted in this embodiment.

A remote controller key (hereinafter simply referred to as “remote control key”) 4 for inputting a destination and various calculation conditions is connected to the controller 16 via an input control section 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 centered on a car mark indicating the current location, and a road map display scale. "Scale key" to zoom in and out, "Rotation key" to select whether the vehicle's traveling direction is displayed at the top or the north of the map is displayed at the top, and "Rotation key" to switch whether to display the vehicle's running trajectory "Track key", "Route key" that allows you to input the route calculation instruction signal with one touch when you want to calculate the shortest time route from the current location to the destination, "Return key" to return to the previous screen during menu operation,
Various keys (neither is shown) such as a "menu key" for displaying a menu screen such as "destination setting" and "route setting" are provided.

The controller 16 uses the remote control key 4 by the driver to determine the destination and various calculation conditions (whether toll roads are prioritized, ferry use is prioritized, or transit points are used). Etc. are input, the input destination data and the like are stored in the SRAM 162, and the route calculation road map data is read from the vehicle-mounted map dedicated disk D, and the destination and vehicle position detection unit 14 is read.
The shortest time route between the navigation links respectively close to the current position detected in step 1 is calculated by using, for example, the Dijkstra method or the potential method. The calculated shortest time route is superimposed and displayed on the road map displayed on the display 3, for example, by a broken line.

Here, the potential method is the following method. In other words, the navigation link near the departure point (or the destination) may be the calculation start link, and the navigation link closest to the destination (or the departure point) may be the calculation end link. Search all links. At this time, the process of sequentially adding travel time estimated values of each navigation link (described later), discarding the route that is not the shortest, and leaving only the route that realizes the shortest route is repeated. As a result, a tree of routes consisting of only the shortest route is finally obtained, so that the shortest time route can be obtained by tracing the route from the calculation end link to the calculation start link in reverse.

The beacon receiver 7 is also connected to the controller 16. When the vehicle enters the transmission area of the road beacon A (see FIG. 1) and the link traffic information transmitted from the road beacon A is received by the beacon receiver 7, the CPU 161 outputs the link traffic information to the SRA.
It is given to M162 and held. The CPU 161 uses the SRAM 16 when calculating the shortest time route by the above method.
When the link traffic information is stored in 2, the travel time estimation value obtained by using the link traffic information is added to the travel time statistical value T _S (t) included in the route calculation road map data. The travel time estimation value is obtained by adding the values, and the shortest time route is calculated based on this travel time estimation value.

FIGS. 5, 6 and 7 are flowcharts for explaining the calculation process of the shortest time route in the vehicle-mounted navigation device 1. The driver operates the remote control key 4 to input the destination and the waypoint before or during the traveling (step S1 in FIG. 5). After that, during traveling, the controller 16 determines whether or not the destination has been reached (step S2), and when the destination is reached, guides the arrival of the destination and erases the memory of the destination information, the shortest time route information, etc. (step S2). S3).

During traveling, it is always determined whether or not the link traffic information is received from the road beacon A (step S4). When the link traffic information is not received from the on-road beacon A, a predetermined point for route guidance, for example, a predetermined distance such as an intersection on the way, is provided on condition that the shortest time route is obtained (step S5). It is determined whether or not it reaches the front side (step S6;
This is performed based on the current position data output from the vehicle position detection unit 14. ), When it is determined that the predetermined point has been reached, the driver guides the route shape and guidance direction to the driver on the display screen of the display 3 or by voice to guide the route (step S7).

When the predetermined point for route guidance has not been reached (NO in step S6), it is determined whether or not the link has been passed (step S8), and if so, the travel time of the link (travel time measurement value). Is obtained (step S9). This measurement is performed based on a clock (not shown) held by the controller 16. In step S10, it is determined whether or not the measurement data is normal, and if normal, the travel time predicted value T _P calculated for this link is calculated.
It is determined whether (described later) is stored as data (step S11), and if stored, the formula described below is stored.
According to (13) to (15), the smoothed value A of the ratio between the travel time measured value T _O and the travel time predicted value T _P is updated and stored (step S
12).

The judgment in step S10 as to whether or not the measurement data is normal is made unless the judgment is made when the vehicle detours or when the vehicle is parked in the parking lot and the service is completed. This is because the amount of measurement data increases abnormally, and it is erroneously determined that the link is heavily congested.
The abnormality of the measurement data can be determined, for example, by stopping for a certain time or longer, being out of the link to be measured, or the travel time measurement value being abnormally large relative to the travel time statistical value.

On the other hand, while traveling, the above-mentioned step S4
When it is determined that the link traffic information is received from the on-road beacon A, the link traffic information can be used by the vehicle-mounted navigation device 1 in consideration of the content of the link traffic information, as shown in FIG. Estimated travel time T
_E (t) (however, t represents the acquisition time of the link traffic information)
Processing for converting to (steps S22 to S2)
8).

More specifically, when the link traffic information represents the travel time data itself (YES in step S23), the travel time data is used as it is as the travel time estimated value T _E (t) ( Step S24). If the link traffic information indicates the congestion length (YES in step S25), the following is calculated based on the congestion length.
Equation (1) is calculated to calculate the travel time estimated value T _E (t) (step S26).

T _E (t) = (L ₁ / V ₁ ) + {(L ₂ −L ₁ ) / V ₂ } (1) However, in the above formula (1), L ₁ is the congestion length, V ₁
Is the average vehicle speed during traffic jam on the traffic information link, L ₂
Represents the link length of the traffic information link, and V ₂ represents the average vehicle speed when there is no traffic congestion in the traffic information link. In addition,
The average vehicle speeds V ₁ and V ₂ are stored as a table in the map-dedicated disk D in association with the traffic information link.

Furthermore, if the link traffic information does not represent the travel time data itself or the congestion length (NO in step S25), the link traffic information is considered to represent the degree of congestion (step S27). Based on the congestion degree, the following equation (2) is calculated to calculate the travel time estimated value T _E (t) (step S28). T _E (t) = L ₂ / V ₃ (2) However, in the equation (2), V ₃ represents the average vehicle speed corresponding to the degree of traffic congestion on the traffic information link, and this average vehicle speed V Similar to the average vehicle speeds V ₁ and V ₂ , ₃ is stored as a table in the map dedicated disk D in association with the traffic information link.

If the shortest time route is obtained by directly applying the travel time estimated value T _E (t) obtained as described above, the instantaneous variation of the travel time estimated value T _E (t) will be severe. Since it is too much (see the graph in FIG. 10), in order to smooth this, an exponential smoothing method in which the travel time statistical value T _S (t) is added is used. Therefore, in steps S29 to S30, the travel time estimated value T _E (t) is smoothed.

First, the route calculation target navigation link and traffic
Information links have a one-to-one correspondence as shown in Fig. 3 (a).
If so, travel time statistics corresponding to the traffic information link
Value T _S(t) is read from SRAM 162 and traveled
Time statistics T_SConversion factor K required to modify (t)
_tAsk for. The conversion coefficient K_tHas an initial value of 1
Estimated travel time T_EThe instantaneous fluctuation of (t) is too intense
Consider the purpose of smoothing and using this
And travel time estimate T_EIt is necessary to absorb the instantaneous fluctuation of (t).
It is necessary. Because of this, if you passed a street beacon before
Link traffic information of the same traffic information link acquired in
Conversion coefficient K adopted based on_t-1Weighted in consideration
Conversion factor K_tAnd

More specifically, the step S
28 estimated travel time T_EWhen (t) is obtained, the travel time
Estimated value T_E(t) and travel time statistics for the traffic information link
Value T _SThe difference from (t) is obtained (step S29). next,
Calculated when passing another road beacon before the present
Stored in non-volatile memory,
Estimated travel time T_ERead (t-1) and travel on this link
Row time statistics T_STake the difference from (t) to obtain the conversion coefficient K_t-1To
Obtain the new conversion coefficient K as shown in the following equation (3)._tTo
New (step S30).

K _t = α (T _E (t) −T _S (t)) + (1−α) K _t−1 (3) However, in the formula (3), α (0 <α < 1) is a smoothing index. If it is close to 1, the past conversion coefficient K _t-1 is weighted, and if it is close to 0, the current travel time estimated value T _E
Weight is attached to (t). Using the conversion coefficient K _t obtained in this way, the travel time estimated value T _E (t) corresponding to the navigation link to be calculated for the route is calculated by the following equation (4).
Is calculated (step S31).

T _E (t) = K _t + T _S (t) (4) In the above description, the difference between the travel time estimated value and the travel time statistical value was focused on. You may pay attention to the ratio of a value and a travel time statistical value. In this case, the above (3)
The equations (4) are as follows. K _t = α (T _E (t) / T _S (t)) ＋ (1-α) K _t-1 ‥‥‥ (5) T _E (t) = K _t · T _S (t) ‥‥‥ (6 ) If the navigation link is included as a part of the traffic information link as shown in FIG.
After the travel time estimated value T _E (t) is calculated based on the formula or the formula (6), the calculation of the following formula (7) is performed, and the travel time estimated value T _E corresponding to the route calculation target navigation link is calculated. (t) is calculated. However, in the formula (7) below, d _Ni represents the link length of the navigation link _i , and d _K represents the link length of the traffic information link.

(D _Ni / d _K ) × T _E (t) → T _E (t) (7) Estimated travel time calculated by the equation (4), the equation (6), or the equation (7). T _E (t) is held in the non-volatile memory. The above process is performed for a series of traffic information links transmitted from the road beacon A (step S2).
1) If the processing for these traffic information links is completed, the process proceeds to step S41 in FIG.

As described above, since the conversion coefficient K _t is obtained in order to absorb the instantaneous fluctuation of the travel time estimated value T _E (t), the travel time estimated value T obtained by using the conversion coefficient K _t.
E (t) is a value that reflects the current traffic conditions and suppresses extreme fluctuations in the actual traffic conditions. Therefore, the shortest time route is calculated using this travel time estimated value T _E (t).

In the route calculation process, when various calculation conditions are input by the driver, the CPU 161 acquires the current position data of the vehicle from the vehicle position detection unit 14 (step S4).
1), the shortest time route between the set destination stored in the SRAM 162 and the recognized current location is the travel time estimated value T _E (t) of the current time stored in the nonvolatile memory. To calculate (step S4
2). At this time, if there is a link for which the travel time estimated value T _E (t) is not obtained (for example, a navigation link of a road that is not the target of traffic information provision), the travel time estimated value T is unavoidable.
_{Use a} fixed travel time value (link length divided by average travel speed) instead of _E (t).

After that, the calculated shortest time route is displayed on the display screen of the display 3 (step S
43), guide instruction information corresponding to the shortest time route is created (step S44). The contents of the guidance instruction information corresponding to this shortest time route are conventionally known such as the direction to the destination, the straight line distance to the destination, the route distance and travel time along the shortest time route, the schematic diagram of the intersection, etc. There is a variety of information available, and any or all of this information is presented to the driver.

By the way, when presenting the travel time along the shortest time route to the destination to the driver, there are the following problems. If the travel time estimated value T _E (t) along the shortest time route to the destination currently calculated is added, the time elapses while traveling along the shortest time route to the destination. As it does, it may happen that it doesn't actually fit. This is because the travel time estimated value T _E (t) is only the travel time estimated value at the present time. For example, if it is the current rush hour and the travel time to the destination is calculated based on the link travel time at the current time, it will be a very large value, but as the car travels, the road gradually becomes vacant. , I was able to drive smoothly, and when I reached my destination, I arrived earlier than planned.

Therefore, it is conceivable to use the travel time statistical value T _S (t) stored in the on-vehicle map dedicated disk D. As described above, the travel time statistic value T _S (t) is the traffic information of the traffic information link provided by the road beacon A in the past certain time period for each provision time, such as season, month, day of the week,
It is a value that is averaged and stored for each one or a plurality of combinations such as weekday / holiday, etc., and is written in the on-vehicle map dedicated disk D, so that it is possible to statistically predict the future travel time to some extent. Have sides.

Therefore, the travel time can be calculated in consideration of the factor of the time that elapses as the vehicle travels along the shortest time route to the destination, but since the link traffic information is not taken into consideration, it is possible to calculate the travel time from the current location link ahead. If the travel time to the destination is calculated based on only the travel time statistical value T _S (t) for the link, the travel time will not reflect the current or near future traffic situation at all. For example, if the road corresponding to the current location link is congested, it is natural to think that the road corresponding to the next link is also congested except for the special case where the congestion ends at this road. Therefore, the travel time statistical value T that does not consider the current situation
It is not appropriate to calculate the travel time to the destination based on _S (t) alone.

Therefore, when the travel time to the destination is obtained based on the travel time statistical value T _S (t), there arises a problem of how to reflect the traffic situation. In this embodiment, based on the travel time statistical value T _S (t), if the link traffic information is obtained from the road beacon A, the travel time statistical value T _S (t) will be included at the future time. And correct it using the current traffic conditions. This corrected value is called a travel time predicted value T _P (t).

In this embodiment, the travel time of the link Li is predicted.
Value T_{P, Li}(t) is calculated by the following equation (8). T_{P, Li}(ti) = T_{S, Li}(ti) ・ T_{E, Li}(t₀) / T_{S, Li}(t₀) ‥‥ (8) where t₀Is the current time. ti is the link Li
It is the time that is predicted to pass through, and this time is
For example, the estimated travel time T of the link on the shortest time route _E(t)
To the current time from the current location link to the current link
It can be obtained by adding.

Travel time statistical value T_{S, Li}(ti), travel time estimation
Value T_{E, Li}(t₀), Travel time statistics T_{S , Li}(t₀) Is all
It is a value for the link Li. The current location Rin
Black L ₀Travel time prediction value T_{P, L0}(t) is T_{P, L0}(t₀) = T_{S, L0}(t₀) ・ T_{E, L0}(t₀) / T_{S, L0}(t₀) = T_{E, L0}(t₀), The estimated travel time T_{E, L0}(t₀)be equivalent to.

The above equation (8) is used for the link L on the shortest time route.
The travel time prediction value T _{P, Li} (t) of i is calculated as the travel time estimation value T _{E, Li} (t ₀ ) of the current time of the link Li and the travel time statistical value T.
It means correction based on the ratio with _{S, Li} (t ₀ ).
For example, if the current road is busy and it takes twice as long as the travel time statistic value, it is predicted that the road to be traveled from now on will also be similarly busy and will take twice as long.
Accordingly, based on the current traffic situation, the link traffic information of the road to be traveled can be corrected to be more current.

For example, as shown in FIG. 8, a vehicle is present at the current location link L ₀ and a series of shortest time routes L ₀ , L ₁ , L ₂ , ..., L to the destination link L _{n-1. Let n-1} be required. The predicted travel time T _P (L ₀ → L _n-1 ) from the link L ₀ to L _n-1 is T _P (L ₀ → L _n-1 ) = ΣT _{P, Li} (ti) (9) (Σ takes from i = 0 to i = n-1).

Next, the correction process of the estimated travel time T _{P in} consideration of the past travel record will be described. The estimated travel time is
It is a predicted value in the future, and past driving results are not taken into consideration. If the vehicle has traveled from the origin to the current location, the travel time measurement value should have been obtained. Therefore, the travel forecast time is corrected in consideration of the ratio of the travel time measurement value from the departure place to the present location and the travel forecast time predicted from the departure location to the present location.

This correction shows that when the sum of the travel time predicted values T _{P, Li} (ti) of the links corresponding to the routes that have been traveled from the departure place to the actual travel time is exactly the same. Can not be considered, the error in the link traffic information,
This is based on the fact that the actual traveling time may be longer or shorter depending on the individual differences of the drivers and the traveling performance of the vehicle.

Therefore, the purpose of this embodiment is to evaluate past travel records and provide more accurate information as the estimated travel time. For example, FIG. 9 illustrates a series of shortest time routes starting from the departure point link L _-n to the destination link L _n-1 , where the vehicle departs from the departure point link L _-n. At present, it is assumed that the vehicle is present at the current location link L ₀ .

The estimated travel time T _P ′ from the link L ₀ to L _n-1 is T _P ′ (L ₀ → L _n-1 ) = A · T _P (L ₀ → L _n-1 ) ... ( 10), A is the ratio of the actual travel time from the departure point link L _-n to the current location link L ₀ and the predicted travel time A = T _O (L _-n → L _-1 ) / _TP ( L _−n → L ₋₁ ) ... (11).

In the above equation (11), the departure point link L_-n
To current location link L_-1Actual Travel Time and Travel Forecast
The ratio of the departure point and the departure point
Black L _-nTo current location link L_-1Travel time for each link up to
Measured value T_{O, Li}(t_i) And travel time prediction value T_{P, Li}(t_i) With
You may employ the average value of each ratio. A = (1 / n) ΣT_{O, Li}(t_i) / T_{P, Li}(t_i) (12) (Σ takes from i = -n to i = -1.) In the equation (12), the travel time measurement value and travel time of each link are calculated.
Ratio to predicted value T_{O, Li}(t _i) / T_{P, Li}(t_i) Is treated equally
Is averaged, but you can use an exponential smoothing method.
Yes.

According to this, first, for the departure point link L _-n and the next link L _{-n + 1} , the weighted smoothed value A _{-n + 1} of the ratio between the travel time measured value and the travel time predicted value is calculated. Ask. A _{-n + 1} = α (T _{O, L-n + 1} (t _{-n + 1} ) / T _{P, L-n + 1} (t _{-n + 1} )) + (1-α) (T _{O, Ln} (t _-n ) / _{TP, Ln} (t _-n )) (13) Next, the smoothed value A _{-n + 1} and the travel time measurement value and travel of the next link L _{-n + 2} Weighted smoothed value A with the ratio of time predicted value
_{-n + 2} is calculated and A _{-n + 2} = α (T _{O, L-n + 2} (t _{-n + 2} ) / T _{P, L-n + 2} (t _{-n + 2} )) + (1 -Α) A _{-n + 1} (14) The same processing is repeated thereafter, and the smoothed value A _-2 and the weight of the travel time measured value of the next link L _-1 and the ratio of the travel time predicted value are weighted. Calculate the smoothed value A _-1 .

A_-1= Α (T_{O, L-2}(t_-2 ) / T_{P, L-2}(t_-2 )) + (1-α) A_-1 (15) This weighted smoothed value A_-1Using the link L₀To L
_n-1Estimated travel time to T _PTo correct. T_P′ (L₀→ L_n-1) = AT_P(L₀→ L_n-1) (16) By adopting the exponential smoothing method in this way,
Ground link L₀Near the passage link, in other words the vehicle is the best
Traveling with more emphasis on the track record of the links that have traveled nearby
Predicted time T_PCan be corrected.

The procedure for calculating the estimated travel time described above is
Assuming the case of FIG. 9 incorporating the exponential smoothing method, description will be made with reference to the flowchart of FIG. The controller 16 links the links L ₀ , L ₁ , and
L ₂ , ..., L _n-1 are processed in order (step S4
5,46). Assuming that the processing of the link L ₁ is assumed, in step S47, the ratio of the travel time estimated value T _{E, L1} (t ₀ ) of the link L ₁ to the travel time statistical value T _{S, L1} (t ₀ ) is calculated. To calculate. Next, referring to the travel time statistical value T _{S, L1} (t ₁ ) at the time in consideration of the travel time of the vehicle, which is stored in the SRAM 162 (step S48), the travel time predicted value T _{P, L1} (t
₁ ) is obtained by the following formula (step S49).

T _{P, L1} (t ₁ ) = T _{S, L1} (t ₁ ) · T _{E, Li} (t ₀ ) / T _{S, Li} (t ₀ ), and this travel time predicted value T _{P, L1} ( t ₁ ) is stored (step S50), the process returns to step S45, and the next link L ₂
The same process is performed for (step S47-50),
The travel time prediction values T _{P, L2} (t ₂ ), T _{P, L3} (t ₃ ), and so on are accumulated. When the cumulative processing of the travel time prediction value up to the destination link L _n-1 is completed (YES in step S46), the process proceeds to step S51, from the departure point link L _-n to the current location link L ₀ based on the past results. The smoothed value A, which is the ratio of the actual travel time to the predicted travel time, is referred to (step S
51). This smoothed value A is
It is calculated and updated based on the equations (13) to (15) (see step S12). Then, the travel estimated time obtained in step S50 is multiplied by the smoothed value A (step S52) to obtain the travel time to the destination, and this travel time is shown to the driver (step S53).

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the above-mentioned embodiment, the link travel time statistical value T _S (t) measured under a plurality of conditions based on various road traffic conditions in the past fixed period is acquired by the ground system such as the information center C. However, it may be provided to each user. However, the information may be acquired by the vehicle, accumulated as the traveling results are accumulated, and made into a database.

Other various design changes can be made within the scope of the present invention.

[0077]

As described above, according to the invention described in claim 1, when the travel time is calculated along the route to be traveled, the traffic condition at the present time is reflected in order to reflect the traffic condition as much as possible. Using the link travel time estimation value of each link, the difference between the link travel time estimation value and the link travel time statistical value currently obtained for the link is used, and the link corresponding to the future time of the link is used. The travel time prediction value is obtained, and the travel time is calculated using this link travel time prediction value.

As a result, it is possible to predict and provide a travel time in which the future traffic condition along the route to be traveled is predicted to some extent based on the current traffic condition, so that the travel time having a higher utility value for the driver can be provided. Can be provided. Further, according to the invention of claim 2 or 3, since the travel time is corrected in consideration of the actual travel time required for traveling in the past route, the actual specific situation is reflected and the variation is suppressed. Get accurate travel times, can be offered to Triba.

Further, according to the invention of claim 4, when the travel time is corrected in consideration of the travel time results required for the past route travel, the travel performance of the link traveled immediately before the current location link With a relatively large weight,
Since the travel time is corrected for the route to be traveled, it is possible to obtain a more accurate travel time that reflects the actual specific situation.

According to the fifth aspect of the invention, when the traffic information is received from the external communication device, the link travel time estimation value of each link reflecting the current traffic situation is obtained based on the traffic information, Since this link travel time estimation value is smoothed and corrected considering the difference between the link travel time estimation value and the link travel time statistical value of the link calculated at the previous time, the past link travel time is also calculated. It is possible to obtain an estimated link travel time value with consideration given to variations.

Since the route is calculated using this link travel time estimation value, a stable and highly reliable shortest time route can be calculated.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a system for providing traffic information to a vehicle-mounted navigation device to which a route calculation device and a travel time prediction providing device of the present invention are applied.

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

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

FIG. 4 is a diagram showing a correspondence table showing a correspondence relationship between traffic information links and navigation links.

FIG. 5 is a flowchart for explaining a process of calculating the shortest time route and travel time in the vehicle-mounted navigation device.

FIG. 6 is a flow chart for explaining a process of calculating the shortest time route and travel time in the vehicle-mounted navigation device.

FIG. 7 is a flowchart for explaining a process of calculating the shortest time route and travel time in the vehicle-mounted navigation device.

FIG. 8 shows that the vehicle is on the current location link L ₀ and the series of shortest time routes L ₀ , L ₁ , L to the destination link L _n-1.
It is a figure which shows ₂ , ..., Ln _-1 .

FIG. 9 shows that a vehicle is present at the current location link L ₀ and has a series of shortest time paths L _−n , L _{−n + 1} , ..., L from the departure value link L _−n to the destination link L _{n−1. 0} , L ₁ , ..., L _n-1
FIG.

FIG. 10 is a graph showing a time variation of travel time of a link having a length of 3 km detected by a vehicle detector.

[Explanation of symbols]

 1 On-vehicle navigation device 2 CD drive 7 Beacon receiver 11 Memory control unit 14 Vehicle position detection unit 16 Controller 161 CPU 162 SRAM A Road beacon B Communication line C Information center D Map-only disc

Claims (5)

[Claims] 1. A statistical value storage unit for storing link travel times measured under a plurality of conditions based on various road traffic conditions during a certain period in the past as link travel time statistical values for each time, and an external device. Receiving means for receiving traffic information including link travel time transmitted from the communication device, and when the traffic information is received by the receiving means, an estimated link travel time value of each link is obtained based on the traffic information. The estimated value acquisition means and the difference between the currently obtained link travel time estimated value and the link travel time statistical value are used to correct the link travel time statistical value corresponding to a future time, and the link travel time predicted value is corrected. And a link travel time estimated value along the predetermined route from the current time, and the travel time is estimated using the link travel time predicted value corresponding to the added time. A travel time providing device comprising: travel time calculating means for calculating. 2. A measuring means for measuring a travel time of a vehicle actually traveling on a road, a travel time calculated by the travel time calculating means for a route along the road on which the vehicle travels, and an actual travel. And a travel time correction means for correcting the travel time calculated by the travel time calculation means for the route to be traveled from now on, using the comparison result of the comparison means. The travel time providing device according to claim 1, wherein: 3. A measurement means for measuring a travel time measurement value, which is a time when the vehicle actually travels on a road corresponding to the link, when the travels on the link, and a travel time measurement value measured by the measurement means. A calculating means for obtaining a ratio with the link travel time predicted value calculated for a route along the road on which the vehicle has traveled in the past, and a route along the road on which the vehicle has traveled for the ratio obtained by the calculating means. A travel time correction unit that corrects the travel time calculated by the travel time calculation unit for a route to be traveled by using an average obtained by adding up for each of the constituent links.
The travel time provision device described. 4. Measuring means for measuring a link travel time measurement value, which is a time when the vehicle actually travels on a road corresponding to the link, when the link travels, and a link travel time measurement value measured by the measuring means. And the ratio calculated with respect to the link travel time predicted value of the link calculated for the route along the road on which the vehicle has traveled, and the ratio calculated for the route traveled by the vehicle before the link. For a link closer to the link, a travel time calculated by the travel time calculation means for the route to be traveled by using a calculating means for relatively smoothing correction with a relatively large weight and a ratio obtained by this calculating means. The travel time providing device according to claim 1, further comprising travel time correction means for correcting the travel time. 5. A road map data storage unit for storing road calculation road map data associated with a link which is a constituent unit of a route network, and a plurality of conditions based on various road traffic conditions in a certain past period. The link travel time measured respectively in the statistic value storage means as a link travel time statistical value, a receiving means for receiving traffic information including the link travel time transmitted from an external communication device, When the traffic information is received by the means, the estimated value acquisition means for obtaining the link travel time estimated value of each link based on the traffic information, and the link travel time estimated value acquired by the estimated value acquisition means, The corrected link travel time estimated value is obtained by making a correction in consideration of the difference between the link travel time estimated value of the link calculated at the previous time and the link travel time statistical value. And an estimated value correction means, and a route calculation means for calculating a route based on the estimated link travel time value corrected by the estimated value correction means and the route calculation road map data stored in the road map data storage means. A route calculation device comprising: