JPH0573798A - Optimum route search device - Google Patents

Abstract

PURPOSE:To provide an optimum route search device which has the search efficiency improved by selecting an intersection as the inspection object based on the direction of a destination point in the movement route network consisting of intersection groups and connection routes connecting them. CONSTITUTION:This system is applied to the optimum route search device, which searches an optimum route from the start point to the destination point based on information related to the movement route network of a moving body consisting of intersection groups and connection routes connecting them, and is provided with selecting means 100, 100A, and 100B which select intersections in the directions near the direction of the destination point from intersection groups and search means 101, 101A, 101B which search an optimum route based on information related to the movement route network consisting of intersections selected by selecting means 100, 100A, and 100B and connection routes connecting them, thus efficiently searching the optimum route.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optimum route search device for an automobile or the like which searches for an optimum route from among travel routes.

[0002]

2. Description of the Related Art Conventionally, in the academic field, optimum route searching techniques such as "MOORE method" and "DIJKSTRA method" in graph theory are known. Further, as an optimal route search method applying these techniques, for example, Japanese Patent Laid-Open No.
"A route search method for moving on a connecting road connecting intersections and groups of intersections" disclosed in Japanese Patent No. 173297, for example, Japanese Patent Laid-Open Publication No.
There is known a "route search method for moving within a certain area while avoiding obstacles" disclosed in Japanese Unexamined Patent Publication No. 3-200207.

Using information about a moving route network of a moving body such as a road map, a starting point manually input by an operator or input by an automatic input device,
Many devices that apply the above-mentioned "MOORE method" technology to devices that search for an optimum route using data of a destination and an intermediate point as a criterion. The "MOORE method" is one of horizontal search methods. First, an outline of this horizontal search method will be described. FIG. 21 is a diagram for explaining the horizontal search method, and shows a travel route network including a departure point and a destination point and intersections 1 to 13 on each route. Now, in this horizontal search, if the shortest route from the starting point to the destination is searched as the optimum route, the route length from the starting point to each intersection reached via each route is set as the level value of each intersection,
Search sequentially for intersections with the smallest level values. First, in the initial processing, the level value at the departure point is set to 0, and the level values at the other intersections are set to sufficiently large values. next,
For intersections that have reached the middle of horizontal search (hereinafter called measurement intersections), calculate the level value of each adjacent intersection, that is, the path length from the departure point, and find the intersection with the smallest level value. The next measurement intersection candidate.

Now, assuming that the distance between the intersections near the departure point is the value shown in FIG. 22, the intersection 1 adjacent to the departure point has a level 10 and the intersection 3 has a level 28. Therefore,
The intersection 1 having the smallest level value from the departure point becomes the next measurement intersection candidate, and the level value of each intersection adjacent thereto is recalculated with the intersection 1 as the measurement intersection. In the figure, there are only 2 intersections adjacent to the intersection 1, and the level value of the intersection 2 is from the departure point to the intersection 2 via the intersection 1
The distance 10 + 15 = 25 for the route to. Next, when the measured intersection is moved to the intersection 2 and the level value of each adjacent intersection is recalculated, the intersection 4 becomes 10 + 15 + 13 = 38,
The intersection 6 becomes 10 + 15 + 37 = 62. Therefore, at the intersections 4 and 6, the intersection 4 becomes the next measurement intersection candidate. However, here, there are two routes from the departure point to the intersection 4 that pass through the intersections 1 and 2, and two routes that pass through the intersection 3. The former route calculates the level value of the intersection 4 as described above. Thus, when the level value of the intersection 4 is calculated by the latter route, it becomes 28 + 9 = 37. In this case, the route with the lowest level value from the departure point is adopted, and the route from the departure point through the intersection 3 to the intersection 4 is adopted. The same search is performed thereafter, and the above processing is repeated until the destination point appears in the next measurement intersection candidate.

This horizontal search method carries out a uniform search in all directions from the starting point, and thus there is a high possibility that the optimum route will be correctly selected. However, this has the disadvantage that the processing takes time. As an optimal route search device that has improved the shortcomings of this horizontal search method, an optimal route search device has been proposed in which the processing time is shortened by limiting the target intersections whose level values are compared to the adjacent intersections of the intersections investigated up to now. (See, for example, JP-A-1-251300).

On the other hand, there is a vertical search method as a search method to be compared with the horizontal search method (for example, Japanese Patent Laid-Open No. 1-180).
No. 012). This vertical search is different from the horizontal search in which the starting point is surveyed evenly. Return to the nearest intersection and take another fork. This process is repeated until a route reaching the destination is found at the shortest distance. For example, in FIG. 21 described above, first, the distance of the route from the departure point to the destination point through the intersections 1 → 2 → 6 → 7 → 10 → 13 is calculated. Next, intersection 1 → 2 → 6 →
The distance of the route passing through 7 → 10 → 11 → 13 is calculated. Among the routes calculated in this way, the route including the destination point and having the shortest distance is selected as the optimum route. This vertical search method takes a shorter time than the horizontal search method when the route can be successfully searched, but takes longer than the horizontal search method when it is difficult to find the route, and the processing time varies depending on the search conditions.

[0007]

However, in the conventional optimum route searching method and optimum route searching apparatus using the above-mentioned search method, when the route search of the moving body moving on the connecting road connecting the intersection groups is performed, We are investigating even intersections that are in a completely different direction from the starting point or the current point as compared to the destination point, which is a waste of search time.

Particularly in the vertical search method, if the search branches are randomly selected, it is extremely unlikely that the optimum route to the destination can be found earlier than the horizontal search. Furthermore, in order to take advantage of the high processing speed, the vertical search method has no choice but to use the first discovered route as the optimal route, but this route is unlikely to be the optimal route. This is because the conventional vertical search method does not consider the directionality to the destination point and extends the search branches indefinitely. Further, in the vertical search method disclosed in Japanese Patent Laid-Open No. 1-180012, the remaining distance from the current intersection to the destination is set to be as small as possible in each of the X-axis and Y-axis directions in the orthogonal grid map. , The adjacent intersection is selected, but this vertical search method is difficult to apply to general road map networks.

An object of the present invention is to select an intersection to be surveyed on the basis of the direction of a destination point in a moving route network consisting of a group of intersections and a connecting route connecting them, and to optimize the optimum route. It is to provide a search device.

[0010]

The present invention will be described with reference to FIG. 1 which is a correspondence diagram of claims. The invention of claim 1 is a moving path network of a moving body, which comprises an intersection group and a connecting path connecting them. It is applied to an optimum route search device that searches for an optimum route from a departure point to a destination point on the basis of information about the selection point, and a selecting unit that selects an intersection in a direction close to the direction of the destination point as an investigation target intersection from the intersection group. 100
And the search means 101 for searching for the optimum route based on the information about the moving route network consisting of the intersection groups selected by the selecting means 100 and the connecting paths connecting them, thereby achieving the above object. The invention according to claim 2 is applied to an optimum route search device for searching for an optimum route from a starting point to a destination point based on information about a moving route network of a moving body that includes a group of intersections and a connecting route connecting them. Area setting means 102 for setting a survey target area of an intersection based on the positional relationship between the departure point and the destination point and the degree of detail of the information about the moving network, and selecting an intersection within the survey target area from the intersection group. And a search means 101A for searching for an optimum route based on information about a travel route network consisting of the intersection groups selected by the selection means 100A and connecting paths connecting them. To achieve. The area setting means 102A of the optimum route searching device according to claim 3 searches the obstacle by the obstacle.
When the route search of 01A is stalled, the area under investigation at the intersection is expanded and reset. The invention according to claim 4 is applied to an optimum route search device that searches for an optimum route from a departure point to a destination point based on information about a moving route network of a moving body that includes a group of intersections and a connecting route connecting them. The difference between the direction of the destination point and the direction of the surveyed intersection as seen from the current point, and the straight line distance from the current point to the surveyed intersection,
A selection unit 100B that sets an evaluation function determined by the path length of the connection path from the current position to the surveyed intersection and selects a transit intersection from the intersections adjacent to the current position according to this evaluation function, and this selection unit. The search means 101B for repeatedly selecting a passing intersection at 100B to search for an optimum route to a destination is provided, thereby achieving the above-mentioned object.

[0011]

According to the present invention, the selecting means 100 selects an intersection having an orientation close to the orientation of the destination point from the group of intersections as an intersection to be investigated, and the searching means 101 selects the selecting means 1
The optimum route is searched for on the basis of the information about the moving route network including the intersection groups selected by 00 and the connecting routes connecting them. In claim 2, the area setting means 102 sets the area to be investigated at the intersection based on the positional relationship between the departure point and the destination point and the degree of detail of the information regarding the moving route network, and the selecting means 100A causes the intersection group to be set. An intersection within the area to be surveyed is selected from among the above, and the searching means 101A causes the selecting means 100
The optimum route is searched based on the information about the moving route network including the intersection group selected by A and the connecting route connecting them. In claim 3, the area setting means 102A expands and resets the area to be searched at the intersection when the route search of the searching means 101A is stalled due to an obstacle, and the selecting means 100A selects the area to be searched from the intersection group. The intersection in the area is selected, and the searching unit 101A searches for the optimum route based on the information about the moving route network including the intersection group selected by the selecting unit 100A and the connecting road connecting them.
In claim 4, the selecting means 100B determines the difference between the direction of the destination point and the direction of the surveyed intersection as viewed from the current point, the straight line distance from the current point to the surveyed intersection, and the distance from the current point to the surveyed intersection. An evaluation function determined by the route length of the connecting path is set, a transit intersection is selected from the intersections adjacent to the current point according to this evaluation function, and the searching means 101B repeatedly selects the transit intersection by the selecting means 100B. To find the optimal route to the destination.

[0012]

FIG. 2 is a block diagram showing the structure of a vehicle navigation system according to an embodiment. This device is a system interface (hereinafter referred to as I / O) unit 1
a, a horizontal search unit 1b and a vertical search unit 1c
It consists of three main units. Each unit 1a-1
c is a microcomputer (hereinafter referred to as CPU) 2
a to 2c, memories 3a to 3c, and interface circuits 4a to 4c. These units 1a to 1c are connected via a communication line 8. Further, the auxiliary storage devices 5a to 5 are provided in the units 1a to 1c, respectively.
c is connected via the interface circuits 4a to 4c. The auxiliary storage devices 5a to 5c store information about a moving route network of a moving body such as a road map and information about obstacles. In the I / O unit 1a,
The speed / direction sensor 6 and the system console 7 are connected via the interface circuit 4a. The speed / direction sensor 6 detects the traveling speed and traveling direction of the vehicle. The system console 7 is composed of a monitor for displaying a map and route information, a keyboard for designating a departure point / destination point, and a man-machine interface device such as a pointing device. Power is supplied to this device from a power supply device (not shown).

In the configuration of the above embodiment, the microcomputers (CPUs) 2b and 2c constitute the area setting means, the selecting means and the searching means, respectively.

In this embodiment, the shortest route is searched as the optimum route to the destination. Therefore, the route length data of the connecting route between the intersections is used. It is also possible to search for the minimum fuel consumption route or the shortest running time route as the optimum route to the destination point. In that case, necessary fuel (energy) data and predicted travel time data are used instead of the above-mentioned route length data.

3 to 5 are flowcharts showing the operation of the I / O unit 1a, and the route search processing will be described with reference to these flowcharts. In step S1, the occupant inputs the departure point and the destination point from the system console 7. Next, if there are obstacles between the departure point and the destination point, investigate the route relay points required to avoid or cross them. First, in step S2, as shown in FIG.
The obstacle data registered in the "obstacle / detour point data table" shown in is read, and in the subsequent step S3, in the sections in both the X and Y axis directions from the departure point to the destination point,
It is determined whether the existing section of the obstacle intersects. If the existing sections intersect, the process proceeds to step S4, and if not, the process proceeds to step S8. As shown in FIG. 6, obstacles are registered in the obstacle / detour point data table in the order of registration numbers, and the existence range of each obstacle is
Small section data within the existing range, detour / crossing point data for each small section, etc. are registered.

In step S4, small section data in which the existence range of the obstacle is minutely divided is investigated, and in the following step S5, the line segment forming the small section of the obstacle is connected to the starting point and the destination point. It is determined whether or not the line segment intersects. If they intersect, the process proceeds to step S6, and if they do not intersect, the process proceeds to step S7. In step S6, the small section including the intersecting line segment and the relay point are registered in the relay point list shown in FIG. It should be noted that, as shown in FIG. 7, the relay point list is registered with the coordinates of the location of each relay point, information about the route, and the like. In step S7, it is determined whether or not all the small section data of the obstacle has been investigated. If the investigation is completed, the procedure proceeds to step S8, and if not completed, the procedure returns to step S4 to investigate the next small section data. To do.

In step S8, it is determined whether or not all obstacle data on the obstacle / detour data table shown in FIG. 6 has been investigated, and when the investigation is completed, step S9
If not, the process returns to step S2 to investigate the next obstacle data. After registering the destination at the end of the relay point list in step S9, step S1 in FIG.
Go to 0.

Next, a route search process between the relay points is performed. In step S10, among the relay points registered in the relay point list, one relay point is selected from each relay point group in the section from one relay point group to the next relay point group, and a temporary departure is made. Point and destination. In step S11, the selected temporary starting point and destination are transmitted to the horizontal search unit 1b and the vertical search unit 1c via the communication line 8. It should be noted that the horizontal search unit 1b and the vertical search unit 1c are in a standby state in a receiving state after being activated. In step S12, a search start command signal is transmitted to the horizontal search unit 1b and the vertical search unit 1c. As a result, the horizontal search unit 1b and the vertical search unit 1c start the route search based on the temporary starting point and destination. The start command may be included in the data transmission of the departure point and the destination point.

In step S13, the route between the relay points is determined based on the search results by the horizontal search and the vertical search,
Register in the relay point list. Here, in many cases, the vertical search can obtain an answer earlier, but as described above, the horizontal search is more likely to obtain a more accurate shortest route.
Therefore, the criterion for determination is determined by the combination of processing speed and accuracy. If a processing device having a sufficiently high processing speed is used, it is possible to wait until the search result of the horizontal search unit 1b is output, compare the search results of the vertical search and the horizontal search, and select a shorter route. In addition,
A processing time may be reduced by providing a time limit for making the final determination and making a determination based on the search result obtained at that time when the time is reached. Step S
At 14, it is determined whether or not the relay point selected as the tentative destination point is a true destination point. If the relay point is a true destination point, the process proceeds to step S15. Select the starting point and destination point of
The above processing is performed.

Next, the relay point obtained in the above process is regarded as an intersection, and a more global route is determined. First, in step S15, the departure point and the destination point are transmitted to the horizontal search unit 1b and the vertical search unit 1c,
In a succeeding step S16, a horizontal and vertical search start command is transmitted to each of the units 1b and 1c to start the search.
The route search of the horizontal search unit 1b and the vertical search unit 1c will be described later. Next, in step S17 of FIG. 5, the respective search results are input from the horizontal search unit 1b and the vertical search unit 1c,
Make a final decision on the route. Next, in step S18, the route from the starting point of the final result to the destination point is used. That is, the optimum route is displayed on the system console 7 or output to the autopilot device to control various actuators based on the route signal.

8 and 9 are flow charts showing the operation of the horizontal search unit 1b, and the horizontal search processing will be described with reference to these flow charts. After starting the horizontal search unit 1b, an initialization process is performed in step S31. Here, the horizontal search end flag and the horizontal search impossible flag are reset. These flags are used for MOOR described later.
It is used to notify the search result by the E method search subroutine. Next, in step S32, the reception of data from the I / O unit 1a is waited, and when the data of the starting point and the destination point described above is received, the process proceeds to step S33 to wait for the reception of the horizontal search start command.
When the horizontal search start command is received, the process proceeds to step S35.

Next, an intersection limited area is set to limit the intersection to be surveyed to an intersection having an orientation close to the orientation of the destination. In this embodiment, a circular intersection limited area f1 is set as shown in FIG. Specifically, first, in step S35, the midpoint of the line segment connecting the departure point and the destination point is calculated, and this midpoint is set as the center of the circle. Next, in step S36, the radius of the circle is calculated based on the length of the line segment connecting the starting point and the destination point and the fineness of the map information used. In step S37, the range in the X-axis direction of the circular intersection limited area is calculated based on the center and radius of the circle. The intersection limited area is not limited to a circular area, and may be an elliptical area f2 shown in FIG. 10, for example, in order to select an intersection closer to the direction of the destination. Further, when a relay point that crosses or bypasses an obstacle between the departure point and the destination point is set, for example, as shown in FIG. 11, an intersection limited area f3 including the departure point to the relay point 1
Alternatively, an intersection limited area f4 including the relay point 1 to the destination may be set.

Next, according to the set intersection limited area, the intersection groups to be investigated are narrowed down from the intersection / connection path data table shown in FIG. At the intersection /
As shown in FIG. 12, in the connecting road data table, in order to improve the efficiency of the process of narrowing down to the intersections in the intersection limited area, the X coordinates of the intersections are arranged in order, and the position coordinates of each intersection, the adjacent intersection list, and the passages are listed. The registration number of the same intersection registered in the intersection list, connection information, etc. are registered. At step S38, the intersection data is read out from the intersection data table, and then at step S39.
Then, it is determined whether or not the X coordinate of the intersection is within the range of the intersection limited area in the X-axis direction, and if it is within the range, step S40.
Otherwise, to step S41. In step S40, the registration number of the intersection is registered in the adjacent intersection list shown in FIG. 13, and in step S41, it is determined whether or not the intersection narrowing processing is completed for all the intersections registered in the intersection list. If it has ended, the process proceeds to step S51 in FIG. 9, and if not, step S38.
Return to and continue the above processing for the next intersection. In addition,
In the adjacent intersection list, as shown in FIG. 13, the level value (route length in this embodiment) for each intersection, adjacent intersection information, measured intersection experienced information, and the same intersection registered in the intersection / connection road data table. The registration number and the like are registered.

In step S51 of FIG. 9, the intersection group narrowed down in the above step is targeted, and M to be described later.
A route search subroutine by the OORE method is executed. In step S52, it is determined whether or not the horizontal search end flag is set, and if it is set, step S56.
Otherwise go to step S53. In step S53, it is determined whether or not the horizontal search impossibility flag is set. If it is set, the process proceeds to step S54, and if not, the process returns to step S37 in FIG. In step S54, the route search information such as the current search position of the vertical search unit 1c is input, and the subsequent step S55.
Then, the intersection limited area is reset based on the current route search information of the vertical search unit 1c.

For example, if the horizontal search is at a dead end and the vertical search has searched the intersections outside the intersection limited area with a certain frequency, the circle of the intersection limited area is enlarged. Further, for example, when an elliptical intersection limited area is set, the area is enlarged as shown in FIG. In the restarted route search, intersections in the newly set area are added to the conventional intersections, and the intersections are sequentially searched from the beginning as described above. In addition, in such a situation where the intersection limited area is reset and the route search is restarted,
The correct route is presumed to make a large detour to the right or left of the straight line connecting the starting point and the destination point. Therefore, in order to place importance on the processing speed, the intersections to be investigated during the re-search are limited to the intersections in the newly set area and the intersections adjacent to them. Alternatively, the intersections to be surveyed may be further narrowed down as follows. That is, new intersections and their adjacent intersections are divided into left and right with a straight line connecting the departure point and the destination point as a boundary, and the vertical search unit 1c.
The intersection of the current route search side of is to be surveyed.

When the horizontal search is completed successfully, step S5
In step 6, the search result is transmitted to the I / O unit 1a, and the program execution ends.

15 and 16 are flowcharts showing a route search subroutine by the MOORE method. In step S61, initialization processing is performed. Here, set a numerical value indicating infinity, for example, 999999, to the route length from the departure point set for all the surveyed intersections,
The route length of the departure point is set to 0, and the departure point is registered as the initial intersection of the measurement intersection. In step S62, the measured intersection, that is, the adjacent intersection of the departure point is registered in the adjacent intersection list shown in FIG. In the following step S63, it is determined whether or not the value obtained by adding the distance to each adjacent intersection to the route length from the departure point of the current measurement intersection is smaller than the route length of each adjacent intersection, and if affirmed, step S64 Then, the route length of the adjacent intersection is updated by the above (route length of the measured intersection) + (distance to the adjacent intersection). When step S63 is denied, step S64 is skipped.

In step S65, it is judged whether or not there is an intersection which is not investigated as a measurement intersection in the adjacent intersection list shown in FIG. 13, and if there is, it proceeds to step S66.
If not, the process proceeds to step S67. The fact that there is no unexamined intersection as a measurement intersection in the adjacent intersection list during the route search by the horizontal search means that the horizontal search cannot be continued. In step S67, the horizontal search impossible flag is set and the result is shown in FIG. Return to the indicated program. On the other hand, in step S66, the adjacent intersection having the minimum route length in the adjacent intersection list is selected as a new measurement intersection, and in step S68 of FIG. 16, whether the newly selected measurement intersection is the destination point or not is determined. Determine. If it is the destination, the process proceeds to step S69, and if not, the process proceeds to step S70. In step S69, the horizontal search end flag is set and the process returns to the program of FIG. 9. On the other hand, in step S70, the adjacent intersections of the measurement intersections are investigated and registered in the adjacent intersection list, and the process returns to step S63 of FIG. The above process is continued.

17 and 18 are flow charts showing the operation of the vertical search unit 1c, and the vertical search processing will be described with reference to this flow chart. In step S81, various initial processes on software are performed, and in the following step S82, it is determined whether or not the data of the starting point and the destination point are received from the I / O unit 1a, and if received, the process proceeds to step S83. In step S83, I / O
It is determined whether or not the vertical search start command is received from the unit 1a, and if it is received, the process proceeds to step S84. Step S
At 84, a departure point is set at the measurement intersection and the vertical search process is started.

In step S85, the horizontal search unit 1b
Determines whether there is a request to send the current search information from
If so, in step S86, information such as the current search position is transmitted to the horizontal unit 1b. In step S87, it is determined whether or not the current measurement intersection has been passed in the past, and if it is a new intersection that has not been passed in the past, the process proceeds to step S88, and if it is an intersection that has been passed in the past, For example, the process proceeds to step S91 in FIG.

In step S88, the probability P that each adjacent intersection adjacent to the current measurement intersection constitutes the shortest route is calculated by the following equation. P = L1 × cos (b) / L2 (1) Here, b is the angle formed by the azimuth of the destination point and the azimuth of each adjacent intersection as viewed from the measurement intersection. For example, in FIG. 19, assuming that the intersection 5 is the measurement intersection, the adjacent intersection 9
The angle formed by the azimuth of the arrow and the azimuth of the destination is b1, and the angle formed by the azimuth of the adjacent intersection 7 and the azimuth of the destination is b2.
Is. L1 is a straight line distance between the measurement intersection and each adjacent intersection, and L2 is a distance along the road between the measurement intersection and each adjacent intersection. Instead of the distance L2, the probability P may be determined using the fuel consumption amount or the running time of the route between the measurement intersection and each adjacent intersection. Continuing step S
At 89, the route length from the departure point to the measurement intersection is calculated. This is calculated by adding the distance from the current measured intersection to the path length of the immediately preceding measured intersection. In step S90 of FIG. 18, the survey results of the current measured intersection and its adjacent intersections are registered in the passing intersection list of FIG.

In step S91, it is determined whether or not there is an unpassed adjacent intersection at the current measurement intersection. If there is an unpassed adjacent intersection, the process proceeds to step S92, and if not, the process proceeds to step S93. In step S92, the intersection having the highest probability P among the unpassed adjacent intersections is set as the next measurement intersection, while in step S93, the next intersection is returned to the shortest route from the departure point to the current measurement intersection. , That intersection is the next measurement intersection. Step S9
In step 4, it is determined whether or not the newly selected measurement intersection is the destination point. If the destination is the destination point, the process proceeds to step S95 and I /
The search result is output to the O unit 1a, and if it is not the destination point, the process returns to step S85 in FIG. 17 to continue the vertical search.

As described above, in the horizontal search, the intersection limited area is set based on the positional relationship between the departure point and the destination point and the fineness of the map information, and the intersection in the intersection limited area is used as the surveyed intersection. In the vertical search, each of the adjacent points is searched by the angle between the direction of the destination and the direction of the surveyed intersection, the straight line distance to the surveyed intersection, and the route length of the connecting road to the surveyed intersection. Since the likelihood of the intersection is determined and the route search is performed via the intersection with the highest likelihood, the search processing efficiency is improved and the search time can be reduced.

Further, when a large-scale obstacle such as a hill or a river exists between the starting point and the destination point and the horizontal search is stalled, the intersection limited area is expanded and reset. , Normally, it is possible to efficiently perform route search targeting intersections in the limited area as much as possible, and even if the search is stuck, it is possible to investigate the intersections in the expanded and reset area and continue the route search, which is rational. You can perform various route search processing.

Further, in the horizontal search, when the intersection limited area is reset, the area is determined in consideration of the search condition of the vertical search, so that the intersection limited area can be appropriately expanded to a necessary range.

For large-scale obstacles such as railroads with few railroad crossings, rivers with few bridges, and hills, the area occupied by them and the relay points such as railroad crossings and bridges for avoiding / crossing are registered in the map information. Incidentally, prior to the search, these relay points are regarded as intersections and the global route search is performed, so that it is possible to avoid the occurrence of a search deadlock in the horizontal search and speed up the search processing.

[0037]

As described above, according to the first aspect of the present invention, an intersection having an orientation close to the orientation of the destination is selected from the intersections as an intersection to be investigated, and the selected intersections are selected. Since the optimum route is searched based on the information about the moving route network including the connection route connecting them, the search processing efficiency is improved and the search time can be reduced. According to the invention of claim 2, the survey target area of the intersection is set based on the positional relationship between the departure point and the destination point and the degree of detail of the information about the moving route network. Since the optimum route is searched based on the information about the moving route network consisting of the connecting routes connecting the search routes, the search processing efficiency is improved and the search time can be reduced. Further, according to the invention of claim 3, when the route search is stalled due to an obstacle, the area to be investigated at the intersection is expanded and reset, so that the intersection is usually targeted within the limited area. Thus, the route search can be executed efficiently, and even if the search is stalled, the route search can be continued by investigating the intersections in the expanded and reset area, and the rational route search processing can be performed. According to the invention of claim 4, the difference between the azimuth of the destination point and the azimuth of the surveyed intersection viewed from the current point, the straight line distance from the current point to the surveyed intersection, and the connection from the current point to the surveyed intersection By setting the evaluation function determined by the route length of the road and selecting the transit intersection from the intersections adjacent to the current point according to this evaluation function, the optimum route to the destination is searched, so it is accurate. The optimum route can be searched efficiently.

[Brief description of drawings]

FIG. 1 is a diagram for responding to a complaint.

FIG. 2 is a block diagram showing the configuration of an embodiment.

FIG. 3 is a flowchart showing a route search operation.

FIG. 4 is a flowchart showing a route search operation.

FIG. 5 is a flowchart showing a route search operation.

FIG. 6 is a diagram showing an obstacle / detour point data table.

FIG. 7 is a diagram showing a relay point list.

FIG. 8 is a flowchart showing a horizontal search operation.

FIG. 9 is a flowchart showing a horizontal search operation.

FIG. 10 is a diagram illustrating a method of setting an intersection limited area.

FIG. 11 is a diagram illustrating another setting method of the intersection limited area.

FIG. 12 is a diagram showing an intersection / connection road data table.

FIG. 13 is a diagram showing an adjacent intersection list.

FIG. 14 is a diagram illustrating a method of resetting an intersection limited area.

FIG. 15 is a flowchart showing a route search subroutine by the MOORE method.

FIG. 16 is a flowchart showing a route search subroutine by the MOORE method.

FIG. 17 is a flowchart showing a vertical search operation.

FIG. 18 is a flowchart showing a vertical search operation.

FIG. 19 is a diagram illustrating a vertical search in consideration of the orientation of a destination point.

FIG. 20 is a diagram showing a passing intersection list.

FIG. 21 is a diagram illustrating a horizontal search method.

FIG. 22 is a diagram illustrating a horizontal search method.

[Explanation of symbols]

1a System interface unit (I / O unit) 1b Horizontal search unit 1c Vertical search unit 2a, 2b, 2c Microcomputer (CPU) 3a, 3b, 3c Memory 4a, 4b, 4c Interface circuit 5a, 5b, 5c Auxiliary storage device 6 speed / direction sensor 7 system console 8 communication line 100, 100A, 100B selection means 101, 101A, 101B search means 102 area setting means

Claims (4)

[Claims] 1. An optimum route search device for searching for an optimum route from a starting point to a destination point based on information about a moving route network of a moving body consisting of intersection groups and connecting paths connecting them, Based on the information about the movement network consisting of selection means for selecting an intersection in the direction close to the direction of the destination point as an investigation target intersection from the inside and the intersection group selected by this selection means and the connecting path connecting them An optimum route search device, comprising: a search unit that searches for the optimum route. 2. An optimum route search device for searching for an optimum route from a starting point to a destination based on information about a moving route network of a moving body, which comprises a group of intersections and a connecting route connecting them, Area setting means for setting a survey target area of an intersection based on a positional relationship with the destination point and a degree of detail of information on the moving road network, and selecting an intersection within the survey target area from the intersection group. An optimum route search comprising: a selecting unit for selecting the optimum route based on information about a moving route network including intersection groups selected by the selecting unit and connecting paths connecting the intersection groups. apparatus. 3. The optimum route search device according to claim 2, wherein when the route search of the search unit is stalled due to an obstacle, the region setting unit expands and resets the survey target region at the intersection. An optimal route search device characterized by the above. 4. An optimum route search device for searching for an optimum route from a starting point to a destination point based on information about a moving route network of a moving body consisting of a group of intersections and a connecting route connecting them, It is determined by the difference between the direction of the destination and the direction of the surveyed intersection, the linear distance from the current point to the surveyed intersection, and the path length of the connecting path from the current point to the surveyed intersection. An evaluation function is set, and selecting means for selecting a via intersection from among the intersections adjacent to the present point according to the evaluating function, and the selecting means repeatedly selects the via intersection to find an optimum route to the destination. An optimum route search device comprising a search means for searching.