JPH0896296A - Searching method for nearest movable body - Google Patents

Abstract

PURPOSE: To quickly extract the nearest movable body by a car location system with comparatively low accuracy without generating a large error by dividing an object range into plural areas having comparatively high correlation between a road distance and a straight distance, comparing a distance between a prescribed point regulated by a node on a network and a movable body and extracting the nearest movable body. CONSTITUTION: A nearest vehicle extracting means 16 selects the necessary number of fire engines 1 existing near a diaster field based upon the positional information of fire engines 1 to be turned out and the coordinates of the disaster field. The range of the field is divided into plural areas having compratively high correlation between a road distance and a straight line and a network is constituted of movable body nodes indicating the positions of the fire engines 1, a prescribed point node indicating the position of the disaster field, a boundary node indicating a position capable of passing on the boundary of the area, and a link connecting respective nodes in the same area including a boundary by a straight line. Then a movable node having the smallest sum of link lengths of the shortest route from the prescribed point node on the network routes is searched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recent mobile object search method for extracting a required number of mobile objects closest to an arbitrary position from a plurality of mobile objects, and is applied to, for example, fire fighters and police officers. It is applicable to an emergency vehicle formation system and the like.

[0002]

2. Description of the Related Art A recent mobile object search method for extracting a required number of mobile objects closest to an arbitrary position from a plurality of mobile objects moving on a road network has been applied to various systems. An example is an emergency vehicle formation system for fire trucks.

In the following, a conventional method for searching for a recent moving body will be described by taking the application to this emergency vehicle formation system as an example.

The emergency vehicle formation system is composed of a plurality of fire engines and one central command center and the like. When a disaster occurs, a necessary number of fire engines closest to the disaster site are organized and directed to the scene. .

For fire engines, a car location device,
An activity management device and a communication device are installed. The car location device obtains the position of the fire engine. The movement management device manages whether or not the fire engine can be dispatched.When crew members input movement information such as patrols, fire extinguishing activities, and waiting, the availability of dispatch according to the behavior is confirmed. can get. The communication device is used for communication with the central command center, and transfers position information from the car location device and mobilization information from the activity management device to the central command center at fixed intervals or in response to a request from the central command center. . Further, the communication device receives a dispatch command from the central command center and notifies the crew when a disaster occurs.

The central command center constantly manages the positions of all fire engines, and when receiving a 119th call when a disaster occurs, issues a dispatch command to the required number of fire engines closest to the disaster site. The location of the disaster site is specified by, for example, the 119th call recipient marking an image map near the site displayed on the reception desk screen. The number of fire engines required is determined by searching the dispatch plan table file created in advance for each disaster scale and type.

In the central command center, conventionally, there have been the following two methods for selecting the required number of fire engines close to the disaster site.

The first conventional method is to compare the straight line distances from the disaster site to the fire engine and select the ones with the shortest distance first. The management of the position of the fire engine and the specification of the position of the disaster site are performed using a coordinate system on an appropriate plane such as latitude and longitude. Change the location of the disaster site to (x0, y0
), The position of the fire engine k in the event of a disaster (xk, yk
If), it calculates a straight line distance ^{(xk -x0) 2 + (yk} -y0) 2 for all mobilized possible fire truck, compared to select a vehicle turn required number from as small as a linear distance .

The second conventional method compares the distance on the road network from the disaster site to the fire engine, that is, the road distance (sometimes referred to in this way by reflecting the travel time), and it is necessary in order from the shortest one. This is a method of selecting the number of units. In this method, in order to calculate the road distance, a digital road map in which the road network is represented by a network composed of nodes and links is created in advance. The car location device mounted on the fire engine performs map matching processing with the digital road map to obtain the position on the road network.
At the central command center, the location of the fire engine is managed as a node moving on the link, and the location of the disaster site is specified as a new node on the network or a node closest to the existing disaster site. When selecting the fire engine closest to the disaster site, the shortest route search is performed starting from the node at the disaster site, and the required number of fire engines is selected from the ones with the shortest distance. The shortest path search method is generally used, for example, Dijkstra method or Moore's algorithm, and the shortest path search algorithm that is easy to realize is applied.

[0010]

The first conventional method can be realized by a car location system having relatively small calculation resources and low positioning accuracy, and is effective in an area where the road distance and the straight distance are highly correlated. Met.

However, when there are rivers, railways, bays, lakes, etc. that are difficult to cross in the target area and the area is divided, a steep mountain area and road network are developed in the target area. When there are mixed urban areas, or when the local road network is not well developed, the error due to approximating the road distance with a straight line distance becomes unacceptably large, which is a practical problem. There was a chance

In the second conventional method, it is necessary to prepare a digital map for all roads through which the fire engine can pass, which requires a lot of man-hours to create the digital map, and There was a problem that we could not respond flexibly to changes. Further, in order to identify the position of the fire engine on the road network, it is necessary to equip the fire engine with a highly accurate car location system. In addition, even if any of the shortest route calculation methods that are commonly used at present is applied to the calculation of the road distance, a large amount of calculation time is required, and it is intended for multiple emergency vehicles such as fire engines. In the system, real-time control was difficult and unrealistic.

[0013]

In order to solve such a problem, according to the present invention, a plurality of moving bodies moving on a road network in a restricted area are located at an arbitrary position in the area. In a recent moving body search method for extracting a predetermined number of moving bodies closest to a given point, the area is divided into a plurality of regions in which the correlation between the road distance and the straight line distance is relatively high, and at least the position of the moving body is determined. The mobile node shown, a predetermined point node showing the position of a given point, the boundary node showing the position where the mobile on the boundary of the area can pass, and a straight line between these nodes in the same area including the boundary Configure a network from the links connecting with, and in this network,
The mobile node having the smallest sum of the link length information of the shortest route on the network route from the predetermined point node is searched, and the mobile node corresponding to this mobile node is selected.

[0014]

In the present invention, the target area is divided into a plurality of areas in which the correlation between the road distance and the straight line distance is relatively high, and the same area is used as the distance between the predetermined point defined by the node on the network and the moving body. If it is within the range, the linear length link length information is used. If it is within a different area,
The path of a polygonal line (sum of link length information) that crosses a defined position (boundary node) on the boundary is used.
By comparing the distances, the shortest moving body is selected.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the method for searching a moving body according to the present invention is applied to an emergency vehicle formation system for a fire engine will be described.

This emergency vehicle formation system is composed of a plurality of fire engines and one central command center as in the conventional case, and when a disaster occurs, the necessary number of fire vehicles closest to the disaster site is selected and sent to the site. It is something to change.

FIG. 2 is a block diagram of an emergency vehicle formation system showing the configuration from the function of selecting a vehicle close to a disaster site.

In FIG. 2, the fire engine 1 has a car location device 11, a movement management device 12, and a communication means 13.
Is equipped with.

The car location device 11 obtains the position of the fire engine 1 as coordinates of an appropriate plane coordinate system such as latitude and longitude. For example, a G using an artificial satellite is used.
It is realized by using PS (Global Positioning System) or the like. The position of the fire engine 1 obtained by the car location device 11 is output to the communication means 13.

The movement management device 12 manages whether or not the fire engine 1 can be dispatched, and when crew members enter dynamic information such as patrol, fire extinguishing, and standby, dispatch according to the state. Availability information is obtained. The dispatch availability information obtained by the activity management device 12 is also output to the communication means 13.

The communication device 13 is used for communication with the central command center 2, and the position information from the car location device 11 and the dispatch from the motion management device 12 are set at regular intervals or when the motion of the fire engine 1 changes. The permission information and the identifier of the fire engine 1 are transferred to the central command center 2. Further, the communication device 13 receives a dispatch command from the central command center 2 and notifies the crew when a disaster occurs.

The central command center 2 comprises a communication means 14, a vehicle position management means 15, a recent vehicle extraction means 16, a 119th report reception means 17, a disaster point identification means 18, and a required vehicle number determination means 19.

The communication means 14 is means for communicating with a plurality of fire engines 1 existing in the target area. The communication means 14 receives the position information, the dispatch availability information and the identifiers sent from each fire engine 1, and the vehicle position management means 15 receives them. Output. The information from each fire engine 1 is sent at regular intervals or when the dynamics of the fire engine 1 change, as described above.
In addition, the communication unit 14 issues a dispatch command to the fire engine 1 extracted recently by the vehicle extraction unit 16.

When the vehicle position management means 15 receives the position information of the fire engine, the dispatch availability information and the identifier from the communication means 14, the vehicle position management means 15 compares it with the information of the corresponding fire engine 1 received last time, and it is newly changed to be dispatchable. The position information and the identifier of the fire engine 1, the fire engine 1 that is newly disabled, or the fire engine 1 that can be dispatched and whose position has moved are output to the vehicle extraction unit 16 recently.

On the other hand, the 119th report receiving means 17 is a means for an operator who is in charge of the receiving board to receive the 119th report by telephone or the like. When the operator receives the 119th report from the disaster site in the 119th report receiving means 17, the operator inputs the position of the disaster site in the disaster point specifying means 18, and inputs the scale and type of the disaster in the required number determining means 19. To do. The operator inputs the position of the disaster site to the disaster point identifying means 18 by, for example, marking the image map around the site displayed on the reception desk screen by the operator.

The disaster point identification means 18 exchanges the coordinates of the input position on the map with an appropriate coordinate system such as latitude and longitude, and outputs it to the vehicle extraction means 16 recently.

The required number determining means 19 holds a dispatch plan table file in which the number of fire engines required for fire extinguishing is planned in advance for each disaster scale and type. The necessary number determining means 19 retrieves the dispatch plan table file based on the scale and type of the disaster input by the operator in the 119th call receiving means 17, and obtains the required number of fire engines. The required number of vehicles thus obtained is recently output to the vehicle extraction means 16.

The vehicle extracting means 16 will be described later based on the position information of the fire engine 1 which can be dispatched from the vehicle position managing means 15 and the coordinates of the disaster site input from the disaster point specifying means 18. The required number of fire trucks 1 near the disaster site is determined by the mobile object search method recently.
The required number input from 9 is selected and output to the communication means 14. Recently in the vehicle extraction means 16,
The recent mobile object search method of selecting the fire engine 1 close to the disaster site is a feature of this embodiment.

Hereinafter, the processing procedure in the recent vehicle extracting means 16 will be described in detail with reference to the drawings.

Recently, two data files, that is, an area division data file (hereinafter, simply referred to as area division data) and a basic network data file (hereinafter, simply referred to as basic network data) are previously created in the vehicle extraction means 16. It is stored.

The area division data represents the boundaries of the target area controlled by the central command center 2 divided into a plurality of areas. The division into regions is such that the road distance between any two points in the same region and the straight line distance have a relatively high correlation depending on the topography of the target area or the characteristics of the road network, and
It is performed so that each area becomes a polygon (in other words, a boundary has a straight line).

FIG. 3 is an explanatory diagram of area division. Figure 3
FIG. 3A is an image diagram showing an example of the target area, and FIG.
(B) is a figure which shows an example of area division.

As shown in FIG. 3 (a), it is assumed that the target area under the control of the central command center 2 is inside the rectangular ABCD, and the target area ABCD is divided into three river areas. 21 is flowing. On the river 21,
Four bridges V1, V2, V3 and V4 are laid, and the fire engine 1 has to use one of these bridges to cross the river 21. It is assumed that the road network is relatively well-developed in other parts of the area, and there is a relatively high correlation between the road distance and the straight line distance between any two points that do not cross the river.

In the example shown here, in order to simplify the explanation and facilitate understanding, it is assumed that the shape of the target area is rectangular and the obstacles that divide the road network are only rivers, but the present invention is not limited to this.

FIG. 3B is an image diagram in which the region shown in FIG. 3A is divided into regions. In this example, target area A
BCD, polygon ABIH, AHGFED, CDEGH
It was divided into three areas I. As described above, since the division is performed so that the road distance between any two points in the same area and the straight line distance have a high correlation, the boundary line in this example is located above the river 21.

The basic network represents a virtual road network obtained by simplifying the road network in the target area. In other words, the road network is virtually represented by a network composed of a set of nodes and links. The nodes of the basic network (hereinafter referred to as boundary nodes) are arranged at the intersections of the boundaries of the areas and the roads through which the fire engine 1 can pass, and the links of the basic networks are the boundaries of the basic networks included in one area. It is the concatenation of every pair of nodes.

A constant called a link evaluation value is assigned to each link. The link evaluation value is a value corresponding to the time required for the fire engine to pass through the link, and in this embodiment, it is calculated and stored as the product of the length of the link and the area resistance set for each area. . The area resistance is a constant set for each area according to the characteristics of the road network, and is a value proportional to the time required to pass a unit distance in the area.
For example, in a mountainous area where undulations are severe or in an area where congestion frequently occurs, the value is set to be larger than that in an area where the road network is developed and the flow of traffic is smooth.

FIG. 4 is a diagram for explaining the basic network, which is an example of the basic network created based on the area division shown in FIG. In FIG. 4, {V1, V2, V
3, V4} is a boundary node, {a12, a13, a14, a23,
a24, a34} are links. In this example, the four bridges V1, V2, V3, V4 are boundary nodes {V1, V2, V
3, V4}.

Next, the processing procedure in the recent vehicle extraction means 16 will be described. FIG. 1 is a flowchart showing a processing procedure in the recent vehicle extracting means 16.

The processing in the vehicle extracting means 16 is repeatedly executed when no disaster has occurred.
It is divided into a normal process shown in (a) and an emergency process shown in FIG. 1 (b) which is started by interruption when a disaster occurs.

The normal process is a process for updating the vehicle network. The vehicle network is a network in which a link connecting the vehicle node indicating the position of the fire engine and the boundary nodes of all the basic networks on the boundary of the area including this vehicle node is added to the basic network.

First, the procedure of the normal vehicle extracting means 16 in normal times will be described.

In the vehicle extracting means 16, recently, from the vehicle position managing means 15, the fire engine 1 which is newly enabled to be dispatched, the fire engine 1 which is newly enabled to be dispatched, or the position which is capable of being dispatched and has moved. It receives any position information and identifier of the fire engine 1 (step 41).

When the received information is the information of the fire engine 1 which is newly disabled, or the fire engine 1 which can be dispatched and has moved its position, the vehicle node corresponding to the fire engine 1 of the vehicle network, Also, all links connected to this vehicle node are deleted (steps 42 and 43). For the fire engine 1 that can be dispatched and whose position has moved, a vehicle node and a corresponding link are immediately formed, as will be described later, even if this deletion is performed.

If the received information is for a fire engine that cannot be dispatched, the process returns to step 41 and the next information is received (step 44).

Next, based on the position information of the fire engine which can be dispatched, it is determined which area the fire engine belongs to by using the area division data (step 45). The fire engine that can be dispatched is the fire engine 1 that has been newly dispatched, and the fire engine 1 that has been dispatched and has moved its position. For determining the belonging area, a method that is widely known as a solution of a point position determination problem, such as a slab method or a bucket method, and that can be easily realized is applied.

Then, a new node is added to the vehicle network as a vehicle node indicating the fire engine 1 (step 46).

Next, a new link that connects the vehicle node newly added in step 46 and the boundary nodes of all the basic networks on the boundary of the area including the vehicle node is connected (step 47).

Then, the link length of the newly connected link is calculated (step 48). For example, the coordinates (xk,
vehicle node located at yk) and coordinates (xi, yi)
The link length daki of the link aki that connects the boundary nodes of the basic network arranged in 1 is calculated according to the following equation (1).

The calculation is performed as follows: daki = √ {(xk-xi) ² + (yk-yi) ² } (1)

Next, the link evaluation value of the newly connected link is calculated (step 49). The link evaluation value is calculated as the product of the calculated link length and the area resistance pre-assigned for each area. The area resistance used here is
Use the same value that was used when the basic network was created.

The normal process in the recent vehicle extracting means 16 as described above is repeatedly executed each time the information on the fire engine 1 whose dynamic state or position has changed is received from the vehicle position managing means 15.

FIG. 5 is a diagram for explaining a vehicle network, FIG. 5 (a) is a diagram showing an example of a vehicle network in normal times, and FIG. 5 (b) is a disaster node added in an emergency. It is a figure which shows an example of a vehicle network.

At a certain time, three fire engines
It is assumed that the vehicle can be dispatched to the positions S1, S2, S3 shown in FIG. At this time, the vehicle network
As shown in FIG. 5A, vehicle nodes {S1, S2, S3} and links {s shown by broken lines are added to the basic network.
11, s14, s21, s22, s23, s31, s32, s33} are added.

Next, an emergency processing procedure in the recent vehicle extracting means 16 will be described with reference to FIG.

The emergency processing is started by interruption when the coordinates of the disaster site and the required number of vehicles are input from the disaster point specifying means 18 and the required number of vehicles determining means 19, respectively.

First, when the coordinates of the disaster scene are input from the disaster spot specifying means 18 in the recent vehicle extracting means 16, it is determined which area the disaster scene belongs to by using the area division data (step 50). ). Like the affiliation area determination of the fire engine 1, the affiliation area determination at the disaster site uses an easily feasible method that is widely known as a solution method for the point position determination problem such as the slab method and the bucket method. Will be performed.

Then, a new node is added to the vehicle network as a disaster site node (step 51).

Next, the newly added disaster site node,
A new link for connecting all the boundary nodes of the basic network on the boundary of the area including the disaster site node and all the vehicle nodes included in the same area as the disaster site node is connected (step 52). .

Then, the link length of the newly connected link is calculated (step 53). The link length calculation method is
It is similar to the method in normal processing. Next, the link evaluation value of the newly connected link is calculated (step 5).
4). The link evaluation value in this case is calculated as a product of the calculated link length and the area resistance pre-assigned for each area, as in the normal processing method.

Then, the required number of vehicles closest to the disaster site is selected using the vehicle network including the disaster site node updated by the above procedure (step 55). The vehicle is selected by searching for the shortest route having the smallest sum of the link evaluation values with the disaster site node as the starting point and one of the vehicle nodes as the reaching point. The shortest path search method is, for example, the Dijkstra method or Moore's algorithm, which is a commonly used and easy-to-implement shortest path search algorithm. The shortest route search starts from the disaster site node and continues until the shortest route of the required number of vehicle nodes is determined, and the required number of fire engines 1 corresponding to the vehicle node with the determined shortest route is selected.

When the shortest route to the required number of vehicle nodes has been established and the search has been completed, the vehicle extraction means 16 provides the communication means 14 with the identifier of the fire engine 1 corresponding to the vehicle node of which the shortest path has been established. After outputting and finishing the process, FIG.
The process returns to the normal process shown in (step 56).

FIG. 5B is a diagram showing an example of a vehicle network to which a disaster site node is added in case of emergency. It is assumed that the fire engine is in a state as shown in the example of FIG. 5A at a certain time, and at that time, the fire engine is notified that a disaster has occurred at the position O. At this time, a disaster site node O and a link {s01, a01, a04} shown by a one-dot chain line are newly added to the vehicle network as shown in FIG. In the case of this example, at least the fire engine related to the vehicle node S1 is selected. Further, in the case of this example, for the vehicle node S2, the sum of the link evaluation values of the links a01 and s21 becomes the evaluation value in the shortest route search, and the vehicle node S3
For, the sum of the link evaluation values of the links a01 and s22 will be the evaluation value in the shortest path search.

According to the above-described embodiment, the target area is divided into a plurality of areas in which the correlation between the road distance and the straight line distance is relatively high.
As a method of comparing the distances between points, two points in the same area are processed by straight lines, and two points in different areas are compared by a polygonal line that crosses a defined position on the boundary. If there are rivers, railways, bays, lakes, etc. that are difficult to do and the area is divided, if there are rugged mountain areas and urban areas with developed road networks in the target area, or Even when the road network is not well developed, a large error caused by approximating the road distance with a straight line does not occur, and a recent fire engine can be extracted at a disaster site at high speed.

Further, compared with the second conventional method, it can be realized by a car location system with relatively low accuracy, and it is not necessary to prepare a digital map or the like for all road networks. Is simple and easy to implement.

In the above embodiments, the recent moving object search method according to the present invention is applied to an emergency vehicle formation system for fire engines, but the application of the present invention is not limited to this, and a police vehicle. The present invention can also be applied to a system for other emergency vehicles such as a car and an ambulance, and further, for example, the present invention can be applied to a car dispatch system for a taxi or a courier truck.

In the above embodiment, the value of the area resistance is set to a predetermined constant, but it dynamically changes according to the degree of congestion of the road network for each area and the moving environment such as weather and time zone. You may let me.

Although the link evaluation value of the basic network is the product of the link length and the area resistance, it may be the link length itself.

Further, the link evaluation value of the basic network is the product of the link length and the area resistance, but it may be evaluated and set individually for each link in advance and used. For example, each area may be subdivided into rectangular sections of a predetermined size, and the moving average time for each section may be set as the link evaluation value. When the link evaluation value is determined for each link in this way, different link evaluation values may be assigned in both directions of one link. Even when the link evaluation value is determined for each link in this way, it may be dynamically changed according to the degree of congestion of the road network and the moving environment such as weather.

Furthermore, the link evaluation value based on the travel time previously investigated is used for the link connecting the boundary nodes, and the product of the link length and the area resistance is used for the other links. good.

The boundary node of the basic network is arranged at the intersection of the boundary line of the area and the road through which the fire engine can pass. If there are a plurality of roads crossing the boundary line of the area in close proximity, the boundary node You may set one boundary node to do.

Further, although the shape of the area in the area division is a polygon, the shape is not limited to the polygon, and an appropriate shape capable of searching the belonging area from the position of the moving body may be used.

[0073]

As described above, according to the present invention, the target area is divided into a plurality of areas in which the correlation between the road distance and the straight line distance is relatively high, and at least the mobile node and the location indicating the position of the mobile object. A network from a predetermined point node indicating the position of a given point, a boundary node indicating a position where a moving object on the boundary line of the area can pass, and a link connecting these nodes with a straight line in the same area including the boundary line In this network, a mobile node having the smallest sum of the link length information of the shortest route on the network route from the predetermined point node is searched for, and the mobile unit corresponding to this mobile node is selected. Therefore, even if the area is divided, areas with different degrees of development of the road network are mixed, and the road network in the area is not well developed, the road distance can be reduced. A large error does not occur by approximating with a line, high-speed moving object extraction can be performed at a high speed, and it can be realized with a relatively low-precision car location system. There is no need to create maps, etc., and the configuration is simple and easy to implement.

[Brief description of drawings]

FIG. 1 is a flowchart showing a procedure of a recent vehicle extraction process according to an embodiment.

FIG. 2 is a block diagram showing an emergency vehicle formation system according to an embodiment.

FIG. 3 is an explanatory diagram showing an example of area division according to the embodiment.

FIG. 4 is an explanatory diagram showing an example of a basic network according to the embodiment.

FIG. 5 is an explanatory diagram showing an example of a vehicle network of the embodiment.

[Explanation of symbols]

15 ... Vehicle position management means, 16 ... Recent vehicle extraction means, 1
7 ... 119 number notification receiving means, 18 ... disaster point identifying means,
19: Required number determining means.

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Claims (7)

[Claims] 1. A predetermined number of moving bodies closest to a given point at an arbitrary position in the area are extracted from a plurality of moving bodies moving on a road network in the restricted area. In the moving body search method, the area is divided into a plurality of areas in which the correlation between the road distance and the straight line distance is relatively high, and at least a moving body node indicating the position of the moving body and a predetermined point indicating the position of a given point. A network is composed of a node, a boundary node indicating a position where a moving body on the boundary line of the area can pass, and a link connecting these nodes with a straight line in the same area including the boundary line. A recent movement characterized by searching for a mobile node having the smallest sum of link length information of the shortest route on the network route from the fixed point node and selecting the mobile node corresponding to this mobile node Search method. 2. The method for searching for a recent mobile body according to claim 1, wherein the link length information is a link length. 3. The link length information includes the link length and
The latest mobile object search method according to claim 1, wherein the latest mobile object search method is a product of a constant value and a constant value assigned in advance to the area where the link is located. 4. A constant value pre-assigned to each area is
4. The recent mobile object search method according to claim 3, wherein the method is dynamically changed according to a mobile environment. 5. The link length information is a link evaluation value that is a fixed value that is assigned to each link in advance corresponding to the time required for a mobile unit to pass through the link. The latest mobile object search method described in 1. 6. A link evaluation value for each link,
The recent mobile object search method according to claim 5, wherein an individual value is assigned to each direction for both directions of each link. 7. The recent mobile object search method according to claim 5, wherein the link evaluation value assigned to each link is dynamically changed according to the moving environment.