JP2014149233A - Route search device and route guidance system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for searching for a similar route in addition to the optimal route from the current position to a destination in a route search device and route guidance system.SOLUTION: The route search device searches for the optimal route from the current position to a destination and a similar route as a cumulative value of link costs lower than a value obtained by adding an allowance cost to a cumulative value of link costs in the optimal route, of a plurality of routes from the current position to the destination. Then, the route search device presents the similar route as a route equivalent to the optimal route to a user of a route guidance device.

Description

  The present invention relates to a route search device and a route guidance system.

  In recent years, car navigation systems, mobile phones, portable game machines, PNDs (Personal Navigation Devices) and PDAs (Personal Digital Assistants) installed in automobiles are known as route search devices that search for routes from the current position to the destination. It has been. Some route search apparatuses present a plurality of routes to the user as routes from the current position to the destination.

  For example, in Patent Document 1, in addition to searching for an optimal route that arrives from the current position to the destination in the shortest time, an allowable amount is set based on the time and distance that can be allowed by the user before arrival. A technique for searching for a route with a good landscape different from the optimum route within the range of the cumulative value of the link cost obtained by adding an allowable amount to the cumulative value of the link cost of the route is disclosed. Further, in Patent Document 2, when a car is traveling on a searched route, when a vehicle approaches a branch point such as an intersection in the middle of a preset route, a new sub route from the branch point to the destination is newly searched. Thus, a technique presented to the user is disclosed. Further, Patent Document 3 discloses a technique for searching for a facility such as a gas station that a user wants to use by using the vicinity of a characteristic point such as a current position or a destination as a search area.

JP 2003-185453 A JP 2001-304890 A JP 2000-234937 A

  However, in the above conventional technique, a sub route is newly searched for in addition to the optimal route under a specific condition and presented to the user. However, the sub route searched under the specific condition is significantly different from the optimal route. In some cases, it is not appropriate to be presented to the user in parallel with the optimal route. Also, for users with a high degree of freedom to change the direction of travel, such as pedestrians and bicycles, such as U-turns or crossing the road when they are passing the route, in parallel with the optimal route In some cases, it is not appropriate to present the searched sub-route, and there is a problem in that it is desired to present a plurality of routes similar to the optimum route to improve the convenience for the user. In addition, if another route is searched again after approaching a specific branch point on the moving route, there is a problem that the processing load of the route search device becomes heavy. In addition, if the route is re-searched for each branch point and the user selects a newly presented sub route, the difference between the optimum route and the selection of the sub route will increase. was there.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

(1) According to one form of this invention, the route search apparatus which searches the path | route from the 1st point which is the arbitrary points on a network to the 2nd point is provided. The route search device includes a route information storage unit that stores data for specifying nodes and links constituting a route and data for specifying a link cost when passing through each link; the first point and the second point A point setting unit that sets the minimum cost at which the cumulative value of the link cost of each link is the minimum among a plurality of routes connecting the first point to the specific node for each of the plurality of specific nodes. An optimal route search unit that searches for a route and other non-minimum cost routes and sets the minimum cost route as an optimal route when the specific node is the second point; an allowable cost for setting an allowable cost A setting unit; for each of the plurality of specific nodes, the minimum cost path and the non-minimum cost path, and the minimum cost path and the non-minimum cost A path storage unit for each node that stores a cumulative value of link costs of each path; a plurality of the specific nodes included in the optimal path are sequentially selected as optimal nodes, and the minimum cost path in the optimal node and the The non-minimum cost route having a difference in cumulative value of link costs with the non-minimum cost route being equal to or less than the allowable cost is selected, and the selected non-minimum cost route and the route from the optimum node to the second point A similar route search unit that sets a similar route that is a combination of the same route as the optimal route; and the optimal route search unit is configured such that a cumulative value of link costs of the minimum cost route and the non-minimum cost route is A search is made up to a value obtained by adding the allowable cost to the link cost accumulated value of the optimum route. According to the route search device of this aspect, a similar route that is a cumulative value of the link cost that is almost equivalent to the optimum route can be presented to the user, so that the degree of freedom of route selection by the user is increased and convenience is improved. Further, since a new route different from the optimum route is not searched for each node, the processing load of the route search device can be reduced.

(2) In the route search device of the above aspect, the similar route search unit sequentially selects the specific nodes that are not included in the optimal route and included in the similar route as sub-optimal nodes. The difference in the cumulative value of the link cost between the minimum cost route and the non-minimum cost route is obtained by subtracting the difference in the cumulative value of the link cost between the optimum route and the similar route including the suboptimal node from the allowable cost. The non-minimum cost route that is the following is selected, and the selected non-minimum cost route and a semi-similar route in which the route from the semi-optimum node to the second point is the same as the similar route is combined. And after setting the semi-similar route as the similar route, the minimum cost path in the semi-optimal node included in the set similar route is set. The difference in the cumulative value of the link cost between the non-minimum cost route and the non-minimum cost route is equal to or less than the value obtained by subtracting the difference in the cumulative cost of the link cost between the optimal route and the similar route including the semi-optimal node from the allowable cost. You may search until there is no non-minimum cost route. According to the route search device of this aspect, since the route of the total value of the link cost that is equal to or less than the allowable cost is set as the similar route, the degree of freedom of route selection by the user is further increased and the convenience is further improved.

(3) According to another aspect of the present invention, there is provided a route guidance system that searches for a route from a first point to a second point, which is an arbitrary point on the network. The route guidance system includes a route information storage unit that stores data for specifying nodes and links constituting a route, and data for specifying a link cost when passing through each link; the first point and the second point A point setting unit that sets the minimum cost at which the cumulative value of the link cost of each link is the minimum among a plurality of routes connecting the first point to the specific node for each of the plurality of specific nodes. An optimal route search unit that searches for a route and other non-minimum cost routes and sets the minimum cost route as an optimal route when the specific node is the second point; an allowable cost for setting an allowable cost A setting unit; for each of the plurality of specific nodes, the minimum cost path and the non-minimum cost path; the minimum cost path and the non-minimum cost; A node-specific route storage unit that stores a cumulative value of link costs of each of the route routes; a plurality of the specific nodes included in the optimum route are sequentially selected as the optimum nodes, and the minimum cost route in the optimum node; The non-minimum cost route having a difference in cumulative value of link costs with the non-minimum cost route being equal to or less than the allowable cost is selected, and the selected non-minimum cost route and the optimum node to the second point are selected. A similar route search unit that sets a similar route in which the route is the same as the optimal route; a route display unit that displays the optimal route and the similar route; and a current position of the route display unit A current position acquisition unit; and the optimum route search unit includes a link cost of the optimum route in which a cumulative value of link costs of the minimum cost route and the non-minimum cost route is I searched until the value obtained by adding the allowable cost preparative cumulative value; the path display unit displays the current position. According to this route guidance system, the user of the route guidance system can easily recognize the optimum route and the similar route, and the current position of the route display unit is also displayed, so that convenience is improved.

(4) In the route guidance system according to the above aspect, the route display is further displayed on the route display unit by changing the display of the similar route based on the difference in the accumulated value of link costs between the optimum route and the similar route. A change unit may be provided. According to this route guidance system, the user of the device equipped with the route display unit calculates the cumulative value of the link cost in the route from the current position to the second point and the link cost in the optimum route from the first point to the second point. The difference from the cumulative value can be recognized easily and in real time, and convenience is improved.

(5) In the route guidance system of the above aspect, the optimum route search unit is adjacent to the specific link connecting one node and the node adjacent to the one node, starting from the one node. When returning to the one node before entering the node, a value obtained by multiplying the link cost of the specific link by a predetermined ratio may be added to the cumulative value of the link cost. According to this route guidance system, when the user of the device equipped with the route display unit has a high degree of freedom in changing the traveling direction, such as a pedestrian or a bicycle, the difference in the cumulative value of the link cost corresponding to the direction change is By calculating in real time, it is possible to make the user recognize the difference in the cumulative value of the link cost for each route and the updated similar route in real time, thereby further improving convenience.

  Note that the present invention can be realized in various modes, such as an information processing device and method, an information terminal device, an information transmission device and method, a mobile terminal device, an information processing server, a route search server, and the like. The present invention can be realized in the form of a computer program for realizing the apparatus, method, and system. Further, these computer programs may be recorded on a computer-readable recording medium (for example, a flexible disk, a CD-ROM, a DVD-ROM, a magneto-optical disk, a memory card, a hard disk, etc.).

It is explanatory drawing which shows schematic structure of the route search system 10 in 1st Embodiment of this invention. It is explanatory drawing which shows the flow of the process which searches for the optimal path | route from search position ST to the destination GL. It is explanatory drawing which shows an example of the node and link in the path | route from search position ST to the destination GL. It is explanatory drawing which shows the outline of the cost total value calculation of each path | route in each node. It is explanatory drawing which shows the outline of the cost total value calculation of each path | route in each node. It is explanatory drawing which shows the flow of the process which searches for a similar path | route from an optimal path | route. It is explanatory drawing which shows the outline of the similar path | route searched in each optimal node. It is explanatory drawing which shows the outline of the searched semi-similar path | route in each suboptimal node. It is explanatory drawing which shows the flow of a process which updates the route information of an optimal path | route and a similar path | route, and changes a display. It is explanatory drawing which shows the outline of the optimal path | route displayed on the display panel 202, and a similar path | route. It is explanatory drawing which shows an example of the relationship between the display of the present position of the mobile telephone 200, an optimal path | route, and a similar path | route. It is explanatory drawing which shows an example of the relationship between the display of the present position of the mobile telephone 200, an optimal path | route, and a similar path | route. It is explanatory drawing which shows an example of the relationship between the display of the present position of the mobile telephone 200, an optimal path | route, and a similar path | route. It is explanatory drawing which shows an example of the route information in 2nd Embodiment. It is explanatory drawing which shows the optimal path | route from the search position ST in the 2nd Embodiment to the destination GL, and a similar path | route. It is explanatory drawing which shows the present location and movement path | route of the user of the mobile telephone 200. FIG. It is explanatory drawing which shows the present location and movement path | route of the user of the mobile telephone 200. FIG.

Next, embodiments of the present invention will be described in the following order.
A. First embodiment:
A-1. Information processing system configuration:
A-2. Optimal route search processing:
A-3. Similar route search processing:
A-4. Route information display change processing:
B. Second embodiment:
C. Variations:

A. First embodiment:
A-1. Information processing system configuration:
FIG. 1 is an explanatory diagram showing a schematic configuration of a route search system 10 according to the first embodiment of the present invention. The route search system 10 of the present embodiment includes a server 100 and a mobile phone 200 as a mobile terminal device. Although only one mobile phone 200 is shown in FIG. 1, the route search system 10 includes various mobile phones 200 and mobile game machines, PND (Personal Navigation Device), PDA (Personal Digital Assistant), and the like. A mobile terminal device may be included.

  The mobile phone 200 includes a GPS receiver 201, a display panel 202, an audio output unit 203, a wireless communication circuit 205, an operation unit 206, a main control unit 210, and a call control unit 220.

  The GPS receiver 201 receives position information for specifying the current position (latitude, longitude) of the mobile phone 200 measured using an artificial satellite constituting a GPS (Global Positioning System) by radio waves. The GPS unit 201 corresponds to the current position acquisition unit in the present invention.

  The display panel 202 includes a liquid crystal display and a drive circuit that drives the liquid crystal display. The display panel 202 is not limited to a liquid crystal display, and various display devices such as an organic EL display can be used. The audio output unit 203 includes a speaker for outputting audio, a drive circuit for driving the speaker, and the like. The wireless communication circuit 205 wirelessly performs data communication or voice communication with the base station BS. The operation unit 206 is an input device that includes a numeric keypad 206a, a cursor key 206b, a touch panel, and the like. The operation unit 206 accepts a destination setting input by the user. The call control unit 220 is a circuit that performs incoming calls and calls for voice calls, conversion of voice signals and electrical signals, and the like.

  The main control unit 210 controls each unit of the mobile phone 200. The main control unit 210 includes a CPU 211, a RAM 212, and a ROM 213. The CPU 211 implements a function for executing various processes described later by loading a program stored in the ROM 213 into the RAM 212 and executing the program. For example, the main control unit 210 controls the display panel 202 to display a map image, a recommended route, a current position, and the like. The main control unit 210 controls the wireless communication circuit 205 to store information on the Internet INT via the base station BS (more specifically, via a transmission / reception antenna, a base station BS, and an exchange). Communicates with unit 110 and route search unit 120. In addition, the main control unit 210 receives position information of the mobile phone 200 measured using GPS via the GPS receiver 201 at regular time intervals, and generates position information.

  The server 100 includes a communication unit 102 that communicates with the mobile phone 200 via the Internet INT, an information storage unit 110, and a route search unit 120. The information storage unit 110 includes a control unit configured by a CPU, a RAM, and a ROM, and includes a storage device 118 that stores information. The storage device 118 is constituted by, for example, a hard disk device. In the storage device 118, a map information database (DB) 114 and a node-specific route information database (DB) 115 are constructed. The map information DB 114 stores, for example, link information, node information, and map image data as image data. When searching for a route from a search position to start a route search to be described later to a destination, the node-specific route information DB 115 links and nodes in the search route to a specific node that is a node arbitrarily selected from the search position. (Hereinafter also referred to as “route”) and a cumulative value of link costs in the route (hereinafter also referred to as “cost cumulative value”) are stored in association with a specific node as node-specific route information. . In the route information by node, for each node, the route having the smallest cost accumulated value from the search position ST is stored as the least cost route, and other routes are stored as non-minimum cost routes and the cost accumulated value is associated with the node. Is remembered. The server 100 corresponds to the route search device in the present invention, and the information storage unit 110 corresponds to the route information storage unit and the node-specific route storage unit in the present invention.

  The route search unit 120 includes a control unit configured by a CPU, a RAM, and a ROM, and includes an optimal route search unit 123 and a similar route search unit 124. When the destination is set in the mobile phone 200 and the location information is transmitted from the mobile phone 200, the route search unit 120 receives the location information and the destination information via the communication unit 102. The optimum route search unit 123 of the route search unit 120 calculates the link cost of each link based on the route information stored in the map information DB 114 and the received position information and destination information, and later to the destination. The optimum route to search is searched. The similar route search unit 124 of the route search unit 120 searches for a similar route described later based on the route information and the optimum route. The route search unit 120 transmits route information including the optimum route to the destination and the similar route to the mobile phone 200 via the communication unit 102. The route search unit 120 corresponds to the point setting unit in the present invention.

A-2. Optimal route search processing:
FIG. 2 is an explanatory diagram showing a flow of processing for searching for a route from the search position ST to the destination GL. As shown in FIG. 2, in the present embodiment, among the routes from the search position ST where the user has searched for a route to a specific node, the optimum route search unit 123 of the route search unit 120 uses the minimum cost route and the non-minimum route. A cost route is searched and a route from the search position ST to the destination GL is searched. The information storage unit 110 stores a minimum cost route and a non-minimum cost route.

  First, the route search unit 120 sets an allowable cost (step S300). In this embodiment, the allowable cost is set to 3 in advance. Details of the allowable cost will be described later. The route search unit 120 corresponds to the allowable cost setting unit in the present invention. Next, the user of the mobile phone 200 sets the destination GL by operating the operation unit 206 (step S301). When the destination GL is set in the mobile phone 200, the main control unit 210 of the mobile phone 200 receives the position information of the search position ST in the mobile phone 200 measured by the GPS unit 201 (step S302). The main control unit 210 transmits the position information of the destination GL and the search position ST to the server 100 via the Internet INT. The optimum route search unit 123 searches for the optimum route by the Dijkstra method based on the destination GL and the search position ST received via the Internet INT.

  FIG. 3 is an explanatory diagram showing an example of nodes and links in the route from the search position ST to the destination GL. FIG. 3 shows the buildings displayed with hatching, the names of the links and nodes, and the link costs for each link. For example, the node N41 and the node N31 are connected by a link L2, and the link cost of the link L2 is 10. Based on the route information shown in FIG. 3 stored in the map information DB 114, the optimum route search unit 123 calculates the minimum cost route and the non-minimum cost route in each node and the cost total value of each route (FIG. 2). Step S303).

  FIG. 4 and FIG. 5 are explanatory diagrams showing an outline of calculating the total cost value of each route in each node. First, as shown in FIG. 4A, the total cost value in each route is calculated with the search position ST as a starting point. At the beginning of the route search process, the cost total value at the search position ST, which is a node, is zero because no link has yet passed. At this time, since there is no accumulated cost value of the route entering the search position ST from the link connected to the search position ST, zero is the accumulated cost value of the minimum cost route at the search position ST (hereinafter referred to as “determined label”). Is also called). The node-specific route information DB 115 of the information storage unit 110 stores a minimum cost route and a confirmed label. In FIG. 4 and FIG. 5, the confirmation label is displayed surrounded by a square.

  Next, in the node N41 that has passed the link L1 from the search position ST, the accumulated cost value of the route that enters from the link L1 to the node N41 becomes 10, and the node as the minimum cost route candidate (hereinafter also referred to as “provisional label”). It is stored in another route information DB 115. In FIG. 4 and FIG. 5, the temporary label is displayed by enclosing the accumulated cost value in a pentagon having a vertex in the direction of entering the node. Similarly, in the node N31 that has passed the link L3 from the search position ST, the temporary label of the route that enters from the link L3 to the node N31 is 21, and is stored in the node-specific route information DB 115.

  Next, as shown in FIG. 4B, the temporary label of the node N41 having the minimum cost accumulated value 10 among all the temporary labels becomes the final label, and the cost accumulated value of each route starting from the node N41. Is calculated. After passing through the link L1 and entering the node N41, passing through the link L2 and entering the node N31, the temporary label of the route becomes 20 with the link cost of the link L2 added. Here, in the route from the search position ST to the node N31, the route passing through the link L3 is larger than the temporary label of the route passing through the link L1 and the link L2, so that the route information for each node as a non-minimum cost route. Stored in the DB 115. When stored as a non-minimum cost route, when searching for a route starting from the node N31, the route search that has passed through the non-minimum cost route is not performed, and the route search is performed based on the minimum cost route. In FIGS. 4 and 5, the accumulated cost value of the non-minimum cost route (hereinafter also referred to as “losing label”) is displayed with the accumulated cost value surrounded by a circle.

  Next, the temporary label of the route that passes through the link L1 and enters the node N41 and then returns to the search position ST through the link L1 is added to the link cost of the link L1 and becomes 20. Since the temporary label of the route is larger than zero of the confirmed label at the search position ST, it is stored in the route information DB 115 by node as a losing label.

  Next, as shown in FIG. 4C, the total cost value of each route is calculated starting from the node N31 having the temporary label with the minimum cost. In the node N31, a route search is performed on the basis of the route (the minimum cost route in the node N31) that has passed through the link L1 and the link L2. When the node N31 passes through the link L4 and enters the node N21, the temporary label of the route becomes 29 after adding the link cost of the link L4. Similarly, when the node N31 passes through the link L5 and enters the node N32, the temporary label of the route becomes 35 with the link cost of the link L5 added.

  When the node N31 passes the link L2 again and returns to the node N41, the temporary label of the route is 30 with the link cost of the link L2 added, and is larger than 10 of the confirmed label at the node N41. Remembered. In this case, in the node N41, since the cost total value of the route that enters the node N41 from all the links connected to the node N41 is stored, the optimum route search unit 123 thereafter selects the route that enters the node N41. Do not search. Similarly, when the node N31 passes through the link L3 and enters the search position ST, the temporary label of the route is 41 by adding the link cost of the link L5, and is larger than the confirmed label zero at the search position ST. , Stored as a losing label. Thereafter, the optimum route search unit 123 does not search for a route that enters the search position ST.

  Next, as shown in FIG. 4D, the total cost value of each route is calculated starting from the node N21. When the route search is performed using the node N21 as a starting point, the cost accumulated value of the route (the minimum cost route of the node N21) that has passed through the link L1, the link L2, and the link L4 is the smallest cost accumulated among all the temporary labels. Since it has a value, it is stored as a confirmed label. When the node N21 passes through the link L6 and enters the node N11, the temporary label of the route becomes 38 with the link cost of the link L6 added. Similarly, when the node N21 passes through the link L7 and enters the node N22, the temporary label of the route becomes 44 by adding the link cost of the link L7. When the node N21 passes through the link L4 again and returns to the node N31, the temporary label of the route becomes 38 with the link cost of the link L4 added, and since the confirmed label already exists in the node N31, Remembered. Further, the temporary label of the route that has passed from the node N31 through the link L5 to the node N32 has the minimum cost accumulated value among all the temporary labels, and is therefore stored as the next confirmed label.

  Next, as shown in FIG. 5A, a cost total value is calculated for each route starting from the node N32. When the node N32 passes through the link L8 and enters the node N22, the temporary label of the route is 45 as the link cost of the link L8 is added, and is larger than 44 of the temporary label in the node N21. Is done.

  When the node N32 passes through the link L9 and enters the node N33, the temporary label of the route becomes 44 by adding the link cost of the link L9. When the node N32 passes through the link L10 and enters the node N43, the temporary label of the route becomes 55 by adding the link cost of the link L10.

  When the node N32 passes through the link L5 again and returns to the node N31, the temporary label of the route becomes 50 by adding the link cost of the link L5. Since the node N31 already has a confirmed label, it is stored as a losing label. Here, since the total cost value of the route that enters the node N31 from all the links connected to the node N31 is stored, the optimum route search unit 123 does not search for the route that enters the node N31. Here, since the temporary label of the node N11 has the minimum cost accumulated value among all the temporary labels, it is stored as a confirmed label. Since the node N11 has a temporary label with the lowest cost accumulation value at this time, the cost accumulation value is calculated for each route as a starting point. When the node N11 passes through the link L11 and enters the node N13, the link cost of the link L11 is added and the accumulated cost value becomes 62. Further, when the node N11 passes through the link L6 and returns to the node N21, the temporary label of the route becomes 47 by adding the link cost of the link L6, and since the confirmed label already exists in the node N21, the losing label Is remembered as Here, the temporary label of the route that has entered the node N33 from the node N32 through the link L9 has the lowest cost among all the temporary labels, and is therefore stored as the next confirmed label. Similarly, the temporary label of the route that has entered the node N22 through the link L7 from the node N21 is also stored as a confirmed label.

  In FIG. 5B, as described above, the cost total value is calculated from all the links connected to each node, the minimum cost path and the non-minimum cost path stored in the node-specific path information DB 115, and the confirmation label. And a losing label. The optimum route search unit 123 extracts and determines the optimum route having the smallest accumulated cost value in the route from the search position ST to the destination GL in each route stored in the node-specific route information DB 115 (FIG. 2). Step S304). In FIG. 5B, the optimum route passes from the search position ST through link L1, node N41, link L2, node N31, link L4, node N21, link L6, node N11, link L11, node N13, and link L16. The route that entered the destination GL is indicated by an arrow. In addition, in the node N23 shown in FIG. 5B, a route with a confirmed label of 54 and a losing label with the same cumulative cost value as the confirmed label of 54 are displayed. Even if the routes are different, if the accumulated cost value is the same, the optimum route search unit 123 arbitrarily sets one as a confirmed label. In the present embodiment, the accumulated cost value of the route entering the node N23 from the link L12 previously searched in the node N23 is set as the confirmed label.

  When the optimal route is determined, the route search unit 120 continues to calculate the total cost that is less than the cost of the optimal route plus the set allowable cost for the route from the search position ST to the destination GL. A temporary label of the value is calculated (step S305 in FIG. 2). In the present embodiment, since a temporary label that is equal to or higher than the cost total value of the optimum route and the allowable cost is not calculated, there is no need to search for an infinite route from the search position ST to the destination GL, and the route can be efficiently routed. Search can be performed.

  Next, the similar route search unit 124 of the route search unit 120 calculates a similar route from the search position ST to the destination GL based on the obtained optimal route and the minimum cost route and the non-minimum cost route at each node. Search is performed (step S306). The details of the similar route search process will be described later.

A-3. Similar route search processing:
FIG. 6 is an explanatory diagram showing a flow of processing for searching for a similar route from the optimum route. In the similar route search process shown in FIG. 6, first, the similar route search unit 124 sequentially determines the difference between the determined label and the losing label (hereinafter, “cost per route” in each optimal node that is a node included in the optimal route. It is determined whether there is a non-minimum cost route whose difference is also referred to as an allowable cost or less (step S322). When it is determined that there is no optimal node having a non-minimum cost route whose cost difference by route is equal to or less than the allowable cost (step S322: NO), the similar route search unit 124 determines that there is no similar route, and determines the similar route. The search process is terminated. When it is determined that there is a non-minimum cost route whose cost difference by route is equal to or less than the allowable cost in a certain optimum node (step S322: YES), the similar route search unit 124 searches for a similar route in the optimum node.

  FIG. 7 is an explanatory diagram showing an outline of a similar route searched for in each optimum node. FIG. 7A shows the searched optimum route and similar route, and the finalized label and the losing label in each optimum node. FIG. 7B shows the definite label, the losing label, and the path-specific cost difference at each optimum node. FIG. 7C shows an outline of the cost difference for each route when each optimum node and a similar route are selected in correspondence with FIG. 7B.

  When the similar route search unit 124 searches for a non-minimum cost route having a route-specific cost difference of 3 or less, as shown in FIGS. 7A and 7B, among the optimal nodes, the node N13 and the node N31 Then, a non-minimum cost route having a path-specific cost difference of 3 or less is extracted. The non-minimum cost route having a path-specific cost difference of 2 at the node N13 passes through the same route as the optimum route from the search position ST to the node N21, and from the node N21 to the link L7, the node N22, the link L12, the node N23, the link The route passes through L13 and enters the node N13, and the route from the node N13 to the destination GL passes through the same route as the optimum route (hereinafter also referred to as “first similar route”).

  Further, a non-minimum cost route having a path-specific cost difference of 1 at the node N31 passes through the link L3 from the search position ST and enters the node N31. , Also called “second similar route”). The similar route search unit 124 determines the first similar route and the second similar route as similar routes (step S323 in FIG. 6).

  Next, the similar route search unit 124 calculates the difference between the accumulated cost values of the optimum route and the similar route from the allowable cost at each suboptimal node that is not included in the optimum route but is included only in the similar route. It is determined whether there is a non-minimum cost route that is equal to or less than the subtracted value (hereinafter also referred to as “difference allowable cost”) (step S324). When it is determined that there is no non-minimum cost route in which the cost difference for each route is equal to or less than the allowable difference cost in the sub-optimal node (step S324: NO), the similar route search unit 124 ends the similar route search process. When it is determined that there is a non-minimum cost route in which a cost difference for each route is equal to or less than the allowable difference cost in a certain suboptimal node (step S322: YES), the similar route search unit 124 uses a semisimilar route in the suboptimal node. Explore.

  FIG. 8 is an explanatory diagram showing an outline of a searched quasi-similar route in each sub-optimal node. FIG. 8A shows the searched optimum route, similar route, semi-similar route, and a definite label and a losing label in each sub-optimal node. FIG. 8B shows the definite label, the losing label, and the cost difference for each route in each suboptimal node, as in FIG. 7B. Further, FIG. 8B shows a value obtained by adding a cost difference for each route in the semi-optimum node included in the semi-similar route and a difference between the accumulated cost value of the similar route including the semi-similar route and the optimum route ( Hereinafter, it is also referred to as “route addition cost”). FIG. 8C shows an outline of the cost difference for each route and the route addition cost when each semi-optimal node and a quasi-similar route are selected, corresponding to FIG. 8B.

  As shown in FIGS. 8A and 8B, the similar route search unit 124 determines that the difference in cost per route is less than or equal to the allowable difference cost between the node N23 and the node N22 among the suboptimal nodes in the first similar route. Extract a non-minimum cost path. The non-minimum cost route having a path-specific cost difference of zero in the node N23 passes through the same route as the first similar route from the search position ST to the node N31, and from the node N31 to the link L5, the node N32, the link L9, and the node N33. , Passes through the link L14, enters the node N23, and passes from the node N23 through the same route as the first similar route (hereinafter also referred to as “first quasi-similar route”). Further, as shown in FIG. 8B, the first quasi-similar route has zero route-specific cost difference at the node N23 compared to the first similar route whose route-specific cost difference is 2. , A route whose accumulated cost value is 2 larger than the optimum route.

  The minimum cost path having a path-specific cost difference of 1 at the node N22 passes the same path as the first similar path from the search position ST to the node N31, and passes through the link L5, the node N32, and the link L8 from the node N31. The node N22 is a route that passes through the same route as the first similar route from the node N22 (hereinafter also referred to as “second quasi-similar route”). Further, as shown in FIG. 8B, the second quasi-similar route has a route-specific cost difference of 1 at the node N22 compared to the first similar route whose route-specific cost difference is 2. , A route whose accumulated cost value is 3 larger than the optimum route. The similar route search unit 124 determines the first quasi-similar route and the second quasi-similar route as quasi-similar routes (step S325 in FIG. 6).

  Next, the similar route search unit 124 sets the quasi-similar route as a similar route (step S326), and if the quasi-optimal node in the newly set similar route does not include the quasi-similar route in the process of step S324 described above. Repeat until judged. When it is determined that there is no semi-optimal node having a non-minimum cost route whose cost difference by route is equal to or less than the difference allowable cost (step S324: NO), the similar route search unit 124 determines that there is no semi-similar route. Then, the similar route search process is terminated.

A-4. Route information display change processing:
FIG. 9 is an explanatory diagram showing the flow of processing for changing the display by updating the route information of the optimum route and the similar route. FIG. 9 shows a processing flow in which the display of the optimum route and the similar route and the display of the current position of the user are changed according to the movement of the user carrying the mobile phone 200. First, the route search unit 120 transmits the route information including the optimum route and the similar route together with the map information stored in the map information DB 114 to the mobile phone 200 via the Internet INT. The main control unit 210 of the mobile phone 200 displays the received route information and map information and the current position of the mobile phone 200 measured by the GPS unit 201 on the display panel 202 (step S341). The display panel 202 corresponds to the route display unit in the present invention.

  FIG. 10 is an explanatory diagram showing an outline of the optimum route and the similar route displayed on the display panel 202. As shown in FIG. 10, on the display panel 202, the current position of the mobile phone 200 is displayed at the position of the search position ST in a circled display (hereinafter also referred to as “position icon”). ing. The route search unit 120 displays the optimum route and the similar route with arrows that distinguish between thickness and color shading. The optimum route is indicated by the thickest and lightest arrow. Similar routes are displayed with thicker and lighter arrows as the route addition cost for the optimum route is smaller. In FIG. 10, the shade of the color is represented by the hatching in the arrow, and the shade is darker as the hatching is finer. The link L1, the link L2, the link L4, the link L6, the link L11, and the link L16 that constitute the optimum route are represented by an arrow M0. A link L3 that constitutes the second similar route having the smallest route addition cost of 1 and does not constitute the optimum route is represented by an arrow M1. The link L7, the link L12, and the link L13 that constitute the first similar route having the route addition cost of 2 and do not constitute the optimum route are represented by an arrow M2. Similarly, the link L5, the link L9, and the link L14 that constitute the first quasi-similar route having the route addition cost of 2 and that do not constitute the first similar route are represented by an arrow M2. A link L8 that constitutes the second quasi-similar route with a path-specific cost difference of 3 and does not constitute the first similar route and the first quasi-similar route is represented by an arrow M3. The route search unit 120 corresponds to the route display change unit in the present invention. Next, when the user carrying the mobile phone 200 moves and the current position of the mobile phone 200 changes, the display panel 202 updates the information on the current position of the mobile phone 200 and changes the display (FIG. 9 step S342).

  FIG. 11 is an explanatory diagram showing an example of the relationship between the display of the current position of the mobile phone 200 and the optimum route and similar route. As shown in FIG. 11, the mobile phone 200 is passing through a link L3 that constitutes the second similar route. In this case, the position icon of the mobile phone 200 is displayed in the same color as the link L3. Further, there is no route to the destination GL in which the route addition cost is equal to or lower than the allowable cost among the routes through which the mobile phone 200 passes through the link L3 and passes through the link L1 and the link L2. Therefore, the route search unit 120 does not display the arrow M0 displayed on the link L1 and the link L2. In this embodiment, the user carrying the mobile phone 200 can be made to recognize the route addition cost of the link through which the user passes, and the route whose cost exceeds the allowable cost in real time. Convenience is improved because no guidance is provided.

  Next, the route search unit 120 determines whether or not the current position of the mobile phone 200 has reached the node through the link (step S343 in FIG. 9). When it is determined that the mobile phone 200 is positioned on the link without arriving at the node (step S343: NO), the route search unit 120 continues to reflect the current position of the mobile phone 200 on the position icon and display panel 202. (Step S342). When it is determined that the mobile phone 200 has arrived at the node (step S343: YES), the route search unit 120 determines whether the arrived node is the destination GL (step S344). When the mobile phone 200 arrives at the node that is the destination GL, the route search unit 120 ends the route guidance.

  When the mobile phone 200 passes through the link L3 and arrives at the node N31 (step S344: NO), the route search unit 120 determines whether or not the link passed before arriving at the node N31 is the minimum cost route at the node N31. Make a decision. Specifically, the route search unit 120 determines whether the route is a minimum cost route or not, based on the value of the route addition cost when the location icon arrives at the node in the link starting from the node at which the location icon arrives. This can be determined by whether there is a link with a small route addition cost. That is, if there is only a link having a route addition cost equal to or higher than the route addition cost when the position icon arrives at the node, the route search unit 120 determines that the passed link is the minimum cost route, and the position icon If there is a link smaller than the route addition cost, it can be determined that the route is not the minimum cost route. When it is determined that the link L3 is the minimum cost route among the routes from the search position ST to the node N31 (step S345: YES), the route search unit 120 continues to update the mobile phone without updating the route information. The current position of 200 is reflected on the position icon and displayed on the display panel 202 (step S342). In the present embodiment, since the link L3 passed before arriving at the node N31 is a non-minimum cost route (step S345: NO), the route search unit 120 determines the route addition cost of the similar route passing through the passed link L3. Is updated to the route information added, and displayed on the display panel 202 (step S346).

  FIG. 12 is an explanatory diagram showing an example of the relationship between the display of the current position of the mobile phone 200 and the optimum route and similar route. As shown in FIG. 12, the mobile phone 200 has arrived at the node N31 via the link L3 from the search position ST. In this case, the mobile phone 200 passes through the link L3 that constitutes the non-minimum cost path instead of the minimum cost path at the node N31. Therefore, the total cost value of the route from the node N31 to the destination GL is larger by 1 as the route addition cost than the optimum route. At the time of passing through the link L3 and arriving at the node N31, there is no route having the same total cost value as the optimum route among the routes from the node N31 to the destination GL. The route search unit 120 updates and displays the route information by adding the route addition cost to the route information to the destination GL.

  When the route information is updated, the route addition cost 1 is added to the link L4, link L6, link L11, and link L16 displayed as the optimum route until the mobile phone 200 arrives at the node N31, and the arrow M0 is added. Is changed to an arrow M1. Similarly, the link L5, the link L7, the link L9, the link L12, the link L13, and the link L14 that have been displayed as the similar routes having the path-specific cost difference are changed from the arrow M2 to the arrow M3. The link L8 that has been displayed as a similar route with a path-specific cost difference of 3 is displayed as a similar route because the cost difference by route exceeds the allowable cost when the user of the mobile phone 200 that has passed the link L3 passes. It will not be done. Further, regarding the link L1, the link L2, and the link L3, when the position icon arrives at the node N31, it becomes impossible to pass in the direction of the arrow, so that it is not displayed as a similar route. For this reason, in the present embodiment, the user of the mobile phone 200 can easily and in real time determine the difference between the accumulated cost value on the route from the current position to the destination GL and the accumulated cost value on the optimum route from the search position ST to the destination GL. Can be recognized, and convenience is improved.

  Next, when the user of the mobile phone 200 moves and the current position of the mobile phone 200 starts from the node N31 and starts to pass through the link L5, the route search unit 120 changes the display of the position icon (FIG. 9 step S341).

  FIG. 13 is an explanatory diagram showing an example of the relationship between the display of the current position of the mobile phone 200 and the optimum route and similar route. As shown in FIG. 13, since the mobile phone 200 is passing through the link L5, the position icon is changed to a display of the same color as the arrow M3. In this case, there is no route that passes through the link L4, the link L6, the link L11, the link L7, and the link L12 in the direction of the arrow and arrives at the destination GL. Therefore, the route search unit 120 does not display the arrows displayed on the link L4, the link L6, the link L11, the link L7, and the link L12. At this time, since the mobile phone 200 has not arrived at the node N13, the display of the arrow M1 of the link L16 is not changed and remains the arrow M1. When the mobile phone 200 arrives at the node N32, the link starting from the node N32 has only the same color as that of the position icon, that is, the link having the same value for the route addition cost. Not done. Thereafter, similarly, when the position icon passes through the nodes N33 and N23 and arrives at the node N13, the route search unit 120 adds the route addition cost of the link L5 and changes the arrow M1 of the link L16 to the arrow M3. As described above, the route search unit 120 updates and displays the route information in the optimum route and the similar route for each link that the mobile phone 200 has passed before the mobile phone 200 arrives at the destination GL. change.

  As described above, the server 100 according to the present embodiment includes the map information DB 114 of the information storage unit 110 that stores the link information, the node information, and the map image data as the image data, and the location information and the purpose from the mobile phone 200. A route search unit 120 that receives the location information and sets an allowable cost. The optimum route search unit 123 of the route search unit 120 calculates the minimum cost route and the non-minimum cost route for each node in the route, and determines the minimum cost route from the search position ST to the destination GL as the optimum route. The node-specific route information DB 115 of the information storage unit 110 stores, for each node, the minimum cost route and the non-minimum cost route, and the accumulated cost values of the minimum cost route and the non-minimum cost route. The similar route search unit 124 of the route search unit 120 searches for the non-minimum cost route in which the difference between the definite label and the losing label is less than or equal to the allowable cost in the optimal node included in the optimal route. A similar route is determined by combining the cost route and the route having the same route from the optimum node to the destination GL as the optimum route. Therefore, in the server 100 according to the present embodiment, a similar route having a cost accumulated value almost equivalent to the optimum route can be presented to the user, so that the degree of freedom of route selection by the user is increased and convenience is improved. Further, since a new sub-route or the like different from the optimum route is not searched for each node, the processing load on the server 100 can be reduced.

  In the server 100 according to the present embodiment, the similar route search unit 124 of the route search unit 120 is similar to the optimal route in the cost difference for each route in each suboptimal node that is not included in the optimal route but included only in the similar route. A non-minimum cost route whose difference between the cost and the total cost value is equal to or less than a difference allowable cost is searched. In addition, the similar route search unit 124 sets a route obtained by combining the searched non-minimum cost route and the route from the semi-optimal node to the destination GL that is the same as the similar route as the semi-similar route. Thereafter, the similar route search unit 124 searches until there is no non-minimum cost route in which the difference between the accumulated cost values of the minimum cost route and the non-minimum cost route in the sub-optimal node is equal to or less than the allowable difference cost. For this reason, the server 100 according to the present embodiment presents all routes of the accumulated cost value that is equal to or less than the allowable cost as similar routes, so that the degree of freedom of route selection by the user is further increased and convenience is further improved.

  In this embodiment, the display panel 202 of the mobile phone 200 displays the searched optimum route and similar route, and also displays the current position of the mobile phone 200 acquired by the GPS unit 201 of the mobile phone 200. Therefore, in this embodiment, the user of the mobile phone 200 can easily recognize the optimum route and the similar route, and the current position of the mobile phone 200 is also displayed, so that convenience is improved.

B. Second embodiment:
FIG. 14 is an explanatory diagram illustrating an example of route information according to the second embodiment. FIG. 14 shows a definite label and a losing label at each node included in the route, and the link costs of each link are all 5. For example, in the node N022, the route entering from the link L55 is the minimum cost route, and the routes entering from the link L56, the link L60, and the link L61 are non-minimum cost routes. Further, the accumulated cost value of the route entering the node N022 from the link L55 and the link L56 is 15, and the accumulated cost value of the route entering the node N022 from the link L60 and the link L61 is 25. In the second embodiment, the allowable cost is set to 30. In the second embodiment, the search position ST, the destination GL, and the allowable cost are different from those in the first embodiment, and the optimum route search process and the like are the same as those in the first embodiment.

  FIG. 15 is an explanatory diagram showing an optimum route and a similar route from the search position ST to the destination GL in the second embodiment. As shown in FIG. 15, the optimum route is a route that arrives at the destination GL from the search position ST through the link L51, the node N031, the link L52, the node N032, the link L54, the node N033, and the link L58. M00 is displayed. Since the link cost of each link is 5, the cost accumulated value of the optimum route is 20. The similar route is a route that has a route addition cost of 10 and passes through the link L53 that enters from the node N031 to the node N021 indicated by the arrow M10. Further, the route addition cost is 20, and the route passes through the link L57 entering from the node N021 to the node N011 indicated by the arrow M20. Further, the route addition cost is 30, and the route passes through the link L62 entering from the node N012 to the node N011 indicated by the arrow M30.

  FIG. 16 is an explanatory diagram showing the current position and movement route of the user of the mobile phone 200. In FIG. 16, the movement path of the user of the mobile phone 200 is indicated by a dotted line. The mobile phone 200 arrives at the node N021 through the link L51, the node N031, and the link L53 from the search position ST, then passes again through the L53, passes through the node N031, the link L52, and the node N032, and is intermediate the link L55. At the spot. In this case, the route addition cost is 10 in the route until the mobile phone 200 arrives at the destination GL. In the second embodiment, the user of the mobile phone 200 makes a U-turn from the midpoint of the link L55 and returns to the node N032.

  FIG. 17 is an explanatory diagram showing the current position and movement route of the user of the mobile phone 200. In FIG. 17, as in FIG. 16, the moving route of the mobile phone 200 is indicated by a dotted line, and the mobile phone 200 is returned from the midpoint of the link L55 to the node N032. When the mobile phone 200 changes direction in the middle of the link and returns to the starting node, the route search unit 120 uses the ratio of the length passed to the total length of the link as the link cost of the link. Multiply to calculate the cost. In FIG. 17, since the mobile phone 200 changes direction in the middle of the link L55 and returns to the node N032, the route search unit 120 multiplies the link cost 5 of the link L55 by one half to make a round trip. Calculate 5 as the cost of minutes. Therefore, as shown in FIG. 17, before the mobile phone 200 returns to the node N032, a route having a route addition cost of 10 is displayed as an arrow M15 with a route addition cost of 15, and the route addition cost is The route that was 20 is displayed with an arrow M25 with a route addition cost of 25. In addition, the route having the route addition cost of 30 has a route addition cost of 35, which is larger than the allowable cost of 30, and is not displayed as a similar route. Therefore, in this embodiment, when the user of the mobile phone 200 has a high degree of freedom in changing the traveling direction, such as a pedestrian or a bicycle, the calculation of the additional cost for each route corresponding to the direction change is performed in real time. This makes it possible for the user to recognize the added cost for each route and the updated similar route in real time, further improving convenience.

C. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

C1. Modification 1:
In the above-described embodiment, the allowable cost is set in advance by the route search unit 120. However, the present invention is not necessarily limited thereto, and the setting of the allowable cost can be variously modified. For example, the allowable cost may be set by the user of the mobile phone 200 operating the operation unit 206, or may be set according to the ratio of the accumulated cost value of the optimum route. Further, the allowable cost may be determined by setting, for example, what time the user wants to arrive by the destination GL. In this modified example, an allowable cost is set according to the arrival time and a similar route is searched, so that the user can spend a meaningful time without having time until the arrival time.

  In the above embodiment, the destination GL is set by the user operating the operation unit 206 of the mobile phone 200. However, the destination GL and various setting input means are not limited thereto, and various modifications can be made. is there. For example, the mobile phone 200 may include a voice input unit that receives voice input from the user, and various settings such as setting of the destination GL may be performed by voice.

  In the above embodiment, the server 100 includes the information storage unit 110 and the route search unit 120 as illustrated in FIG. 1, but the apparatus including the information storage unit 110 and the route search unit 120 is not limited to this mode. Various modifications are possible. For example, the information storage unit 110 and the route search unit 120 may be provided in different servers, or the route search unit 120 may be mounted on the mobile phone 200. Further, the optimum route search unit 123 and the similar route search unit 124 in the route search unit 120 may be provided in different servers 100, respectively. Further, the map information DB 114 and the node-specific route information DB 115 may be stored in the same database.

C2. Modification 2:
In the above-described embodiment, in the route information display update process, the optimum route from the search position ST to the destination GL and the route with a smaller total cost value in the similar route are displayed with arrows that are thicker and lighter in color. The manner in which the user recognizes the similar route is not limited to this, and various modifications can be made. For example, the thicknesses and sizes of the arrows indicating the optimum route and the similar route may be displayed separately with different colors without being changed, and conversely, the thicknesses and sizes of the arrows are different and the colors are the same. May be. Moreover, the aspect of blinking an arrow may be sufficient and you may display other than an arrow. In addition, the voice output unit 203 may guide the user with the optimal route and the similar route without displaying on the display panel 202 of the mobile phone 200, or may be guided by display and voice.

C3. Modification 3:
In the second embodiment, when the user of the mobile phone 200 changes direction at the link, the cost to be added to the route addition cost is calculated based on the length that the user has passed through the link. The calculation method is not limited to this, and various modifications are possible. For example, when the user changes direction at the link, the cost may be calculated more than when the user simply passes through the link.

C4. Modification 4:
In the above embodiment, the order of searching for the similar route and the semi-similar route is not particularly described. However, by setting the order of searching for the similar route and the semi-similar route, the similar route and the semi-similar route can be efficiently used. Can be searched. For example, in the similar route search shown in FIG. 7 in the first embodiment, the similar route search unit 124 searches for a similar route in the node N31 whose cost difference by route is smaller than that of the node N13, and then searches for the similar route in the node N13. You may search. In the quasi-similar route search shown in FIG. 8, the similar route search unit 124 searches for a quasi-similar route in the node N22 after searching for a quasi-similar route in the node N23 whose path-specific addition cost is lower than that of the node N22. Also good. In this modification, a route with a small cost difference by route and a route difference by route addition cost is preferentially searched. Therefore, a similar route and a semi-similar route having a small accumulated cost value of a route from the search position ST to the destination GL are obtained. It is searched efficiently.

  In addition, among the constituent elements in the above-described embodiment, elements other than the elements described in the independent claims are additional elements, and can be omitted or combined as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Route search system 100 ... Server 102 ... Communication part 110 ... Information storage part 114 ... Map information database 115 ... Route information database classified by node 118 ... Storage apparatus 120 ... Route search part 123 ... Optimal route search part 124 ... Similar route search part DESCRIPTION OF SYMBOLS 200 ... Mobile phone 201 ... GPS unit 202 ... Display panel 203 ... Audio | voice output part 205 ... Wireless communication circuit 206 ... Operation part 206a ... Numeric keypad 206b ... Cursor key 210 ... Main control part 211 ... CPU
220 ... Call control unit GL ... Destination BS ... Base station ST ... Search location INT ... Internet

Claims (6)

A route search device for searching a route from a first point to a second point, which is an arbitrary point on the network,
A path information storage unit for storing data for specifying nodes and links constituting the path and data for specifying link costs when passing through each link;
A point setting unit for setting the first point and the second point;
For each of a plurality of specific nodes, among a plurality of paths connecting the first point to the specific node, a minimum cost path that minimizes the cumulative value of link costs of each link and other non-minimum cost paths And an optimal route search unit that sets the minimum cost route when the specific node is the second point as an optimal route;
An allowable cost setting unit for setting the allowable cost;
A path storage unit by node for storing the minimum cost path and the non-minimum cost path, and a cumulative value of link costs of the minimum cost path and the non-minimum cost path for each of the plurality of specific nodes; ,
A plurality of the specific nodes included in the optimum route are sequentially selected as optimum nodes, and a difference in the cumulative value of link costs between the minimum cost route and the non-minimum cost route in the optimum node is equal to or less than the allowable cost. Similar route search that selects the non-minimum cost route and sets a similar route in which the selected non-minimum cost route and the route from the optimum node to the second point are the same as the optimum route And comprising
The optimum route searching unit searches for a cumulative value of link costs of the minimum cost route and a non-minimum cost route to a value obtained by adding the allowable cost to a cumulative value of link cost of the optimum route. The route search device according to claim 1,
The similar route search unit sequentially selects the specific nodes not included in the optimal route and included in the similar route as sub-optimal nodes, and the minimum cost route and the non-minimum cost route in the sub-optimal node The non-minimum cost route is selected such that the difference in the cumulative value of link costs is less than or equal to the value obtained by subtracting the difference in the cumulative value of link costs between the optimal route and the similar route including the suboptimal node from the allowable cost. A semi-similar route combining the selected non-minimum cost route and the same route as the similar route from the semi-optimal node to the second point is set, and the semi-similar route is further set as the similar After setting as a route, a link cost between the minimum cost route and the non-minimum cost route in the suboptimal node included in the set similar route. Search until there is no non-minimum cost route in which the difference in the cumulative value is less than or equal to the allowable cost minus the difference in the cumulative value of link costs between the optimal route and the similar route including the semi-optimal node. Route search device. A route guidance system for searching for a route from a first point to a second point, which is an arbitrary point on the network,
A path information storage unit for storing data for specifying nodes and links constituting the path and data for specifying link costs when passing through each link;
A point setting unit for setting the first point and the second point;
For each of a plurality of specific nodes, among a plurality of paths connecting the first point to the specific node, a minimum cost path that minimizes the cumulative value of link costs of each link and other non-minimum cost paths And an optimal route search unit that sets the minimum cost route when the specific node is the second point as an optimal route;
An allowable cost setting unit for setting the allowable cost;
A path storage unit by node for storing the minimum cost path and the non-minimum cost path, and a cumulative value of link costs of the minimum cost path and the non-minimum cost path for each of the plurality of specific nodes; ,
A plurality of the specific nodes included in the optimum route are sequentially selected as optimum nodes, and a difference in the cumulative value of link costs between the minimum cost route and the non-minimum cost route in the optimum node is equal to or less than the allowable cost. Similar route search that selects the non-minimum cost route and sets a similar route in which the selected non-minimum cost route and the route from the optimum node to the second point are the same as the optimum route And
A route display unit for displaying the optimum route and the similar route;
A current position acquisition unit for acquiring a current position of the route display unit,
The optimal route search unit searches for a cumulative value of link costs of the minimum cost route and non-minimum cost route to a value obtained by adding the allowable cost to a link cost cumulative value of the optimal route, and the route display unit A route guidance system that displays the current location. The route guidance system according to claim 3,
The similar route search unit sequentially selects the specific nodes not included in the optimal route and included in the similar route as sub-optimal nodes, and the minimum cost route and the non-minimum cost route in the sub-optimal node The non-minimum cost route is selected such that the difference in the cumulative value of link costs is less than or equal to the value obtained by subtracting the difference in the cumulative value of link costs between the optimal route and the similar route including the suboptimal node from the allowable cost. A semi-similar route combining the selected non-minimum cost route and the same route as the similar route from the semi-optimal node to the second point is set, and the semi-similar route is further set as the similar After setting as a route, a link cost between the minimum cost route and the non-minimum cost route in the suboptimal node included in the set similar route. Search until there is no non-minimum cost route in which the difference in the cumulative value is less than or equal to the allowable cost minus the difference in the cumulative value of link costs between the optimal route and the similar route including the semi-optimal node. Route guidance system. The route guidance system according to claim 3 or 4, further comprising:
A route guidance system comprising: a route display change unit that changes a display of the similar route based on a difference in a cumulative value of link costs between the optimum route and the similar route and causes the route display unit to display the same. A route guidance system according to any one of claims 3 to 5,
The optimal route search unit is configured to connect the one node to a node adjacent to the one node before leaving the one node and entering the adjacent node. A route guidance system that adds a value obtained by multiplying the link cost of the specific link by a predetermined ratio to the cumulative value of the link cost when the link is folded back.

Images