JPH112536A - Route retrieving method of on board navigation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a route retrieving method for use with an on board navigation system, whereby the vehicle can arrive at the destination by the desired time of arrival while saving as much of the toll as possible. SOLUTION: Once a destination and the desired time of arrival has been set via a control part 2, a control part 15 retrieves a candidate for a route that allows the vehicle to take the shortest time to arrive at the destination, and calculates the estimated time of arrival when the vehicle travels along the candidate for the route. If the estimated time of arrival is earlier than the desired time of arrival by a predetermined time or more, another candidate for a route whereby the vehicle does not need to pass a section of a toll road involved in the former candidate for the route is newly retrieved, and the estimated time of arrival when the vehicle travels along the latter candidate for the route is calculated. Thus sections not including a toll road are increased, and the route is retrieved as the estimated time of arrival is compared with the desired time of arrival.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of searching for an optimal guidance route to a destination, and a method of searching for a guidance route of a vehicle-mounted navigation device for guiding a vehicle to the destination along the guidance route.

[0002]

2. Description of the Related Art An on-vehicle navigation device is a map data storage device such as a CD-ROM or an IC card storing map data, a display device such as a liquid crystal display, a gyro, a GPS (Global Positioning System).
And a vehicle movement detection device that detects the current position and current direction of the vehicle such as a mileage sensor, reads map data including the current position of the vehicle from a map data storage device, and detects a vehicle position based on the map data. The surrounding map image is drawn on the display screen, the vehicle position mark (location) is displayed on the map image, and the map image is scroll-displayed according to the movement of the vehicle, or the map image is fixed on the screen and the vehicle is By moving the position mark, the user can see at a glance where the vehicle is currently traveling.

[0003] In addition, usually, a car navigation system is equipped with a route guidance function that allows a user to easily travel to a desired destination without making a mistake on a road. According to this route guidance function, the lowest cost route from the starting point to the destination using the map data is automatically searched by performing a simulation calculation such as the horizontal search method or the Dijkstra method, and the searched route is guided. The route is stored as a route, and during driving, the guidance route is drawn on the map image in a different color from the other roads and displayed thicker, or displayed on the screen, or a certain distance to the intersection where the vehicle should change the route on the guidance route When the vehicle approaches, the user is guided to the destination by displaying an arrow indicating the course at an intersection where the course on the map image should be changed.

The cost is a value obtained by multiplying a constant according to a road width, a road type (such as a general road or an expressway), a right turn, a left turn, and the like based on the distance, a predicted traveling time of the vehicle, and the like. , The degree of appropriateness as a guidance route is quantified. Even if there are two routes having the same distance, the cost differs depending on whether the user specifies, for example, whether to use a toll road, or gives priority to distance or time.

A map stored in a map data storage device such as a CD-ROM has a longitude width of an appropriate size according to a scale level such as 1/12500, 1/25000, 1/50000, and 1/100000. Roads and the like are stored as a coordinate set of vertices (nodes) represented by longitude and latitude. A road is formed by connecting two or more nodes, and a portion connecting the two nodes is called a road link. The map data includes (1) a road layer including a road list, a node table, an intersection configuration node list, and the like; (2) a background layer for displaying roads, buildings, facilities, parks, rivers, and the like on a map screen; (3) Administrative division names such as municipalities,
It is composed of a character / symbol layer for displaying characters such as road names, intersection names and building names, and map symbols.

[0006]

However, in the conventional in-vehicle navigation device, when a vehicle travels along a guidance route when, for example, meeting with an acquaintance at a destination, the time to arrive at the destination is shortened. Sometimes you have to wait a long time at the destination until the scheduled time. In such a case, even if the arrival time at the destination is delayed, it may be better to save the toll without going through the toll road.

Accordingly, an object of the present invention is to provide a guidance route search method for a vehicle-mounted navigation device that searches for a guidance route that arrives at a destination by a desired arrival time and saves a toll as much as possible. is there.

[0008]

An object of the present invention is to provide a vehicle-mounted navigation system having map data storage means for storing map data and vehicle position detection means for detecting the position of a vehicle, and for guiding the vehicle to a destination. In the guidance route searching method of the device, when the destination and the desired arrival time are set, a route having the least number of toll road traffic sections among the routes that can reach the destination by the desired arrival time is set as the guidance route. The problem is solved by a method of searching for a guidance route of an in-vehicle navigation device characterized by searching.

Another object of the present invention is to provide a navigation route for an on-vehicle navigation device that has map data storage means for storing map data and vehicle position detection means for detecting the position of a vehicle, and guides the vehicle to a destination. In the search method, when the destination and the desired arrival time are set, (i) a first guide route candidate with the shortest required time to the destination is searched with high speed priority, and the first guide route candidate is set as the first guide route candidate. Calculating a first estimated time of arrival at the destination when traveling along the route, and when the first estimated time of arrival is earlier than the desired time of arrival by a predetermined time or more, (ii) the first guidance route A second guidance route candidate having the shortest required time when the vehicle does not pass through a part of the toll road included in the candidate is searched, and a second guidance route to the destination when traveling along the second guidance route candidate is searched. Find the estimated time of arrival for 2, (iii) comparing the second expected arrival time with the desired arrival time, and determining that the second expected arrival time is before the desired arrival time and the difference between the two is within the predetermined time; Is the guide route candidate, and when the second estimated arrival time is later than the desired arrival time, the first guide route candidate is used as the guide route, and the second expected arrival time is the desired arrival time. (Iv) repeating the processing from (ii) with the second guide route candidate as a new first guide route candidate when the time is earlier than the predetermined time. It is solved by the route search method.

The operation of the present invention will be described below. In the present invention, among the routes that can reach the destination by the desired arrival time, a route with the least number of toll road sections is searched for as a guidance route. For example, when the destination and the desired arrival time are set by the user, first, a route that arrives at the destination in the shortest time is searched, and the route is set as a first guide route candidate. Then, a first estimated arrival time at the destination when the vehicle travels along the first guidance route candidate is obtained and compared with the desired arrival time. If the first expected arrival time is earlier than the desired arrival time and the time difference is within a predetermined time, the first guide route candidate is determined as a guide route.

When the first estimated arrival time is earlier than the desired arrival time by the predetermined time or more, there is sufficient room, and the first estimated time when the vehicle does not pass through a partial section of the toll road included in the first guide route candidate is considered. A second guide route candidate is searched for, and a second estimated time of arrival at the destination when the vehicle travels along the second guide route candidate is determined. Then, the second estimated arrival time is compared with the desired arrival time, and if the second expected arrival time is earlier than the desired arrival time and the time difference is within the predetermined time, the second guidance route candidate is displayed as the guidance route. To decide. If the second estimated arrival time is later than the desired arrival time, the first guidance route candidate is determined as a guidance route.

When the second estimated arrival time is earlier than the desired arrival time by the predetermined time or more, there is still room to spare, so the second guide route candidate is newly set as the first guide route candidate, and Repeat the process. That is, the first
Search for a second guidance route candidate that does not pass through a section of the toll road included in the route considered as the guidance route candidate, and go to the destination when the vehicle travels along the second guidance route candidate Of the second estimated time of arrival is determined.

As described above, according to the present invention, a guidance route that arrives earlier than the desired arrival time and the estimated arrival time is close to the desired arrival time is searched. It is possible to arrive at the destination before the time, and tolls can be saved because there are few sections passing through the toll road.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing an in-vehicle navigation device that realizes a guidance route search method according to an embodiment of the present invention. Reference numeral 1 denotes a CD-ROM storing map data. The CD-ROM 1 stores a road layer, a background layer, and a character / symbol layer. Note that instead of a CD-ROM, a DVD-R
An OM (Digital Versatile Disk) may be used.

Reference numeral 2 denotes a navigation device body 10 to be described later.
Is an operation unit provided with various operation buttons and the like for operating. Reference numeral 3 denotes a GPS receiver that receives a GPS signal transmitted from a GPS satellite and detects the longitude and latitude of the current position. Reference numeral 4 denotes a self-contained navigation sensor. The self-contained navigation sensor 4 includes an angle sensor 4a such as a gyro that detects a vehicle rotation angle, and a traveling distance sensor 4b that generates a pulse for each predetermined traveling distance. Reference numeral 7 denotes a liquid crystal display device.
The display device 7 displays a map around the current position of the vehicle, a guidance route from the departure point to the destination, a vehicle position mark, and other guidance information.

The navigation apparatus main body 10 comprises the following. A map buffer 11 temporarily stores map data read from the CD-ROM 1. Reference numeral 12 denotes an interface connected to the operation unit 2;
Is an interface connected to the GPS receiver 3, and 14 is an interface connected to the self-contained navigation sensor 4.
Reference numeral 15 denotes a control unit. The control unit 15 detects the current position of the vehicle based on various types of information input from the interfaces 13 and 14, and reads map data of a predetermined area from the CD-ROM 1 to the map buffer 11. Or search for an optimal route from the departure place to the destination under the set search conditions.

Reference numeral 17 denotes a map drawing unit for generating a map image using map data stored in the map buffer 11, and reference numeral 18 denotes a VRA for storing the map image generated by the map drawing unit 17.
M. 19 is a VRAM according to an instruction from the control unit 15.
An image reading unit that reads a map image in a range to be displayed on the display device 7 from among the map images stored in the display device 18;
The control unit 15 can smoothly scroll the map image displayed on the display device 7 by controlling the image reading unit 19.

Reference numeral 20 denotes a guidance route storage unit for storing the guidance route searched by the control unit 15, and reference numeral 21 denotes a guidance route drawing unit for drawing the guidance route. The control unit 1 is stored in the guidance route storage unit 20.
5 are recorded from the starting point to the destination. When displaying the map, the guide route drawing unit 21 reads the guide route information (node sequence) from the guide route storage unit 20 and draws the guide route in a color and line width different from those of other roads.

Reference numeral 22 denotes an operation screen generating unit for generating various menu screens (operation screens) according to the operation status, and reference numeral 23 denotes a mark generating unit for generating various marks such as a vehicle position mark and a cursor. Reference numeral 24 denotes an image synthesizing unit, and an image reading unit 19
In the map image read out from the VRAM 18, various marks generated by the mark generation unit 23 and the operation screen generation unit 2
The operation screen generated in step 2, the guidance route drawn by the guidance route drawing unit 21, and the like are superimposed and displayed on the display device 7.

In the on-vehicle navigation device configured as described above, the control unit 15 detects the current position of the vehicle from the GPS signal received by the GPS receiver 3 and the signal input from the self-contained navigation sensor 4, and -Map data of the area including the current position of the vehicle from the ROM 1 is stored in the map buffer 1
Read to 1. Then, the control unit 15 controls the GPS receiver 3
The self-vehicle position detected by a signal input from the self-contained navigation sensor 4 is corrected (map matching) so that the vehicle is located on the road using the map data read into the map buffer 11.

Further, the control unit 15 superimposes and displays the vehicle position mark on the map image displayed on the display device 7, and moves the vehicle position mark as the vehicle moves, or scrolls the map image. The current position of the vehicle is known at a glance. 2 to 5 are flowcharts showing the operation of the navigation device of the present embodiment when searching for a guidance route.

When the user operates the operation unit 2 to enter the guidance route search mode, at step S11, the control unit 15
Displays on the display device 7 a message requesting the setting of the destination. When the user operates the operation unit 2 to set a destination, the process proceeds to step S12, and the control unit 15
A message requesting selection of whether or not to search for a guidance route with priority on economy is displayed on the display device 7. If the user selects to search for a guidance route with priority on economy (YES), the process proceeds from step S12 to step S21.
Otherwise, if not (NO), step S
Go to step 13.

In step S13, the control unit 15
A message requesting selection of whether or not to search for a guidance route with high speed priority (toll road priority) is displayed on the display device 7. If the user selects to search for a guide route with high speed priority (YES), the process proceeds to step S14, and the control unit 15 sets the current position of the vehicle as the departure point and searches for a guide route with high speed priority. That is, the control unit 15 sets the cost per unit length of the toll road to be smaller than that of the general road, searches for the route with the lowest cost to the destination, and sets the route as the guidance route. And the control unit 15
Stores a row of nodes constituting the guidance route in the guidance route storage unit 2.
After being stored in 0, the process proceeds to step S16.

On the other hand, if the user does not select high-speed priority in step S13 (NO), step S1
The process proceeds to step 5 to search for a guidance route with priority given to general roads. That is, the control unit 15 sets the cost per unit length of the toll road higher than that of the general road to make it difficult for the toll road to be selected as the guidance route, and then searches for the route with the lowest cost to the destination. And the route is referred to as a guide route. And
The control unit 15 stores the sequence of the nodes constituting the guidance route in the guidance route storage unit 20, and then proceeds to step S16.

In step S16, the control unit 15 displays the map image and the guidance route on the display device 7 in a superimposed manner. The processing flow of steps S13 to S16 is the same as in the related art. On the other hand, when the user selects the economy priority in step S12, the process proceeds to step S21, and the control unit 15 displays a message requesting the input of the desired arrival time on the display device 7. When the user inputs the desired arrival time via the operation unit 2, step S2
Then, the control unit 15 searches for a guidance route candidate that can arrive at the destination earliest with high speed priority. When the guidance route candidate is searched, the process proceeds to step S23, and the estimated arrival time at the destination when the vehicle travels along the guidance route candidate is calculated. In this case, the control unit 15 controls the CD-R
The vehicle traveling speed for each road is set in consideration of the legal speed recorded in the OM1, the number of lanes and signals for each road, and the state of statistical congestion due to time zones and the like, and arrives at the destination. Calculate the time (expected arrival time).

Thereafter, the process proceeds to step S24, where the control unit 15 compares the desired arrival time with the expected arrival time. Then, the process proceeds to step S25, and if the difference between the two times is within a predetermined time (for example, the expected arrival time is earlier than the desired arrival time, and the difference is within 30 minutes) (in the case of YES),
Move to step S27. Note that the predetermined time may be arbitrarily changed by a user.

In step S27, the control unit 15 stores the train of nodes constituting the guidance route in the guidance route storage unit 20, using the guidance route candidate as a guidance route. Thereafter, the control unit 15 displays the map image and the guidance route on the display device 7 in a superimposed manner, and further displays the desired arrival time and the estimated arrival time. If the difference between the desired arrival time and the expected arrival time is not within the predetermined time in step S25 (NO), the process proceeds to step S26, and the control unit 15 determines whether the expected arrival time is earlier than the desired arrival time. Find out. If the expected arrival time is earlier than the desired arrival time (in the case of YES), the process moves to step S31, and if the expected arrival time is later than the desired arrival time (in the case of NO), that is, the destination is reached by the desired arrival time. If it is not possible to arrive at, the process proceeds to step S27. In step S27,
The control unit 15 stores the train of nodes constituting the guidance route in the guidance route storage unit 20, using the guidance route candidate searched in step S22 as the guidance route. After that, the control unit 15
Displays the guide route together with the map image on the display device 7, and further displays the desired arrival time and the estimated arrival time. If NO in step S26, a message indicating that there is no route that can be reached by the desired arrival time is displayed on the display device 7 without moving to step S27. You may be prompted to re-enter the time.

In step S31, the control unit 15
It is checked whether toll roads are included in the guidance route candidates. If no toll road is included (NO),
The process proceeds to step S27, and the control unit 15 proceeds to step S22.
The guide route candidate searched for in (1) is set as a guide route, and a row of nodes constituting the guide route is stored in the guide route storage unit 20. Thereafter, the control unit 15 displays the map image and the guidance route in a superimposed manner on the display device 7, and further displays the desired arrival time and the estimated arrival time.

On the other hand, if the toll road is included in the guidance route candidate in step S31 (in the case of YES), the process proceeds to step S32. In step S32, the control unit 15 checks whether or not the guidance route candidate includes two or more toll roads. If only one location is included (NO), the process proceeds to step S41, and if two or more locations are included (YES), step S3 is performed.
Move to 3.

In step S33, the control unit 15
The toll road closer to the destination among the toll roads included in the guide route candidates is deleted. That is, the control unit 15 replaces the cost of the toll road closest to the destination among the toll roads included in the guidance route candidate with a large value so that this toll road is not included in the guidance route candidate. Then, the process proceeds to step S34 to search for a route with the lowest cost to the destination, and sets that route as a guide route candidate.
Since the search at this time only needs to be performed on the part that is replaced with the deleted toll road (the other parts are not described in step S2).
2), the processing can be performed in a short time.

Thereafter, the process proceeds to step S35, where the control unit 15 calculates an expected arrival time at the destination when the vehicle travels along the guide route candidate searched for in step S34. Next, the process proceeds to step S36, where the control unit 15
Compare the expected arrival time with the expected arrival time. Then, in step S37, if the difference between the desired arrival time and the expected arrival time is within the predetermined time (in the case of YES), the process proceeds to step S27, and the control unit 15 determines the guidance route candidate searched in step S34 as the guidance route. Is stored in the guidance route storage unit 20 as a sequence of nodes constituting the guidance route. Thereafter, the control unit 15 superimposes and displays the guidance route together with the map image on the display device 7, and further displays the desired arrival time and the estimated arrival time.

On the other hand, if the difference between the desired arrival time and the expected arrival time is not within the predetermined time in step S37 (in the case of NO), the process proceeds to step S38, where the control unit 15 determines that the expected arrival time is longer than the desired arrival time. Check if it is too early. If the estimated arrival time is earlier than the desired arrival time (in the case of YES), the process returns to step S32, and the above processing is repeated.

If NO in the step S38, the process shifts to a step S39 to change the guidance route candidate to the original state (that is,
The state before the toll road is deleted in step S32). Then, the process returns to step S32. In step S32, the toll road once deleted in step S33 before that is excluded, and it is checked whether there are two or more remaining toll roads. If there is only one toll road (NO), the process proceeds to step S41. On the other hand, if two or more toll roads remain, the next toll road (the second closest to the destination) is deleted in step S33, and step S3 is executed.
The processing after 4 is repeated. If the difference between the desired arrival time and the expected arrival time is within the predetermined time in step S37, the process proceeds to step S27, in which the guide route candidate is set as the guide route, and the row of nodes constituting the guide route is stored in the guide route storage unit 20. To memorize. Thereafter, the guidance route is superimposed and displayed on the display device 7 together with the map image, the desired arrival time and the estimated arrival time are further displayed, and the process is terminated.

In step S41, one section of the toll road closest to the destination is deleted, that is, the cost of the section is replaced with an extremely large value. Explore. The search at this time may be limited to the portion that is replaced with the section deleted in step S41, so that the search is completed in a short time. Then, in step S43, the expected arrival time is calculated, and in step S44, the desired arrival time and the expected arrival time are compared. Then, the process proceeds to step S45, and if the difference between the desired arrival time and the expected arrival time is within the predetermined time (in the case of YES), the process proceeds to step S27. And the control unit 1
5 stores, in the guidance route storage unit 20, a sequence of nodes constituting the guidance route, using the guidance route candidate searched in step S42 as a guidance route. Then, the display device 7
, The guidance route is superimposed and displayed together with the map image,
Further, the desired arrival time and the estimated arrival time are displayed, and the process is terminated.

On the other hand, if the time difference between the expected arrival time and the desired arrival time is not within the predetermined time in step S45 (NO), the process shifts to step S46 to determine whether the expected arrival time is earlier than the desired arrival time. Check. If the estimated arrival time is earlier than the desired arrival time (in the case of YES),
Returning to step S41, the above processing is repeated. At this time, in step S41, the section closest to the destination is deleted except for the section once deleted.

If NO in the step S46, the process shifts to a step S47, where the guidance route candidate is returned to the original state (that is,
(Before deleting the section of the toll road in step S41)
Return to Then, the process proceeds to step S27, where the control unit 15
Stores the train of nodes constituting the guide route in the guide route storage unit 20 using the guide route candidate as the guide route. Thereafter, the control unit 15 superimposes and displays the guidance route together with the map image on the display device 7, and further displays the desired arrival time and the estimated arrival time.

After determining the guidance route in this way, the control unit 15 detects the current position of the vehicle based on the signals from the GPS receiver 3 and the self-contained navigation sensor 4 and adjusts the display device 7 in accordance with the movement of the vehicle. The vehicle guides the vehicle to the destination by scrolling the map image displayed on the screen or displaying an arrow indicating the traveling direction of the vehicle when approaching the intersection.

In the present embodiment, as described above, when the priority on economy is selected, after requesting the input of the desired arrival time, a route arriving at the destination in the shortest time is searched, and the guidance route candidate is searched. The expected arrival time when traveling along the guide route candidate is compared with the desired arrival time, and when the expected arrival time is earlier than the desired arrival time by a predetermined time or more, the toll included in the guide route candidate is included. Repeats the process of searching for a new guide route candidate that can reach the destination in the shortest time when it does not pass through a section of the road, and arrives at the destination before the desired arrival time and closest to the desired arrival time Search for possible guidance routes. This has the effect of reducing the number of sections that pass through the toll road and saving tolls.

The control unit 15 appropriately calculates the expected arrival time to the destination in accordance with the actual running of the vehicle. If the expected arrival time is later than the desired arrival time due to the influence of traffic congestion, etc. The process from S22 is automatically performed to search for a new guidance route from the current position to the destination,
The vehicle may arrive at the destination by the desired arrival time. Also, instead of searching for a new guidance route,
The toll road and the section of the toll road deleted in steps S33 and S41 may be stored, and the vehicle may be restored in order from the one closest to the current position of the vehicle so that the vehicle can arrive at the destination by the desired arrival time. . In this case, step S3
In S41, as described above, the toll road and the section of the toll road are deleted from the side closer to the destination, so that even after the vehicle approaches the destination, the toll road or the section of the toll road is restored. It is possible to make it.

In the above-described embodiment, the guide route candidate is searched once with high speed priority, and then the toll road or its section is deleted. However, on the contrary, the guide route candidate is searched with general road priority. Until the expected arrival time is earlier than the desired arrival time, the optimal guide route may be searched for by increasing the section of the toll road or the portion of the toll road from the side closer to the current position.

Further, in the above embodiment, step S3
In step S41, the number of toll roads is reduced, and in step S41, the number of toll roads is reduced.
It is also possible to go directly to step S41 from step 26 and delete only the section of the toll road from the beginning.

[0042]

As described above, according to the guidance route searching method of the on-vehicle navigation device of the present invention, among the routes that can be reached by the desired arrival time to the destination, the toll road traffic section is the most. Since a small number of routes are searched for as a guide route, the sections that pass through the toll road are reduced, tolls can be saved, and the effect of avoiding arriving at the destination too early and increasing the waiting time can be achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an in-vehicle navigation device that realizes a guidance route search method according to an embodiment of the present invention.

FIG. 2 is a flowchart (part 1) illustrating an operation of the navigation device of the present embodiment when searching for a guidance route.

FIG. 3 is a flowchart (part 2) illustrating an operation of the navigation device of the present embodiment when searching for a guidance route.

FIG. 4 is a flowchart (part 3) illustrating an operation of the navigation device of the present embodiment when searching for a guidance route.

FIG. 5 is a flowchart (part 4) illustrating an operation of the navigation device of the present embodiment when searching for a guidance route.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CD-ROM 2 Operation part 3 GPS receiver 4 Self-contained navigation sensor 7 Display device 10 Navigation device main body 11 Map buffer 12-14 Interface 15 Control part 17 Map drawing part 18 VRAM 19 Readout part 20 Guide route storage part 21 Guide route drawing Unit 22 Operation screen generation unit 23 Various mark drawing units 24 Image synthesis unit

Claims (2)

[Claims] 1. A guidance route searching method for an in-vehicle navigation device, comprising: map data storage means for storing map data; and vehicle position detection means for detecting a position of a vehicle. When the destination and the desired arrival time are set, a route that has the least number of toll road traffic sections among the routes that can reach the destination by the desired arrival time is searched for as a guidance route. A navigation route search method for a navigation device. 2. A guidance route searching method for an in-vehicle navigation device, comprising: map data storage means for storing map data; and vehicle position detection means for detecting a position of a vehicle. When the destination and the desired arrival time are set, (i) when the first guidance route candidate with the shortest required time to the destination is searched with high speed priority and the vehicle travels along the first guidance route candidate Calculating a first estimated time of arrival at the destination, and when the first estimated time is earlier than the desired time by a predetermined time or more, (ii) a fee included in the first guide route candidate A second guidance route candidate having the shortest required time when the vehicle does not pass through a partial section of the road is searched, and a second estimated arrival time at the destination when the vehicle travels along the second guidance route candidate (Iii) said second arrival schedule Comparing the time with the desired arrival time, and when the second estimated arrival time is before the desired arrival time and the difference between the two is within the predetermined time, the second guidance route candidate is set as a guidance route; When the second estimated arrival time is later than the desired arrival time, the first guidance route candidate is set as a guidance route, and when the second expected arrival time is earlier than the desired arrival time by the predetermined time or more. (Iv) A method of searching for a guidance route of an in-vehicle navigation device, wherein the process from (ii) is repeated with the second guidance route candidate as a new first guidance route candidate.