JPH07320194A - Route guide method - Google Patents

Abstract

PURPOSE:To provide a simple route guide method which doesn't require special map data and reduces the burden on a memory and elieminates a need of the wait time. CONSTITUTION:In the time when a vehicle runs on a going path from a point of departure to a destination, pass nodes on road data are detected and are stored in a memory 17 in order in accoraance with the detection vehicle position of a vehicle position detecting part 3 and road data read out from a CD-ROM 1 by a map matching part 12 and a pass node register part 18; and in the time when the vehicle runs on a return path, a course guide picture plotting part 20 takes the pass node string stored in the memory 17 in the opposite order as guide route data and uses this data to obtain the intersection and the course which exist in the front of the vehicle position on the guide route and where the course change is necessary, and a map picture plotting part 13 ploats a course guide picture consisting of the intersection form and the arrow indicating the course in the upper left of a video RAM 14, where the map picture including the vehicle position is plotted, based on the obtained intersection and course, and the picture is displayed on a display device 4 to guide the vehicle to the intersection and the course.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a route guidance method, and in particular, in an in-vehicle navigation device, it is not necessary to search for an optimal route connecting a departure place and a destination using road data.
The present invention relates to a route guidance method capable of guiding a traveling direction of a vehicle on a return route from a destination to a departure place.

[0002]

2. Description of the Related Art There is a vehicle-mounted navigation device that presents the present location of a vehicle on a map so that a driver can easily reach a desired location. In this device, the position of the vehicle is detected, the map data around the vehicle position is read from the CD-ROM, the map image is drawn in the video RAM, and the vehicle position mark is drawn on the map image.
The image of M is converted into a video signal and output to a display device to be displayed on the screen. Then, as the current position changes due to the movement of the vehicle, the vehicle position mark on the screen is moved, or the vehicle position mark is fixed at the center of the screen and the map is scrolled. The information is available at a glance.

The map stored in the CD-ROM is divided into areas of appropriate longitude and latitude widths according to the scale level, and roads are represented by vertices (nodes) represented by coordinates of longitude and latitude. ) Is shown as a set. A part connecting two nodes is called a link. As shown in FIG. 12, the road data included in each map is composed of a road list RLDT, a node table NDTB, and an intersection node list CRDT. Among these, the road list RLDT is related to the road concerned, national roads and highways. , Other types of data such as roads, the total number of nodes on the road, the numbers on the node table NDTB of each node forming the road, and the width of the road between the nodes. The width data of the nth node number indicates the width of a link connecting the node related to the nth node number and the node related to the (n + 1) th node number. Also, the intersection configuration node list C
The RDT is a set of numbers on the node table NDTB of the node at the other end of the link (referred to as an intersection composing node) for each intersection on the map, and the node table NDTB is a list of all nodes on the map. Yes, coordinate information (longitude, latitude) for each node, an intersection identification flag indicating whether or not the node is an intersection, and if it is an intersection, it points to the corresponding intersection constituent node set on the intersection constituent node list CRDT and must be an intersection. For example, it is composed of a pointer or the like that points to the road to which the node belongs.

On the other hand, some on-vehicle navigation devices have a route guidance function for guiding a vehicle so that it can travel along an optimal route from a starting point to a destination. With such a function, when the driver sets the starting point and the destination before traveling, the simulation calculation is performed by the Dijkst method and the horizontal search method using the map data of the CD-ROM, and for example, the starting point and the destination can be calculated in the shortest distance. The optimum guide route to be connected is obtained, and the guide route data including the node sequence forming the guide route and the leading start point data and the last destination data is stored in the guide route memory. Then, while traveling, the part in the map display area of the screen is read out from the node sequence of the guide route memory, and the guide route is displayed in a different color from other roads on the map image, and the driver is displayed. Knows which way to go to which way to reach the destination.

[0005]

However, in order to search for an optimum route connecting a starting point and a destination using map data, it is necessary to include data dedicated to route search such as an intersection netlist in the map data. In addition, the intersection netlist of a large number of intersections must be read into the buffer memory in order to execute the calculation of the Dijkstra method and the horizontal search method, which requires a large memory capacity, and further, the starting point and the destination. If the distance between them is too long, there is a problem that it takes a long time to complete the search. From the above, an object of the present invention is to provide a simple route guidance method that does not require special map data, has a small memory load, and does not require waiting time.

[0006]

SUMMARY OF THE INVENTION In the present invention, the above object is to provide a map data storage means for storing map data, a means for detecting a vehicle position, and a vehicle position while traveling on an outward route from a departure place to a destination. From the road data in the map data,
Means for sequentially storing in the memory while detecting transit nodes on the road data, and when traveling on the return route from the destination to the departure point, the transit node sequence stored in the memory is set in reverse order as guide route data, This is achieved by means for obtaining a route at an intersection existing in front of the vehicle position on the guide route using the guide route data and means for performing an intersection route guidance based on the obtained route.

[0007]

According to one aspect of the present invention, while traveling on the outward route from the starting point to the destination, the vehicle position and the road data are sequentially stored in the memory while detecting transit nodes on the road data. When traveling on the return route from the ground to the departure point, the passing node sequence stored in the memory is reversed in order to form the guide route data, and using the guide route data, the intersection existing in front of the vehicle position on the guide route is used. The route of the intersection is obtained, and the intersection route guidance is performed based on the obtained route. As a result, when the driver travels from the starting point to the destination and then returns to the starting point, he / she can obtain the guidance route data consisting of a node sequence connecting the destination to the starting point without special route search. Since the guide route data can be used to guide the route at an intersection existing in front of the vehicle position on the guide route,
To guide the driver on the return route, prepare map data including special data for route search such as intersection netlist, or secure a large storage capacity in the buffer memory, You do not have to wait until the search for the route connecting the two ends.

According to another aspect of the present invention, while traveling on the outward route from the starting point to the destination, the passing position of the vehicle is detected and stored in the memory in order, and the return route from the destination to the starting point is detected. When traveling, reverse the passage position sequence stored in the memory and find the shortest route from the passage position sequence to reach the departure point as guide route data, and use the guide route data to determine the departure point data. Route guidance to. As a result, when the driver travels from the starting point to the destination and then returns to the starting point, he / she can obtain the guide route data consisting of the vehicle position sequence connecting the destination to the starting point without special route search. ,
Since the route guidance to the departure place can be performed using the guidance route data, in order to perform the route guidance for the return route, map data including special data for route search such as an intersection netlist is prepared, or a buffer is prepared. You do not have to secure a large memory capacity in the memory or wait until the search for the route connecting the destination and the departure point is completed, and in the middle of the outbound route,
Even if you are stopping at a place different from your destination, you can guide you to the starting point on a return route without stopping.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram of a vehicle-mounted navigation device embodying a first route guidance method according to the present invention. In the figure, 1 is a CD-which serves as a map data storage means.
ROM 2 is an operation panel, which includes a registration start key for registering a guide route, a registration end key, a guide route shortening key, a route guide mode key for setting and canceling a route guide mode, and the like. Reference numeral 3 is a vehicle position detection unit that detects the vehicle direction and vehicle position by self-contained navigation or satellite navigation, and 4 is a display device, which inputs a video signal to display a map on the screen, a vehicle position mark, an emphasis guide route, an intersection guidance image. And so on.

Reference numeral 10 denotes a navigation controller having a microcomputer configuration, which draws a map image around the vehicle position together with the vehicle position mark and displays it on the screen of the display device 4, or the destination after the registration start key is pressed at the departure point. Until the registration end key is pressed at, the passing nodes of the vehicle are detected and stored in the memory in order, and if they are reversed, the guide route data is obtained, and the route guide mode key is used to set the route guide mode. Then, using the guide route data stored in the memory, the emphasized guide route and the intersection route guidance image are superimposed on the map image and displayed on the display device 4. Of these, 11 is a buffer memory for temporarily storing the map data read from the CD-ROM 1,
The reference numeral 2 corrects the vehicle position detected by the vehicle position detection unit 3 on the road by map matching using the road data (see FIG. 12) in the map data. At this time, the road is determined from the corrected vehicle position and the road data. It is a map matching unit that also detects a set (presence link) of a front node first existing in the front of the vehicle and a rear node first existing in the rear of the vehicle.

A map image drawing unit 13 draws a map image for one screen centered on the vehicle position using the map data based on the corrected vehicle position, and is stored in a memory described later in the guide route mode. A portion included in the map image is read from the passage node sequence (route guidance data), and an emphasized guidance route that is thickly emphasized with a broken line is drawn on the map image. Reference numeral 14 is a video RAM for storing a map image, 15 is a mark drawing unit for drawing a vehicle position mark in the vehicle azimuth direction detected by the vehicle position detecting unit 3 in the center of the video RAM 14, and 16 is a video RAM. The image conversion unit reads out an image, converts it into a predetermined image signal, and outputs the image signal to the display device 4.

Reference numeral 17 is a memory for sequentially storing passing nodes of a vehicle with an intersection identification flag, and reference numeral 18 is a passing node registration unit. As shown in FIG. 2, the registration start key is pressed on the operation panel 2 to enter the registration mode. Then, the backward node detected by the map matching unit 12 at that time point is set as the departure point node, and the intersection identification flag is attached to the first node in the memory 17. After that, when the vehicle passes through the previous front node, the rear node output from the map matching unit 12 changes, and this rear node indicates the node that has passed immediately before. Therefore, each time the rear node changes, the rear node after the change. The nodes are sequentially stored in the second and subsequent storage areas of the memory 17 together with the intersection identification flag as the passing nodes of this time. The passing nodes stored in the memory 17 are the longitude and latitude coordinates, and the map matching unit 12 along with the intersection identification flag sets the node table ND in the road data.
It is read from TB and passed to the transit node registration unit. The transit node is registered until the registration mode is released by pressing the registration end key. The route guidance image drawing unit, which will be described later, treats the passage node sequences in the memory 17 in reverse order and sets them as guide route data.

When the guide route shortening key 19 is pressed,
It is a guide route shortening unit that obtains the shortest guide route from the destination node to the place of departure from the transit node sequence stored in the memory 17. Here, the same transit node is searched from the memory 17,
When present, all transit nodes between them are erased together with the intersection identification flag to be changed to the shortest guide route data.
For example, as shown by the alternate long and short dash line in FIG. 3, when detouring from the intersection CP _B to P on the way from the departure point S to the destination O and returning to the intersection CP _B again toward the destination O, the memory 17 is stored. As shown on the left side of FIG. 4, since there are two intersection nodes CP _{B which} are one of the passing nodes, all the passing nodes between them are deleted and the right side of FIG. 4 is obtained. Then, it becomes the same as the passing node sequence when the vehicle goes from the starting point S to the destination O without detouring as shown by the broken line in FIG. 3, and the shortest guide route data is obtained.

Reference numeral 20 denotes a route guidance image drawing section which draws a route guidance image on a part of the screen when a vehicle approaches an intersection on which the route should be changed in the route guidance mode within a certain amount. Among the guide route data in which the forward node and the rear node detected by the matching unit 12 and the corrected vehicle position are used as clues, the passing node sequence stored in the memory 17 is viewed in reverse order, and the first route in the forward direction of the vehicle travels. Look for the existing intersection node (the intersection identification flag is set), and the transit node immediately before the guidance target intersection,
For example, a guidance target intersection and a passage node that is one ahead of the guidance target intersection and having an angle of 30 ° or more are searched for as the guidance target intersection, and the distance between the current vehicle position and the guidance target intersection is calculated. A certain distance (eg 500
m) When it is below, the shape of the guidance target intersection is calculated by referring to the intersection constituent node list CRDT and the node table NDTB in the road data, and the video RAM 14 is calculated.
The shape of the guidance target intersection is drawn with the upper right end of the route guidance image area, and in the guidance route data, the passage node before the guidance target intersection, the guidance target intersection, and the passage ahead of the guidance target intersection. Draw an arrow that shows the same direction as the direction connecting the nodes, overlapping the shape of the guidance target intersection,
At the bottom of the route guidance image area, a character indicating the distance between the vehicle position and the guidance target intersection is also drawn (FIG. 8 (2), FIG. 9).
(See (1)).

5 to 7 are flow charts showing the operation of the navigation controller 10, and FIGS. 8 and 9 are explanatory diagrams of screen display examples of the display device 4, which will be described below with reference to these figures. It is assumed that the memory 17 has been cleared in advance and the guide route mode has been canceled. When the vehicle starts traveling, the vehicle position detector 3 periodically detects the vehicle position and the vehicle direction, and the navigation controller 10 inputs these data (step 1 in FIG. 5).
01). The map matching unit 12 reads the map data including the vehicle position from the CD-ROM 1 into the buffer memory 11 and corrects the map on the road by performing map matching, and the corrected vehicle position data is stored in the map image drawing unit 13 and the route guidance image drawing unit 20. (Step 102), detects the existing link, outputs the backward node together with the intersection identification flag to the transit node registration unit 18, and outputs the forward node and the backward node to the route guidance image drawing unit 20 ( Step 103).

The map image drawing unit 13 reads out map data including the vehicle position from the buffer memory 11 based on the corrected vehicle position data, and draws a map image in the video RAM 14 with the vehicle position at the center and the north facing upward. (Step 104). Next, since the current route guidance mode is canceled (step 105), the mark drawing unit 15 directs the vehicle azimuth direction to the center of the video RAM 14 based on the vehicle azimuth data output from the vehicle position detector 3. A mark is drawn (step 106). Video ram
The image of 14 is always read by the video conversion unit 16,
It is converted into a predetermined video signal, output to the display device 4, and displayed on the screen (step 107, see FIG. 8 (1)). In the same manner, every time the vehicle position changes, the map image drawing unit 13 redraws the map image so that the new vehicle position comes to the center of the video RAM 14, and the mark drawing unit 15 changes the new vehicle azimuth direction. The oriented vehicle position mark is redrawn in the center of the video RAM 14. As a result, as the vehicle moves, the map image is always scrolled so that the center of the screen is the vehicle position. As a result, the map around the vehicle position is always displayed on the screen together with the vehicle position mark, so that the driver can confirm the current location on the map.

Since the driver travels from the starting point S to the destination O in FIG. 3 and then returns to the starting point S again, the driver travels without receiving route guidance on the outbound route, but on the return route it is the same as the outbound route. When the user wants to receive route guidance to return the route as it is, he / she presses the registration start key at the place of departure S. Then, the navigation controller 10 sets the guide route registration mode (steps 108 to 110), and the transit node registration unit 18 sets the backward node and the intersection identification flag output by the map matching unit 12 at that time to 1 in the memory 17. Store in the th storage area (step 11
1) From then on, each time the backward node output by the map matching unit 12 changes, it is stored in the second and subsequent storage areas of the memory 17 together with the intersection identification flag (steps 112 and 113). Intersection C on the way to destination O
It dropped in the P in P _B, again, when came back at the intersection CP _B, so that the intersection node CP _B is stored twice the memory 17 as a transit node (see left side of FIG. 4).

When the registration end key is pressed at the destination O, the navigation controller 10 cancels the guide route registration mode (steps 114 and 115), and the transit node registration unit 18 causes the transit node in the memory 17 to exit. Complete the registration of. At this time, when the transit node sequence stored in the memory 17 is viewed in reverse order, it is the guidance route data for the return route connecting the destination O to the departure point S, and the route guidance is performed using this data. You can

When the driver wants to return to the departure place S while returning to P on the return route after finishing the travel at the destination O, he presses the route guidance mode key once. Then, the navigation controller 10 confirms that the guidance route data is stored in the memory 17, and then sets the route guidance mode (steps 201 to 203 in FIG. 6). In the route guidance mode, the map matching unit 12 corrects the vehicle position detected by the vehicle position detection unit 3 on the road and detects the existing link (steps 101 to 10 in FIG. 5).
3) The map image drawing unit 13 draws a map image centered on the vehicle position on the video RAM 14 based on the corrected vehicle position (step 104), and further enters from the memory 17 into the map area drawn on the video RAM 14. The passing node sequence is read out, and an emphasized guide route is drawn in a predetermined color and emphasized by a thick broken line on the map image (step 10).
5, step 301 in FIG. 7). Thereafter, the mark drawing unit 15 draws the vehicle position mark in the vehicle azimuth direction detected by the vehicle position detection unit 3 in the center of the video RAM 17 (step 302).

Subsequently, the route guidance image drawing section 20 has not yet displayed the route guidance image (step 30).
3) In the guide route data in which the passage node sequence stored in the memory 17 is viewed in reverse order, using the front node detected by the map matching unit 12 and the corrected vehicle position as a clue,
For example, the angle when searching for the foremost intersection node in front of the vehicle traveling direction and connecting the passage node immediately before the guidance target intersection, the guidance target intersection, and the passage node immediately before the guidance target intersection is 30 Degrees above are specified as guidance target intersections (step 304), and the distance between the current vehicle position and the guidance target intersection is calculated (step 30).
5) When it is within a certain distance (here, 500 m) (step 306), the shape of the guidance target intersection is calculated by referring to the intersection configuration lead list CRDT and the node table NDTB in the road data, and the video RAM 14 is calculated.
The shape of the guidance target intersection is drawn with the upper right end of the route guidance image area, and in the guidance route data, the passage node before the guidance target intersection, the guidance target intersection, and the passage ahead of the guidance target intersection. Draw an arrow that shows the same direction as the direction connecting the nodes, overlapping the shape of the guidance target intersection,
In addition, a character indicating the distance between the vehicle position and the guidance target intersection is also drawn at the bottom of the route guidance image area (step 30).
7).

The image in the video RAM 14 is converted into a video conversion unit 16
Read out, converted into a video signal, output to the display device 4, and displayed on the screen (step 30).
8). Here, assuming that CP _D in FIG. 3 becomes the guide target intersection, the screen becomes as shown in FIG. 8 (2), along with the current vehicle position on the map is shown, route guide image is displayed on the upper left corner of the screen The driver knows that the driver should turn right at the intersection 450m ahead.

By displaying the emphasized guide route on the map image, the driver can know which road the vehicle can travel to reach the starting point S, and the distance display in the route guidance image can be displayed as the vehicle travels. The driver can concretely know which intersection to turn at by changing to 350 m, 300 m, ... When the vehicle turns right at the guidance target intersection, the route guidance image drawing unit 20 finds that the rear node input from the map matching unit 12 matches the guidance target intersection CP _D and the vehicle has passed the guidance target intersection. Video R
The drawing of the route guidance image of AM14 is stopped, and the route guidance image display on the screen disappears (steps 309 and 310). After that, the next guidance target intersection is found and 500m
When approaching within the range, a new route guidance image is drawn again to show the driver the route at the guidance target intersection, and when the vehicle passes the guidance target intersection, the route guidance image display on the screen disappears. Hereinafter, the same processing is repeated.
Therefore, it is possible to reliably return to the starting point S through the same route as the outward route.

Since the route guidance data in the memory 17 has not been minimized, when approaching the intersection CP _B within 500 m, the route guidance image is displayed as shown in FIG. Is displayed, it is possible to detour to P again on the way of the return trip.

In contrast to this, when the destination O is reached and the required route is completed and the return route returns straight to the starting point S without detouring to P, press the guidance route shortening key before setting the route guidance mode. Press. Then, the guide route shortening unit 19
Searches the memory 17 for the same transit node, and when present, erases all transit nodes between them along with the intersection identification flag to change to the shortest guide route data (steps 115 to 117 in FIG. 5). As shown in the left side of FIG. 4, there are two intersection nodes CP _{B in the} memory 17, which are one of the passing nodes CP _i. Therefore, all the passing nodes between them are deleted to obtain the right side of FIG. Then, it becomes the same as the passing node sequence when the vehicle goes from the starting point S to the destination O without detouring as shown by the broken line in FIG. 3, and the shortest guide route data is obtained.

After that, the route guidance mode is set and the vehicle travels on the return route from the destination O to the departure point S, and at the intersection C
When approaching P _B , the route at the intersection CP _B is straight, so it is not a guidance target intersection, and the route guidance image for the intersection CP _B is not displayed (see FIG. 9 (2)). Therefore, the driver goes straight through the intersection CP _B, and can return straight to the place of departure S.

According to this embodiment, each transit node is detected while traveling from the starting point to the destination and stored in the memory 17 in order, and when traveling on the return route, the route guidance mode is set. Then, the map image drawing unit 13 and the route guidance image drawing unit 20 handle the passage node sequences stored in the memory 17 in reverse order, and use them as guide route data to draw the emphasized guide route on the map image or draw the route in front of the vehicle. The route guidance image showing the route at the intersection to be changed in the vehicle position-
Since it was drawn on the upper left of the map image together with the distance between the guidance target intersections and was displayed on the screen, the intersection net required to search the optimal route connecting the destination and the departure point in the map data of the CD-ROM. Even if there is no data for route search such as the list, it is possible to guide the return route, and in addition, it is not necessary to read the data for route search in a wide range including the destination and the departure point into the buffer memory. Is small, and the user is not required to wait until the search for the optimum route is completed.

When the guide route shortening key is pressed when reaching the destination, the guide route shortening unit 19 searches the memory 17 for the same transit node and deletes all transit nodes between them. Even if the vehicle detours in the middle of the outward route, the return route can be guided by a route that does not detour, and the vehicle can quickly return to the place of departure.

In the above embodiment, the guide route data stored in the memory 17 is shortened by pressing the guide route shortening key before starting the route guide.
During the route guidance, each time the map image drawing unit 13 tries to draw an emphasized guidance route, or each time the route guidance image drawing unit 20 tries to specify the next guidance target intersection, it is sequentially stored in the memory 17. It is possible to determine whether or not there is a detour route in the guide route by deciding whether or not there is the same transit node in the route and ignoring the transit node between them when there is the same transit node. Further, the guidance target intersection may include not only an intersection on which the route should be changed on the guide route but also an intersection that goes straight.

Further, although the guide route data is obtained by detecting the passing node on the outward route and storing it in the memory in order, the corrected vehicle position data is stored in the memory every time the vehicle travels a fixed distance L _0. It may be stored and obtained. In this case, the detour route is removed from the guide route as shown in FIG. 10 when the two vehicle position data F _A and F _B stored in the memory are close to each other. If they are, they are considered to be the detour crossing point CP _B , so they F _A ,
This can be realized by deleting or ignoring the vehicle position data between F _B , and the route guidance is based on the vehicle position data string stored in the memory by the map image drawing unit as shown in FIG. The highlighted guide route drawn with a thick broken line is drawn on the map image, or the route guidance image drawing unit includes the vehicle position data closest to the vehicle existing in the forward direction of the vehicle in the guide route data composed of the vehicle position data string. This can be performed by calculating the direction connecting the vehicle position data closest to the second and drawing a route mark indicating the calculated direction near the vehicle position mark.

[0030]

As described above, according to one aspect of the present invention, while traveling on the outward route from the starting point to the destination, the passing node on the road data is detected from the vehicle position and the road data and stored in the memory in order. Every time the vehicle travels on the return route from the destination to the departure point, the transit node sequence stored in the memory is used in reverse order as guide route data, and the guide route data is used to exist in front of the vehicle position on the guide route. By obtaining the route at the intersection and performing the route guidance based on the obtained route, the driver can drive from the starting point to the destination and then return to the starting point without special route search. It is possible to obtain guide route data consisting of a node sequence connecting the destination to the departure place, and use the guide route data to guide the route at an intersection existing in front of the vehicle position on the guide route. One In order to guide the driver through the route, prepare map data including special data for route search such as intersection netlist, or secure a large storage capacity in the buffer memory, and determine the destination and departure point. You do not have to wait until the search for the connecting route is completed.

According to another aspect of the present invention, while the vehicle is traveling on the outward route from the departure point to the destination, the passing position of the vehicle is detected and stored in the memory in order, and the destination from the departure point to the departure point is stored. When traveling on the return route, the passage position sequence stored in the memory is reversed, and the route that reaches the departure point in the passage position sequence at the shortest is searched for as guide route data, and the guide route data is used. By guiding the route to the departure point,
When the driver travels from the starting point to the destination and then returns to the starting point, it obtains guidance route data consisting of a vehicle position data string connecting the destination to the starting point without performing a special route search. Since it is possible to guide the route to the departure point using the guide route data, in order to guide the return route, prepare map data that contains special data for route search such as intersection netlist, or use buffer memory. You don't have to reserve a large amount of memory, or wait until the search for the route connecting the destination and the departure point is completed, and even if you are stopping at a place different from the destination on the way of the outbound route, The return route can be guided to the place of departure without stopping.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a vehicle-mounted navigation device that embodies a route guidance method according to the present invention.

FIG. 2 is an explanatory diagram of passing node strings stored in a memory.

FIG. 3 is an explanatory diagram showing a relationship between a travel route from a departure place to a destination and a guide route.

FIG. 4 is an explanatory diagram of a guide route shortening method.

FIG. 5 is a first diagram showing the operation of the navigation controller.
2 is a flowchart of.

FIG. 6 is a second diagram showing the operation of the navigation controller.
2 is a flowchart of.

FIG. 7 is a third view showing the operation of the navigation controller.
2 is a flowchart of.

FIG. 8 is an explanatory diagram of a screen display example.

FIG. 9 is an explanatory diagram of a screen display example.

FIG. 10 is an explanatory diagram of another route guidance method of the present invention.

FIG. 11 is an explanatory diagram of another route guidance method of the present invention.

FIG. 12 is an explanatory diagram showing a structure of road data in map data.

[Explanation of Codes] 1 CD-ROM 3 Vehicle position detection unit 4 Display device 10 Navigation controller 11 Buffer memory 12 Map matching unit 13 Map image drawing unit 14 Video RAM 15 Mark drawing unit 17 Memory 18 Passing node registration unit 19 Shortening of guide route Part 20 Route guidance image drawing part

Claims (2)

[Claims] 1. While traveling on an outbound route from a starting point to a destination,
The vehicle position and the road data are collated and stored in the memory in order while detecting passage nodes on the road data. When traveling on the return route from the destination to the departure point, the passage node sequence stored in the memory is stored. The reverse route is used as guide route data, the route at an intersection existing in front of the vehicle position on the guide route is obtained using the guide route data, and intersection route guidance is performed based on the obtained route. The method of displaying the driving guidance image of the in-vehicle navigator. 2. While traveling on the outward route from the starting point to the destination,
The passing position of the vehicle is detected and stored in the memory in order, and when traveling on the return route from the destination to the starting point, the passing position sequence stored in the memory is reversed and the shortest passing position sequence is selected. The route guidance method is characterized in that the route reaching the departure place is searched for as the guidance route data, and the route guidance to the departure place is performed using the guidance route data.