EP0392374A1 - Method for the transmission of guide information - Google Patents

Abstract

In a traffic guidance system, a vehicle (FZ), when passing a stationary guidance beacon (BK), receives therefrom guidance information items (LK1, LK2, LK3) for all destination points which can be reached from the guidance beacon. For transmitting the guidance information items, all destination points (Z) to which the same guidance information applies, are combined to form in each case one destination area (F1, F2, F3), each destination area being bounded by a polygonal line of any type. The allocation of a selected destination point (Z) in the vehicle is effected by a comparison with the boundary lines (GR1, GR2, GR3) of the destination areas. The destination point (Z) must be allocated in each case to the destination area (F3), with the boundary line of which a coordinate system placed through the destination point exhibits an odd number of points of intersection in each direction of the compass. <IMAGE>

Description

The invention relates to a method for transmitting guidance information and for selecting guidance information to be displayed in a traffic guidance system.

In traffic control systems of this type, the driver selects a specific destination in the vehicle, and guidance information corresponding to this destination is displayed to him in time and place in order to show him the fastest and / or cheapest route to his destination. Since this guidance information should take into account both the geographical conditions and the respective traffic conditions, it must be transferred to the vehicle at certain points, for example on beacons. There are basically two options for this transfer:

In known guidance systems (ATZ-Automobiltechnische Zeitschrift 81 (1979), pages 3 to 7), guidance information is transmitted in dialog traffic between the road device and a specific vehicle for a single destination selected in the vehicle. For this dialogue traffic a relatively close coupling between the road device and the passing vehicle is required, which requires the laborious laying of induction loops and the like.

In other known control systems (e.g. EP-A-0 025 193), the roadside devices are kept relatively simple in that the target information is not exchanged in dialog communication between the vehicle and the road device, but rather cyclically transmits all the relevant target information to all passing vehicles are, each vehicle selects the associated information for itself and its specific destination from the totality of the information received. This makes it possible to transmit the target information from the master beacon in a non-directional manner, so that the use of complex coupling loops for dialog traffic can be dispensed with.

In the latter system, therefore, all the target information in question must be emitted one after the other in such rapid succession that a passing vehicle can receive and store all this information and thus also the target information specifically required by it in the short time of passing. In order to be able to transmit all the associated information in a short time in the case of a very large number of possible destination points, it is therefore necessary to combine destination points with the same guidance information into destination areas and to jointly assign the corresponding guidance information for the transmission. In the system according to EP-A-0 025 193, a selection network is provided for this purpose, the meshes of which increase exponentially with increasing distance from the beacon location. In this way, the information can be transmitted for a very large target area with a reasonable amount of data.

However, since the road network does not always run regularly and, in particular, destination points that are close to each other due to geographical conditions must be approached on different routes, difficulties can arise if such points are located in a common target area in the regularly constructed selection network. This applies, for example, to target points on different sides of a river if there is no bridge in the area of the target points. In order to remedy this difficulty, a further development of this system has already been proposed in EP-A-0 261 450 in such a way that the target areas are formed from target segments in the form of convex polygons, which are defined on the basis of geographical boundary areas. As a result, there are already additional options for assigning target points with the same guidance information to a common target area, so that the ge Common guidance information only needs to be transmitted once.

In the system described there, the target areas are determined by the coordinates of their corner points, and the assignment of a specific target point to the target area of transmitted guidance information is done by comparing the target point with the corner points of the respective target areas. Only target points that lie within the convex shape of the polygon can be correctly assigned.

As it turned out, however, the geographical conditions that determine the route to certain destination points are so complicated in many cases that destination points with the same guiding information do not lie within a convex surface structure. In such cases, according to the previous system, several target segments or target areas must be formed and transmitted with the same guidance information.

The aim of the present invention is to provide a method in a control system of the type mentioned at the outset, with which all target points can be combined with a specific control information for transmission to a common target surface, even if the target surface does not have a continuously convex shape, in which Vehicle the relevant guidance information can be easily selected for a specific destination.

According to the invention, this method for the transmission and for the selection of guidance information to be displayed has the following features:
- When a vehicle passes a stationary beacon, it receives guidance information for all of the target points that can be reached from the beacon;
- For the transmission of the guidance information, all target points for which the same guidance information applies are combined to form one target area, the boundary line for each de target area is formed by a polygon of any kind;
- This traverse for each target surface is transferred with its geometric course;
- The associated target information is transmitted to each target area;
- In the vehicle, the target area belonging to it is selected by entering a target point, namely by comparing the target point coordinates with the boundary lines (polygon lines) of the individual target areas and
- The guidance information belonging to the selected target area is displayed in the vehicle.

According to the invention, the corner points of the polygons themselves are instead related to the target point when determining in which target area a selected target point lies, rather the boundary lines of the polygons are related, so that even with concave border lines a reliable assignment of target point and target area and thus information belonging to the target area is possible. In this way, the number of target areas and thus the number of guidance information to be transmitted can be kept small compared to the size of the entire target area, whereby a very large target area, for example of the size of the whole of Europe, can be detected at a given transmission rate on a beacon can.

The target area for a specific target point is expediently determined by examining a coordinate cross placed through the target point for intersections with the boundary line of each target area, the target area including the target point being determined from the number of intersections. In this case, the guidance information of that target surface is advantageously selected for the target point, with the boundary line of which the coordinate cross has an odd number of intersection points in each direction. In this way, even with boundary lines with concave sections, a safe Determination can be made on which side of the border line the selected target point lies.

For the transfer of the boundary line course for the target areas, however, it is expedient to transfer this in the form of the coordinates of their corner points. Otherwise, the same considerations apply to the transmission of information, for example for the organization of the transmission telegrams or for the gradation from small target areas in the near area to large target areas in the far area, as in the previously registered systems, for example in EP-A-0 261 450 and EP-A-0 025 193, to which express reference is made here.

• FIG 1 die schematische darstellung eines Zielgebietes, das in drei Zielflächen unterteilt ist,
• FIG 2 ein Flußdiagramm für die Zuordnung eines Zielpunktes zu einer bestimmten Zielfläche.

An exemplary embodiment of the invention is explained in more detail below with reference to the drawing. It shows

• 1 shows the schematic representation of a target area which is divided into three target areas,
• 2 shows a flow chart for the assignment of a target point to a specific target surface.

1 schematically shows a target area in the form of a rectangle with the corner points E7, E13, E14 and E15, which is subdivided into three target areas F1, F2 and F3 due to geographical or traffic-related circumstances. This target area can be part of an even larger system area, so that the target areas F1, F2 and F3 are in the long range (in the sense of EP-A-0 261 450). It is assumed that a vehicle FZ receives guidance information for the entire target area from a beacon BK. First guide information Li1 is used for guiding the vehicle S to all points in the target area F1, the guide information Li2 for guiding the target area F2 and the guide information Li3 for guiding the vehicle to all selected target points in the target area F3. The boundary lines of the individual target areas are designed as any polyline, whereby concave and convex areas alternate.

A target point Z was selected in the vehicle. From the data received by the beacon BK, that guidance information must now be selected in the vehicle that corresponds to the destination point entered in the vehicle, ie guides the vehicle driver to the selected destination point Z. It must therefore be determined in which target area the target point Z lies with the coordinates x _z and y _z . For this purpose, a coordinate cross with the axes in the east-west direction and north-south direction is placed through the point Z, and it is examined how many intersection points this coordinate cross in each direction with the boundary lines of the individual target areas F1, F2 and F3 having.

In FIG. 1, the boundary lines are each designated GR1, GR2 and GR3, with certain sections of these boundary lines naturally being assigned to both the one and the other target area. The target area F1 is defined by the polygon with the corner points E1, E2, E3, E4, E5, E6, E7, E8 and E1, the target area F2 by the corner points E8, E13, E14, E12, E11, E10, E9 and E1, while the target surface F3 has the corner points E1, E9, E10, E11, E12, E15, E6, E5, E4, E3, E2 and E1.

To assign the target point Z to a target area, proceed as follows:
If one follows the x _z coordinate from point Z to the east, then the intersection line GR1 results in the intersection points SO1, SO2, SO3 and SO4 (four intersection points). The y _z coordinate has two intersections with the boundary line GR1 in the north direction, namely SN1 and SN2. In the west direction, the x _z coordinate with the boundary line GR has no intersection point, nor does the y _z coordinate in the south direction.

If the boundary line GR2 is now examined in the same way, there are only two intersections with the x coordinate in the west direction, namely the intersections SW1 and SW2, and two intersections of the y coordinate in the south direction, namely the intersections SS1 and SS2.

For the boundary line GR3 for the area F3, on the other hand, there are intersections with all four coordinate branches, namely:
- Five intersections in the east direction, namely SO1, SO2, SO3, SO4 and SO5;
- An intersection in the north direction, namely SN1;
- An intersection in the west direction, namely SW1 and
- An intersection in the south direction, namely SS1.

Since an odd number of intersections with the coordinate cross through Z was found for the boundary line GR3 in every direction, the point Z must lie in the target area F3. In the vehicle, the guide information Li1 is accordingly selected to achieve the target point Z.

2 shows an example for the comparison between the coordinate cross of the target point and the individual straight sections of the boundary lines in the form of a river flow chart. As an example, the section between the corner points E1 (x₁, y₁) and E₂ (x₂, y₂) is selected from the boundary line GR1.

After the start step S1, step S2 examines whether the coordinate y _{z is} between y 1 and y 2. If this is not the case, then there is no intersection in the east-west direction and it is possible to proceed directly to step S7. In the other case, the x coordinate of the intersection SOW in the X direction is calculated (step S3). If this x coordinate x _{ow has been} calculated, it is checked in step S4 whether it is smaller than x _z or larger. Accordingly, it is determined in steps S5 and S6 that the intersection SOW lies west or east of Z. Depending on the result, an intersection SW or an intersection SO is counted in corresponding memories.

In step S7, the same process is repeated for the north-south direction. It is checked whether x _{z is} between x₁ and x₂. If this is the case, the y coordinate of the intersection SMS in the north-south direction is checked in step S8. So will in step S9 it is examined whether this y coordinate y _{ow is} smaller or larger than y _z . Accordingly, an intersection point south of Z or north of Z is determined (steps S10 and S11), and a corresponding intersection point is counted in the associated memories SS and SN.

This procedure must be carried out for each straight section of a boundary line, for example for the boundary line GR1 for the straight sections E1-E2, E2-E3, E3-E4 etc. to E8-E1. The same applies accordingly to the boundary lines GR2 and GR3. At the end, the intersection memories SW, SO, SS and SN need only be queried for each boundary line. As mentioned above, the point Z lies in the target area whose boundary line has an odd number of intersection points in each direction.

Claims (4)

1. Method for transmitting guidance information and for selecting guidance information to be displayed in a traffic guidance system with the following features:
- A vehicle (FZ) receives guide information (LK1, LK2, LK3) when it passes a stationary beacon (BK) for all of the target points (Z) that can be reached from the beacon;
- for the transmission of the guidance information, all target points for which the same guidance information applies are combined into one target area (F1, F2, F3), the boundary line for each target area being defined by a polygon (E1, E2, E3, E4, ES, E6, E7, E8; E8, E13, E14, E12, E11, E10, E9, E1; E1, E9, E10, E11, E12, E15, E6, E5, E4, E3, E2) of any kind;
- This traverse for each target surface is transferred with its geometric course;
- The associated target information is transmitted to each target area (F1, F2, F3);
- In the vehicle, the target area (F3) belonging to this is selected by entering a target point (Z), by comparing the target point coordinates (x _z , y _z ) with the boundary lines (polygons) of the individual target areas and
- The guidance information (Li) belonging to the selected target area is displayed in the vehicle. 2. The method according to claim 1, characterized in that for determining the target surface (F3) a coordinate cross placed by the target point (Z) on intersection points (SO1 to SO5, SN1, SN2; SW1, SW2; SS1, SS2) with the boundary line ( GR1, GR2, GR3) of each target area (F1, F2, F3) is examined, the target area (F3) including the target point being determined from the number of intersection points. 3. The method according to claim 2, characterized in that the Leitinforma for the target point (Z) tion of the target surface (F₃) is selected, with the boundary line (GR3), the coordinate cross has an odd number of intersections in each direction. 4. The method according to any one of claims 1 to 3, characterized in that the boundary line course for the target areas (F1, F2, F3) is transmitted by the coordinates of their corner points (E1 to E15) and by the sequence of the corner points.

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