GB2142143A

GB2142143A - Travel direction display

Info

Publication number: GB2142143A
Application number: GB08411031A
Authority: GB
Inventors: Herbert Bilitza; Ernst Peter Neukirchner; Otmar Pilsak; Dietmar Schloegl
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1983-06-21
Filing date: 1984-04-30
Publication date: 1985-01-09
Also published as: IT1175504B; IT8421407A0; GB8411031D0; GB2142143B; DE3322195C2; DE3322195A1

Abstract

The recommended turning for a driver to take at an intersection is determined from a memory, and displayed in a manner wherein the geometrical structure of the road intersection from the relevant driver's angle is visible. The display device exhibits a star structure and is controlled so that only the bars (2,4,5,7,8) forming the junction layout are represented. Those roads forming the recommended route 4,7 are represented in a different manner from the others. The urban plan memory receives its information from a location system. <IMAGE>

Description

SPECIFICATION Travel direction display The invention starts from a device to display an intersection structure from the driver's angle according to the pre-characterising clause of the main claim. It is already known in the case of tracking and information systems for motor drivers to represent road sections by means of graphic symbols. Such a motor driver's information system has become known, for example, under the name ALI. The display operating section employed there gives instructions as to the direction in which the car driver must steer his vehicle in order to reach his destination as quickly as possible, without coming into traffic jams for example. This system, which is principally used for motorways, has been found very successful.However, this information is not sufficient if it is desired to introduce such a car driver's guide system into closely meshed districts, for example in towns. Particularly in large towns, intersections exhibit a large number of possible branches, so that only incomplete information can be given to the driver by the known display devices. It is particularly unfavourable if the driver of a vehicle is approaching a road intersection with a large number of branches and he then has only an incomplete display of the intersection. This can easily result in incorrect decisions, so that the driver selects a wrong route, because in addition to the display device he is also occupied by the generally heavy traffic in the intersection.

Advantages ofthe invention The device according to the invention with the characterising features of the main claim has the advantage compared to the above that the driver receives an indication of the entire intersection structure even before the intersection. The road on which the driver is reaching an intersection is always represented in the same place. The driver is continuously able, before the intersection, for example beneath a street lamp, to learn the appearance of the intersection and, on the basis of the different thicknesses of the intersection arrows, to decide in good time which lane he can most advantageously take.

The measures enumerated in the subordinate claims make possible advantageous further developments and improvements of the device disclosed in the main claim. It is favourable to take the intersection structure from an urban plan memorywhich enables the corresponding memories on the basis of a location system. It is thereby possible in a simple manner to represent the intersection information on the display, which is advantageously constructed as an LCD display. A substantial simplification of circuit technology occurs in that the information of the memory is referred to the driver's route and converted in a computer.By means of this measure it is unnecessary to reserve a particular memory place for each direction from which the driver approaches the intersection, but the storage of the intersection once for all relative to a specific point, for example to north, is sufficient.

Drawing An exemplary embodiment of the invention is illustrated in the drawing and explained more fully in the following description.

Figure 1 shows the display device diagrammaticalliy and Figure 2 shows a circuit arrangement to modulate the display device.

Description of the exemplary embodiments Tracking systems for individual traffic on motorways and urban road systems have been proposed and tested in practice with increasing frequency in recent times. The object of these systems is to guide the driver of a vehicle to his destination by the fastest possible route, whilst disruptions of road traffic, such as traffic jams or work sites should be taken into consideration. Such a tracking system has become known, for example, under the name EVA and described in NTZ, volume 36, 1983, issue 4, 204ff. Further information, particularly for route searching, for this navigation system is described loc. cit. on page 220ff. It is an essential point of such systems to communicate reliable information to the car driver, so that he is enabled to find the routes ascertained by the system reliably.

Figure 1 shows a display device 15, by which a vehicle driver can be given an optical representation of the travel direction recommendations, the travel direction recommendation being referred to the geometrical structure of the road intersection from the driver's angle. This results in the driver being given particularly simple and reliable information, so that he can get his bearings easily. The actual display device 15 is constructed as an LCD display and exhibits, in the exemplary embodiment, eight direction arrows 0 - 7 which can be modulated by the electronics to be described later. The display device according to Figure 1 employs a symmetrical, eightarmed star structure, in which the individual arms can be switched on and off separately and their width can be varied in two stages.However, the invention is not restricted to eight-armed structures, the number of the arms may be extended as desired for higher resolution.

The arm 4 of the star structure is always allocated to the road on which the driver is approaching an intersection, the arrival road. All other departing roads are allocated to the eight possible angular regions 0 - 7 of the symmetrical star, corresponding to their angle relative to the arrival road 4. All arms for which at least one allocation exists in the urban plan memory are switched on on the display device.

The recommended travel direction is ascertained by a route search system and represented on the display by a wide representation of the associated star arm (arms 4, 7).

Figure 2 shows in the form of a block circuit diagram an arrangement to modulate the display control means. The instantaneous information as to the position of the vehicle must be obtained by the location system 10. The data ascertained there are transferred to the urban plan memory 11, in which, for example, the information on the urban plan of a town or on the local conditions of a region is stored.

This information is transferable into a computer 12 which performs the determination of the angles of the departing roads relative to the arrival road.

These data are transferred to the display modulation means 14, which modulates the display device 15.

The intersection can be represented by means of this arrangement. The route search system 13 also communicates with the modulation device 14. The most advantageous route is determined by the route search system 13 and represented widened on the display. This is the case, for example, of the arms 4 and 7 in Figure 1. A vehicle driver who has to travel on the arm 4 for example, now knows that he has to make a half left turn at the intersection, and that the remaining three roads indicated serve only to assist him in finding his way.

The representation of the relevant intersection structure from the driver's angle facilitates the interpretation of the overlaid travel direction recommendation and hence his orientation.

The corresponding memory addresses of the urban town memory 11 which contain the information of the next intersection are called up by the location system 10. The memory now contains the angles of all roads departing from and arriving at the intersection, the angle referring to the north direction. The information as to the present arrival road also comes through the location system. This serves to address the memory and permits both the detection of the angle which the arrival road forms with the north direction and also the detection of all the angles of the departing roads relative to the north. The relative angles of the departure roads to the arrival road are obtained from the angular differences of the departing roads to the arrival road and are determined in the computer 12. An allocation of the calculated angles to the eight arms leads to modulation of the corresponding arm of the display.

The more arms are provided in the display device, the more accurate does the representation become.

The number of arms is essentially determined by the resolution of the display device and by the size of the admissible data words. It is possible to represent all roads relatively accurately depending upon the degree of resolution by rounding off.

Claims

1. Device to display an intersection structure from the driver's angle by means of a display device wherein different travel direction possibilities and the route can be indicated in different thicknesses, characterised in that the display device (15) exhibits a star structure, that the road on which the driver is approaching the intersection is always associated with a specific arm (4) of the star structure, and that only those arms (0, 2, 4, 5, 7) which correspond to the intersection structure are switched on.

2. Device according to Claim 1, charcterised in that the display device (15) is constructed as an LCD display.

3. Device according to Claim 1 or 2, characterised in that the intersection structure is derived from an urban plan memory which enables the corresponding memories on the basis of a location system (10).

4. Device according to any of the previous Claims, characterised in that the information of the memory (11) is referred to the driver's route and converted in a computer (12).

5. A display device substantially as herein described with reference to the accompanying drawing.