EP0790591B1 - Locationdatabase for determining routes within a road traffic network - Google Patents

Description

The invention relates to a location database for the determination of routes within a traffic network and one Radio receiver with a device for receiving and Decoding of digitally coded traffic reports.

With the radio data system (RDS) an additional and inaudible transmission of digital data parallel to Broadcast programs in a data channel. Specifications of the radio data system for FM radio are among others in the publication Tech. 3244-E, March 1984 of the European Runfunk Union (EBU). Radio receivers with suitable RDS decoders can transmitted data in addition to radio reception with the Record and decode the same receiver. For the Data transmission is 32 groups of 104 bits each provided, each of the transmitted groups one each certain service is assigned. Group 8a is for Time for the transmission of digitally coded Traffic announcements provided.

The structure and coding of these traffic reports are in CEN Draft pr. ENV / 278/4/1/0011 set on the Proposed norm ALERT C, November 1990, published by the RDS ATT ALERT Consortium. The essential elements A traffic announcement is the place of the event (Location) and the event (Event). These details are cataloged, that is, every traffic-relevant place and a unique code for every traffic-relevant event is assigned. The concatenation of the locations in the location table along existing roads shows the course. Except the usual facilities of a receiving device with a RDS decoders are used to use the traffic information channel TMC (Traffic Message Channel) Decoding devices for Storage, further processing and output of the Traffic announcements required.

The one for decoding the digitally encoded Traffic reports required location databases exist from lists of junctions, motorway junctions, Motorway triangles, exits to parking lots and the like Locations, each on a traffic route (motorway, Bundesstraße) lying places by references to each other are chained. Since not all places from both The directions are to be reached, the concatenations indicated separately for both directions by going to each location a predecessor or successor in the location database is entered. If a place has no successor, for example at the end of a street, this is indicated by marked a special entry. Places like For example, intersections on multiple traffic routes are with all of these traffic routes with each other location codes entered.

This location database structure, so no relationships between the same places on different traffic routes are recognizable, is sufficient for the decoding of the Traffic-news. For the output of the decoded Traffic announcements are then the same for each Place also provided the same name, which is in coded form each time the same location appears in the location database is specified. However, this information is only used to output the actual name as an alphanumeric display or Voice output.

There is an advantage of digitally coded traffic reports in that these are not as language patterns, but as data are available, which are processed in a variety of ways can. This makes, for example, a selection of Traffic announcements possible, so the driver only receives those traffic reports that affect his expected red and possibly in question receive upcoming redirects.

It is a prerequisite for such a selection however, that the computer carrying out this selection the expected route is known. This can be done by the expected route is entered manually. Another option is the destination enter and have the route determined by the computer. Suitable calculation methods are known and for example available within PC programs. It will however, a road map is required which is the one in question upcoming roads and intersections as well as the distances between the intersections and other places.

EP-A-0 760 565 A1 describes one method and one Device for selecting traffic information known become, in which a route guidance by means of Traffic information is possible. For this purpose, the Additional table necessary for RDS-TMC operation Information that enables route calculation. The table is enriched with a board of complementary attributes, which specifies the distance between each location on the table are adjacent to the location in question. Furthermore, too Indications given as two places on a bypass can be achieved that are not in the RDS-TMC table is included. This will make it possible to find the way between two places or a detour to be taken to calculate.

The object of the present invention is a Location database for the determination of routes within a Traffic network indicate the one hand on this Location database based and on the other hand also a decoding of digitally coded traffic reports according to specified Procedure allows.

This object is achieved by the features of patent claim 1 solved.

The location database according to the invention also has the Advantage that only a small storage capacity per location is required. In addition, the inventive Location database on already created for the TMC system Location databases are largely used by only information is added.

A reduction in storage capacity is according to one Continuing education possible because of each location and traffic route just a cross reference to the same place on another Traffic route is provided, with locations on more than two traffic routes cyclically executed the cross references are. This gives each of these locations only one Cross-reference. It is then not necessary per location Storage space for the largest number of possible Provide traffic routes on which a place lies.

There are many in the known location database for the TMC system Places exist that do not include predecessor / successor relationships no links to other streets or places have. The following is in connection with the location database according to the invention describes a location as genuine, if it has a cross-reference. The other places will be as fake designated. When determining a route from Wanted entry to entry, so that without further Many measures in the location database according to the invention fake places are edited, which makes a significant Computational effort results. This effort can be combined with another Further development of the invention can be reduced in that in the data sets for locations on a traffic route, which are also on another traffic route, references to the each next place on the traffic route, which is also on at least one other traffic route are. This enables the search algorithm to go straight from to jump from one real place (network node) to the next.

Location databases used for decoding digitally encoded Traffic reports serve, do not have to be a complete one Road network included. In such location databases are missing for example, crucial in some places Road connections: partly because parts of the Motorways are still under construction or because of connectors are not listed in the location database. At a appropriate coding of traffic reports on this The limits of the local database can be taken into account Traffic reports can still be decoded.

When planning the route, the driver is still the one take into account the route concerned and for example in Take a few kilometers of main road instead of one Detour to drive on highways. So that the determination of the Route these anyway in the local database as dead ends can take into account the streets shown is according to a another development of the invention in location databases, which contain the coordinates of the locations, provided that furthermore, locations not encoded by a The traffic route provided for traffic reports is connected, are cross-referenced.

These cross references and the inequality of the Coordinates of the affected places can be the route investigating computers recognize that the affected locations are not are the same, but are the endpoints of another traffic route.

For location databases where distances between the Locations are given, the consideration of is not for the decoding of the traffic routes provided is possible that further selected places that are except on one for the Decoding provided on another traffic route for the decoding is not intended traffic route Reference is made to the further traffic route and that the further traffic route with the places where clues are available on the further traffic route in the Location database is listed. Here, the length of the other traffic routes are taken into account in that Distances between locations on the others Traffic routes are stored.

An evaluation of the additional routes in route determination is also possible in that for the additional ways Street type (location type) is saved.

Those records, which cross references and references to other traffic routes contain a larger number of information bits. Depending on the design of the Location database according to the invention can be such Records by multiple words, for example 16-bit words, longer than records of places without cross references and Be clues. By replenishing this additional A database is created with spaces with spaces constant record length. This simplifies Management of such a database, however, leads to increased Memory requirements. To such an increase as little as According to another training, keeping it possible is possible provided that one in each of the data sets Additional information from at least one bit about the Existence of cross references and / or references and where applicable, on the number and / or type of Cross-references and / or the information is included.

A radio receiver with a device for receiving and for decoding digitally coded traffic reports with A location database is identified by a Establishment of routes using the Location database according to one of the preceding claims.

To the often lower cruising speed on the others Traffic routes can be considered at the Radio receiver according to the invention can be provided that at the determination of routes an evaluation of the lengths of the Traffic routes take place according to the respective road type.

A further development of the radio receiver according to the invention consists of the determined routes for the selection of received digitally coded traffic reports that only those traffic reports are used are output which relate to the determined routes. According to a further development, it can be provided that the routes determined can be represented graphically.

Fig. 1

einen Ausschnitt aus einer ersten erfindungsgemäßen Ortsdatenbank,

Fig. 2

eine schematische Darstellung einer Kreuzung von zwei Verkehrswegen,

Fig. 3

eine schematische Darstellung einer Kreuzung von drei Verkehrswegen,

Fig. 4

einen Auszug aus einer zweiten erfindungsgemäßen Ortsdatenbank und

Fig. 5

eine Straßenkarte zur Erläuterung der Ortsdatenbank gemäß Fig. 4.

Exemplary embodiments of the invention are shown in the drawing using several figures and are explained in more detail in the following description. It shows:

Fig. 1

a section from a first location database according to the invention,

Fig. 2

a schematic representation of an intersection of two traffic routes,

Fig. 3

a schematic representation of an intersection of three traffic routes,

Fig. 4

an extract from a second location database according to the invention and

Fig. 5

4 shows a road map to explain the location database according to FIG. 4.

The section shown in Fig. 1 from a Location database contains six records, four of which are to locations on the A1 motorway, one to a location on the A61 motorway and another to a location on the A53 motorway Respectively. As with the location database, each record contains according to ALERT C, a location code, a location type (Type), the indication of the street number (Road Number), the type the junction (Exit Type), the name of the respective Place and references to the previous and the following Location (offset +, offset-). In the location database shown the place names are written out for the sake of clarity shown, located in the realized location database there is, however, a place name code below which in a Place name database the place name is stored. This one has the advantage that the location database does not differ long place names must be taken into account that the encoded place names take up less space and that if necessary, foreign language in the place name database Place names for foreign drivers should be listed can.

As can be seen from Fig. 1, are seen geographically same places - in this case the place Bliesheim - in the Location database listed completely independently of each other and also provided with different location codes. To one To enable route determination are shown in the Location database cross-references (cross-ref.) For those locations registered that lie on several traffic routes. Since the Place Bliesheim - what is meant here is not the community, but the motorway junction - they are on three traffic routes Cross-references cyclically interchanged, so that with each data record only a cross reference is necessary.

There are references under the location code 4144 (Bliesheim an der A1) to the previous location 4143, the subsequent location 4145 and the geographically identical location 6380 on the A61 motorway entered. The latter contains a reference to the location 7235 on the A553 and this one Cross-reference to location 4144 on the A1 motorway. On Program for determining routes can thus be easier Realize that places 4144, 6380 and 7235 are one represent only place within the transport network. in the Incidentally, there is a record for place 7235 Feature. Since the A553 motorway ends at this location as a subsequent place a special mark entered, namely 0xffff.

00:

kein Querverweis, beim Auslesen der Datenbank aus dem Speicher werden die auf "Offset-" folgenden Daten als Beginn des nächsten Datensatzes angesehen,

01:

Querverweis auf einen anderen Verkehrsweg,

10:

"Sprungverweis", d.h. Hinweis auf einen echten Ort,

11:

"fiktiver Verweis", d.h. Hinweis auf einen weiteren, fiktiven Verkehrsweg.

As already mentioned, storage space can be saved in the location database according to the invention by using additional information. If two bits are inserted per data record in the database according to FIG. 1, these can have the following meaning, for example:

00:

no cross-reference, when reading out the database from the memory, the data following "offset" are regarded as the start of the next data record,

01:

Cross-reference to another traffic route,

10:

"Jump reference", ie reference to a real place,

11:

"Fictitious reference", ie reference to another, fictitious traffic route.

In the latter three cases, the "offset" interpreted the following data as a cross-reference or reference.

2 shows sections of two streets A, B in the area of one Crossing. In the known location database, locations 1, 2, 3, 4 registered as belonging to the street B, while the Locations 5, 6, 7, 8 are designated as locations on street A. Arrows between these locations indicate the references Offset + and Offset on. Geographically, however, places 3 and 7 is the same as what occurs in the location database according to the invention a cross-reference 9 is documented.

In the example shown in FIG. 3, another crosses Street C, streets A and B in the same place. In the known location database, however, are locations 10, 11, 12, 13 only listed in connection with street C. As before 1, the locations are therefore 3, 7 and 12 with cross references 14, 15 and 16 provided in cyclical sequence to a different "location" within each the intersection.

Fig. 4 shows a section of a location database, the Locations in the area shown as a road map in Fig. 5 contains. In the location database according to FIG. 4, the Autobahn A31 a gap between the junctions Nürnberg-Gostenhof and Nürnberg-Hafen-Ost on what at the Entries 0xffff is recognizable. Since using intermediate city expressways it makes sense to do this when determining a route be taken into account. In the location database according to FIG. 4 are therefore cross references to the places 6644 and 6645 Places 15006 and 15007 on one with respect to the Location database fictional street F between these two locations specified. A place type was used for these two places Designation FCT_LOC selected, which means that these places lying on a fictional street. According to her The endpoints of this fictional road are the Provide locations with references Offset +, Offset- and 0xffff. These locations also have cross-references to the locations 6644 and 6645, each with a geographical Form place.

Since the shortest route and Alternatives are to be found, is an indication over the length of a mesh edge as an optimization criterion required. There are predecessors and in the location database Successor of a node specified, but one is missing Information about the evaluation of these relationships. It is therefore an addition of this information is required, whereby under Rating does not necessarily understand the distance because there are other criteria when choosing the route Can play a role. So one factor comes into consideration: a combination of route, road conditions, average journey time and other influences.

A simple form of the evaluation criterion is the distance, which can exist as such in the location database or can be calculated as the straight line between two locations with the coordinates x ₁ , y ₁ and x ₂ , y ₂ as follows: s = [(x 2 -x 1 ) 2 + (Y 2 -y 1 ) 2 ] ½ ,

Another form of length evaluation for route search can be done according to the so-called taxi driver standard using the following equation: s = x 2 -x 1 + y 2 -y 1 , This estimation can be carried out much faster by a simple processor.

Claims (12)

1. Location database for ascertaining routes within a public road network using a location database which is provided for decoding digitally coded traffic announcements and contains locations required for decoding digitally coded traffic announcements as location codes, where a respective location code as a public road and references to neighbouring locations situated on the same public road associated with it in a data record, where the location codes are provided with cross-references (9, 12, 14, 16) which refer to the same location (3, 7, 12) on other public roads within the location database, and where the cross-references are respectively formed by the location code of the location situated on the other public road.
2. Location database according to Claim 1, characterized in that only one cross-reference to the same location on another public road is provided per location and public road, the cross-references (12, 14, 16) being produced cyclically for locations on more than two public roads.
3. Location database according to one of the preceding claims, characterized in that the data records for locations on a public road which are situated on a further public road contain references to the respective next locations on the public road which are likewise situated on at least one further public road.
4. Location database according to one of the preceding claims, where the coordinates of the locations are indicated, characterized in that locations which are connected by a public road not provided for coding traffic announcements are additionally provided with mutual cross-references.
5. Location database according to one of Claims 1 to 3, where distances between the locations are indicated, characterized in that selected locations situated not only on a public road provided for decoding but also on a further public road, which is not provided for decoding, additionally have an indication of the further public road provided for them, and in that the further public road is listed in the location database with the locations for which indications of the further public road are available.
6. Location database according to Claim 5, characterized in that distances between the locations on the further public roads are stored.
7. Location database according to one of Claims 5 or 6, characterized in that the road type (Location Type) is stored for the further public roads.
8. Location database according to one of the preceding claims, characterized in that the data records each contain an additional information item comprising at least one bit relating to the presence of cross-references and/or indications and possibly relating to the number and/or type of the cross-references and/or indications.
9. Broadcast radio receiver having a device for receiving and for decoding digitally coded traffic announcements using a location database, characterized by a device for ascertaining routes using the location database according to one of the preceding claims.
10. Broadcast radio receiver according to Claim 9 characterized in that, when ascertaining the routes, the lengths of the public roads are assessed on the basis of the respective road type.
11. Broadcast radio receiver according to one of Claims 9 or 10, characterized in that the ascertained routes are used for selecting received digitally coded traffic announcements such that only those traffic announcements affecting the ascertained routes are output.
12. Broadcast radio receiver according to one of Claims 9 to 11, characterized in that the ascertained routes can be displayed graphically.

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