EP0290679B1 - Device for receiving and processing road information messages - Google Patents

Abstract

Device for receiving and processing road information messages transmitted in digital form, each message including at least a first section for indicating the zone of the road network to which the message refers, which device includes for the control of the data processing a data processing unit which is connected to a bus for the transfer of data, to which bus are also connected a reception memory for temporarily storing the received messages, a selection unit enabling the selection from among the stored messages of those concerning a zone to be designated and a presentation unit for presenting the selected messages. The device also includes a message analysis unit which includes a zones table memory, which analysis unit is provided for recognizing the zone in question each time a message is received on the basis of the said first section of the received message and for storing in the zones table, by means of at least one indicator for each message, the received messages according to the zone to which they belong, which selection unit is provided for accessing the zones table and for carrying out the said selection by fetching messages for the designated zone in the zones table.

Description

The present invention as defined in the claims relates to a device for receiving and processing road information messages sent in digital form, each message comprising at least a first section for indicating the area of the road network to which it relates. the message, which device comprises for the control of data processing a data processing unit which is connected to a bus for data transfer, to which bus are also connected a reception memory for temporarily storing the messages received, a unit for selection for selecting from the stored messages those relating to an area to be designated and a presentation unit for presenting the selected messages.

Such a device is known from the article entitled "Design FM receiver which implement the data dissemination system" SR Ely D. Kopitz and published in the Journal of the EBU Technical ^No. 204, April 1984 , p. 50-58. In the system described, the traffic information messages are coded according to the specifications of the radio data system RDS (Radio Data System) and transmitted from a radio station. A first section of each message sent indicates the area of the road network to which the message relates. This area can be formed by a road or by a region of a country. When the device receives a traffic information message, it will, temporarily under the control of the data processing unit, store the message in the reception memory. The user who wishes the traffic information messages for a zone according to his choice will use the selection unit to indicate the zone chosen to the central unit. Under the control of this data processing unit, the content of the reception memory will be scanned entirely in search of messages relating to the designated area. Each message thus identified will be transmitted to the message presentation unit that the presentation to the user. Thus the user is able to receive only traffic information messages relating to the area of his choice.

A disadvantage of the known system is that during each request made by the user, the reception memory is scanned entirely. This imposes a heavy load on the data processing unit during each request and can, when there is a large quantity of messages stored in the reception memory, impose a relatively long search time.

In patent application GB-A-2 050 767 a device for receiving and processing road information is described, in which for each zone of the road network a reception memory is provided.

The invention aims to provide a device for receiving and processing traffic information messages where the storage and retrieval of information is organized in a more efficient manner.

A device for receiving and processing traffic information messages according to the invention is characterized in that the device comprises a message analysis unit which comprises a memory-table of the zones, which analysis unit is provided for recognizing on each reception of a message the zone in question on the basis of said first section of the message received and to store in the zone table, by means of at least one indicator for each message, the messages received according to the zones to which they belong , which selection unit is provided to have access to the zone table and to carry out said selection by taking messages from the zone table for the designated zone.
The message analysis unit will, after each reception of a message, analyze the first section of the message in order to recognize the zone to which it relates. When the analysis unit has recognized the zone to which the received message relates, it will store at least one indicator for this message in the zone table at a location designated for this zone. This indicator is for example formed by the address where the message in question is stored in the reception memory. When the user has indicated his choice, the selection unit will select from the zone table only the place designated for the zone requested. Thus, the selection is made more quickly since it is no longer necessary, during each request, to browse the entire content of the reception memory but only to take the indicators stored in the place designated for the requested area.

A first preferred form of a device according to the invention is characterized in that the memory-table of the zones includes a route table where the messages are arranged according to the routes to which they relate and in that the indicators consist of the addresses at which the messages in question are stored in the reception memory. Thus the selection and the arrangement in the route table can be carried out on the basis of the category and the number of the routes.

A second preferred form of a device according to the invention is characterized in that the device is equipped with a tracking unit for locating in a received message the region to which it relates, which message analysis unit is linked to the tracking unit and in that the zone memory table includes a table of regions where the messages are arranged according to the regions to which they relate and in that the indicators consist of the addresses to which the messages in question are stored in the reception memory.
The locating unit makes it possible to locate in a received message the region to which it relates and thus offers the possibility of carrying out a selection and storage on the basis of the regions.

Preferably, the device comprises a correspondence-routes-regions table for storing for a predetermined number of roads in the road network to which the correspondence-routes-regions table relates an overflow index indicating the maximum number of traffic messages for each of the routes. of said predetermined number, said device being equipped with a verification unit connected to the correspondence-routes-regions table and to the routes table to verify whether the number of messages stored for each route does not reach the number indicated by l overflow index for the route in question, and to eliminate the presence of a message for a route for which the number of messages stored in the route table has reached the number indicated by the overflow index.
The use of an overflow index and of the verification unit makes it possible to limit the number of messages to be memorized and to better share the content of the reception memory between the different zones.

Preferably the verification unit is provided for carrying out said elimination of the presence of the oldest message among said number of messages.
The oldest messages are thus regularly eliminated, thus not obstructing the reception memory for the reception of new messages.

Preferably, the locating unit comprises a correspondence table-roads-regions where are stored for each of the roads a predetermined number of roads of a road network at least one index indicating at least one region crossed by the road in question .
The use of a correspondence-routes-regions table allows a certain freedom in the choice of the division of one or more countries into a number of regions. Thus it is possible either to divide a country according to the existing provinces or departments, or to take for each region a predetermined area.

A third preferred form of a device according to the invention is characterized in that the verification unit is also provided for locating with the aid of the correspondence-routes-regions table respectively of the correspondence table-regions-routes to which region respectively to which route relates the message whose presence has been eliminated and to also eliminate from the table of regions respectively of the table of routes the message whose presence in the table of routes respectively of the regions has been eliminated.
When the device is provided with a route table and a region table, it is essential when the presence of a message has been eliminated in one of the two tables, to also eliminate the presence of this message in the 'another table.

In a device where each message message includes at least one sequence composed of two blocks, and where each block comprises an information part and a control part, the control part further comprising an offset word for the synchronization of the blocks, and where for a predetermined block a first and a second word shift is usable, a preferred form of this device is characterized in that, for the first sequence of a message the first shift word is used and for the other sequences of this same message the second shift word is used, and in that the device is provided with a decoder for decoding the offset word of a received message and generating a positioning signal when decoding a first offset word, which device comprises a sequence counter connected to the decoder, which sequence counter is positionable under the control of a positioning signal.
Thus it is possible to distinguish in a received message whether it is a first sequence of a new message or not. The sequence counter makes it possible to check the correct order of reception of the sequences.

Preferably the selection unit is provided with means allowing the selection between an intersection and / or a union of at least two zones.
Thus it is possible to formulate a choice on one or more zones or on an intersection of two or more zones.

In the case where the message comprises several sections in which coded words representing each part of the information of the message are repeated each time, it is advantageous that the device is provided with a conversion memory connected to the presentation unit and which is addressable by different code words and where other code words are stored for the presentation of the message.
Thus it is possible to use the same code words in different countries and to make by means of the other code words a conversion into the language of the user and to store in the conversion memory only the information necessary to cover the or the countries concerned.

Preferably each message has a third section where an offset value is used to indicate another place relative to the place mentioned in the second section, and in that the device is provided with an address generator to form an address for the conversion memory on the basis of the second and third section of the message . Thus it is possible to designate two different places in the same message while limiting the number of bits used in the message.

When the device according to the invention is connected the device is connected to a road navigation system for vehicles, which navigation system is equipped with means for determining a route between a point of departure and a destination, it is advantageous that the system of navigation is equipped with means for transmitting to the selection unit at least one area traversed by said route and for receiving messages concerning the designated area, said means for determining a route being provided for analyzing the received message and for recognizing in the message received if there is a traffic problem in the designated area and to determine a new route in the event of a traffic problem.
When the road navigation system is connected to the device according to the invention, it can itself select the messages for the zone or zones crossed by the route which it has just determined. When it now appears that there is a traffic problem on the initially determined route, the means for determining a route can then determine a new route, in order to circumvent the traffic problem. Thus the device according to the invention can play its part in improving road safety.

• La figure 1 illustre l'environnement dans lequel un dispositif selon l'invention est utilisé.
• La figure 2 illustre les différents composant de la structure en groupe du système RDS.
• La figure 3(a-f) illustre plus en détail un exemple des parties SMR1 et SMR2 d'un groupe en format RDS.
• La figure 4 illustre schématiquement un exemple d'un dispositif selon l'invention.
• La figure 5 illustre au moyen d'un organigramme un exemple d'un processeur d'analyse du message.
• La figure 6 illustre un exemple du contenu d'une partie de deux messages.
• La figure 7a respectivement 7b illustre un exemple de la table de régions respectivements des routes.
• La figure 8a respectivement 8b illustre un exemple de la table de correspondance-routes-régions respectivement de la table de correspondance-régions-routes.
• La figure 9 illustre au moyen d'un organigramme l'analyse du contenu des messages reçues.
• La figure 10 illustre un exemple d'un clavier de commande.
• La figure 11 illustre au moyen d'un organigramme un exemple d'un programme de sélection de messages.
• La figure 12a respectivement 12b, illustre une exemple de la table d'extension respectivement de la table des lieux.
• La figure 13 illustre au moyen d'un organigramme un exemple d'un sous-programme de présentation du message.
• Les figures 14a et 14b illustrent une forme alternative des subséquences SMR2 de deux groupes successifs.
• La figure 15 illustre une différente configuration de la table d'extension.

The invention will now be described in more detail using the figures in which:

• Figure 1 illustrates the environment in which a device according to the invention is used.
• Figure 2 illustrates the different components of the group structure of the RDS system.
• Figure 3 (af) illustrates in more detail an example of the SMR1 and SMR2 parts of a group in RDS format.
• Figure 4 schematically illustrates an example of a device according to the invention.
• FIG. 5 illustrates by means of a flow diagram an example of a message analysis processor.
• Figure 6 illustrates an example of the content of part of two messages.
• FIG. 7a respectively 7b illustrates an example of the table of respective regions of the routes.
• FIG. 8a respectively 8b illustrates an example of the correspondence-routes-regions table respectively of the correspondence-regions-routes table.
• FIG. 9 illustrates by means of a flowchart the analysis of the content of the messages received.
• Figure 10 illustrates an example of a control keyboard.
• FIG. 11 illustrates by means of a flow diagram an example of a message selection program.
• FIG. 12a respectively 12b illustrates an example of the extension table respectively of the places table.
• FIG. 13 illustrates by means of a flowchart an example of a message presentation subroutine.
• Figures 14a and 14b illustrate an alternative form of the SMR2 sequences of two successive groups.
• Figure 15 illustrates a different configuration of the extension table.

Figure 1 illustrates the environment in which a device according to the invention is used. A national (or regional) road information center (1) collects all the road information (accident, roadworks, traffic jam, freezing rain, etc.) that it receives. This traffic information is then selected and that which has a value for the proper functioning of road traffic is transmitted by means of a link 3 to a radio station 4. The radio station is equipped to code the messages and transmit them in accordance RDS (Radio Data System).
This RDS system is for example described in the article "Design of FM receivers which implement the data broadcasting system" by SR Ely and D. Kopitz and published in the EBU-Technical Review ^No. 204, April 1984 p. 50-58. The radio station can also add other messages, to those provided to it by the traffic information center, for example the presence of radar control at a determined location. To this end the radio station is equipped with a unit 5 formed for example of a keyboard and an RDS encoder.
The messages in RDS format are then transmitted on the air using transmitter 2 of the radio station.

To receive messages in RDS format, a vehicle 7 must be equipped with a receiving antenna 8 and a radio receiver 9 capable of receiving and decoding messages transmitted in RDS format. The radio receiver 9 furthermore comprises a radio (cassette player) 10 a keyboard 11. Thus a person traveling on board a vehicle 7 equipped with a radio receiver 9 is able to receive the information in RDS formats transmitted by the transmitter 2. Unlike the known system for broadcasting road information, where the driver is obliged to have his radio receiver open and tuned to a station transmitting in the language of the country the traffic information of the entire national network in serial and at predetermined times, the RDS system offers the user the possibility of having at any time of the day road information of a route or a region according to his own choice and to hear this traffic information in his own language.

• PI (16 bits) c'est l'identification du programme A et les 10 bits de contrôle qui servent à la protection et à l'identification du bloc.
• Les parties B, C et D des autres blocs ont la même fonction dans leurs blocs respectives que la partie A dans le bloc BL1. Le bloc BL2 comprend:
• TG ce sont 5 bits qui identifient le groupe, par exemple information routière, information concernant les programmes radio, etc.
• TP c'est un bit qui informe si la station donne des messages routiers
• PTY ce sont cinq bits qui indiquent le type de programme, par exemple sport, musique classique, etc.
• SYNC c'est un mot de synchronisation utilisé pour le traitement du message par le récepteur; qui se décompose de la manière suivante:
  • EB c'est un bit d'extension qui, lorsque positioné, par exemple à la valeur EB=1 indique une autre application du message que celle initialement prévue, par exemple un radiotexte
  • BB c'est un bit qui indique une liaison entre les messages successif dans ce sens que sa valeur est changée chaque fois qu'un nouveaux message n'ayant pas de rapport avec le précédent message est émis. Par exemple si les groupes, d'un message N ont le bit BB=1, les groupes des messages N-1 et N+1 auront le bit BB=0.
  • SI ce sont trois bits d'identification de séquence qui servent à identifier l'orde des séquences dans un message.

Si par exemple un message comporte trois séquences, la première respectivement la seconde et la troisième séquence auront SI=010 respectivement SI=001 et SI=000. Un message comportera donc dans l'exemple choisi huit séquences au maximum. L'avantage du comptage par décrémentation réside dans le fait que le système peut ainsi être au courant du nombre de séquence d'un même message qui suiveront et peut aussi détecter si des séquences sont manquantes. Les blocs BL3 et BL4 comprenent SMR1, SMR2 ce sont deux sous-séquences de chacune 16 bits comportant les informations routières même et dont l'ensemble forme une séquence identifiée par les bits SI.Figure 2 illustrates the different components of the group structure of the RDS system. The group has 104 bits and is divided into four blocks. Each block is made up of a 16-bit information part and a 10-bit part for protecting this information. The BL1 block includes:

• PI (16 bits) is the identification of program A and the 10 control bits which are used to protect and identify the block.
• Parts B, C and D of the other blocks have the same function in their respective blocks as part A in block BL1. BL2 block includes:
• TG these are 5 bits which identify the group, for example traffic information, information concerning radio programs, etc.
• TP is a bit which informs if the station gives traffic messages
• PTY these are five bits which indicate the type of program, for example sport, classical music, etc.
• SYNC is a synchronization word used for the processing of the message by the receiver; which breaks down as follows:
  • EB is an extension bit which, when set, for example to the value EB = 1 indicates another application of the message than that initially planned, for example a radio text
  • BB is a bit which indicates a link between successive messages in the sense that its value is changed each time a new message unrelated to the previous message is sent. For example if the groups of a message N have the bit BB = 1, the groups of messages N-1 and N + 1 will have the bit BB = 0.
  • IF three sequence identification bits are used to identify the sequence of sequences in a message.

If for example a message has three sequences, the first respectively the second and the third sequence will have SI = 010 respectively SI = 001 and SI = 000. In the example chosen, a message will therefore consist of a maximum of eight sequences. The advantage of counting by decrementation lies in the fact that the system can thus be aware of the number of sequences of the same message which will follow and can also detect if sequences are missing. The blocks BL3 and BL4 comprise SMR1, SMR2, these are two sub-sequences of each 16 bits comprising the road information itself and the whole of which forms a sequence identified by the bits SI.

The messages, if they remain current, are repeated and if not they are updated approximately every five minutes. In this period of approximately five minutes, the transmitter can transmit 420 traffic information messages in RDS format using 25% of the total capacity of the RDS resource.

HDD = 00

signifie que le message est uniquement destiné à être présente au conducteur par voie auditive (synthése de paroles).

HDD = 01

signifie que le message peut être présente au conducteur par voie auditive et/ou par visualisation sur un écran.

HDD = 10

signifie que le message est destiné à actualiser une mémoire contenant des données géographiques et qui fait par exemple partie d'un système de navigation dont le véhicle pourrait être équipé. Un telle message indique par exemple qu'une route est déplacée ou ajoutée au réseau.

HDD = 11

signifie que le message est destiné à une unité de traiment de données, par exemple un microprocesseur dont le dispositif est équipé. Un tel message indique par exemple que le précédent message était faux, ou qu'il faut annuler des messages.

Les codes HDD = 00 et HDD = 01 indiquent l'intention de celui qui a émis le message. Il est évident que le récepteur peut être conçu conformément à des normes de securité, pour réagir à un message codé en HDD = 01 en présentant ce message uniquement par voie auditive si le véhicule est par exemple en marche.Figure 3 illustrates in more detail an example of the SMR1 and SMR2 parts of a group in RDS format. In general, the same message will consist of two sequences distributed over two successive groups. FIGS. 3a and c respectively 3b and d represent the sub-sequences SMR1 and SMR2 of two successive groups. The SMR1 sub-sequence illustrated in FIG. 3a comprises the bits, HDD which are two bits representing the destination of the message in the device, for example

HDD = 00

means that the message is only intended to be present to the driver by auditory means (speech synthesis).

HDD = 01

means that the message can be presented to the driver by hearing and / or by visualization on a screen.

HDD = 10

means that the message is intended to update a memory containing geographic data and which is for example part of a navigation system with which the vehicle could be equipped. Such a message indicates for example that a route is moved or added to the network.

HDD = 11

means that the message is intended for a data processing unit, for example a microprocessor with which the device is equipped. Such a message indicates for example that the previous message was false, or that messages must be canceled.

The codes HDD = 00 and HDD = 01 indicate the intention of the person who sent the message. It is obvious that the receiver can be designed in accordance with safety standards, to react to a message coded in HDD = 01 by presenting this message only by auditory means if the vehicle is for example in motion.

HC = 00 :

information de trafic routier

HC = 01 :

information méteologique

HC = 10 :

information d'alarme

HC = 11 :

annonces.

LM qui est un bit, qui lorsqu'il est positioné, par exemple à la valeur 1, indique que le message comporte plus de deux séquences. Lorsque le récepteur reçoit une trame portant LM = 1, il est informé que le message comportera plus de deux séquences et qu'il s'agit donc d'un message "long". De tels messages long peuvent par exemple être utilisé pour des information routières concernant d'autres pays que celui où se trouve l'émetteur, ou pour des informations concernant des catégories de véhicule (par exemple des poids lourds).
HT qui sont six bits qui indiquent la cause qui est à l'origine de l'émission du message en question. Cette cause est naturellement en relation directe avec la catégorie HC. Ces six bits offrent la possibilité de former 65 différentes causes par catégorie d'information, et puisqu'il y a quatre catégories d'information un total de 4 x 64 = 256 différentes informations peuvent ainsi être formées.
EFF qui sont cinq bits indiquant la conséquence de la cause HT. Ces cinq bits offrent la possibilité de former 32 différentes conséquences et en combinaison avec HT et HC 4 x 64 x 32 = 8192 différentes informations peuvent ainsi être formées.The SMR1 sub-sequence illustrated in FIG. 3a also includes the bits:
HC which are two bits indicating four different categories of information, for example:

HC = 00:

road traffic information

HC = 01:

meteological information

HC = 10:

alarm information

HC = 11:

advertisement.

LM which is a bit, which when set, for example to the value 1, indicates that the message comprises more than two sequences. When the receiver receives a frame carrying LM = 1, it is informed that the message will comprise more than two sequences and that it is therefore a "long" message. Such long messages can for example be used for traffic information relating to countries other than that where the transmitter is located, or for information relating to categories of vehicle (for example heavy goods vehicles).
HT which are six bits which indicate the cause which is at the origin of the emission of the message in question. This cause is of course directly related to the HC category. These six bits offer the possibility of forming 65 different causes per information category, and since there are four information categories a total of 4 x 64 = 256 different information can thus be formed.
EFF which are five bits indicating the consequence of the HT cause. These five bits offer the possibility of forming 32 different consequences and in combination with HT and HC 4 x 64 x 32 = 8192 different information can thus be formed.

HD = 00 =

information auditive uniquement

HC = 01 =

information méteorologique

LM = 0 =

message court (2 séquences)

HT = 000001 :

chutes de neige

EFF = 00101 :

route bloquée.

Ce message informe donc le conducteur par voie auditive uniquement qu'à cause de chutes de neige la route est bloquée. Le décodage et la présentation de ce message est réalisé au moyen du dispositif selon l'invention qui sera décrit plus en détail ci-dessous.Consider for example the message having a SMR1 part equal to 00010 000001 00101. The different sections of this message therefore indicate for example

HD = 00 =

hearing information only

HC = 01 =

meteorological information

LM = 0 =

short message (2 sequences)

HT = 000001:

snowfall

EFF = 00101:

road blocked.

This message therefore informs the driver by hearing only that because of snowfall the road is blocked. The decoding and presentation of this message is carried out by means of the device according to the invention which will be described in more detail below.

The SMR2 sub-sequence illustrated in Figure 3b is composed only by PR-LOC information. This PR-LOC information is composed of 16 bits and indicates the place or the surroundings to which the message relates (for example a tunnel, a motorway exit or the name of a city).

CLR =

00 autoroute
CLR = 01 route nationale
CLR = 10 route départementale
CLR = 11 autres.

La section RNN est composé de 14 bits et indique le numéro de la route à laquelle se rapporte le message. En combinaison avec CLR un total de 4 x 16384 = 65536 différentes routes peuvent ainsi être indiquées. Cette énorme capacité permet de coder ainsi toutes les routes d'un même pays sans avoir recours à des tables de conversion d'un pays à l'autre.The SMR1 sub-sequence of the second sequence of the message and illustrated in FIG. 3c comprises the sections CLR, RNN. The CLR section has 2 bits which indicate the class to which the route belongs, for example

CLR =

00 highway
CLR = 01 national road
CLR = 10 departmental road
CLR = 11 others.

The RNN section is made up of 14 bits and indicates the number of the route to which the message relates. In combination with CLR a total of 4 x 16384 = 65536 different routes can thus be indicated. This enormous capacity makes it possible to code all the routes in the same country without having to use conversion tables from one country to another.

0 0000

de deuxième endroit dans la même direction

1 0000

de deuxième endroit dans la direction opposée

0 0001 à 1111

décalage positif entre 1 et 15 à ajouter à PR-LOC

1 0001 à 1111

un décalage négatif entre 1 et 15 à ajouter à PR-LOC.

La section ST comporte 6 bits et indique une estimation de la durée du problème auquel le message se rapporte, par exemple au cas ou le message indique une route bloquée, la partie ST indique par exemple une heure à laquelle la route sera probablement à nouveau ouverte à la circultion. Les 64 = 2⁶ possibilités offertent par les 6 bits peuvent par exemple être divises en 48 (1/2 heures par jours) + 7 (jours par semaine) + 4 (semaines par mois) + 5 (mois). La section SAV comporte 5 bits qui indiquent des conseils routiers statique, comme par exemple "équipement d'hiver nécessaire" ou "réduire la vitesse". Au cas ou les 5 bits de la section SAV (figure 3d) ne suffisent pas, les avis peuvent être complémentes au moyen de messages longs (partie DAV des figures 3e et f), dans ces parties DAV peuvent alors être repris des conseils dynamiques, qui peuvent le cas échéant completer les conseils statiques. Par exemple dans le cas d'un SAV "réduire la vitesse". La partie DAV peut indiquer "à 70 Km/h".The SMR2 sub-sequence of the second message sequence and illustrated in Figure 3d includes the DIR OFFS, ST and SAV sections.
The DIR section has a bit that indicates the direction. The OFFS section has four bits and is used to provide a more detailed specification of the location (PR-LOC) to which the message relates. The OFFS section therefore indicates a second location in relation to the location cited in PR-LOC. The DIR section and the OFFS section can for example indicate:

0 0000

from second place in the same direction

1 0000

from second place in the opposite direction

0 0001 to 1111

positive offset between 1 and 15 to add to PR-LOC

1,0001 to 1,111

a negative offset between 1 and 15 to add to PR-LOC.

The ST section has 6 bits and indicates an estimate of the duration of the problem to which the message relates, for example in case the message indicates a blocked route, the ST section indicates for example a time at which the route will probably be opened again to circultion. The 64 = 2 ⁶ possibilities offered by the 6 bits can for example be divided into 48 (1/2 hours per day) + 7 (days per week) + 4 (weeks per month) + 5 (months). The after-sales service section has 5 bits which indicate static driving advice, such as "winter equipment required" or "reduce speed". If the 5 bits of the after-sales service section (figure 3d) are not enough, the notices can be supplemented by means of long messages (part DAV of figures 3e and f), in these parts DAV can then be taken from dynamic advice, which can supplement the static advice if necessary. For example in the case of a service "reduce speed". The DAV part can indicate "at 70 km / h".

The SMR1 subsequence illustrated in FIG. 3e comprises the sections PA, STT and DAV. The STT section (6 bits) indicates a start time (for example from "22.00 hours"). The PA section has 4 bits and is used to indicate a country other than that covered by the transmitting station.

FIG. 4 schematically illustrates an example of a device according to the invention. The device comprises a data collector terminal equipment (DCE) which further comprises a radio receiver 30 connected to an antenna 38 and provided to receive coded messages in RDS format. The DCE is connected to a terminal data processing equipment (DTE) which further comprises a reception memory 31 for storing the messages received by the DCE, which memory is in turn linked to a bus 32 for transporting information (addresses + data). To the bus 32 are also connected a data processing unit 33, for example a microprocessor, a read-only memory 35 a working memory 34, an extension table 36 and a table of places, a presentation unit formed by a generator speech 39 and an image generator 40 and a selection unit further comprising a keyboard 43, all these elements are part of the terminal data processing equipment. An output of the speech generator 39 respectively of the image generator 40 is connected to a loudspeaker 41 (which may be the same as that used by the radio) respectively to a display unit. The image generator and its display unit are optional.

• 50 STRT démarrage du processus d'analyse.
• 51,62 TG? les bits TG qui identifient le groupe sont analysés afin de vérifier s'il s'agit d'un message contentant de l'information routière.
• 52 PG1 Au cas où les bits TG indiquent qu'il ne s'agit pas d'information routière, l'unité de traitement de données (33) saute vers un autre programme PG1 qui traitera alors le message en question.
• 53,63 EB=0? le bit d'extension est vérifié afin de détecter s'il porte la valeur EB=0, indiquant que le message n'est pas utilisé pour d'autres applications que de l'information routière.
• 54 PG2 Au cas où le bit d'extension a la valeur EB=1, l'unité de traitement de données saute vers un autre programme PG2 qui traitera alors le message en question.

Each message in RDS format received by the radio receiver is immediately stored in the reception memory 31 under the control of the data processing unit. The data processing unit is informed, by means of a signal transmitted on line 44, each time that a new message is received. The data processing unit then starts a process of analysis of the message whose an example which will be described by means of the flowchart illustrated in FIG. 5. The different stages of the analysis process will now be described below.

• 50 STRT start of the analysis process.
• 51.62 TG? the bits TG which identify the group are analyzed in order to check whether it is a message containing traffic information.
• 52 PG1 If the bits TG indicate that it is not traffic information, the data processing unit (33) jumps to another program PG1 which will then process the message in question.
• 53.63 EB = 0? the extension bit is checked to detect if it has the value EB = 0, indicating that the message is not used for applications other than traffic information.
• 54 PG2 If the extension bit has the value EB = 1, the data processing unit jumps to another PG2 program which will then process the message in question.

• 56,64 BB(n-1)=BB(n)? C'est un test qui sert à constater si le bit de liaison BB du groupe reçue (groupe n) est égale au bit de liaison du précedent groupe (groupe n-1). Un résultat négatif de cette opération indique qu'il s'agit d'une nouveau message. Afin d'effecteur cette opération, le bit BB(n-1) est par exemple mémorisé dans un registre tampon de l'unité de traitement de données.
• 57 BB(n) -> ;SI - > CS L'unité de traitement de données charge la valeur BB(n) dans le registre tampon et postione, sous contrôle du signal de positonement, un compteur de séquences CS à la valeur SI. La valeur SI étant la valeur indiquée par les bits d'identification de séquence du groupe reçue. Le compteur CS est utilisé d'une part pour indiquer le nombre d'adresses à réserver dans la mémoire de réception, d'autre part pour former les adresses dans la mémoire de réception auxquelles les séquences doivent être mémorisées.
• 58 ST SMR1, SMR2 L'unité de traitement de données forme, avec l'aide du compteur CS, les adresses auxquelles les sub-séquences SMR1 et SMR2 d'une séquence reçue doivent être mémorisées dans la mémoire de réception, et mémorise ensuite les sub-séquences SMR1 et SMR2 aux adresses indiquées.
• 59 CS=0? C'est un test qui sert à vérifier si le compteur CS indique la valeur "0" indiquant que toutes les séquences d'un même message ont été mémorisées.
• 60 STP Indique la fin du processus, qui est atteint lorsque toutes les séquences d'un même message ont été mémorisées (CS=0).
• 61 CS=CS-1 Décrémentation d'une unité de la valeur indiqué par le compteur CS.
• 65 SI=CS C'est un test qui sert à vérifier si la valeur indiquée par les bits d'identification de séquence d'un nouveau groupe reçu correspondent à la valeur indiqué par le compteur CS. Ainsi l'unité de traitement de données peut vérifier si le nouveau groupe reçu comporte bien le bon numéro de séquence. Si tel n'est pas le cas le traitement du message est interrompu.

The programs PG1 and PG2 will not be described in detail since the device according to the invention more particularly processes messages comprising road information. 55 OFF-C '? It is a test which is used to check whether the sequence received is the first of a new message. In a preferred form of the device according to the invention, this verification is carried out using the shift word included in block BL3 of the group. To indicate that it is a first sequence of a new message a first shift word (C ') is used instead of a second shift word (C) which is used to indicate the other sequences of the message (see annex 1 on this subject (page 33, March 1984 edition) specifications of the RDS system for the broadcasting of frequency-modulated radio data published by the European Broadcasting Union). The data processing unit then performs an offset operation on the block BL3 to determine whether the first offset word C 'has been used. The offset of the first offset word will generate a position signal which will therefore indicate to the data processing unit that it is indeed the first sequence of the message. In the event that this first offset word is not detected, either due to an error in block BL3, or due to a value different from this first offset word, the data processing unit will abandon the message and wait for the arrival of 'another group.

• 56.64 BB (n-1) = BB (n)? It is a test which is used to determine whether the link bit BB of the group received (group n) is equal to the link bit of the previous group (group n-1). A negative result of this operation indicates that this is a new message. In order to perform this operation, the bit BB (n-1) is for example stored in a buffer register of the data processing unit.
• 57 BB (n) -> ; SI -> CS The data processing unit loads the value BB (n) into the buffer register and postion, under control of the position signal, a sequence counter CS at the value SI. The value SI being the value indicated by the group sequence identification bits received. The counter CS is used on the one hand to indicate the number of addresses to be reserved in the reception memory, on the other hand to form the addresses in the reception memory to which the sequences must be stored.
• 58 ST SMR1, SMR2 The data processing unit forms, with the help of the counter CS, the addresses at which the sub-sequences SMR1 and SMR2 of a received sequence must be stored in the reception memory, and then stores the SMR1 and SMR2 sub-sequences at the addresses indicated.
• 59 CS = 0? It is a test which is used to check if the counter CS indicates the value "0" indicating that all the sequences of the same message have been memorized.
• 60 STP Indicates the end of the process, which is reached when all the sequences of the same message have been stored (CS = 0).
• 61 CS = CS-1 Decrement by one the value indicated by the counter CS.
• 65 SI = CS This is a test which is used to check whether the value indicated by the sequence identification bits of a new group received correspond to the value indicated by the counter CS. Thus the data processing unit can check whether the new group received has the correct sequence number. If this is not the case the processing of the message is interrupted.

The different stages of the analysis process will now be illustrated with the help of an example given in FIG. 6, where these parts of the group which play a role in the analysis process are listed. In this FIG. 6, the message MB comprises two sequences and only the last sequence of the message MA is repeated in order to illustrate the change of the link bit BB. The value TG = 1000 indicates that this is a message containing traffic information. Suppose that the message MA has been processed and therefore that the value BB = 1 is stored in the buffer register. When the radio receiver has received the first group of the message MB, it informs the data processing unit which starts (50) the analysis process. Since this is traffic information (TG = 1000) and the extension bit EB = 0, the tests in steps 51 (TG?) And 53 (EB = 0?) Are positive and we pass in step 55 (OFF-C '?). During this step the data processing unit finds that the shift word of the block BL3 is a first shift word (type C '). It is therefore a first sequence of the message and we go to the next step 56 (BB (n-1) = BB (n)?) Where we see that BB (n-1) = 1 and BB (n) = 0 and therefore BB (n-1 ≠ BB (n). This negative result leads the data processing unit to go to step 57 where the value BB (n) = 0 is stored in the buffer register and where the counter CS is set to the value CS = SI = 001. The data processing unit then goes to step 58 where the address ADD1 is formed and where the parts SMR1 are stored ( YY) and SMR2 (Y'Y ') at the address ADD1. The address ADD1 is for example formed as follows
ADD1 = FF + CS
The value FF being the address of the first free location in the reception memory, this value is for example stored in a second buffer register of the data processing unit. (The values YY and Y'Y 'represent the content of the parts SMR1 and SMR2). The data processing unit then goes to step 59 (CS = 0?) And finds that since CS = 001 it is different from 0 it can therefore go to step 61 to form CS = 001-001 = 000 . The data processing unit then waits for the reception of a new group, for example the group MB (2), and when this new group is received steps 62 (TG = 11) 63 (EB = 0) and 64 ( BB (n-1) = 0 = BB (n)) are executed. During step 65 the data processing unit finds that SI = CS, and goes to step 58 where the addresses ADD2 = FF + 001 are formed and where the values ZZ and Z'Z 'are stored l' ADD2 address. During step 59 we note that CS = 0 and we go to 60 to complete the process.

Now consider the case where SI = 010 in the group MB (2) (Figure 6). In this case, the data processing unit notes during step 65 that SI = 010 and CS = 000. SI is therefore different from CS and the data processing unit will go to step 51. It can thus be seen that a group having the wrong sequence number is not taken into account. The same would be valid if the group MB (2) would have BB = 1 (negative result in the test of step 64).

After having stored a received message in the reception memory, the data processing unit will analyze the content of the message in order to detect to which zone (route, region) the message relates. To this end, the data processing unit uses a table memory of the zones formed by two tables which are illustrated in FIGS. 7 a and b. These tables form, in a preferred form of the device according to the invention, part of the working memory (34, FIG. 4) of the device. It will be clear that these tables can also be formed by two individual memories (RAM type) connected to the bus 32. FIG. 7a illustrates the table of regions which is used to classify the messages according to the geographic regions to which it relates. These regions can correspond to the geographic division of the country (province, department) or be formed by an arbitrary division of the country. The table is in matrix form and can be addressed by row and by column. In the first column, the indices indicating the different regions are stored (for example the regions B2 and B5). The columns entitled ADD-MES are used to store indicators, for example the addresses (ADD) to which messages belonging to the region of their respective rows are stored in the reception memory. In the example in FIG. 7a, there are messages at addresses 12, 21, 34 and 38 for region B2 and for region B5 there is a message at address 50. The column CS / R indicates the number of messages for the region in question (four for B2, one for B5) and the DEB column indicates the overflow index for the region in question.

The overflow index for the region is a number assigned to this region which indicates the maximum number of messages allocated for the region in question. In an elementary form of the device according to the invention, this overflow index is the same for each region and the DEG-REG column is not included in the table of regions. However, in a preferred form of the device according to the invention, a dedicated overflow index is assigned to each region. The advantage of this preferred form is that the density of road traffic varies from region to region and from road to road. Thus in France, for example, the Paris region, with high traffic density, will have a higher overflow index than that of Auvergne. It is obvious that the greater the density of traffic, the greater the probability that there will be one or more traffic messages. The overflow index thus makes it possible to equitably share the present capacity of the tables and of the reception memory. The different overflow indices are for example stored in a table as described below.

FIG. 7b illustrates the route table which is used to classify the messages according to the numbering of the routes (class + number, CLR, RNN) to which they relate. The route table is organized in the same way as that of the regions. The CS / RNN column indicates the number of messages for the route in question and the DEB-RN column indicates the overflow index for the route in question.

Before coming to explain how the route table and the region table are loaded, it is necessary to describe how the region to which it relates is obtained from a received message. As explained with the aid of FIG. 3, the message does not include a part where the region in question is taken up. However, an indicator indicating the region could be taken up in the PR-LOC part and then the analysis based on the region using the PR-LOC part.

The device according to the invention uses, to recognize to which region a received message relates, a correspondence-route-regions table, which is illustrated in FIG. 8a. This correspondence-routes-region table can be taken up in the read-only memory 35 of DTE or can be formed by an independent memory connected to the bus, which could even, if necessary, be in the form of a cassette or a memory card, allowing regular updating of the correspondence-routes-regions table.

The route-regions correspondence table can be addressed using the CLR-RNN part of the message. The correspondence-routes-regions table includes a REG-ALL column where the regions crossed by the road in question are mentioned, and a DEB column where the overflow index of the road in question is mentioned. For example, the A1 motorway crosses regions B8 and B9 and has an overflow index equal to 8.

The device according to the invention also comprises a correspondence table-regions-routes which is illustrated in FIG. 8b and which, like the correspondence table-routes-regions, can be taken up in the read-only memory 35 of DTE or be formed an independent memory connected to the bus. The correspondence-regions-roads table is addressable by means of the region code (REG) and comprises an RNN-ALL column where the roads crossing the region in question are mentioned, and a DEB column where the index of overflow of the region in question.

In order to identify to which region a message received relates to the data processing unit goes into function tracking unit, now proceed as described below. Suppose that this is a message for the A2 motorway (CLR = A, RNN = 2). The data processing unit will then address row A2 in the correspondence-routes-regions table and read there the references to regions B3 and B4, as well as a value overflow index = 12. The data processing unit is thus informed that the message referring to the A2 motorway also relates to regions B3 and B4. To find the overflow index of regions B3 and B4, the data processing unit will take this data from rows B3 and B4 of the correspondence table of the regions.

• 71AD CLR-RNN : les sections CLR-RNN (figure 3c) du message sont lués afin d'identifier la route concernée.
• 72 E TB? : c'est un test pour vérifier si des messages concernant la route, à laquelle se rapporte le nouveau message reçu, sont déjà repris dans la table des route (figure 7b). A cette fin l'unité de traitement de données parcoure la colonne CLR-RNN de la table des routes.
• 73 CCOL au cas où il y a déjà d'autres messages présent pour la route en question, l'unité de traitement de données a repéré lors de l'étape 72 la rangée (R) où était repris ces autres messages, et elle va maintenant chercher la première colonne (C) libre dans la rangée en question.
• 74,86RD-MA l'adresse à laquelle est stockée le message reçu dans la mémoire de réception est repérée.
• 75,87 WRT cette adresse est maintenant inscrite dans la table des routes à l'endroit (R-C) déterminé durant l'étape 73.
• 76CS/R=CS/R+1 ;C/RNN=CS/RNN+1 le compteur CS/RNN de la rangée (R) en question est incrémenté d'une unité, indiquant ainsi qu'un message supplémentaire a été mémorisé. (Le compteur CS/R sera incrémenté à son tour lorsque l'étappe 76 sera parcouru pour une séconde fois à l'occasion de la classification de messages selon les régions, comme décrit plus loin).
• 77 DEB? c'est un test pour vérifier si le comptage indiqué par le compteur CS/RNN (ou CS/R lors du sécond parcours) n'a pas atteint le niveau indiqué par l'indice de débordement (DEB-RNN) de la route (ou de la région DEB-REG).
• 78 RD-PAA au cas où le nombre indiqué dans la colonne CS/RNN (ou CS/R) est égal au nombre indiqué par l'indice de débordement (DEB-REG ou DEB-RNN), l'adresse (PAA) du plus ancien message, c'est à dire dans le cas présent celui indiqué dans la première colonne de la partie ADD-MES, est lue.
• 79 DT-PAA le message mémorisé à l'adresse PAA est éliminee, ainsi que l'adresse PAA mentionnée dans la première colonne (partie ADD-MES). Les adresses mentionnées dans les autres colonnes de la rangé en question sont avancées d'une colonne vers la gauche.
• 80 CS/RNN=CS/RNN-1 puisqu'un message a été détruit le compteur CS/RNN de la rangée en question est décrémenté d'une unité.
• 81AT RNG? C'est un test pour vérifier si le message qui a été éliminée est également mentionné en d'autres endroit de la table des routes. Ceci est par exemple le cas lorsqu'un message se rapporte à deux différentes routes, comme lors d'un accident sur en croissement ou de verglas dans une région. Ce test est exécuté en parcourant la table des routes à la recherche de l'adresse PAA.
• 82DT-AT RNG: Au cas où l'adresse PAA a été repéré en d'autres endroits de la table des routes, cette référence y sera détruite et les adresses mentionnées dans les autres colonnes de la rangée en question sont avancées d'une colonne vers la gauche.
• 83 DT ATB? c'est un test pour vérifier si le message qui a été détruit est aussi mentionné dans la table des régions. A cette fin l'unité de traitement de données va à l'aide de la table de correspondance-routes-régions déterminer la région à laquelle appartient le message détruit. Lorsque l'unité de traitement de données va à nouveau parcourir les étapes 73 à 84 pour ranger le message reçu dans la table des régions, elle éffectuera, si nécessaire, également une opération de destruction de messages. Lors de cette nouvelle étape 83 l'unité de traitement de données va alors utiliser la table correspondance des régions afin de déterminer à quelle route le message qui a été détruit et qui faisait partie de la table des régions, se réfère.
• 84 DT :CS/R=CS/R-1 si le message qui, a été détruit, se trouve aussi dans la table des régions, sa ou ses référence(s) y est (sont) anulée(s), les autres messages sont avancés d'une colonne et le compteur CS/R est décrémenté d'une unité. Toutes traces du message qui a été détruit sont ainsi éffacées.
• 85 CRAN au cas où un message reçu concerne une route pour laquelle il n'y a pas encore eu d'autres messages (réponse négative lors l'étape 72), l'unité de traitement de données choisit une nouvelle rangé, pour y inscrire l'adresse du message reçu, qui sera alors inscrit dans la première colonne.
• 88 CS/R=1 :CN/RNN=1 au cas où une nouvelle rangée a été réservée, les compteurs (CS/R ou CS/RNN) sont positionnés à la valeur "1".
• 89 S-DEB: L'indice de débordement pour la route (région) en question est prélevé et stocké dans la colonne DEB-RNN (DER-REG) de la nouvelle rangée choisie.
• 90 REG? c'est un test pour vérifier si le message a déjà été analysé sur base de la région a laquelle il se rapporte.
• 91 AD REG en cas de réponse négative lors du test 90, un drapeau est positionné pour indiquer que l'analyse sur base de la région a lieu. L'unité de traitement de données va alors à l'aide de la section CLR-RNN et à l'aide de la table de correspondance-routes déterminer, selon la méthode décrite si dessus, la région à laquelle se réfère le message. Le programme sera ensuite repris à partir de l'étape 72 en prenant cette fois-ci en considération la table des régions.
• 92 STP si lors du test 77 l'on constate que l'analyse sur base de la région a eu lieu, le drapeau est remis à zéro et le programme d'analyse et terminé.

Let us return now to the analysis of the content of the messages and to the use of the route and region tables. FIG. 9 illustrates by means of a flowchart the analysis of the content of the messages received. This content analysis is carried out each time a new message has been stored in the reception memory, that is to say after the completion of the process described in FIG. 5. The data processing unit in its function d the analysis unit starts (70) then the analysis of the content to execute the steps mentioned below.

• 71AD CLR-RNN : the CLR-RNN sections (figure 3c) of the message are read in order to identify the route concerned.
• 72 E TB? : this is a test to check whether messages concerning the route, to which the new received message relates, are already included in the route table (Figure 7b). To this end, the data processing unit traverses the CLR-RNN column of the route table.
• 73 CCOL in case there are already other messages present for the route in question, the data processing unit has identified in step 72 the row (R) where these other messages were taken up, and it will now look for the first free column (C) in the row in question.
• 74,86RD-MA the address at which the received message is stored in the reception memory is identified.
• 75.87 WRT this address is now entered in the route table at the location (RC) determined during step 73.
• 76CS / R = CS / R + 1 ; C / RNN = CS / RNN + 1 the CS / RNN counter in the row (R) in question is incremented by one, thus indicating that an additional message has been memorized. (The counter CS / R will in turn be incremented when step 76 is traversed for a second time during the classification of messages according to the regions, as described below).
• 77 DEB? it is a test to check whether the count indicated by the counter CS / RNN (or CS / R during the second journey) has not reached the level indicated by the overflow index (DEB-RNN) of the road ( or from the DEB-REG region).
• 78 RD-PAA in case the number indicated in the column CS / RNN (or CS / R) is equal to the number indicated by the overflow index (DEB-REG or DEB-RNN), the address (PAA) of oldest message, ie in this case the one indicated in the first column of the ADD-MES part, is read.
• 79 DT-PAA the message stored at the PAA address is deleted, as well as the PAA address mentioned in the first column (ADD-MES part). The addresses mentioned in the other columns of the row in question are advanced one column to the left.
• 80 CS / RNN = CS / RNN-1 since a message has been destroyed the CS / RNN counter in the row in question is decremented by one.
• 81AT RNG? It is a test to check whether the message which has been eliminated is also mentioned elsewhere in the route table. This is for example the case when a message relates to two different routes, such as during an accident on a crossing or ice in a region. This test is executed by browsing the route table in search of the PAA address.
• 82DT-AT RNG: If the PAA address has been located in other places in the route table, this reference will be destroyed there and the addresses mentioned in the other columns of the row in question are advanced by one column towards the left.
• 83 DT ATB? it is a test to check if the message which was destroyed is also mentioned in the table of regions. To this end, the data processing unit uses the correspondence-routes-regions table to determine the region to which the destroyed message belongs. When the unit of data processing will again go through steps 73 to 84 to store the message received in the table of regions, it will also perform, if necessary, a message destruction operation. During this new step 83, the data processing unit will then use the region correspondence table in order to determine to which route the message which has been destroyed and which was part of the region table, refers.
• 84 DT : CS / R = CS / R-1 if the message which has been destroyed is also found in the table of regions, its reference (s) is (are) canceled, the other messages are advanced one column and the CS / R counter is decremented by one. All traces of the message that has been destroyed are thus erased.
• 85 CRAN in the event that a message received relates to a route for which there have not yet been other messages (negative response in step 72), the data processing unit chooses a new row, to register there the address of the message received, which will then be entered in the first column.
• 88 CS / R = 1 : CN / RNN = 1 in case a new row has been reserved, the counters (CS / R or CS / RNN) are set to the value "1".
• 89 S-DEB: The overflow index for the road (region) in question is taken and stored in the DEB-RNN (DER-REG) column of the new row selected.
• 90 REG? it is a test to check if the message has already been analyzed on the basis of the region to which it relates.
• 91 AD REG in the event of a negative response during test 90, a flag is positioned to indicate that the analysis based on the region takes place. The data processing unit then goes using the CLR-RNN section and using the route correspondence table to determine, according to the method described above, the region to which the message refers. The program will then be resumed from step 72, this time taking into account the table of regions.
• 92 STP if during test 77 it is found that the analysis on the basis of the region has taken place, the flag is reset and the analysis program is finished.

The destruction of the presence of a message following a number of messages greater than that indicated by the overflow index is an integral part of the analysis program as described above. It will however be clear that this is only an example and that other achievements are possible. Thus the test on the basis of the overflow index and the destruction which possibly follows therefrom can form an independent program which will be carried out for example in a dead time of the data processing unit.

We now come to the selection of messages. FIG. 10 illustrates an example of a control keyboard forming part of the device according to the invention. The control keyboard includes a display unit, for example an LCD 91 unit which makes it possible to display numbers as well as letters making it possible to indicate categories of roads (motorway, national road, departmental road) or regions (surface , department) from one or more countries. The CLR / RNN key is used to indicate the choice of a route and the REG key is used to indicate the choice of a region. The + / + key is used in selection mode on the one hand to increment the number displayed on the display unit 91 and on the other hand to indicate a union operation, that is to say that the user wishes to information on one or more routes and regions. In presentation mode, that is to say during the presentation of messages, this + / + key is used for a positive movement of a pointer in a selection table. The - / VAL key is used in selection mode on the one hand to indicate an intersection between a road and a region and on the other hand to validate the number displayed on the display unit. In presentation mode this - / VAL key is used to move the pointer negatively in the selection table. The ENT key allows you to enter the choice you have made. The REP key repeats the last message presented. The ST key stops the presentation. The EJ key cancels a message. The TDC key is used for transparency. Each button has a diode (LED, indicated by a dot) which lights up temporarily when the button in question is pressed. It will be clear that the control keyboard illustrated in FIG. 10 is only an example and that other achievements are possible.

The control keyboard also includes an encoder (not shown in Figure 10) which, among other things, encodes the signal produced when the ENT key is pressed to form a digital word which is transmitted via bus 32 to the control unit. data processing.

When a driver or other user wants traffic information on a route of his choice, he will press the CLR / RNN key, which will cause the display of a first class of routes, for example the letter A indicating a highway, on the display unit. If the required route class is displayed, the user will press the ENT key so as to send his choice to the data processing unit. If a road class other than that required is displayed, the user will press the + / + key to display other road classes.
After entering the required road class, the user will again press the CLR / RNN key, which will cause the display of figures on the display unit. Using the + / + key, the user will increment the number displayed until the required route number appears, and then enter this number using the ENT key. If the user wants road information on a region, he will operate in the same way as choosing a route by pressing the REG key. The indication of a specific region can be done for example by means of a number, for example 75 for the Paris region.

The choice of a number can be made decimal by decimal using each time the - / VAL key to validate the displayed decimal.

If the user wants an intersection between a route and a region, he will first enter the desired route and after pressing the ENT key he will press the - / VAL key, to indicate the intersection operation, before to introduce the desired region. A union operation is introduced by pressing the + / + key between the introduction of the choice of route and region.

• 101 CL le contenu d'une table de sélection est éffacé. Cette table de sélection est par exemple constituée d'une partie de la mémoire de travail, et sert à mémoriser temporairement les messages sélectionés, par exemple au moyen des adresses auxquelles ils sont mémorisés dans la mémoire de réception.
• 102 RD-SEL lecture du mot binaire identificant le choix de l'utilisateur. Au cas où ce choix comporte une opération d'union ou d'intersection uniquement la partie se référant au choix d'une route ou d'une région sera pris en considération lors de cette étape.
• 103 RD-CNT le contenu de la table de sélection est lu.
• 104 INTER? c'est un test pour vérifier si une opération d'intersection est requise?
• 105, 107 DT-CH l'unité de traitement de données va parcourir la première colonne de la table des régions et/ou de la table des routes, selon le choix de l'utilisateur, pour vérifier s'il y a des messages pour la région ou la route que l'utilisateur a choisi. A cette fin l'unité de traitement de données compare par exemple chaque mot de cette première colonne avec le mot binaire reçu et lors d'un résultat positif de la comparaison, les adresses stockées à la rangée où se trouve la route ou la région requise sont prélevées.
• 106 ST-COMM le contenu de la table de sélection est comparé avec les adresses prélevées dans la rangée repérée lors de l'étape 105 et, puisqu'une opération d'intersection est requise, uniquement ces adresses qui sont aussi bien dans la table de sélection que dans la rangée repérée sont maintenues dans la table de sélection, les autres sont éffacées.
• 108 ST-DIFF le contenu de la table de sélection est comparé avec les adresses prélevées dans la rangée repérée lors de l'étape 107 et, puisqu'une opération d'union est requise, les adresses présentes dans la rangée repérée et qui ne sont pas encore repris dans la table de sélection y sont introduites.
• 109 ED-SEL? c'est un test pour vérifier si tout le choix de l'opérateur a été pris en considération.
• 110 TRAIT c'est un sous programme de traitement, qui sera décrit en détail ci-dessous (figure 13), et qui va permettre lors de son exécution la présentation des messages requis par l'utilisateur.
• 111 M-FSEL au cas où tout le choix de l'utilisateur n'a pas encore été pris en considération, l'opération à effectuer (union our intersection) est repérée. Ce repérage sera alors pris en compte lors de la prochaine étape 104.
• 112 TDC? c'est un test pour vérifier si la touche TDC (transparence) a été utilisée lors de la sélection.
• 113 N-MSS? au cas où la touche TDC a été utilisée l'unité de traitement de données va vérifier régulièrement si de nouveau messages sont parvenus, et si tel est le cas le programme sera repris à partir de l'étape 102.
• 114 STP c'est la fin du programme de sélection.

When the data processing unit receives keyboard commands it will start (100) the selection program illustrated in figure 11 by means of a flowchart. The data processing unit will then execute the steps of the selection program mentioned below.

• 101 CL the content of a selection table is deleted. This selection table is for example made up of part of the working memory, and is used to temporarily store the selected messages, for example by means of the addresses at which they are stored in the reception memory.
• 102 RD-SEL reading of the binary word identifying the choice of the user. In the event that this choice involves a union or intersection operation, only the part referring to the choice of a route or a region will be taken into account during this stage.
• 103 RD-CNT the content of the selection table is read.
• 104 INTER? is this a test to check if an intersection operation is required?
• 105, 107 DT-CH the data processing unit will scan the first column of the region table and / or the route table, as the user chooses, to check if there are messages for the region or route that the user has chosen. To this end, the data processing unit compares, for example, each word in this first column with the binary word received and, when the comparison is positive, the addresses stored in the row where the required route or region is located. are collected.
• 106 ST-COMM the content of the selection table is compared with the addresses taken from the row identified in step 105 and, since an intersection operation is required, only those addresses which are as well in the selection in the row marked are kept in the selection table, the others are deleted.
• 108 ST-DIFF the content of the selection table is compared with the addresses taken from the row identified in step 107 and, since a union operation is required, the addresses present in the row identified and which are not not yet included in the selection table are introduced there.
• 109 ED-SEL? it is a test to check whether all the operator's choices have been taken into account.
• 110 TRAIT is a processing subroutine, which will be described in detail below (figure 13), and which will allow, during its execution, the presentation of the messages required by the user.
• 111 M-FSEL in case all the user's choice has not yet been taken into account, the operation to be performed (union or intersection) is identified. This identification will then be taken into account during the next step 104.
• 112 TDC? it is a test to check if the TDC (transparency) key was used during the selection.
• 113 N-MSS? in case the TDC key has been used the data processing unit will regularly check if new messages have arrived, and if this is the case the program will be resumed from step 102.
• 114 STP is the end of the selection program.

Let us now suppose, by way of example, that the driver wants traffic information on the A8 motorway in crossing region B2 and that the route table and the region table are loaded as illustrated in FIGS. 71 and 7b. On the keyboard 43 he will then press the CLR key and then the ENT key when the letter A will appear on the display unit. By means of the + / + key it will advance the indicated counting until the number 8 appears. Then he will successively press the keys - / VAL, ENT, - / VAL, where the last press on the key - / VAL indicates the intersection. Similarly, he will then introduce the region B2.

The keyboard will encode the signals of these keys and form one or more binary words which it sends to the data processing unit, which will then start the execution of the selection program by erasing the content of the selection table ( step 101). Data processing unit will then read part A8 of the choice and the content of the selection table. Since the first part of the driver selection is always a union operation, the data processing unit will, after execution of step 104, go to step 107 where it will check if there are messages for the A8 motorway stored in the route table and where it will find these messages in the first row. The data processing unit will take these addresses 12, 13, 28, 34, 38, 52, 71 and store them in the selection table (step 108). During step 109 the data processing unit finds that all of the choices have not yet been taken into consideration and it will go to step 111 where it will locate the intersection operation. It then goes again to step 102 to read the choice B2 there and to step 103 to read the content of the selection table there. During step 104 the unit then notes that an intersection operation is required and proceeds to step 105 where it notes that there are messages for the region B2 and takes the addresses 12, 21, 34 , 38. In step 106, the intersection operation is carried out and the addresses 12, 34, 38, which form the intersection between A8 and B2, are kept in the selection table, while the other addresses are deleted. . Since all the choice has now been taken into consideration (step 109) the data processing unit passes to the subroutine 110 to present to the driver the messages stored at addresses 12, 34 and 38 of the reception memory. Since the TDC key has not been used, the selection program has ended.

It will be clear that a union or intersection operation is not limited to a region and a route but that it can be extended to several choices, such as for example (B2 U B5) (A8 U RN64) or the symbol U indicates a union operation and the symbol ∩ an intersection operation. Such a choice will then require several courses in the selection program.

The choice of the user can also be formulated as follows. Indeed one can imagine that when a driver is going to take a motorway which spans several hundred kilometers, such as for example the A5 motorway in federal Germany, which goes from Darmstadt to Basel, and that when the driver does not will only use part of this highway, for example the part between Heidelberg and Karlsruhe, he will only be interested in the traffic messages concerning the part he is going to take. The driver will then ask using the keyboard, the intersection between A5 and the Heidelberg - Karlsruhe region. If the keyboard would also be able to allow selection on the basis of the exit numbers of a motorway, it would suffice to type on the keyboard the numbers of the exits concerned.

Traffic information can also play a role in the planning of a route such as carried out by a road navigation system for vehicles. In such car navigation systems are for example described in the article "Elektronische Lotsen" appeared in Funkschau ^No. 22, 1986, p. 99-102. A road navigation system for vehicles is equipped with means for determining a route between a starting point and a destination. The device according to the invention can be connected to a road navigation system and thus the means for determining the route can take into account the road information relating to the roads which make up the journey to be traveled.

Let us now suppose that the navigation system must determine a route between a starting point and a destination introduced by the driver and that the route as determined in the first place comprises inter alia a motorway whose exit to be taken would be blocked due to works. When the navigation system has determined its route, it then goes for each route or only for the main routes of its route, asking the device according to the invention for the traffic messages. This can be done for example by transmitting to the data processing unit a call indicating that traffic information is requested, and the binary code of the route or routes in question. The data processing unit will then process these requests in a similar way to that used for commands from the keyboard, and transmit the required information to the navigation system. In this traffic information, the navigation system will now detect that the exit from the motorway to be taken according to the blocked route, and will ask the means for determining a route to determine a new route where the exit in question will be avoided. The navigation system in cooperation with the device according to the invention thus allows the driver avoid obstacles or traffic jams.

Since each message includes an ST part, indicating a probable duration of the problem, this ST part can also be taken into account in determining the route. Take again the example of the blocked highway exit and suppose that the ST section indicates "until 4:00 pm" and that the motorist leaves at 3:00 pm. 30 and that the exit in question is 150 km from the starting point. The navigation system will then be equipped with means to take this information into consideration. Thus he will be equipped with a computer which will indicate to him that at an average speed of 100 km / h on the highway he will need an hour and a half to reach this exit. This one and a half hour value will then be added to the present time (3.30 p.m.) indicated by the car clock (3.30 p.m. + 1.30 a.m. = 5.00 p.m.). The navigation system will be equipped to compare this calculated time (5:00 p.m.) to the time indicated in ST (4:00 p.m.) and it will note that for the time the motorist has reached the exit in question it will be again opened. In this case, the means for determining a route will not receive orders to determine a new route. Similarly, the navigation system in cooperation with the device according to the invention can also take the STT section into consideration when determining an route.

Before coming to explain how the presentation to the user of a selected message is carried out, it is necessary to describe in more detail two tables which will be used for the realization of this presentation.

The device according to the invention uses to allow the presentation of a message, an extension table (36, Figure 4) and a table of places (37, Figure 4), which are illustrated in Figures 12a and b respectively. This extension table and this places table can also be included in the read-only memory 35 and DTE. If they are made up of independent memories connected to the bus, they could even, if necessary, be in the form of cassettes or memory cards.

The extension table (FIG. 12a) is addressable by means of the CLR-RNN part of the message as well as the PR-LOC part. For each road there is a number of reserved row, and a row includes an ORD part indicating a specific place of the road, for example for a motorway an exit or a resting place, and for a national or departmental road a crossing. A row also includes an ADR part indicating a place in the table of places. Advantageously, each row is not necessarily filled with information, this makes it possible in the event that there is the possibility of writing in the table (EEPROM memory, or magnetic tape) to add thereto at the required places new information, by example of new motorway exits.

The places table can be addressed using the address taken from the extension table (ADR column), and has a TXT APP column reserved for the name of the place indicated, a PAR column where the code to be stored is stored. speech generator to form a word into words, and a REG column indicates the region to which the indicated place belongs.

In order to present to the speech generator a message received the data processing unit has now to proceed as described below. Suppose that this is a message for the A7 motorway (= CLR-RNN) in federal Germany and that the PR-LOC part indicates the value 2 of the message received, it then takes the CLR-RNN part and the PR-LOC part. The CLR-RNN, PR-LOC parties now form an A7.2 address to address a place in the extension table. The data processing unit will address this space A7.2 and take there data 1024 which it will use to address the table of places. At the place with the address 1024 of the table of places it will find the code 022c which it presents to the generator of words which will form "HAMBURG" in the form of words. Then the data processing unit will take the DIR-OFFS part of the message. Suppose now that this DIR-OFFS part indicates the binary value 0 1010 indicating a positive offset of 10 to add to PR-LOC. The give processing unit will now add this value 10 to PR-LOC = 2 and obtain the value 12, which forms an address for another location in the extension table. At location A7.12 east memorized the value 1247 and at the address 1247 of the table of places is stored the code 021Q. The data processing unit then presents this value 021Q to the speech generator which will form "KIEL" in the form of speech.

This shows the advantage of using the OFFS part of the message, the extension table and the places table. The use of the DIR-OFFS part makes it possible to indicate a second location in the message while limiting the number of bits necessary for this operation since the DIR-OFFS part always indicates a value relative to the PR-LOC value. Thus it is not necessary to mention a second value for CLR-RNN (16 bits) nor to mention a second value for PR-LOC (16 bits). The OFFS part thus compresses the information from this second location into 5 bits. The extension table and the places table then make it possible to return this second place in the manner described above. The DIR-OFFS section, the extension table and the places table offer the same advantage when presenting messages as will be described later in the description.

• 120 HDD=00?      l'unité de traitement de données verifie si
• 121 HDD=01?      HDD à la valeur indiquée?
• 122 HDD=10?
• 123 ADO mise en route du générateur de paroles (39, figure 4)
• 124 VD+ADO mise en route des générateurs de paroles et d'images (40, figure 4)
• 125 MEM engendrer un signal d'écriture pour la mémoire où sont stockés des données géographiques
• 126 µp réservation d'un premier registre tampon dans l'unité traitement de données. Puisque HDD n'a pas une des valeurs 00,01,10, HDD à la valeur 11 et est donc destiné à l'unité de traitements de données
• 127 HC+HT+EFF la combinaison des valeurs HC+HT+EFF forme une ou plusieurs adresses pour adresser un ou plusieurs endroits dans une mémoire locale du générateur de paroles et où d'images, selon qu'il a été activé. Aux adresses indiqués se trouvent des mots binaire au moyen desquels la représentation auditive ou visuelle de l'information codé en HC+HT+EFF sera réalisé
• 128 PRES C'est la présentation à l'utilisateur de l'information codé en HC+HT+EFF
• 129 CLR/RNN+PR-LOC+DIR REG+PR-LOC La table d'extension est adressée au moyen de l'adresse formée par CLR/RNN+PR+LOC et le mot ADR qui est mémorisé à cet endroit est lu
• 130 ADRS Le mot ADR est utilisé pour adresser la table des lieux et le code qui est mémorisé à cet endroit est transmis vers le générateur de paroles et/ou d'images.
• 131, 134 PRESA A l'aide du code qu'il a reçu le générateur en question va réaliser la presentation de l'information codé en CLR/RNN+PR-LOC+DIR
• 132 OFFS? C'est un test pour vérifier s'il y a une valeur OFFS différente de 00000 ou de 10000, indiquant une deuxième localisation dans le message.
• 133 PR-LOC+OFF Au cas où il y a une deuxième localisation dans le message, la valeur OFF est ajoutée à la valeur PR-LOC et va ainsi former une adresse pour un deuxième endroit dans la table d'extension et dans la table des lieux.
• 135 LM? C'est un test pour vérifier s'il s'agit du'un message long.
• 136 AUT Les autres parties (SAV, DAV) du groupe, si présentes, sont transmis au générateur en question et présentées à l'utilisateur.
• 137 STP C'est la fin du programme.

The presentation of the message (step 110, FIG. 11) will now be described in more detail with the aid of the flow chart illustrated in FIG. 13.

• 120 HDD = 00? the data processing unit checks whether
• 121 HDD = 01? HDD at the value indicated?
• 122 HDD = 10?
• 123 ADO starting the speech generator (39, figure 4)
• 124 VD + ADO start- up of speech and image generators (40, figure 4)
• 125 MEM generate a write signal for the memory where geographic data is stored
• 126 µp reservation of a first buffer register in the data processing unit. Since HDD does not have one of the values 00.01,10, HDD has the value 11 and is therefore intended for the data processing unit
• 127 HC + HT + EFF the combination of the values HC + HT + EFF forms one or more addresses to address one or more places in a local memory of the speech generator and where of images, depending on whether it has been activated. At the addresses indicated are words binary by means of which the auditory or visual representation of the information coded in HC + HT + EFF will be achieved
• 128 PRES This is the presentation to the user of information coded in HC + HT + EFF
• 129 CLR / RNN + PR-LOC + DIR REG + PR-LOC The extension table is addressed using the address formed by CLR / RNN + PR + LOC and the word ADR which is stored there is read
• 130 ADRS The word ADR is used to address the table of places and the code which is stored there is transmitted to the speech and / or image generator.
• 131, 134 PRESA Using the code it received, the generator in question will present the information coded in CLR / RNN + PR-LOC + DIR
• 132 OFFS? It is a test to check if there is an OFFS value other than 00000 or 10000, indicating a second location in the message.
• 133 PR-LOC + OFF If there is a second location in the message, the OFF value is added to the PR-LOC value and will thus form an address for a second location in the extension table and in the table. places.
• 135 LM? It is a test to check if it is a long message.
• 136 AUT The other parts (SAV, DAV) of the group, if present, are transmitted to the generator in question and presented to the user.
• 137 STP This is the end of the program.

Figures 14a and b illustrate an alternative form of the SMR2 sub-sequences of two successive groups. The sub-sequence illustrated in FIG. 14a comprises a LOC1 part (8 bits) and a LOC2 part (8 bits) which each indicate a respective location to which the message relates. In the sub-sequence illustrated in FIG. 14b, the DIR, ST and SAV parts are similar to those of the groups illustrated in FIG. 3d, and the SCTN part represents a section of the route, mentioned in the CLR-RNN part of the message, for example the section between the Karlsruhe and Strassbourg exits on the A8 motorway in federal Germany. When the format illustrated in Figures 14a and b is used, each route of the road network has been divided into different sections (32 sections maximum if the SCTN part has 5 bits) and the locations LOC1 and LOC2 then relate to the section mentioned in SCTN.

• une première sub-section 143 où est repris un nombre N indiquant en combien de tronçon la route Ri en question est divisée;
• une seconde sub-section 144 comprend une seconde liste d'adresses 144 qui est adressable au moyen de la partie SCTN du message (figure 14b) et indique pour chaque SCTN(i) une adresse SA(i) qui est la première adresse d'une troisième sub-section 145-j
• m troisième sub-sections 145-j (1≤j≤m). Les différents endroits de chaque troisième sub-section étant adressable au moyen de la partie LOC1 ou LOC2 du message et a chaque endroit ainsi adressé est mémorisé une adresse ADR (voire figure 12a) indiquant une endroit dans la table des lieux.

The choice of format illustrated in FIGS. 14a and b naturally implies a different configuration of the extension table, which is illustrated in FIG. 15. This different configuration is situated at the level of the addressing of this table, the content of the ADR part being equal to that shown in figure 12a but organized in a different way. For clarity, the ADR part has not been shown in FIG. 15. The extension table 140 illustrated in FIG. 15 includes a first list of addresses 141 and n sections 142-i (1 1 i i n ). The first address of each section 142-i is indicated by a letter Pi. The first address list 141 comprises these n addresses Pi and to each route Ri of the road network is assigned a Pi address. The first address list is addressable by means of the CLR-RNN part of the message and indicates for the route CLR-RNN = Ri an address Pi which is the first address in section 142-i of the extension table. Each section 142-i includes:

• a first sub-section 143 where a number N is indicated indicating in how many sections the road Ri in question is divided;
• a second subsection 144 includes a second address list 144 which is addressable by means of the SCTN part of the message (FIG. 14b) and indicates for each SCTN (i) an address SA (i) which is the first address of a third subsection 145-j
• m third sub-sections 145-j (1≤j≤m). The different places of each third sub-section being addressable by means of the LOC1 or LOC2 part of the message and at each place thus addressed is stored an ADR address (see FIG. 12a) indicating a place in the table of places.

• CLR-RNN = R8 (=A8)
• SCTN = 2
• LOC1 = XX
• LOC2 = YY

Lorsqu'un tel message devra être présenté au conducteur, l'unité de traitement de données va adresser dans la première liste d'adresse 141 l'endroit R8 et y prélever l'adresse P8, indiquant la première adresse de la section 142-8. A cette adresse P8 est mémorisé le nombre N, par exemple N=11 indiquant que la route R8 comporte 11 tronçons. L'unité de traitement de données va ensuite former l'adresse P8+SCTN=P8+2 pour adresser l'endroit P8+2 dans la seconde liste où est mémorisé à l'endroit P8+2 l'adresse SA2 indiquant la première adresse de la sub-section 145-2. L'unité de traitement de données va ensuite former l'adresse SA2+LOC1=SA2+XX pour lire à l'adresse SA2+XX l'adresse ADR1 qui est stockée. Cette adresse ADR1 indique alors l'endroit dans la table des lieux où est mémorisé le nom du lieu auquel se rapporte la partie LOC1 du message. La présentation de cette partie se fera alors de la façon décrite auparavant. L'unité de traitement de données va également former l'adresse SA2+LOC2=SA2+YY et prélever l'adresse ADR2 mémorisé à cette endroit SA2+YY pour former un second lieu auquel se rapporte le message. Ainsi il est possible d'indiquer deux endroit dans un même tronçon d'une même route au moyen d'un même message.The addressing of this extension table illustrated in FIG. 15 will now be described by means of an example. Suppose the following message (format figure 14):

• CLR-RNN = R8 (= A8)
• SCTN = 2
• LOC1 = XX
• LOC2 = YY

When such a message must be presented to the driver, the data processing unit will address in the first address list 141 location R8 and take the address P8 there, indicating the first address in section 142-8 . At this address P8 is stored the number N, for example N = 11 indicating that the route R8 has 11 sections. The data processing unit will then form the address P8 + SCTN = P8 + 2 to address the location P8 + 2 in the second list where the address SA2 indicating the first address is stored at location P8 + 2 of subsection 145-2. The data processing unit will then form the address SA2 + LOC1 = SA2 + XX to read from the address SA2 + XX the address ADR1 which is stored. This address ADR1 then indicates the place in the table of places where the name of the place to which the LOC1 part of the message relates is stored. The presentation of this part will then be done as described previously. The data processing unit will also form the address SA2 + LOC2 = SA2 + YY and take the address ADR2 memorized at this location SA2 + YY to form a second place to which the message relates. Thus it is possible to indicate two places in the same section of the same road by means of the same message.

Claims (19)

1. A device for receiving and processing road information messages transmitted in digital form, each message including at least a first section for indicating the zone of a road network whereto the message refers, which device includes, for the control of the data processing, a data processing unit (33) which is connected to a bus (32) for the transfer of data, to which bus there are also connected a reception memory (31) for temporarily storing the messages received, a reception unit enabling the selection, from among the messages stored, of the messages concerning a zone to be designated, and a presentation unit for presenting the messages selected, characterized in that the device includes a message analysis unit which includes a zone-table memory, which analysis unit is arranged to recognize the zone in question, each time a message is received, on the basis of said first section of the message received and to store in the zone table, using at least one indicator for each message, the messages received according to the zones whereto they relate, which selection unit is arranged to access the zone table and to carry out said selection by fetching messages for the designated zone in the zone table.
2. A device as claimed in the first Claim, wherein the different zones of a road network correspond to the roads and are indicated by a category and a road number, characterized in that the zone-table memory includes a table of roads in which the messages are placed according to the roads whereto they relate, and in that the indicators are constituted by the addresses at which the messages in question are stored in the reception memory (31).
3. A receiving device as claimed in Claim 1 or 2, wherein the different zones of a road network correspond to regions of at least one country, characterized in that the device is fitted with a referencing unit in order to mark in a message received the region whereto it relates, which message analysis unit is connected to the referencing unit, in that the zone-table memory includes a region table in which the messages are placed according to the regions whereto they relate and in that the indicators are constituted by the addresses at which the messages in question are stored in the reception memory.
4. A device as claimed in Claim 2, characterized in that the device includes a road-region correspondence table (34) for storing, for a predetermined number of roads of the road network to which the road region correspondence table refers, an overflow index indicating the maximum number of road messages for each of the roads of said predetermined number, said device being provided with a verification unit connected to the road-region correspondence table (34) and to the road table in order to verify if the number of messages stored for each road does not reach the number indicated by the overflow index for the road in question, and to eliminate the presence of a message for a road for which the number of messages stored in the road table has reached the number indicated by the overflow index.
5. A device as claimed in Claim 4, characterized in that the referencing unit includes a road-region correspondence table (34) wherein there is stored, for each of the roads of a predetermined number of roads of a road network, at least one index indicating at least one region traversed by the road in question.
6. A device as claimed in Claim 3 or 5, characterized in that the device includes a region-road correspondence table (34) for storing, for a predetermined number of regions, an overflow index indicating the maximum number of road messages for each of the regions of said predetermined number, said device being provided with a verification unit connected to the region-road correspondence table (34) and to the region table and being arranged to verify if the number of messages stored for each region does not reach the number indicated by the overflow index for the region in question, and to eliminate the presence of a message for a region whose number of messages stored in the region table has reached the number indicated by the overflow index.
7. A device as claimed in Claim 4 or 6, characterized in that the verification unit is arranged to carry out the said elimination of the presence of the oldest message from among said number of messages.
8. A device as claimed in Claim 6, characterized in that the region-road correspondence table (34) includes, for each region stored therein, at least one road traversing the region.
9. A device as claimed in the Claims 5 and 8, characterized in that the verification unit is also arranged to mark, with the aid of the road-region correspondence table (34) and the region-road correspondence table (34), respectively, to which region and to which road, respectively, the message whose presence has been eliminated relates and also to eliminate from the region table and from the road table, respectively, the message whose presence in the road table and region table, respectively, has been eliminated.
10. A device as claimed in any one of the Claims 4 or 6, characterized in that to each road and to each region, respectively, stored in the road-region correspondence table (34) and in the region-road correspondence table, respectively, there is assigned a dedicated overflow index which is stored in the road-region correspondence table (34) and the region-road correspondence table (34), respectively.
11. A device as claimed in any one of the preceding Claims, wherein each message includes at least one sequence composed of two blocks and wherein each block includes an information section and a control section, the control section also including a shift word for the synchronization of the blocks, and wherein a first and a second shift word can be used for a predetermined block, characterized in that the first shift word is used for the first sequences of a message and the second shift word is used for the other sequences of the same message, and in that the device is provided with a decoder for decoding the shift word of a message received and for generating a set signal during the decoding of a first shift word, which device includes a sequence counter which is connected to the decoder and can be set under the control of a set signal.
12. A device as claimed in Claim 1, characterized in that the selection unit (43) is provided with means enabling selection between an intersection and/or a union of at least two zones.
13. A device as claimed in Claim 1, characterized in that the selection unit (43) is provided with a key for activating the immediate presentation, after reception, of a message for a selected zone.
14. A device as claimed in Claim 1, wherein the message includes several sections with coded words each time representing various parts of the information of the message, characterized in that the device is provided with a conversion memory which is connected to the presentation unit and is addressable by different coded words, in which stored other coded words are stored for the presentation of the message.
15. A device as claimed in Claim 14, wherein a second section of the message contains a location situated in the zone whereto the message refers, characterized in that in the conversion table there are stored, in the form of other coded words, different locations of at least one country whereto the road information refers.
16. A device as claimed in Claim 15, characterized in that each message includes a third section with a shift value enabling the indication of another location with respect to the location contained in the second section, the device being provided with an address generator for forming an address for the conversion memory on the basis of the second and third sections of the message.
17. A device as claimed in Claim 15, characterized in that the second section is divided into a first subsection, indicating a segment in the zone entered in the first section, a second and a third subsection indicating a first and a second location, respectively, in the segment indicated in the first subsection, and in that the conversion memory is divided into n sections and includes a first list of addresses indicating the first address of each of the n sections, a location in the first list of addresses being addressable by the first section of the message, each of the n sections being divided into m subsections and including a second list of addresses which is addressable by said first subsection of the message and includes the first addresses of each of the m subsections, a location in one of the m subsections being addressable by the second or the third subsections.
18. A device as claimed in Claim 16 or 17, characterized in that the conversion memory includes an extension table and a location table, the extension table including, for each address formed by the first and the second and/or on the basis of the first, the second and the third section, an address indicating a location in the location table.
19. A device as claimed in Claim 1, characterized in that the service is connected to a road navigation system for vehicles, said navigation system being provided with means for determining a route between a start point and a destination, characterized in that the navigation system is provided with means for transmitting to the selection unit at least one zone traversed by said route and for receiving the messages relating to the designated zone, said means for determining a route being arranged to analyze the message received and to recognize, in the message received, if there is a traffic problem in the designated zone and to determine a new route in the case of a traffic problem.

Images