FR2642875A1 - INFORMATION COLLECTION AND DISSEMINATION SYSTEM FOR MOTORISTS - Google Patents

Abstract

This system comprises: - information-collecting means (100) for gathering and centralising a set of information relating to the state of the traffic in a given zone, in particular an urban zone, each item of information corresponding to a segment included between two predetermined characteristic sites, - means (210) for transforming this set of information into a series of elementary digital information each consisting of an identifier of segment and of direction of flow and of a state variable representing the state of traffic of this segment in the said direction of flow; - means (220) for formulating, on the basis of this series of digital information, a scrolling, continuous and cyclic sequence of information consisting of the elementary digital information from all the relevant segments, this sequence being regularly updated as a function of the change in the information gathered; - means (330, 340, 350) for broadcasting this scrolling sequence of information over the air; and - on board the said vehicles: means (360) of receiving the said scrolling sequence of information thus broadcast, discriminator means (240) for selecting, from the set of elementary information, that likely to interest the driver, as a function of a predetermined criterion inserted by the latter; and means for presenting the driver with the elementary information thus picked out.

Description

Information collection and dissemination system for motorists La

  present invention relates to collection and dissemination system

information for motorists.

  It is common to broadcast information bulletins during radio broadcasts warning motorists of traffic problems (traffic jams, accidents, etc.) on certain arteries or

  certain traffic nodes of an agglomeration.

  This information can only be ad hoc information, in a limited number, and it is also not personalized according to the driver, who will indiscriminately receive all of the messages thus broadcast. It is for this reason that we have recently developed specific guidance systems which provide each driver with personalized information on the route he must follow, indicate alternate routes if necessary, allow him to locate its position in the city, etc. - We can notably cite the system developed by Siemens AG with the support of the University of Berlin and Robert Bosch GmbH under the name Aliscout, which is based on a system of bidirectional infrared data exchange between the vehicles to be guided and

  beacons placed at different crossroads.

  In this system, each automobile is equipped with various sensors

  (distance traveled, speed, steering compass, etc.) and a transmitter-

  receiver operating as an answering machine.

  When approaching a crossroads, and upon reception of an interrogation signal emitted by the beacon of this crossroads, the responder of the vehicle will transmit to the beacon the information collected by the sensors of this vehicle. This information will then be transmitted by the beacon to a central computer which will compare this information with homologous information given by the same vehicle to the previous beacon and will determine the traffic flow and the possible drift of the trajectory.

  actual vehicle compared to the originally planned trajectory.

  In return, the host center will send guide information to the beacon which will be transmitted to the vehicle by the beacon. This guidance information will appear for example on a screen in the form of an arrow indicating to the driver the direction to take to reach the next beacon of his route (or, if the host center has determined that this is preferable, the next beacon of an itinerary of

  clearance), as well as the distance as the crow flies to it.

  Such a system is for example described in a document entitled LISB Leitund Informationssystem Berlin -ALISCOUT im Gro / 3felduersuch,

  published by Siemens AG under the reference A 1900-N9-11.

  Obviously, such a system, although effective, is extremely cumbersome and expensive to set up. Indeed: -From the point of view of the ground infrastructure, in particular due to the high density of crossroad beacons necessary for a satisfactory functioning of the system in urban areas, it is necessary to install a system which is entirely new ( without the possibility of reusing often existing equipment such as the systems already in place intended for traffic regulation by synchronization of traffic lights) and without the possibility of progressive installation - hence investments

  2) very heavy for the community.

  In addition, this system requires a large number of bidirectional links both between beacons and vehicles and between beacons and host center. The increase in the number of crossroad beacons therefore requires a correlative increase in the size of the network, which limits the possibilities of rapid generalization of the system, taking into account the cost and the complexity that such an infrastructure entails. - From the point of view of the equipment on board by each of the vehicles wishing to participate in the system, these must all be provided not only with infrared transmitter / receiver equipment and with a certain number of sensors allowing the system to know their movements, but also a sophisticated interface allowing the driver to be guided via a screen and a voice synthesizer. This very complete set represents a significant cost for individual equipment. Finally, it appears that there is a potential clientele of motorists who simply wish to benefit from precise and personalized information on the traffic status of the route they plan to take; this in order to adapt or modify this itinerary accordingly taking into account the. knowing that they already have places, without having to submit to automatic guidance over which they are not masters. The invention aims to remedy the drawbacks of the aforementioned system, by proposing a system for collecting and disseminating information which: -for collecting the information, uses, in addition to or as a variant of the aforementioned system, other techniques and other existing data acquisition systems - in particular the systems already in place intended for traffic regulation by synchronization of traffic lights, and - for the dissemination of information, makes it possible to offer to a large audience of users the dissemination of information via a suitable channel, in addition to the subscriber guidance system having

chose this system.

  It will indeed be seen that, although simplified compared to the aforementioned known system, the system of the invention can be implemented for a low cost in each vehicle wishing to take advantage of the information

  developed and disseminated by the system of the invention.

  In addition, and as will also be explained, the increase in the number of these vehicles does not entail any need to increase the

  network transmission capacities leading to the server center.

  Despite this, as will be seen, the driver equipped with a receiver of the information broadcast by the system according to the invention can

  know the traffic situation on the entire route he plans to take -

  and only on this route - as well as, if applicable, on areas

neighbors of this route.

  The fact of selectively presenting information to the driver according to the route he has chosen makes it possible to provide very fine information (the agglomeration being for example divided into a thousand characteristic places of which one will be able to know the state of the traffic each), while only providing information of interest to the driver given his route, for example information

  relating to ten or fifteen characteristic places.

  More specifically, the system of the invention comprises, for this purpose: - information collection means, for collecting and centralizing a set of information relating to the state of traffic in a given area, in particular an urban area, each of the pieces of information in this set of information corresponding to a predetermined characteristic place, means for transforming this set of information into a series of elementary digital information each consisting of an identifier of a characteristic place and a variable of state representative of the state of this place from the point of view of its degree of fluidity of traffic or its occupation by vehicles; means for developing, from this series of digital information, a continuous scrolling sequence of information consisting of elementary digital information from all the characteristic places considered, this sequence being regularly updated as a function of the evolution of the information collected; means for broadcasting this scrolling sequence of information by radio; and - on board vehicles: means for receiving the scrolling sequence of information thus broadcast, discriminating means for selecting, from among all of the elementary information, that likely to interest the driver according to a predetermined criterion introduced by the latter, and means for presenting the driver with the elementary information thus discriminated. Very advantageously, the means of collecting information comprise, in a plurality of characteristic places, transmitter-receiver beacons cooperating with answering machines installed on board a subset of witness vehicles constituting a sample of all the vehicles participating in traffic, these witness vehicles being provided with distance traveled and / or orientation sensors the information of which is returned by the transponder responders when

  these emit an interrogation signal.

  These means of collecting information can for example be constituted by the aforementioned Aliscout system, but for which only a limited number of vehicles will be fitted (which will be called in the

  continuation of the description "floating vehicles") which will be used as vehicles

  witnesses and who will be chosen from among the vehicles circulating

  intensive (taxis, buses, couriers, public service vehicles, etc.).

  If such an information collection system is used, one can: either use the complete system described above, which will ensure the guidance of floating vehicles, which are by nature M vehicles for which this guidance is the most useful, or use only a simplified system, with a unidirectional link from the beacon to the server center and without a system for decoding and displaying guidance information on board vehicles. Such a simplified system would only provide the sole function of traffic analysis by tracking floating vehicles, necessary but sufficient for the implementation of the system of the invention. Advantageously, the defying sequence of information is broadcast over the air by a method of broadcasting digital data with a subcarrier added to a broadcast transmission signal, the receivers on board vehicles being broadcasting receivers equipped with a decoder ensuring separation of signal information

  digital with audio program signal.

  : One can in particular use for this purpose the RDS system (Radio Data System) for the diffusion of digital data by radio in frequency modulation, and whose specifications were defined by the European Radiocommunication Union, these specifications being notably detailed in the document referenced Tech. 3244 published in

March 1984 by this organization.

  Indeed, the specifications of the RDS system provide for the possibility, in addition to the dissemination of a certain number of standard information (type and name of the transmitter, other frequencies of emission of the same program, time and date, radio text information) to have "data channels for external use" making it possible to transmit messages of any length and format and which can convey characters

  alphanumeric or any other digital data.

  The advantage of the RDS system is that it can be used by simple car radios fitted with an appropriate decoder, and of which various models are currently available or under development. To use the guidance information of the invention, it will then suffice to connect to the digital data output of the car radio a box comprising the circuits and

appropriate control means.

  Compared to a guidance system such as the aforementioned Aliscout system, this saves both the specific data broadcasting system (which is, in the case of the invention, an already existing FM radio transmitter, including it is sufficient only to appropriately code the signal on transmission) and the specific receiver on board the vehicle, which

  could be a simple car radio with an RDS decoder.

  Alternatively, instead of using the carrier frequency of one or more radio stations, other radio frequencies could possibly be used. According to other advantageous characteristics: - the means of collecting information comprise means for transmitting indications relating to the state of occupation of areas of

  parking, each of these parking areas corresponds to

  laying in a characteristic place; the predetermined criterion according to which the discriminating means act comprises a route formed by a sequence of characteristic places previously introduced by the user, the discriminating means then selecting only the elementary digital information corresponding to the characteristic places of this route and, possibly , to characteristic places close to this route; the state variable of the elementary digital information comprises a parameter for indicating the direction of traffic and a parameter for the fluidity of traffic in this direction of traffic; - the means to present information to the driver

  discriminated elementaries are speech synthesis means.

  We will now give a detailed example of the implementation of

  the invention, with reference to the appended figures.

  FIG. 1 is a block diagram of the system of the invention,

  showing the different functions implemented.

  Figure 2 is a representation of a route chosen by the

  conductor as well as the surrounding characteristic places thereof.

  In FIG. 1, the reference 100 designates the information collection system which can be, as indicated above, a coupling of a system of the Aliscout type, complete or simplified, with systems based on loops put in place. for traffic regulation by

  synchronization of traffic lights.

  This system essentially comprises a set 110 of elements

  installed in floating vehicles (as defined above, i.e.

  say witness vehicles in limited number chosen from vehicles circulating intensively), beacons 120 installed in a certain number of characteristic places, and a centralizing server 130 and

  processing the information collected by the tags.

  The elements 110 on board the floating vehicles essentially comprise an on-board computer 111 receiving the signals from an electronic compass 112 giving the absolute orientation of the vehicle relative to magnetic north and an odometer 113 counting the number of turns of wheels (therefore the distance traveled) since the last signposted. A keyboard 114 makes it possible to introduce a certain amount of information such as a vehicle identifier (necessary for

  ability to locate and track a vehicle from one beacon to another).

  The computer 111 communicates with an infrared responder 115 receiving an interrogation signal from the beacon 120 and returning to the latter, on reception of this interrogation signal, the values measured by Ies

sensors.

  Each beacon 120 comprises, for example mounted on a three-color light 121, an infrared transceiver 122 exchanging information with the vehicles of the system, as well as a computer 123 managing these exchanges of information and ensuring the interfacing with the server center 130 The server center 130 makes it possible both to calculate the route (block 131) when using the possibilities (not necessary for the implementation of the invention) of specific guidance of floating vehicles by sending information via the beacon) and traffic analysis based on the information

  collected, with possible visualization (block 132).

  Characteristically of the invention, the information produced by block 132 is used to develop elementary digital information representative of the state of traffic at each location

  characteristic of the agglomeration.

  By "characteristic places" is meant the various places in the agglomeration for which the state of traffic or the state of occupation by vehicles is decisive information for regulating traffic. These characteristic places may, without being exhaustive, be: traffic nodes such as crossroads, squares, etc., traffic arteries (avenues, boulevards, expressways) or sections of arteries, - delimited areas (such and such a district), - parking areas: it is no longer a question of fluidity of the

  traffic, but of occupancy rate by vehicles.

  It is of course possible to combine these different types of characteristic places. The choice of the characteristic places is carried out so as to achieve a complete grid of the agglomeration, while making it possible to describe the

  almost all possible routes in a simple and unambiguous way.

  It is thus estimated, that for an agglomeration such as Paris intra muros, a thousand characteristic places must make it possible to return

  sufficiently complete and detailed traffic status report.

  Each characteristic place will be associated with a "state variable", which will be information representative of the state of this place from the point of view of its degree of fluidity of traffic (nodes or arteries of circulation) or its

  occupancy by vehicles (specific areas, parking areas).

  This state variable is a numeric variable giving information from a state of maximum congestion to a state of

total fluidity.

  At a minimum, this state variable can be coded on a single bit (which gives two states: fluid / congested), but preferably it is coded on a larger number of bits, for example two or three bits, which provides more nuanced information (four possible states

  on two bits, eight possible states on three bits, etc.).

  Advantageously, for certain characteristic places (in particular the arteries), the parameter of traffic flow is combined with a parameter indicating the direction of traffic. Indeed, the traffic can be fluid in one direction and congested in the other so that if one did not distinguish the direction of traffic one would deliver to the driver information which does not

  would not be representative of the real situation.

  The state variables that we have just defined can be obtained from different sources: o - analysis of the circulation of floating vehicles by the assembly 100 described above and illustrated in FIG. 1, the location of the beacons corresponding to that of a certain number of selected characteristic locations, -magnetic sensors used for the regulation of traffic lights, -counting of entrances / exits in car parks, -cameras, information transmitted by police cars, etc. To simplify the preparation of the information in block 210, it is desirable to collect this information from a system which is the

  as automated and homogeneous as possible.

  It is for this reason that we prefer to collect most of this information from beacons interrogating floating vehicles. However, the system of the invention does not exclude, as a variant or in addition, the use of other modes of data collection. Block 210 thus develops a series of elementary digital information each consisting of a characteristic location identifier.

  and a state variable, as defined above.

  Preferably, it will be possible to manually force the value of certain state variables, for example by means of an input console 230, in order to deliberately influence the course of traffic, regardless of the state of traffic. A typical case is that where one wishes to clear a crossroads by diverting the vehicles which

were considering going there.

  This block 210 can also weight the information which it produces as a function of a certain number of parameters, so as to adapt the messages broadcast to the circumstances or to anticipate a probable development. The weighting factors can, among other things, be: - the degree of evolution of the state variable between its instantaneous value and its previous value, - the value of the state variable the day before at the same time (taking into account holidays, non-working days, etc.) - the value of the state variable on the same day the previous year, - the values of the state variables of certain neighboring characteristic places (in order to anticipate chain reactions, for example in case

  accident at a point on an artery).

  The elementary digital information produced by block 210 is then grouped (block 220) to develop a "segment of information" consisting of all of the elementary digital information, placed end to end, of all the characteristic places of the agglomeration. The segment thus developed will constitute a continuous scrolling sequence of information which will be the subject of coding, advantageously the RDS coding mentioned above. The type of modulation used in RDS is amplitude modulation with two sidebands with carrier suppression and two-phase differential coded signals. Such coding allows, for a total transmitted bit rate of 1187.5 bits per second, a useful information bit rate of 730 bits per second for all of the information transmitted, approximately 80 bits per second being reserved for the data channel to external use, which is the route used by the present invention to transmit

guidance signals.

  As it scrolls, the segment will be updated, the periodicity of the scrolling then corresponding to the periodicity of the update. 2 In the example cited above of 1000 characteristic places, if we choose a state variable with 10 positions per place, we can code the elementary digital information on 16 bits which, once grouped together, will form a segment of 16 000 bits. If we consider that RDS coding authorizes a useful bit rate of information of 80 bits per second, we can have a periodicity of scrolling of the system (and therefore of updating information of 200 seconds, ie 3 '20 ", quite worth

  compatible with effective guidance in built-up areas, even in the presence of-

  very rapidly changing traffic conditions.

  Of course, these values are given only by way of example. Given the specific cases, and with the constraint of the maximum speed allowed by the data dissemination system, a compromise must be sought between - the number of characteristic locations, - the number of status positions that each location can take, and

  - the periodicity of scrolling of the segment.

  The elementary digital information segment thus coded is broadcast to the vehicle by a broadcasting chain comprising

  transmitter means 310 to 350 and a receiver 360 in each vehicle.

  On transmission, the audio signal coming from a recording control unit (block 310) is transformed (block 320) into a modulation signal in a conventional manner, for example with stereo coding at 1i pilot frequency. The audio signal is then multiplexed (block 340) with the

  signal from the RDS encoder (block 350), for example on a sub-

  carrier at 57 kHz (harmonic 3 of the pilot signal subcarrier

stereo at 19 kHz).

  The signal thus multiplexed is directed to a broadcasting transmitter

  330 frequency modulation of conventional type.

  In addition, the various vehicles are equipped with 360 receivers, which

  are car radio receivers fitted with conventional RDS decoders.

  The digital output of the data channel for external use of the RDS 360 receiver is connected to a box 240, specific to the invention, which will therefore receive from this output, continuously, the scrolling sequence

  of information disseminated by the system.

  The basic digital information will be decoded and presented to the driver visually in clear on a screen and / or

  preferably by text-to-speech means 260.

  However, the driver is not presented with all of the

information disseminated.

  Indeed, given the large number of characteristic places (a thousand, in the example considered) and the relatively high periodicity (3.2 minutes) of scrolling, the motorist would hear an uninterrupted series of messages, and would have a lot of hard to hear and remember only the messages that interest him, and this at the cost of attention

prejudicial to his safety.

  Provision is therefore made in the housing 240 for discriminating means so as to select, from among all of the elementary digital information, only that likely to interest the driver, as a function of one or more predetermined criteria introduced. (s) by

this by means of a keyboard 250.

  This selects the relevant messages and only returns these

relevant messages.

  The predetermined criterion may in particular include a route composed on the keyboard 250 by the driver by means of a map on which the different characteristic places of

  the agglomeration and their identification code (the code to type on the keyboard).

  The driver can thus compose for example (Figure 2) the route

A B C D E.

  In this case, for each elementary digital information received, the box 240 will test the identifier of the characteristic location of this information and will not return to the driver the corresponding state variable unless this identifier of the characteristic location corresponds to the route previously chosen ( that is, in the example illustrated, the only inventory variables A, B, C, D and E); the driver will therefore only receive the relevant messages - in the example illustrated, five messages out of a total of one thousand

messages received.

  It is possible to provide a certain number of variants or improvements: - the storage of several pre-constituted routes, which will be recalled by a simple key press, - the coding, for the same origin / destination pair, of several alternative routes that the driver can test one after the other, -the incorporation into a given route of variants which will be returned at the same time as the route itself,

  - the isolated interrogation of a given characteristic place.

  Furthermore, provision can be made not only for information relating to the characteristic places of the chosen route (ABCDE, in the example illustrated), but also to neighboring characteristic places (the black dots in FIG. 2, the corresponding white dots at characteristic places for which we do not return

user information).

  A more or less wide "corridor" is thus defined around the route, the width of this corridor depending on the degree of precision of the given route, that is to say on the number of intermediate points between

  the origin and destination that the user provided to the device.

  By thus disseminating to the driver information relating to the chosen route and its immediate environment, we can take into account the

  possible deviations, en route, from the planned route.

Claims (7)

  1. A system for collecting and disseminating information for motorists, characterized in that it comprises: means (100) for collecting information, for collecting and centralizing a set of information relating to the state of the traffic in a given area, in particular an urban area, each of the pieces of information in this set of information corresponding to a predetermined characteristic location, means (210) for transforming this set of information into a series of elementary digital information each consisting : * of an identifier of characteristic place and * of a state variable representative of the state of this place from the point of view of its degree of fluidity of traffic or of its occupation by m vehicles; means (220) for developing, from this series of digital information, a continuous scrolling sequence of information consisting of elementary digital information from all   characteristic places considered, this sequence being regular   rement updated according to the evolution of the information collected -means (330, 340, 350) to broadcast over the air this scrolling sequence of information; and - on board vehicles: * means (360) for receiving the scrolling sequence of information thus broadcast, * discriminator means (240) for selecting, from among all of the elementary information, those likely to interest the driver according to a predetermined criterion introduced by it, and * means for presenting the information to the driver elementaries thus discriminated against.   2. The system of claim 1, in which the information collection means comprise, in a plurality of characteristic locations, transceiver beacons (120) cooperating with answering machines (115) installed on board a sub- set of witness vehicles constituting a sample of all the vehicles participating in traffic, these witness vehicles being provided with distance traveled (113) and / or orientation (112) sensors, the information of which is returned by the responders to the beacons when these emit an interrogation signal.   3. The system of one of claims 1 or 2, wherein the sequence   of information is broadcast over the air by a method of broadcasting digital data with a subcarrier added to a broadcast broadcast signal, the receivers (360) on board vehicles being broadcast receivers equipped with a decoder ensuring separation of digital signal information from signal audio program.   4. The system of claim 1 to 3, in which the means for collecting information comprise means for transmitting indications relating to the state of occupation of parking areas, each of these parking areas corresponding to a characteristic place.   5. The system of one of claims 1 to 4, in which the criterion   predetermined according to which the discriminating means act comprises a route formed by a sequence of characteristic places (AE) previously introduced by the user, the discriminating means then selecting only the elementary digital information corresponding to the best characteristics of this route and,   possibly to characteristic places close to this route.   6. The system of one of claims 1 to 5, in which the variable   basic digital information state includes a traffic direction indication parameter and a traffic flow parameter in this direction of circulation.   7. The system of one of claims 1 to 6, wherein the means   to present the discriminated elementary information to the driver   are speech synthesis means.