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(11) | EP 0 389 488 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
VEHICLE LOCATION SYSTEMS SYSTEM ZUR ORTUNG DES FAHRZEUGES SYSTEMES DE LOCALISATION DE VEHICULES |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0002] Automatic vehicle location systems are commonly used to control vehicle operations by Taxi fleets, Distribution Organisations, Emergency Services, etc. Conventional location systems enable a controller to keep track of the location of the vehicles in a fleet and. to use this information in allocating a job to a particular vehicle. Information other than the location of a vehicle is usually needed in deciding which vehicle will perform a job. This information will also need to be monitored by the controller. The location information may in some situations need to be continuously monitored. In large vehicle fleets this is not a reasonable proposition if a single radio channel is all that is available for transmission of data. For example, a taxi may move at an average speed of 10m/s. In allocating a job in a crowded city centre, a precision of as little as 100m may be needed for the location of a vehicle. Thus a positional update every 10s would be needed from each vehicle in a fleet. This represents much more data than could be accommodated in a single radio data channel.
[0003] The present invention provides a method of job allocation for an automatic vehicle location system having a controller and a plurality of mobile vehicles with a two-way radio link between the controller and the vehicles, the method comprising the steps of transmitting a message from the controller to the vehicles the message including information about the job location, comparing at each vehicle the requirements of the job with the status of the vehicle and, if the result of the comparison is such that the vehicle is suitable for the said job, transmitting a response message from the vehicle to the controller after a time delay dependent upon the distance of the vehicle from the location of the job.
[0004] In accordance with the invention there is also provided a job allocation system for use with an automatic vehicle location system comprising a central controller, transmitting means at the controller, receiving means at the controller, a plurality of mobile vehicles each vehicle including means to receive job request messages from the controller, means to compare the requirements of the requested job with the status of the vehicle, means to transmit a response message to the controller if the result of the comparison is such that the vehicle is suitable for the job, and means to vary the time taken to transmit a response to a job request message in accordance with the distance of the vehicle from the location of the job.
[0005] Furthermore, the invention provides apparatus for use at a mobile vehicle in an automatic vehicle location system comprising means to receive a job request message, means to compare the requirements of the requested job with the status of the vehicle, means to transmit a response message to the controller if the result of the comparison is that the vehicle is suitable for the job, and means to vary the time taken to transmit a response to a job request message in accordance with the distance of the vehicle from the location of the job.
[0007] Various pieces of information are used by the controller of a fleet of vehicles when allocating jobs to specific vehicles. These may include the following:
1) The type of job and the vehicle and/or crew's ability to perform it;
2) The time when the job is to be performed and the availability of vehicles; and
3) The location of the job and the distance a vehicle would need to travel to the job.
[0009] In the current invention, each vehicle in a fleet has a microcomputer to perform all the vehicle location tasks. In addition to this, the microcomputer is used to assess the suitability of the vehicle for a given job or task.
[0010] When the controller of the fleet receives a job request, it will broadcast a data message containing all the information relevant to carrying out that job to all the vehicles in the fleet.
[0011] The microcomputer at each vehicle then assesses the suitability of the vehicle for the job in terms of location, and any other constraints in the data message. If the microcomputer decides that the vehicle is a suitable candidate for the job then it will transmit a response message back to the controller. This message to the controller volunteers the vehicle for the job.
[0012] The information transmitted from the controller to the vehicles may contain such information as "only those within 100m need reply", or "only those with two hours available for the job need reply". These constraints might result in only one or two responses being transmitted and would thus cut down the amount of radio traffic. The effect of interrogating the vehicles in this manner is to create an intelligent distributed database.
[0013] There will be instances when there is more than one suitable contender for a job. One method of overcoming this problem would be to re-try the interrogation process at a pseudo-random time interval after finding more than one contender. There are however alternative and more efficient methods.
[0014] Firstly, the time which vehicles take to respond to an interrogation could be arranged to be proportional to the distance of the vehicle from the location of the job. Once a vehicle in the fleet has volunteered for the job then the other vehicles can be "stood-down" by the controller broadcasting a further message.
[0015] Secondly, the system could use a dynamic area window to minimise the number of responses received and thereby maximise the response time. This area window could vary with both time of day and job location. For example, in the west end of London on a Friday night there would be a high concentration of taxis and so a job would be offered only to taxis within a short distance of the job. Conversely, for a job in the east end of London, early on a Sunday morning, a large area would be used to find a taxi suitable for the job. The controller could be programmed to vary the area window with the time of day or could learn in an adaptive way depending on its success in getting responses.
[0016] The controller in the above system will normally have a gazeteer of street names against grid squares to enable job locations to be easily identified. Where roads are longer than the vehicle density the gazeteer will not always be satisfactory. The vehicle location system could therefore be adapted to improve the quality of its gazeteer as more jobs are performed. Since the controller knows the address of a job location (e.g. 61 High Street) it can interrogate the vehicle for its exact location when arriving at the job location. This could be stored in memory and used for reference in future calls. Thus a fairly crude gazeteer can be self-refining.
[0018] In a conventional system in which the selection of a vehicle is done centrally, a fleet of 500 vehicles with a position update for each vehicle every 10 seconds would require 3000 messages every minute plus, say, one job allocation per minute. In a system in accordance with the invention the same job could be carried out with 1 offer, 1 acceptance, and 1 job details - a total of three messages.
1. A method of allocation for an automatic vehicle location system having a controller
and a plurality of mobile vehicles with a two-way radio link between the controller
and the vehicles, the method comprisng the steps of transmitting a message including
information about the job location, comparing at each vehicle the requirements of
the job with the status of the vehicle and, if the result of the comparison is such
that the vehicle is suitable for the job, transmitting a response message from the
vehicle to the controller after a time delay dependent upon the distance of the vehicle
from the location of the job.
2. A method according to claim 1, in which only vehicles within a predetermined area
may respond to the message from the controller.
3. A method according to claim 2, in which the predetermined area is selected by and
may be altered by the controller.
4. A method according to claim 1, 2 or 3, including the steps of the controller interrogating
a vehicle for its exact location on arrival at a job location, the vehicle transmitting
its exact location to the controller, and the controller storing the exact location
in memory thereby improving the quality of a gazeteer stored in memory.
5. A job allocation system for use with an automatic vehicle location system, comprising
a central controller, tranmitting means at the controller, receiving means at the
controller, a plurality of mobile vehicles each vehicle including means to receive
job request messages from the controller, means to compare the requirements of the
job with the status of the vehicle, means to transmit a response message to the controller
if the result of the comparison, is that the vehicle is suitable for the job, and
means to vary the time taken to transmit a response to a job request message in accordance
with the distance of the vehicle from the location of the job.
6. Apparatus for use at a mobile vehicle in an automatic vehicle location system comprising
means to receive a job request message, means to compare the requirements of the requested
job with the status of the vehicle, means to transmit a response meessage to the controller
if the result of the comparison is that the vehicle is suitable for the job, and means
to vary the time taken to transmit a response to a job request message in accordance
with the distance of the vehicle from the location of the job.
1. Zuweisungsverfahren für ein automatisches Fahrzeugortungssystem, aufweisend eine Steuereinheit
und mehrere mobile Fahrzeuge mit einem wechselseitigen Funkübertragungsweg zwischen
der Steuereinheit und den Fahrzeugen, wobei das Verfahren aufweist die Schritte der
Übertragung einer Information über den Auftragsort enthaltenden Nachricht, des Vergleichens
der Anforderungen des Auftrags an jedem Fahrzeug mit dem Zustand des Fahrzeugs und,
falls das Ergebnis des Vergleichs derart ist, daß das Fahrzeug für den Auftrag geeignet
ist, des Übertragens einer Antwortnachricht vom Fahrzeug zur Steuereinheit nach einer
von der Distanz des Fahrzeugs vom Ort des Auftrags abhängigen Zeitverzögerung.
2. Verfahren nach Anspruch 1, in welchem nur Fahrzeuge innerhalb eines vorbestimmten
Bereichs auf die Nachricht von der Steuereinheit antworten können.
3. Verfahren nach Anspruch 2, in welchem der vorbestimmte Bereich von der Steuereinheit
ausgewählt wird und durch diese geändert werden kann.
4. Verfahren nach Anspruch 1, 2 oder 3, umfassend die Schritte des Befragens eines Fahrzeug
nach seiner exakten Position bei Ankunft an einem Auftragsort durch die Steuereinheit,
wobei das Fahrzeug seine exakte Position zur Steuereinheit überträgt, und der Speicherung
der exakten Position in einem Speicher durch die Steuereinheit, wodurch die Qualität
eines im Speicher gespeicherten geographischen Verzeichnisses verbessert wird.
5. Auftragszuweisungsverfahren zur Verwendung in einem automatischen Fahrzeugortungssystem,
aufweisend eine zentrale Steuereinheit, eine Übertragungseinrichtung an der Steuereinheit,
eine Empfangseinrichtung an der Steuereinheit, mehrere mobile Fahrzeuge, wobei jedes
Fahrzeug eine Einrichtung zum Empfang von Auftragsnachfragenachrichten von der Steuereinheit
umfaßt, eine Einrichtung zum Vergleichen der Anforderungen des Auftrags mit dem Zustand
des Fahrzeugs, eine Einrichtung zur Übertragung einer Antwortnachricht zur Steuereinheit,
falls das Ergebnis des Vergleichs ist, daß das Fahrzeug für den Auftrag geeignet ist,
und eine Einrichtung zur Variation der zur Übertragung einer Antwort auf eine Auftragsnachfragenachricht
in Anspruch genommenen Zeit entsprechend der Distanz des Fahrzeugs vom Ort des Auftrags.
6. Vorrichtung zur Verwendung an einem mobilen Fahrzeug in einem automatischen Fahrzeugortungssystem,
aufweisend eine Einrichtung zum Empfang einer Auftragsnachfragenachricht, eine Einrichtung
zum Vergleichen der Anforderungen des nachgefragten Auftrags mit dem Zustand des Fahrzeugs,
eine Einrichtung zum Übertragen einer Antwortnachricht zur Steuereinheit, falls das
Ergebnis des Vergleichs ist, daß das Fahrzeug für den Auftrag geeignet ist, und eine
Einrichtung zur Variation der zur Übertragung einer Antwort auf eine Auftragsnachfragenachricht
in Anspruch genommenen Zeit entsprechend der Distanz des Fahrzeugs vom Ort des Auftrags.
1. Procédé d'affectation pour un système automatique de localisation de véhicules comportant
un contrôleur et plusieurs véhicules mobiles avec une liaison radio bilatérale entre
le contrôleur et les véhicules, le procédé comportant les étapes de transmission d'un
message du contrôleur aux véhicules, le message comportant des informations relatives
à la localisation du travail, comparaison pour chaque véhicule des exigences du travail
avec l'état du véhicule et, si le résultat de la comparaison est tel que le véhicule
convient pour ledit travail, émission d'un message de réponse du véhicule au contrôleur
après une durée qui dépend de la distance du véhicule à la localisation du travail.
2. Procédé selon la revendication 1, dans lequel seuls les véhicules situés dans une
zone prédéterminée peuvent répondre au message provenant du contrôleur.
3. Procédé selon la revendication 2, dans lequel la zone prédéterminée est choisie et
peut être modifiée par le contrôleur.
4. Procédé selon la revendication 1, 2 ou 3, comportant les étapes de demande à un véhicule
par le contrôleur de son emplacement exact à l'arrivée sur la localisation d'un travail,
le véhicule émettant son emplacement exact au contrôleur, et le contrôleur stockant
l'emplacement exact en mémoire, améliorant par ce moyen la qualité d'un répertoire
géographique stocké en mémoire.
5. Système d'affectation de travaux destiné à être utilisé avec un système automatique
de localisation de véhicules, comportant un contrôleur central, un moyen d'émission
situé dans le contrôleur, un moyen de réception situé dans le contrôleur, plusieurs
véhicules mobiles, chaque véhicule contenant un moyen pour recevoir des messages de
demande de travail provenant du contrôleur, un moyen pour comparer les exigences du
travail demandé avec l'état du véhicule, un moyen pour émettre un message de réponse
au contrôleur si le résultat de la comparaison est tel que le véhicule convient pour
le travail, et un moyen pour faire varier le retard pour émettre une réponse à un
message de demande de travail selon la distance du véhicule à la localisation du travail.
6. Appareil destiné à être utilisé dans un véhicule mobile dans un système automatique
de localisation de véhicules comportant un moyen pour recevoir un message de demande
de travail, un moyen pour comparer les exigences du travail demandé à l'état du véhicule,
un moyen pour transmettre un message de réponse au contrôleur si le résultat de la
comparaison est que le véhicule convient au travail, et un moyen pour faire varier
le retard pour émettre une réponse à un message de demande de travail selon la distance
du véhicule à la localisation du travail.