EP0029201B1 - Method for traffic coverage in a guiding and information system for individual traffic - Google Patents

Abstract

In a method for traffic determination, a routing and information system for individual motor vehicle traffic is used, in which by way of stationary routing station poles, route information and local information are transmitted to the passing vehicles. For the determination of the traffic situation, the traveling times between two routing station poles are measured in individual vehicles with timing units. These traveling times are transmitted, together with the local information of the first routing station pole passed by a vehicle, to the second routing station pole and are considered in determining new route recommendations.

Description

The invention relates to a method for recording traffic in a guidance and information system for individual traffic, with stationary beacons arranged in the area of the roadways, which constantly transmit guidance information and location information about their location to the passing vehicles, each with a destination in the individual vehicles specified and certain guidance information selected according to this destination.

Such a method is described in EP-A-00 21 060 (prior art according to Art. 54 (3) EPC). There, the individual beacons cyclically transmit the guidance information for all possible destinations to all passing vehicles. The recommendations that apply to a specific destination are selected in the vehicle. This has the advantage over other known systems that only one-way transmission, namely from the guide beacons to the vehicles, is required for pure route guidance. In contrast to this, in other known systems (eg “Ali, system for route guidance and traffic data acquisition in“ Radio Mentor Electronic ”, 1978, pages 103 to 108) it is provided that the destination is first passed from the vehicle to the beacon and then the relevant information is selected there and transferred to the vehicle. The information is transmitted there in a dialog between the beacons and each individual vehicle. EP-A-00 24 010 (state of the art according to Art. 54 (3) EPC) also describes an information transmission system for vehicles in which information about the selected destination is transmitted from the individual vehicle to beacons. In this case, however, this does not serve to select certain guidance information, but rather to obtain general data about the current traffic volume and the traffic volume to be expected at the destinations. This information can be evaluated either in the lead beacon itself or in a higher-level control center.

To date, detectors have been used to record the traffic situation, with which the number, direction, speed and, if applicable, the type of vehicles passing through, or the time gaps and the degree of occupancy, have been measured at essential points in the road network. These values are used to draw an indirect conclusion about the occupancy status of entire streets, although these measured values only provide information about the traffic situation at the narrowly limited measuring cross-section. A traffic obstacle between two measuring points that are at a distance from one another, for example, is not perceived as long as the traffic in front of and behind these measuring points remains fluid.

In addition, DE-A-20 51 747 also discloses a method for monitoring the timetable of public transport, in which stationary beacons arranged in the area of the lanes transmit location information about their location to the vehicles passing through. It is also provided that in addition to the address of the beacon, a start command for a time measuring device is also transmitted to the vehicle and that the measured travel time is transmitted from the vehicle to a monitoring center. These actual travel times can then be compared in the head office with the timetable, so that, in the event of disruptions, appropriate arrangements can be made for the cheapest handling of local public transport.

The object of the invention is to provide a measurement method for traffic detection for a method for traffic detection in a control and information system of the type mentioned at the beginning, with which the traffic situation for individual traffic over entire distances can be detected and evaluated quickly and safely.

According to the invention, this object is achieved in that the destination data is transmitted to the beacon from the respective vehicle and evaluated to obtain data on the general traffic situation, and that the address of the beacon and a start command for one in the vehicle are also sent from the respective beacon to the passing vehicle provided that the time measuring device is started with the start command and that the measured travel time together with the address of the preceding guide beacon and the guide information obtained there is transmitted to the following guide beacon.

According to the method according to the invention, the vehicles themselves are used as measurement objects and data carriers. When a vehicle arrives at a beacon, it is queried and provides reliable information about the actual travel time. From the measured travel times of a large number of vehicles, the traffic situation in the relevant section of the route can be determined very well. It is sufficient if only some of the vehicles are equipped with a route guidance device and can also be queried for travel time measurement. This is because these individual vehicles that can be queried move in the general flow of traffic and thus form individual flow measuring devices, the driving behavior of which enables a reliable conclusion to be drawn about the overall traffic situation.

Expediently, moving averages are formed in the measuring beacons from the measured travel times of the individual vehicles. With such a moving averaging, trends in traffic flows are quickly recognized.

The anomalous behavior of individual vehicles remains without significant influence.

In general, the guide beacons will be located at a greater distance from each other. The distances between them can be described as a series of path vectors. Correspondingly, EP-A-0 021 060 provides that guidance beacons are given to the vehicles in each case in the form of a chain of guidance vectors. Accordingly, it is also expedient for the travel times in the vehicle to be measured individually between the individual guide points of a guide vector chain, stored in the vehicle and transmitted to the following guide beacon together with the data of the guide vector chain. This makes it possible to record the traffic situation more precisely, even at great distances between the beacons.

If a vehicle does not follow the guidance recommendation, this can be determined in the vehicle using a navigation device. Such a deviation from the guiding recommendation of the next guiding beacon is expediently reported and evaluated. The number of vehicles deviating from the guidance recommendations can be saved in the beacon and evaluated to assess the traffic situation. If, for example, such messages accumulate at certain control points, this fact can also be reported to a higher-level control computer. It is an indication that either a control point was not provided with correct coordinates or that there is actually a traffic obstruction in this area. It can then be checked whether this disability is of a longer duration. The relevant guidance recommendation may have to be modified. Furthermore, it can be provided that the time measurement in the vehicle is interrupted when the vehicle stops and the engine is switched off.

In a further embodiment of the invention, it can also be provided that guidance instructions are transmitted between adjacent beacons by means of the vehicles. In this case, the vehicles are also sent instructions on the recommended guide vector chains for the next guide beacons with the guide recommendation telegrams for their own direction of travel. Such information can be stored in the respective vehicle and queried by the next beacon as it passes. In this way, the next measuring beacon can easily be informed of which route should be recommended to the vehicles with the opposite direction of travel. In this way, with a selection logic for alternative routes in the individual beacons and the devices for retransferring the guidance instructions using the vehicle devices, a traffic-dependent guidance system for the short range can be realized without the need for a higher-level host computer. In a further embodiment of the invention, however, provision is made for the measured travel times and other information, such as deviations from the route, to be transmitted to a central control computer and to be evaluated by the latter in order to develop new guidance recommendations.

• Figur 1 das Schema eines Straßennetzes in einem begrenzten Bereich,
• Figur 2 einen Ausschnitt aus Fig. 1 zur Erläuterung der Leitvektoren,
• Figur 3 die Einrichtungen in einem Fahrzeug,
• Figur 4 die Einrichtungen in einer Leitbake.
• Figur 5 zusätzliche Einrichtungen im Fahrzeug,
• Figur 6 zusätzliche Einrichtungen in der Leitbake.
• Figur 1 zeigt das Schema eines Straßennetzes in einem begrenzten Bereich. Gezeigt sind die Kreuzungen K1, K2 und K3 mit jeweils einer Leitbake. Wegen der Trennung der beiden Funktionen wird hier unterschieden zwischen jeweils einer Leitbake LB1, LB2 usw. und einer Meßbake MB1, MB2 usw. In der Praxis werden Leitbaken und Meßbaken in einem Gerät an der Straßenkreuzung untergebracht sein. Deswegen wurde in der vorhergehenden Beschreibung jeweils nur von einer Leitbake gesprochen, die sowohl Leitempfehlungen senden als auch Informationen empfangen kann.

The invention is explained in more detail using an exemplary embodiment with reference to the drawing. It shows

• 1 shows the diagram of a road network in a limited area,
• FIG. 2 shows a detail from FIG. 1 to explain the guide vectors,
• FIG. 3 the devices in a vehicle,
• Figure 4 shows the facilities in a beacon.
• FIG. 5 additional devices in the vehicle,
• Figure 6 additional facilities in the beacon.
• Figure 1 shows the scheme of a road network in a limited area. The intersections K1, K2 and K3 are shown, each with a guide beacon. Because of the separation of the two functions, a distinction is made here between a beacon LB1, LB2 etc. and a beacon MB1, MB2 etc. In practice, beacons and beacons will be housed in one device at the crossroads. For this reason, the previous description only spoke of a beacon that can both send guidance recommendations and receive information.

The following traffic flow is assumed for the illustration in the drawing: A vehicle FZ1 approaches the intersection K1 and receives from the side beacon LB1 the guidance recommendation to use the route to the intersection K2 described by the guidance points LP1, LP2 to LP5. During the journey, the vehicle device in vehicle FZ1 measures the respective travel times between the mentioned control points LP1 to LPS. At the intersection, the beacon LB2 receives another guidance recommendation telegram for the next section of the route. Simultaneously with this telegram, the vehicle device is requested to transmit the measuring beacon MB2 (combined with the beacon LB2), among other things, the measured travel times of the preceding route sections.

After querying a number of vehicles by the MB2 beacon and after evaluating these measured travel times, the latter can come to the conclusion that the route via the LP1 and LP6 control points to LP5 is more favorable for the given traffic situation. ' This information is used in vehicles in the opposite direction, e.g. B. the vehicle FZ2 given. This information is transmitted in addition to the guidance recommendations that the FZ2 vehicle receives from the beacon LB2 anyway. If the vehicle FZ2 then passes the lead beacon LB1 or the measurement beacon MB1, in addition to its own measured travel time, this guide recommendation given is also queried, stored and used to correct the guide recommendations for the other passing vehicles.

The vehicle is approaching behind the FZ1 vehicle witness FZ3 of the intersection K1. It is assumed here that this vehicle FZ3 still receives the same guidance recommendation as the vehicle FZ1, that is to say the guidance vectors via the guidance points LP1, LP2 to LP5. However, this vehicle deviates from the recommended route at control point LP3, because e.g. B. a police officer makes a detour at point A because of an accident. The vehicle FZ3 therefore does not reach the intersection K2, but via the point LP7 to the intersection K3 and reports to the measuring beacon MB3 there that it has left the recommended route at the control point LP3. If many more redirected vehicles arrive at the beacon MB3, a corresponding message is sent to the higher-level control computer LR. This can also direct the beacon LB1 directly to recommend an alternative route to the intersection K2 for other vehicles.

The meaning of the guide vectors is shown in FIG. 2 in a detail from FIG. Each guide vector LV1, LV2 etc. is determined according to its magnitude (absolute value) s1, s2 etc. and by its angle value w1, w2 etc. with respect to a predetermined direction, for example the angle with respect to the north direction N.

• a) die Adresse (LB « 1 •) der gerade passierten Leitbake LB,
• b) die Adresse (VK « 1 ») der empfohlenen Leitvektorkette VK,
• c) die Koordinaten (xy) aller Leitpunkte LP der empfohlenen Vektorkette. Eine solche Vektorkette ist in Fig. 1 beispielsweise LPO, LP1 bis LP8.

In Fig. 3, the vehicle devices are shown schematically to show the gain of experience in the vehicles. Each vehicle has a receiving device 21 which receives data and telegrams emitted by this beacon when it passes a beacon (eg LB1). These data telegrams are checked and processed for transmission errors in the on-board computer 22 in the area CF21 in a manner not shown. All data relating to guidance recommendations are extracted from these data telegrams and stored in the memory area SB21 of the memory 23. The individual data are as follows:

• a) the address (LB «1 •) of the beacon LB just passed,
• b) the address (VK «1») of the recommended guide vector chain VK,
• c) the coordinates (xy) of all guiding points LP of the recommended vector chain. Such a vector chain is, for example, LPO, LP1 to LP8 in FIG. 1.

Immediately after the storage of this data, the on-board computer 22 calculates in the functional area CF21a from the coordinates of the guide points x, y the amounts s and the angles w for the individual guide vectors LV1, LV2 etc. These values are stored in the memory area SB22 of the memory 23.

The well-known dead reckoning is carried out in the computer area CF23. Starting from the coordinates of the guide points LPO (ie from the coordinates of the last passed guide beacon, in the example of FIG. 1 from the coordinates of the guide beacon LB1), the direction of travel measurement by the magnetic field probe 24 and the path impulses of the path measuring device 25 become the distance covered by amount s 'and direction w' are determined and stored in the memory area SB23. Due to unavoidable measurement errors, these determined values s 'and w' deviate somewhat from the actual values s and w.

In the CF22 computer area, it is checked whether the deviations are within predetermined limits; in the event of an impermissibly large deviation, an alarm signal «a is set and stored in the memory area SB24. In the event of an impermissibly small deviation, a correction is made as soon as a striking change in direction enables conclusions to be drawn about the actual position of the vehicle. For example, a distinctive change in direction of 90 ° takes place at the control point LP1 (FIG. 1). As soon as this change of direction is recognized by the magnetic field probe 24 in the navigation device CF23, the coordinates of this guide point are used as the starting point for the further dead reckoning. In addition, in the computer area CF22, the travel time "t is determined with the help of the timer 26, which was required for driving through the distance described for a specific guidance vector LV. This travel time t is stored in the memory area SB24 for each guide vector. In addition, downtimes "h", e.g. B. in front of traffic lights, measured with the help of the timer 26 and the path measuring device 25 and also stored in the memory area SB24.

The values t, h and a are thus stored in the memory area SB24, in such a way that they can be uniquely assigned to the guide vectors LV and the guide points LP (in the memory area SB21).

In the computer area CF24, the empirical values t, h and a are transmitted in connection with the address of the source beacon, the guide vector chain and the guide points or guide vectors at the next beacon via the transmitting device 27.

4 shows the devices in the respective beacons for processing the empirical values transmitted by the vehicles. The receiving devices 31 of the beacons (e.g. LB2 in FIG. 1) receive the data telegrams of all passing vehicles. The telegrams are checked and processed for transmission errors in the functional area CF31 of the beacon computer 32 in a manner not shown in detail. The beacon computer takes the transmitted empirical values t, h and a from these telegrams (see description of FIG. 3) and transfers them to the functional area CF32.

The number z of vehicles per time interval from which data is received is counted in this area CF32. Furthermore, the moving averages f, _f i and ä of the empirical values t, h and a are calculated. These values are stored in the memory area SB31 of the memory 33, specifically the respective origin beacon LB with the associated address, e.g. B. LB «1», the used vector chain VK with their address, e.g. B. «1" or «« 2 and assigned to the control points LP1, LP2 etc.

In the storage area SB32, the reference values z ^* , t ^* , h ^* and a ^* determined for example by traffic engineers for the above-mentioned variables z, t, h and a are stored according to the same ordering principle. The guide beacon computer 32 now continuously checks in its functional area CF33 how far the number of vehicles z from which empirical values have been received and the averaged empirical values approach or exceed the reference values z ^* , t ^* , h ^* and a ^* . Depending on these relationships, the beacon computer 32 calculates in the functional area CF34 how, for example, the distribution of the traffic approaching via the routing point LPO (beacon LB1) is to be carried out over the various possible travel routes. In the calculation of the distribution values, which is not shown in any more detail, the average travel times t, the average stop times h, but also the exceeding of the predetermined alarm reference values a ^{* are used for} each section of the route.

These distribution values are stored in the memory area SB33. In the example in FIG. 4, it is assumed that the traffic from the beacon LB1 is to be divided between the lead vector chains VK1 and VK2 in a ratio of 80% to 20%. The guidance vector chain comprises the route between the guidance points LP1, LP2, LP3, LP4, LP5 and LP8, the guidance vector chain with the address 2 comprises the route between the guidance points LP1, LP6, LP5 and LP8.

In a comparable manner, exceedances of the alarm values are registered in the memory area SB34. In the example of fig. 4 it is assumed that the number of alarm values of the vector chain with the address " ₁ from the beacon with the address" 1 at the control point LP8 was higher than the relevant reference value a ^* allows. This exceeding can already be seen from the alarm value a = 8 in the memory area SB31 at the control point LP8, which is greater than the corresponding reference value a ^* = 5 in the memory area SB32.

Corresponding tables for the distribution and alarm values are kept in the memory areas SB33 and SB34 for all neighboring beacons with the addresses «2,« 3 ", etc.

The functional area CF35 of the computer 32 compiles the data telegram for the transmission of the distribution values including the associated addressing to all vehicles that are approaching the beacon LB2. This telegram is transmitted via the transmission device 34.

In the functional area CF36 of the computer 32, a corresponding data telegram for the transmission of the distribution and alarm values is compiled on a higher-level host computer. This data telegram is transmitted via the transmission device 35.

FIG. 5 shows the additional devices in the vehicle that are required for the retransmission of the distribution values. The receiving devices 21 of all vehicles passing a beacon (eg LB2 in FIG. 1) receive data telegrams which are checked and processed for transmission errors by the on-board computer 22 in its area CF21 in a manner not shown in detail. The tables with the distribution values extracted from these telegrams are stored in the memory area SB41 of the memory 23.

After the on-board computer 22 has extracted the data for the guidance recommendation and, based on the travel destination entered by the vehicle driver, has decided on one of the guidance recommendations (guidance vector chain LV) according to a method not described here, the next guidance beacon to be approached is known. With this knowledge, the functional unit CF25 can delete all distribution value data intended for other beacons in the memory area SB41 and overwrite the data for the next target beacon in the memory area SB42. In the example of vehicle FZ2 in FIG. 1, only the distribution values for the beacons with the address 1 are adopted, the distribution values for other beacons are deleted or overwritten at the next beacon.

If the vehicle approaches this next beacon, the data in the memory area SB42 are retrieved again by the on-board computer 22, inserted in the data telegram for the beacon in the area CF24 and transmitted to the beacon together with the experience data (see description of FIG. 3).

FIG. 6 shows the additional devices in the beacons which are used to process the distribution values in the beacons. The receiving device 31 of the leading beacon (e.g. leading beacon LB1 in FIG. 1) receives the data telegrams of all passing vehicles. The telegrams are checked and processed for transmission errors in the functional area CF31 of the beacon computer 32 in a manner not shown in detail. The distribution values (percentages in Fig. 4) are transferred to the functional area CF31a. There it is checked whether the distribution values are still current. If the travel times t of the deliverer vehicle, in the example the travel time of the vehicle FZ2 from the guide beacon LB2 to the guide beacon LB1, are far above the relevant mean values f, the data transferred are out of date.

The current average value is formed from current distribution values and stored in the memory area SB35. An updated overview of the desired traffic flow distribution between alternative routes to all neighboring beacons can therefore be found in this memory area. In the example shown, this is a distribution between the vector chains VK1 and VK2 of 75% and 25%. Furthermore, there may be three alternative routes, for example, for alternative routes to a beacon LBJ, not shown, on which the traffic according to the ratio 60% (route ij) to 30% (Route ik) should be distributed to 10% (route il). According to the example shown, the traffic to a beacon LBF, also not shown, could be distributed over routes fg with 20%, route fh with 30%, route fk with 50% and route fj with 0%.

The functional area CF37 of the beacon computer 32 has the task of using a timer 36 to distribute the traffic flows over the alternative travel routes as indicated by the distribution values (%). This happens e.g. B. in that the master vector chain VK1 is written in 75 of 100 time intervals to reach the master beacon LB2 in the memory area SB36. Thereafter, the master vector chain VK2 would be in this memory area for 25 time intervals. The same applies to the alternative routes to all other neighboring beacons. The functional unit CF36 of the beacon computer 32 compiles the data telegrams for the vehicles in accordance with the regulation stored in the memory area SB36. The guide point coordinates (x, y) of that vector chain are now transmitted to the vehicles via the transmission device, which are currently listed in the memory area SB36.

Claims (9)

1. A method for traffic recording in a guidance and information system for individual transport, with stationary guide beacons (LB1, LB2, LB3) which are arranged in the region of the roadways and which constantly convey items of guidance information and location information relating to their location to the passing vehicles (FZ1, FZ2, FZ3), where, in each of the individual vehicles (FZ1, FZ2, FZ3), a travel target is input and in accordance with this travel target specific items of guidance information are selected, characterised in that from the vehicle in question (FZ1, FZ2, FZ3) the items of travel target data are transmitted to the guide beacon (LB1/MB1, LB2/MB2, LB3/MB3) and are analysed in order to obtain data relating to the general traffic situation, that moreover from the guide beacon in question (LB1, LB2, LB3) to the passing vehicle (FZ1, FZ2, FZ3) there is in each case transmitted the address of the guide beacon (LB1, LB2, LB3) and a start command for a time measuring device (26) arranged in the vehicle, that the start command sets the time measuring device (26) in motion, and that to the following guide beacon (LB1, MB1 ; LB2, MB2; LB3, MB3) there is in each case transmitted the measured travel time together with the address of the preceding guide beacon (LB1, LB2, LB3) and the items of guidance information obtained therein.

2. A method as claimed in claim 1, characterised in that in the individual guide beacons, running mean values are in each case formed from the travel times which are measured in the vehicles and transmitted to the guide beacons.

3. A method as claimed in claim 1 or 2, characterised in that the travel times between the individual guide points (LP1 ... LP5, LP6) of a chain of guide vectors are individually measured, stored in the vehicle (FZ1, FZ2, FZ3) and transmitted to the following guide beacon (LB2) together with the data of the chain of guide vectors.

4. A method as claimed in one of the claims 1 to 3, characterised in that a deviation of the vehicle (FZ3) from the selected guidance information is stored and communicated to the next guide beacon (LB3) which is passed.

5. A method as claimed in claim 4, characterised in that the number of vehicles which deviate from specified items of guidance information is stored and analysed in order to access the traffic situation.

6. A method as claimed in one of the claims 1 to 5, characterised in that the travel time measurement in a vehicle is stopped and erased in the event of an interruption in the journey.

7. A method as claimed in one of the claims 1 to 6, characterised in that the travel time - measured values which are transmitted from the vehicles (FZ1, FZ2, FZ3) to a guide beacon (LB1, LB2, LB3) are used in the guide beacon for the preparation of new items of guidance information.

8. A method as claimed in claim 7, characterised in that in addition to the items of guidance information for their own direction of travel, individual vehicles (FZ2) are also supplied by a guide beacon (LB2) with items of guidance information relating to the opposite direction, which latter are called up by the next following guide beacon (LB1).

9. A method as claimed in one of the claims 1 to 8, characterised in that the travel times or route deviations which are reported by the individual vehicles (FZ1, FZ2, FZ3) to guide beacons (LB1, LB2, LB3) are transmitted to a central guidance computer (LR) by which they are analysed in order to prepare new items of guidance information.

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