EP0561818B1 - Vehicle-guidance and target-tracking system - Google Patents

Abstract

PCT No. PCT/DE91/00926 Sec. 371 Date Mar. 24, 1994 Sec. 102(e) Date Mar. 24, 1994 PCT Filed Nov. 27, 1991 PCT Pub. No. WO92/10824 PCT Pub. Date Jun. 25, 1992.A vehicle and destination guidance system is proposed wherein a destination can be input by entering the destination and the street in clear language into a vehicle device. The vehicle device is in communication with a beacon device in which, in addition to the various destinations, street names and the associated coordinates are stored. On demand by the vehicle device, the beacon device selects the associated destination coordinates and transmits them to the vehicle device. Additional data can be transmitted in the transmitted telegram which, for example, contain traffic information or street maps. The system is also usable for automatic toll deductions.

Description

State of the art

The invention relates to a vehicle guidance and guidance system according to the preamble of the main claim. From Bosch Technical Reports, Volume 8 (1986), Issue 1/2, pages 26 to 31, the vehicle control and guidance system "Ali-Scont" is already known, in which the destination can be entered in the form of coordinates using an alphanumeric keyboard and at the coordinate data taken from a road map can be entered into an internal memory. Previously entered destinations with a short name can be selected using the "Step" button in the on-screen scrolling process. Furthermore, the map-based location and navigation system "Travelpilot" is known, in which the entire road network in Germany is stored on a compact disc and is available to the location and navigation system. However, it has been found that the internal memory of the system must be quite large, or a relatively expensive CD device is required if a large number of target points have to be stored with their coordinates. If you consider that this memory must then be present in practically every vehicle, overall there is a very large technical outlay with correspondingly high costs.

A navigation system for route guidance of a road vehicle is known from EP 317 181 A2, in which parts of a road map are sent to a vehicle device when a beacon passes. This data is stored in the vehicle device. With the help of a route search algorithm, a destination route is selected from the stored data and specified to the driver of the vehicle. In this vehicle device, the memory must be relatively large so that it can also save a larger section of the road map if its destination is further away from the beacon.

From US 4,357,593 a route guidance system for individual vehicles is known, in which a beacon transmits vehicle guidance information to the passing vehicles. The driving instructions are selected in such a way that a specific area is assigned concentrically around the beacon to a target vector. If a desired target falls into one of these areas, the beacon can transmit corresponding direction vectors to the vehicle device.

Advantages of the invention

The vehicle guidance and route guidance system according to the invention with the characterizing features of the main claim has the advantage that the memory requirement in the vehicle can be kept relatively small, since it is only required for the temporary storage of the entered name or only for certain simple search tasks. Since it only has the place names with the coordinates of the center of the place, its capacity is limited to a range that can be represented on commercially available integrated circuits. Another advantage is the fact that the data stored in the beacon can be constantly adapted to the current conditions by a centrally controlled device. For control purposes, the vehicles passing the beacon can also be counted and guided in predetermined directions.

Advantageous further developments and improvements of the vehicle guidance and guidance system specified in the main claim are possible through the measures listed in the subclaims. It is particularly advantageous to use an RDS-TMC memory in the car radio, which can only be changed slightly since it has already saved place names. Only additional geographic coordinates of a street map need to be saved for these place names. As a result, the vehicle device is inexpensive to manufacture.

Advantages also result from the use of the system for automatically executable control and checking purposes, which result from the checking of access authorizations and / or charging of parking and toll charges.

It is particularly favorable that the street names of destinations or data from street maps with the corresponding coordinates are stored in the beacon memory. This memory always contains the current road data and can be queried by any number of vehicles.

A particular advantage can be seen in the fact that the map is displayed in the vicinity of the beacon in a detailed form, so that orientation of the driver is facilitated.

Since at a greater distance to the destination the transmission of a
Guide vector chain is sufficient, the output of the route can be made very simple. In particular, simple path symbols can be output.

To improve clarity, a colored map is particularly convenient.

Since the range of the beacon transceiver is relatively short, the individual route guidance in areas without beacon infrastructure is achieved by coupling a location and navigation system.

The transmission of the position coordinates of a neighboring beacon is particularly helpful for setting up the navigation system or for correcting position data that is coupled with it. By transmitting the coordinates for the location of the beacon, the position of the vehicle can be determined to within a few meters.

In the city area in particular, acoustic data output with route guidance and / or traffic information is advantageous since the driver can concentrate fully on the traffic and is not distracted by looking at advertisements.

Further advantages result from the fact that the vehicle guidance and guidance system enables automatic toll billing without further major effort. Further advantages of the invention can be found in the description.

drawing

An embodiment of the invention is shown in the drawing and explained in more detail in the following description. FIG. 1 shows the block diagram of a vehicle device, FIG. 2 shows the block diagram of a beacon device, FIG. 3 shows a flow diagram and FIG. 4a, 4b shows a functional diagram of the exemplary embodiment.

Description of the embodiment

The vehicle guidance and guidance system essentially has two device components: a vehicle device and a fixed beacon device. The block diagram of the vehicle device shows, according to FIG. 1, essential functional parts of the invention. An input 11 is connected to a control device 12, which has a destination memory 17 for place names and their coordinate pairs. The control unit is connected to a display 13 for outputting traffic management information. Furthermore, there are connections to the car radio, in particular to the memory of the receiving section for the traffic message channels (TMC) and for the speech output 16 to the NF amplifier of the car radio. A location and navigation system 21 has a compass, wheel sensors, a device for coupling location 15 and a device map matching 14 for determining coordinates by comparing maps. Furthermore, there is a card memory 20 for storing card data transmitted by the beacon. The map matching device 14 is connected to the map memory 20. A connection to the display 13 is provided to display the map data and the position of the vehicle. The map matching device 14 is also connected to the control device 12. Another output of the control device 12 leads to a further buffer for received guide vector chains 18.

A transmitting / receiving device 19 is connected both to the control unit 12 and to the intermediate memory 18 and card memory 20. The transmission / reception device contains known transmission and reception stages for a desired frequency band.

In the block diagram of the beacon device according to FIG. 2, the transmitting and / or receiving device 30 is initially connected to a request register 31. The request register 31 is connected to a name comparator 33, which has access to the street name memory 34. The

Inquiry register 31 is also connected via a vehicle number register 32, which in turn also has access to street name memory 34. The vehicle number register 32 is connected to the transmitting device and / or receiving device 30 for transmitting information to the vehicle. A control device 36 is connected on the one hand to the transceiver 30 and, on the other hand, to various memories such as guide vector chain memory 37 and the memory 38 for street maps in the near and far range. The control device 36 is also connected via an interface 35 to a central computer, not shown, from which a plurality of beacon devices can be controlled.

Furthermore, the beacon device can be equipped with a receiving part for the radio data system (RDS-TMC), in particular if there is no control by a central computer.

FIG. 3 shows a flow diagram for the search for street names in the memory of the beacon device. In position 40 it is first queried whether there is a request to search for coordinate pairs for a street name. The controller remains in this loop as long as there is no request. If, on the other hand, there is a request, the name of the searched street is stored in a register in position 41. Positions 42 to 44 determine the first, second and third letter of the name. In position 45 the names are searched with this combination of characters. If only one word is found that the three previously determined Contains letters, then the name found is the search word. It is transferred to control unit 36 in position 47 with the associated pair of coordinates. The search is now complete and the program starts again in position 40.

If, on the other hand, several names were found with this combination of characters, the fourth letter is determined in position 48 and all names with this combination of characters are searched for. In position 49 there is the same query as in position 46. If there is only one name found, then in position 50 the associated coordinate pair is output to control unit 36 and a return to the beginning of the program in position 40 is initiated.

If several names were found again, the process is repeated by determining the fifth letter in position 51. In the subsequent query 52, the data found is output in position 53 or the further decoding of a sixth letter in position 54. This search is continued until the name sought is found and its pair of coordinates has been determined.

The function of the exemplary embodiment is explained in more detail below.

The vehicle guidance and guidance system has a modular vehicle device that contains various components such as a location and navigation system (optional), input and output device for destinations, road maps and / or directions in the form of symbol arrows or voice output. It is considered to be particularly advantageous that the entry of the destination (destination and street) takes place in plain text, the coordinates for the searched street being taken from the memory of the beacon device. The memory of the beacon device is relatively large, while the vehicle memory, on the other hand, is made relatively small and is therefore inexpensive to manufacture. In order to save storage space, a link to the memory of a car radio can be provided. The use of the is particularly advantageous

Memory of the device for decoding the Traffic Message Channel (TMC), since place names are already stored in it. Only the coordinates of the center of the place belonging to the place name have to be saved.

The vehicle guidance and route guidance system serves, while largely maintaining anonymity, to support the driver of a vehicle in the search for its destination. In addition to road maps or route suggestions, he receives information about the traffic situation, traffic jams, detours, black ice, etc. The system can also be used for the automatic processing of access authorizations, charging of parking or toll fees for roads or spaces subject to toll, since the vehicles cross the street recessed induction loops are detected and can be addressed individually using the beacon devices.

The functioning of the vehicle control and guidance system will be explained in more detail using an example. A driver wants to drive from Hanover to Hildesheim on the 'Blauer Kamp' street. He enters the destination 11 Hildesheim and then the street name 'Blauer Kamp' in plain text into the input unit 11 using a keyboard or a remote control. The control device 12 first saves the entered data and shows it on the display 13 for control purposes. The control unit 12 of the vehicle recognizes the place name 'Hildesheim' from the first word and searches in the destination memory 17 for the corresponding coordinates for the center of the place of Hildesheim. If a TMC memory is available, the corresponding data is taken from this memory. The storage of location data in a TMC memory are known in DE-OS 38 10 180 and DE-OS 39 14 104.

On the basis of the current location coordinates and those of the target location 'Hildesheim', the vehicle device calculates the target direction and distance according to known trigonometric formulas and shows these values on the display 13. The driver now drives in this direction until he passes a first beacon, for example at the 'Anderten' junction on the A7 motorway.

• 1. Koordinatenpaar des Ortsmittelpunkts der Gemeinde, auf deren Gebiet die Bake steht (OMK von Anderten)
• 2. Koordinatenpaar des exakten Bakenstandorts (mit Offset)
• 3. Digitalisiertes Straßennetz, bis zur übernächsten Bake exakt, darüberhinaus kleinmaßstäbig (Fernstraßennetz)
• 4. Farbflächen-Information (Umriß und Farbart)
• 5. Routenbaum (Leitvektorketten-Kollektiv), evtl. nach Fahrzeugklassen geordnet
• 6. Zeitschlitze mit Zufallsnummern für Anfrage Fahrzeug

When passing the beacon, the vehicle receives the following information, which is emitted collectively and cyclically by the beacon:

• 1. Coordinate pair of the center of the village, on whose territory the beacon is located (OMK von Anderten)
• 2nd coordinate pair of the exact beacon location (with offset)
• 3. Digitized road network, exact down to the next but one beacon, furthermore small-scale (trunk road network)
• 4. Color area information (outline and color type)
• 5. Route tree (leading vector chain collective), possibly arranged according to vehicle classes
• 6. Time slots with random numbers for vehicle inquiry

The vehicle device now checks whether the local center coordinates (OMK) of Hildesheim are identical to those of the beacon location (Anderten). Since this is not the case, the vehicle device looks for the guide vector chain assigned to the OMK from Hildesheim, in the example A7, from the route tree received by the beacon and displays it on the display 13. A complete map route can also be provided on request. The map can be displayed in various scales.

When driving past there is now the possibility that certain information is sent from the vehicle to the beacon for traffic control purposes. The information can be the travel time since the last beacon passed and possibly an individual vehicle identification. This information is sent to the beacon in the time slot of its self-generated random number as a telegram.

The process described above is repeated from beacon to beacon until the vehicle device identifies identical OMK's for the beacon and the destination Hildesheim.

• 1. Fahrzeit seit Passieren der letzten Bake
• 2. Als Ziel gewählter Straßenname (z.B. Blauer Kamp)
• 3. evtl. individuelle Fahrzeugkennung

The vehicle now sends a telegram in the time slot of its self-generated random number, which receives the following information:

• 1. Travel time since passing the last beacon
• 2. Street name chosen as destination (eg Blauer Kamp)
• 3. Possibly individual vehicle identification

For the time slot method, the vehicle device selects a specific random number as the vehicle code and sends it to the beacon. The beacon can now send the individual data (e.g. coordinates for the street, house number, hotel, petrol station, etc.) back to the vehicle using this random number.

In the beacon device in which the street names of Hildesheim are stored with the associated coordinates, the pair of coordinates assigned to the street name is now determined with the aid of the search tree method shown in FIG. 3 and together with the street name and the random vehicle number within a fixed time (approx. 100 ms) transferred back to the vehicle device.

In the vehicle device, with the help of this coordinate pair from the route tree, the guide vector chain is determined and displayed, which leads to the target area in which the street 'Blauer Kamp' is located. If the destination is in the close-up area shown exactly, the guide vector chain leads directly to the selected street (e.g. Blauer Kamp). It is intended to indicate the point of the street that is closest to the route, provided that there is no further information such as house number or hotel etc.

If there are other beacons on the way to the destination, a guide vector chain can also be sent up to the beacon that is closest to the 'Blauer Kamp' destination.

The search algorithm for decoding the street 'Blauer Kamp' is described below. The transceiver receives the telegram and initially stores it in the request register 31. The street name and the vehicle are then decoded in the name comparator 33 or register 32. The street name memory 34 has several areas which are arranged alphabetically so that they can be found quickly using the search tree method.

According to FIG. 3, to find the street name, the program is first started in position 40 and the street name 'Blauer Kamp' is stored in position 41. To save storage space, it is advisable to generally use upper or lower case letters.

In positions 42 to 44, the first three letters of the search word are now decoded, that is 'BLA'. In position 45 the memory area is now searched in which all the words with the letters 'BLA' are listed. The request in position 46 is such that it is only checked whether there are one or more words with this combination of letters. If there is only one word, the search is finished. The associated coordinate pairs are now sent to the vehicle via the transmitting / receiving device 30.

If the word has not yet been found, the next letter, in the example 'U', is decoded and now the new search word 'BLUE' is determined and the corresponding memory area is read out in position 48. The same query is made in position 49 as in position 46. This search structure continues until the name 'Blauer Kamp' has been found (positions 50 to 54).

Since the coordinates of the target point 'Blauer Kamp' are now known, the distance to the target point can be determined. The distance can be output both in the voice output 16 via the NF amplifier of the car radio or visually via the data output, the display 13.

In a further embodiment of the invention, the complete road network and its coordinates are stored in all beacon devices. For Germany, for example, this data can be stored on a compact disc. Since the closest beacon now contains all target data, the vehicle can be directed as follows.

On the basis of the pair of coordinates, the sequence of road sections (guide vector chain) leading in the direction of destination can be selected in the beacon and sent to the vehicle. Since the beacon in the vicinity of the vehicle knows the coordinates of the destination, it can transmit a road map to the vehicle which shows the area of the current location of the vehicle and is continuously changed as long as the vehicle is moving in the direction of the destination. If the vehicle comes into the range of another beacon, this beacon takes over the guiding function in the same way and continues the vehicle until the next beacon, and so on, until the vehicle has reached its destination. These guiding vector chains enable the vehicle to be guided successively to the target area. If the vehicle arrives in an area that does not have sufficient beacon infrastructure, then the further navigation is carried out with the location and navigation system 21 with the known coupling location 15. Since in the area of a beacon the coordinates thereof roughly match the coordinates of the location of the Vehicle, this location data can be compared with the location data coupled from the location and navigation system 21 and corrected if necessary. This reduces the error for the positioning and navigation system 21.

Since a detailed map is transmitted from the beacon device to the vehicle device in the vicinity of the beacon, target objects such as hotels, train stations, post offices, banks, petrol stations, etc. can also be displayed. To improve the clarity, it is provided that the street map is colored, for example main streets, one-way streets or superordinate destination points and the chosen route are highlighted in color.

The beacon device mentioned in the exemplary embodiment (FIG. 2) operates in the microwave frequency range at 5.8 GHz. Four channels with 5 MHz bandwidth each are available in the range from 5.755 GHz to 5.815 GHz. Amplitude modulation at a data rate of 1.125 Mbit / s is used for the data transmission from the beacon device to the vehicle device (FIG. 4a). The 5.8 GHz carrier signal is switched on or off depending on the information bit. Such a type of modulation is also known as ASK ( a mplitude s shift k eying) or OOK ( o n o ff k eying). The beacon device has a flat antenna using stripline technology (microstrip) for transmission and reception.

The vehicle device is also equipped with a flat stripline antenna. The advantage of the chosen modulation method ASK is in particular that the information can be obtained from the microwave signal with a simple envelope detector (diode). A complex receiving device of the vehicle device is therefore not necessary.

In the case of data transmission from the vehicle to the beacon according to FIG. 4b, the beacon device sends an unmodulated 5.8 GHz carrier signal (CW signal) in the time slots provided for this purpose. This signal is received by the vehicle device, possibly amplified and fed to a modulator. In this example, the 5.8 GHz carrier signal is modulated by means of a diode with a frequency of either 1.5 MHz or 2.0 MHz, which is dependent on the information bit, and then sent back to the beacon device (transponder principle). The data rate is 125 kbit / s. In this way, two side bands, in each of which the information as FSK signal (f requency s hift eying k) is created in the frequency domain in addition to the carrier. The beacon device receives the microwave signal modulated by the vehicle device and carries out a frequency conversion into the baseband and then an FSK demodulation.

In the method described here, it is particularly advantageous that a very simple microwave circuit without its own oscillator and frequency converter can be used in the vehicle device with regard to the transmitting and receiving device. This accommodates an inexpensive manufacture.

The toll system is designed for automatic vehicle recognition and billing. It contains two components, the so-called 'On board unit' (OBU) and the base station installed on the street side. The OBU and base station exchange coded information via a microwave or infrared communication link, which is required for toll collection. The individual sequence is as follows:

When a vehicle enters the toll area, the OBU of the vehicle receives a signal from a first transmitter, which is generally mounted on a first sign bridge or beacon, which activates a demodulator. The received signal contains data of the station code, the toll amount and another key word for statistical evaluations. After checking for validity, the 'on board unit' is now activated. The OBU decrypts the received information, subtracts the toll amount, for example for the road to be traveled, from a toll card, which can be inserted into the toll device, for example, as a credit card, and prepares the acknowledgment message. The OBU now returns to the stand-by mode.

A second transmitter, which is generally mounted on a subsequent second gantry or beacon, requests the acknowledgment message prepared by the OBU. The OBU reactivates and sends the acknowledgment message with two repetitions to a receiver mounted on the same bridge. The road device checks the receipt received and ends the process if the result is positive. If the debit is not confirmed, the license plates of the vehicle, preferably from the front and rear, are preferably recorded by a video camera.

As an alternative solution to the prepaid card, it is provided that the user is automatically debited from an account. In this case, the transfer of a personal identifier is required to enable the toll charges to be debited from the user's account.

In addition to a card reader for the prepaid card, practically no additional devices are required, since the control is carried out by means of a program using the vehicle and beacon devices already present.

Both the control device 12 and 36 of the vehicle and the beacon have a microcomputer with a memory and input / output ports. They are controlled by a program that is structured according to the description. The other units such as memory, display etc. are devices known to the person skilled in the art and need not be described in detail.

Claims (19)

1. Vehicle-guidance and destination-tracking system with a vehicle device, located in a vehicle, with a data input device, a data output device, a destination memory for place names, with a data memory for street plans or guide vectors and with a first transmitting and/or receiving means and with at least one fixed device of a beacon, located outside the vehicle, which fixed device has a second transmitting and/or receiving means, which is at least temporarily in connection with the first transmitting and/or receiving means, located in the vehicle, and which fixed device has a further data memory, in which preferably a street plan or guide vectors are stored, which can be transmitted to the vehicle device, characterized in that

   a) the data input device (11) of the vehicle device is designed for the input of a destination, preferably the place name and/or the street name, in plain text,

   b) the destination memory (17) contains coordinates of location centre points (OMK) corresponding to the destinations which can be input,

   c) the vehicle device has means (12) by which a destination vector can be determined from the vehicle position and the coordinates of the location centre point (OMK) of the destination and can be output on a display (13),

   d) the beacon device is designed to transmit to the vehicle, when passing, the location centre point coordinates (OMK) of the location assigned to the beacon, the pair of coordinates of the beacon site (possibly with an offset), a digitized road network, coloured area information and/or a route tree with guide vector chains of the major road network,

   e) the vehicle device has means (12) which compare the received information with the destination coordinates, such that, if they deviate, a guide vector for the beacon nearest in the direction of the destination can be determined and that, if they match, the beacon device transmits to the vehicle device parts of the street plan of the destination region and/or guide vectors to the destination point (street name input).
2. Vehicle-guidance and destination-tracking system according to Claim 1, characterized in that the data memory (17) of the vehicle device is a component part of a car radio, preferably of the apparatus for the traffic message channel (TMC memory).
3. Vehicle-guidance and destination-tracking system according to Claim 1 or 2, characterized in that the memory of the beacon device has further information with respect to access authorizations and/or chargings for parking fees and toll fees.
4. Vehicle-guidance and destination-tracking system according to one of the preceding claims, characterized in that the digitized road network is stored in the street plan (34) of the beacon device as far as the next-but-one beacon.
5. Vehicle-guidance and destination-tracking system according to one of the preceding claims, characterized in that, at the request of a vehicle, a series of road sections (guide vector chain) which contains the route in the direction of the destination of the journey, can be transmitted to the vehicle from the beacon.
6. Vehicle-guidance and destination-tracking system according to one of the preceding claims, characterized in that the output of the direction of travel data takes place on the data output 13 by arrow symbols and/or voice output.
7. Vehicle-guidance and destination-tracking system according to one of the preceding claims, characterized in that the output of the direction of travel data takes place on a map display.
8. Vehicle-guidance and destination-tracking system according to Claim 7, characterized in that the travel route or guide vector chain is marked in colour.
9. Vehicle-guidance and destination-tracking system according to one of the preceding claims, characterized in that a direction-finding and navigation device is provided in the vehicle, and in that a correction of the dead-reckoning navigation can be carried out from the coordinates received from the beacon.
10. Vehicle-guidance and destination-tracking system according to one of the preceding claims, characterized in that the vehicle device and/or the beacon device has a means for the handling of user fees, preferably for parking fees and toll fees.
11. Vehicle-guidance and destination-tracking system according to Claim 10, characterized in that the beacon device registers the movement of a vehicle and/or identifies the vehicle.
12. Vehicle-guidance and destination-tracking system according to Claim 10 or 11, characterized in that there can be inserted into the means of the vehicle a credit card from which an amount due as a toll can be debited.
13. Vehicle-guidance and destination-tracking system according to Claim 12, characterized in that the debiting of a fee can be carried out after clearance of the credit card.
14. Vehicle-guidance and destination-tracking system according to one of Claims 10 to 13, characterized in that, in the case of an invalid credit card, an automatic recording of the registration number of the vehicle takes place.
15. Beacon device for a vehicle-guidance and destination-tracking system according to one of Claims 1 to 14, with a transmitting and/or receiving means, which is at least temporarily in connection with a transmitting/receiving means located in the vehicle, with a memory for a digitized road map and with a control device, characterized

    a) in that the memory (34) contains at least the following further data: location centre point coordinates (OMK) of the location assigned to the beacon, the pair of coordinates of the beacon site (possibly with an offset), coloured area information, a route tree with guide vector chains of the major road network,

    b) in that the control device (36) determines on the basis of the destination received from the vehicle device a series of road sections (guide vector chain) leading in the direction of the destination and

    c) in that the beacon device is designed to transmit to the vehicle the location centre point coordinates (OMK) of the location assigned to the beacon, the pair of coordinates of the beacon site (possibly with an offset), a digitized road network, coloured area information and/or, on request by the vehicle device, the route tree with the guide vector chain.
16. Beacon device according to Claim 15, characterized in that the beacon device receives from an individual vehicle device within a time slot a message with a random number as the vehicle code, by means of which it can respond to the vehicle device with the same random number.
17. Vehicle device for a guidance and destination-tracking system according to one of Claims 1 to 14, with a data input device for the input of alphanumeric characters, a data output device, a data memory for place names and with a first transmitting/receiving means, which is at least temporarily in connection with a further external transmitting/receiving means, characterized in that the input of place names and street names takes place in plain text, in that the data memory (17) has pairs of coordinates of the location centre point (OMK), assigned to the input place name, and in that means (12) are provided by which a destination vector is determined from the vehicle position and the coordinates of the location centre point (OMK) and is output on a display (13), in that coordinates of a street name can be called up from a beacon device via the transmitting/receiving means (19) and in that the vehicle device is set up for receiving at least one of the following items of information: location centre point coordinates (OMK) of the location assigned to the beacon, the pair of coordinates of the beacon site (possibly with an offset), a digitized road network in the local area of the beacon, preferably as far as the next-but-one beacon, coloured area information, a route tree leading in the direction of the destination, with a guide vector chain.
18. Vehicle-guidance and destination-tracking system according to one of Claims 1 to 14, characterized in that the transmitting/receiving means (19; 30) of the beacon device and of the vehicle device is suitable for carrying out in the microwave range a data transmission with an amplitude modulation at a predetermined data rate, the carrier signal being switched on or off as a function of the information bit (amplitude shift keying or on/off keying).
19. Vehicle-guidance and destination-tracking system according to Claim 18, characterized in that the beacon and vehicle device is designed to detect the information from the microwave signal by means of an envelope detector, preferably a diode.

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