WO2020064247A1

WO2020064247A1 - Method for synchronizing measurement pulse signals of at least two participants of a vehicle positioning system

Info

Publication number: WO2020064247A1
Application number: PCT/EP2019/072906
Authority: WO
Inventors: Sebastian Dietz; Stephan Bartz; Thomas Röhrl
Original assignee: Vitesco Technologies GmbH
Priority date: 2018-09-26
Filing date: 2019-08-28
Publication date: 2020-04-02
Also published as: DE102018216468B3

Abstract

The invention relates to a method for synchronizing measurement pulse signals (SP; SP, MP1, MP2, MP3, MP4) of at least two participants of a vehicle positioning system, wherein a measurement pulse signal (SP; SP, MP1, MP2, MP3, MP4) has a start pulse (SP) having at least one identification data bit of a participant unit and has measurement pulses (MP1, MP2, MP3, MP4) following one another systematically, a defined time shift of the transmission of the measurement pulse signal within a period duration of a repetition rate being initiated in each participant as a result of the detection of a start pulse (SP) disturbed by adjacent participants or the detection of a disturbed measurement pulse (MP1, MP2, MP3, MP4). The measurement pulse signals (SP, MP1, MP2, MP3, MP4) of the individual participants thus order themselves one after the other in a period duration and can be transmitted in a synchronized manner.

Description

description

Method for synchronizing measuring pulse signals of at least two participants in a vehicle positioning system

The inductive charging of electric vehicles has great potential to enable the vehicle's energy storage to be easily recharged in future in private garages and also in public parking lots.

The transmission of the energy takes place according to the schematic representation in FIG. 1 from a primary coil, which is installed in a so-called base plate 3 and is mounted in or on the floor of a parking lot 1, to a secondary coil, which is in a vehicle plate 6 in the vehicle 2 is installed. The primary and secondary coils are often connected with capacitors to form resonators in order to achieve reactive power compensation. The two coils or the base plate and the vehicle plate 3, 6 have no mechanical contact and the energy is transmitted via the air gap between the coils or plates.

The primary coil is supplied with energy from the AC voltage supply network 5, from solar cells or other energy sources that are available. The conversion of the respectively available voltage is carried out by a charging station 4 (often called a wall box), which generates, for example, 85 kHz alternating voltage from the available voltage of, for example, 50 Hz alternating voltage of the network, via the transformer formed from the two resonators is transmitted to vehicle 2. On the vehicle side, the received voltage is rectified in a charger 7 and supplied to the energy store 8, for example a lithium-ion battery. An electric motor 9 for the vehicle 2 is then supplied from this energy store 8.

In inductive charging, the positioning of the vehicle plate above the base plate plays a crucial role in enabling energy transfer. Only if the two plates are positioned one above the other with a tolerance of a few centimeters, energy transfer with sufficient efficiency is possible. Because the worse the two coils are one above the other, the worse the energy transfer will be, since the coupling factor of the transformer becomes lower and consequently its efficiency decreases, while the undesired stray fields increase.

The driver can hardly estimate whether there is an exact positioning between the two coils under the vehicle, since he has to maneuver with a few centimeters without visual contact, which is difficult to guarantee without aids.

The US 2015/073642 A1 discloses a vehicle positioning system in an apparatus for inductive energy transmission, in which positioning signals are exchanged between beacons in the base plate and in the vehicle plate, but different frequencies are used for different participants, which requires considerable effort.

If a time-division multiplexing method is used instead, there is the problem that the individual vehicles that want to position or park in the vicinity of one another are disturbed by the respective positioning signals of the neighbors, since the individual parking processes are asynchronous to one another.

The object of the invention is therefore to provide a method for synchronizing measuring pulse signals of at least two participants in a vehicle positioning system.

The object is achieved by a method according to claim 1. Advantageous further developments are given in the subclaims.

The invention is accordingly a method for synchronizing measuring pulse signals of at least two participants in a vehicle positioning system, in which each subscriber has a stationary unit for sending a measuring pulse signal of defined strength via a first wireless interface and for receiving information about the strength of the measuring pulse signal at the location of a mobile unit via a second wireless interface,

and a mobile unit for receiving the measuring pulse signal via the first wireless interface and for sending the information about the strength of the measuring pulse signal at the location of the mobile unit via the second wireless interface,

wherein the measuring pulse signal consists of at least one start pulse and is transmitted at a first repetition rate, which is inversely proportional to a first period, and the start pulse includes an identification date of the stationary and / or the mobile unit, information about the period and a checksum to check the integrity of the start pulse,

wherein the first period is selected so that all measuring pulse signals comprising both a starting pulse and measuring pulses and also neighboring participants of the vehicle positioning system have space in time,

wherein each participant of the vehicle positioning system carries out the following steps for the synchronization of all measuring pulse signals receivable by one participant:

A A communication channel is established between the stationary unit of a subscriber and his mobile unit via the second wireless interface and an identification date of the stationary unit is transmitted from the stationary to the mobile unit and an identification date of the mobile unit is transmitted from the mobile to the stationary unit. as well as information about the period duration;

B The stationary unit cycles with the

Repetition rate sent a measuring pulse signal with at least one start pulse;

C All start pulses received during the period are checked by the mobile unit based on the checksum whether they are error-free; D If the check shows that no start pulse is error-free, the stationary unit is informed via the second interface that the start of the start pulse should be shifted by a randomly selected period of time, whereby a complete measuring pulse signal must still be within the period; then the procedure is started again at B;

E If the verification is received in at least one

Start pulse does not result in an error, the mobile unit uses the identification date of the stationary unit to check whether an undisturbed start pulse with the identification date of the stationary unit has been received;

F If an undisturbed start pulse with the identification date of the stationary unit was received, the length of the measuring pulse signal is used to check whether measuring pulses were also received;

G If no measuring pulses have been received, information about a correctly received start pulse is sent from the mobile to the stationary unit via the second interface, whereupon the stationary unit sends the entire measuring pulse signal in the next cycle, including measuring pulses of defined strength and order; then the procedure is started again at B;

H If measuring pulses have been received, it is checked whether the measuring pulses are undisturbed;

I If the measuring pulses are undisturbed, it will

The process started again at B and the measuring pulse signal was sent periodically until the end of the process;

J If the measuring pulses are disturbed, the

The time of the fault is determined and the start of the start pulse is increased by one

Time span corresponding to the duration of a

Measuring pulse signal plus a pause plus the time of the start of the fault. speaks, postponed; after that it will

Process started again at B;

K If no start pulse with the identification date of the stationary unit was received, the procedure is started again at B.

This process is shown in FIG. 11 as a schematic flow diagram.

A vehicle positioning system is thus provided, in which a plurality of participants are positioned independently of one another, a participant having a stationary unit, which can be the base plate in connection with a charging station and transmitting antennas for transmitting the measuring pulse signals, and a mobile unit, the vehicle plate can be and has receiving antennas for receiving the measuring pulse signals, is formed. The transmission path for the measuring pulse signals is a first wireless interface. Communication for the mutual transmission of identification data of the stationary and the mobile unit and for the transmission of the measured strength of the received measuring pulse signals from the mobile unit to the stationary unit takes place via a second wireless interface, which in one embodiment of the invention can be a WLAN connection.

In a sensible design of the vehicle positioning system, up to four transmit antennas are provided in the stationary unit. The magnetic fields of defined field strength generated by these antennas are measured by up to four sensors in the mobile unit and transmitted to the stationary unit via the second interface. In order to make this information available to the stationary unit, the previously established communication connection is made via the second

Interface used.

On the basis of the measured magnetic field strengths, the position between the vehicle and Base plate and thus between the primary and the secondary coil of the power transmission transformer can be determined.

The transmitting antennas do not generate their magnetic fields at the same time but one after the other. 2, the measuring pulse signal consists of a starting pulse SP and four measuring pulses MP1, MP2, MP3, MP4, if four transmitting antennas are used. In the example shown, each measuring pulse has a duration of 4 ms, with a pause of 1 ms between the measuring pulses, which results in a duration of 20 ms for the measuring pulse part of the measuring pulse signal. This signal is repeated cyclically to ensure a continuous position measurement.

If only the measuring pulses MP1, MP2, MP3, MP4 were sent, it would not be possible for the mobile unit to find out which signals are intended for them and which are possibly intended for mobile units of neighboring subscribers. Adjacent stationary units can already emit measuring pulses that interfere with the positioning process.

For this reason, the measuring pulses MP1, MP2, MP3, MP4 are preceded by a starting pulse SP, which is used by the mobile unit to identify the origin of the measuring pulse signals received.

The start pulse SP, often called “header”, preferably contains an identification date of the stationary unit Station_ID, an identification date of the mobile unit Auto_ID and a CRC checksum CRC. If this does not match the remaining bits of the start pulse SP, it must be assumed that that there was an overlap or other errors during the reception of the start pulse. In addition, information about the length of the period T of the repetition frequency of the measuring pulse signals is transmitted in the start pulse. The start pulse also has a start and a stop bit. This is shown in FIG 3. The start pulse SP has a length of 6.15 ms, which means that the entire measuring pulse signal has a length of 26.15 ms. As soon as several vehicles park in adjacent parking spaces, the measurement pulse signals of the individual participants of the entire vehicle positioning system may overlap. This would lead to an overlay of the start pulses and / or the measurement pulses and to an incorrect or no position calculation.

Neither the vehicles nor the stations have a common communication link, which means that synchronization using such an interface is not possible. If, for example, several charging stations with associated base plates are installed in adjacent parking spaces in a parking garage, the method according to the invention eliminates this mutual influence.

In the time-division multiplex method according to the invention, the stationary units of the respective participants send theirs

Measuring pulse signals on the same frequency, but at different times. If a mobile unit - i.e. a vehicle - can clearly identify the measuring pulse signal intended for it, undisturbed position measurements can be carried out. For this, however, it is imperative that no measuring pulse signal from a stationary unit of another subscriber arrives at the mobile unit at the same time. If this were the case, the actual useful signal and the signal of the interfering stationary unit (s) would interfere and a position determination would possibly be highly error-prone. However, if the method presented here ensures that a temporal overlap of the position signals is avoided, error-free positioning is possible.

According to the method according to the invention, before the parking process, there is already a communication channel (for example WLAN) via the second interface between a vehicle and the charging station at the parking lot on which the vehicle is to be parked and charged, that is to say between the stationary and the mobile unit of a subscriber, open. If a vehicle registers at a charging station, the charging station shares its identity with the vehicle. Date of station_ID with. The vehicle can also tell the station its identification date Auto_ID. This vehicle identification date can be predetermined or selected from the vehicle at random from a set of vehicle identification data. If the stationary unit now sends this information in the start signal SP of the measuring pulse signal, the mobile unit can uniquely identify the measuring pulse signal which is intended for it. Measuring pulse signals which are not intended for the mobile unit can thus be rejected by the latter.

If several vehicles park simultaneously, neither the vehicles, i.e. the mobile units, are synchronized with each other, nor are the charging stations, ie the stationary units, synchronized with one another. The consequence of this is that the measuring pulse signals emitted by the stationary units are randomly distributed over time. In terms of time, the repetition rates or period durations are designed such that measuring pulse signals from several stationary units can be sent in succession before this sequence is repeated. Due to the lack of synchronization of the transmitters with one another, however, the measuring pulse signals of the individual stationary units will often initially overlap.

If both measuring pulse signals overlap in the starting pulse, none of the measuring pulse signals can be assigned to a charging station. If there is an overlap during the measurement pulses, this can lead to incorrect or missing positioning of one vehicle and to an illegible start pulse for the other vehicle.

As shown in FIGS. 2 and 3, the start pulse SP is longer in time than a measurement pulse MP1, MP2, MP3, MP4 plus a pause time. 4 to 7 different cases of mutual influence of the measuring pulse signals of two participants are shown. For the sake of simplicity, the measuring pulses of the charging station B are omitted in FIGS. 4 to 7. The

Measuring pulse signal of charging station A is with a solid line drawn while the measuring pulse signal of the charging station B is shown in dashed lines.

If the start pulse SP_B of one charging station is sent simultaneously with the measuring pulses MP1, MP2, MP3, MP4 of the other charging station, this starting pulse SP_B consequently always overlaps with at least one of the pause times between the measuring pulses MP1, MP2, MP3, MP4. If appropriate coding (e.g. Manchester code) ensures that a start pulse cannot permanently take the value zero within the duration of a pause, this results in a measurable difference to the undisturbed pause time.

An overlap of two measuring pulse signals can thus be detected in any case. In addition, it is then also known at which point or at what point in time such an overlap has occurred (which measuring pulse or already at the starting pulse). For two charging stations A and B there are two different cases.

1. A start pulse is readable and the second start pulse lies in the measuring pulses of the first measuring pulse signal.

2. Both start pulses overlap and, if necessary, all measurement pulses.

In the first case, which in conjunction with FIGS. 8, the start pulse SP_A of the charging station A can be read. The start pulse SP_B of the charging station B is disturbed by at least one measuring pulse of the charging station A and can therefore not be assigned to any station.

However, since the charging station A knows from the measurement information transmitted by the vehicle assigned to it via the second interface, when the disturbance from the charging station B occurred (tüberiapp) r, the time difference between the two overlapping measuring pulse signals is known. The length (t _Sign ai) of the interference signal is also known or can be measured. Since both measuring pulse signals cyclically with the period T and this is known, the charging station A can calculate how much its measuring pulse signal has to be delayed so as not to collide with that of the charging station B. So that can

Measuring pulse signal of charging station A will be delayed accordingly once in the next cycle. Thus, the charging stations A and B send synchronized to each other after a single overlap and do not overlap.

It is important here that only the measuring pulse signals, which can be clearly assigned to a charging station on the basis of a decodable starting pulse, may be delayed accordingly. Measuring pulse signals whose start pulses cannot be decoded or read cannot be shifted because they cannot be clearly assigned.

In the second case, which is shown in FIG. 4, the measuring pulse signals from charging station A and charging station B already overlap in their two starting pulses SP_A, SP_B. Since no measuring pulse signal can thus be assigned, none of the measuring pulse signals would be shifted, which would lead to a permanent disturbance in the positioning. Therefore, if no measuring pulse signal is readable, all measuring pulse signals have to be delayed by a random time. This continues until the measuring pulse signals either no longer interfere or the first case occurs.

Since the second interface usually has a significantly longer range (e.g. 50m) than the first interface between the transmit and receive antennas in the vehicle plate (mobile unit) or the base plate (stationary unit) (eg 5m), communication also takes over the second interface sets before the actual positioning process via the first interface.

Since the transmission of the measuring pulse signals starts after the transmission of the identification data vehicle_ID, auto_ID, a charging station sends a long time until the vehicle comes within the positioning range of its charging station. As a result, this charging station potentially interferes with other positioning processes Parking spaces in which vehicles also want to park, although the actual positioning process cannot begin at all.

In order to avoid this early disturbance, according to the invention initially only the start pulse of the measuring pulse signal is sent. The measuring pulses are only sent when a vehicle belonging to a charging station detects this start pulse and communicates this to the charging station via the second interface. Since a start pulse is only a fraction of the total length of the measuring pulse signal, there is a shorter disturbance of other measuring pulse signals.

This procedure also has the advantage that measuring pulse signals that cannot be shifted due to range problems can be identified by other charging stations. The case from FIG. 8 that the measuring pulse signal B cannot be read because the measuring pulse signal A cannot be delayed cannot occur according to the method according to the invention. The starting pulse of the measuring pulse signal of the charging station A could only disturb the starting pulse of the measuring pulse signal of the charging station B or its measuring pulses. If the starting pulse of the measuring pulse signal from charging station B were disturbed, the measuring pulse signals from both charging station B and charging station A would have to be delayed at random. Since the measuring pulse signal of charging station A cannot be delayed, but that of charging station B can, the problem is solved. If the starting pulse of the measuring pulse signal of the charging station A lies in the measuring pulses of the measuring pulse signal of the charging station B, the starting pulse of the measuring pulse signal of the charging station B can be read and the measuring pulse signal of the charging station B could be shifted by the measured time.

According to a further development of the method according to the invention, a changeable period is provided, the mobile unit measuring the length of time of the received signal with measuring pulse signals contained therein and determining how many stationary units are sending measuring pulse signals and checking whether the period is sufficiently long to include all measuring pulse signals or is too long, and if there is no match, the information is transmitted to the stationary unit as to how long the period should be.

So far it was assumed that the period of the

Measuring pulse signals is fixed and that only two charging stations send measuring pulse signals at the same time. In reality, however, several charging stations can send at the same time. If the period should look such that all measuring pulse signals can be accommodated in one period, the system would be wasted unnecessarily. Especially since this case should occur extremely rarely. In reality, according to FIG. 9, six adjacent parking spaces A to F can be equipped with charging stations and base plates in order to enable inductive charging and positioning according to the invention. These neighboring positioning processes can influence each other.

In order to nevertheless guarantee a fast repetition rate of the position data, the period duration is made adaptable according to the development of the invention. 3, a few data bits T are also provided for the period in the start pulse SP.

If, for example, a charging station transmits a measuring pulse signal without a pause, which is disturbed by a measuring pulse signal from a second charging station, the period T must be increased at least to such an extent that both measuring pulse signals, including a safety margin, can be accommodated. This is communicated to a charging station of each participant via its second interface. If this has happened, the charging station sends with the new period and a synchronization of each participant is possible again. In the case of additional charging stations, the same principle must be applied again for increasing the duration of the period and for synchronization. This is always possible, since all participants can receive and decode the start pulses not only of the measuring pulse signals assigned to them but also of the other participants and thus recognize them can determine how many participants are currently carrying out positioning procedures and who may be disturbed.

In the same way, the period is reduced again if, after successful positioning, a participant ceases to exist and the time slot previously reserved for him would now keep the repetition rate at a lower than required value for the remaining participants. In this way, the period is always adapted to the currently required length with the maximum possible repetition rate in the manner according to the invention.

Even in the event that no identification date can be identified in a signal measured first, in one embodiment of the invention the period can be extended by at least the duration of a measuring pulse signal. It can happen that two participants are already active and the set period is set for these two participants. If a third participant arrives, his measuring pulse signal can interfere with both starting pulses of the first active participants, so that no starting pulse can be recognized. In this case, the period is still extended, since it can be assumed that more than two participants are active.

In a further development of the method according to the invention, if at least one further start pulse of another participant is identified by the mobile unit of a subscriber with an identification date Stations_ID belonging to the stationary unit of the first subscriber, this is communicated to the stationary unit via the second interface and the identification date Station_ID changed.

It can happen that a newly installed charging station happens to have the same preprogrammed identification date Station_ID as a neighboring station. The adaptive algorithm according to the invention recognizes the identification data of the neighboring stations and can be Customize his own identification date, Station_ID, if necessary.

However, a charging station can only recognize from the associated, already positioning vehicle which other identification data have already been allocated in the environment, since only this can receive the measuring pulse signals from the other charging stations. If your own charging station has a specific identification date and sends a charging station with the same identification date, the identification date of the charging station will be changed to another free identification date. The rule here is that the charging station, which first receives the information about the same identification date as its own, randomly adjusts its identification date to a free identification date. A participant independently saves which identification data is free for each signal of the other participants measured by the sensors.

By using a random drive

Stuff identification date in the start pulse enables an identifi cation of the randomly identical station identification date of another station.

In addition to the recognition of which other identification data of other participants or charging stations are present on the parking area, a recognition can be carried out of which identification data the charging stations of the nearby parking lots each have. An identification date of a specific charging station, the position of which is ascertained, is thus specifically assigned. This is done via the field strengths of the measuring pulse signals, which are measured in front of a passing vehicle. From this it can be estimated where the sending charging station must be.

If the vehicles regularly report the other identified identification data when parking, the station knows the neighboring identification data and can do so when reassigning his identification date take this into account. The disadvantage here is that the measurement of neighboring identification data is only possible if a vehicle is parked at the same time.

If, in a further development according to the invention, an additional receiving unit 10 is installed in a stationary unit, it can even scan for neighboring stationary units. In addition, there is also the possibility here that, before the measurement pulse signals are sent, it is possible to “listen” as to whether another stationary unit is transmitting. If this is the case, the one stationary unit 1, 3, 4 could be in communication with the other before the first transmission Synchronize stationary unit This approach helps in different situations and improves performance and increases the learning ability of the stationary unit, but synchronization via the mobile unit is still necessary.

For example, as shown in FIG. 9, if the vehicle wants to park in parking lot B and the charging station in parking lot D also sends out measuring pulse signals, this can lead to the following problem: the charging station in parking lot B is too far away to use its receiving unit 10 to receive the signals of the charging station in parking lot D. On the other hand, due to its physical proximity to the charging station in car park D, the vehicle very well measures its measuring pulse signals. Therefore, the charging station in parking lot B must be synchronized with the charging station in parking lot D using the procedures described above.

It is also possible to store the field strengths of the measuring pulse signals from other charging stations compared to the calculated vehicle position. If the vehicle positions in FIG. 9, for example, as shown in parking lot B and the charging station in parking lot D is active, its position can best be determined by, for example, a maximum search. If the vehicle is in the position shown in FIG. 9 and knows its relative position in comparison to the floor unit at parking lot B, Then the further course of the journey can provide information about the position of the charging station at parking space D. While the car is traveling across the parking spaces, it will register a maximum of the amplitude of the charging station at parking space D at parking space D. This means that it is known that the transmitter must be level with parking lots A and D. If the charging station at parking lot B now stores the position and height of the amplitude, it already knows that the interfering signal from the charging station at parking lot D is potentially left of it (viewed from above). If there is another fault, the vehicle will not find the maximum in exactly the same position as the previous vehicle. The vehicle will most likely measure the maximum either closer or further away. Thus, by comparing the two maximum values, the correct parking space D can be assigned to the charging station that is interfering with a measuring pulse signal.

By means of the method according to the invention, the shifting time when two starting pulses come together can be adjusted and compared in the next incident with the charging station at the neighboring parking lot, so that each charging station enables better adaptation not by accident but by self-learning. As soon as two start pulses are sent overlapping in time, the two measuring pulse signals are shifted randomly. The random shift when the measuring pulse signals meet for the first time can form the basis for the next incident.

The invention will be explained in more detail below on the basis of exemplary embodiments with the aid of figures. Show

1 shows a participant of a vehicle positioning system with a vehicle and a charging station with a base plate connected thereto according to the prior art,

2 shows a schematic measuring pulse signal,

Fig. 3 a more detailed start pulse, 4 shows a first example of an overlap of an entire measuring pulse signal with a further starting pulse,

Fig. 5 shows a second example of an overlap of an entire

Measuring pulse signal with a further starting pulse,

Fig. 6 shows a third example of an overlap of an entire

Measuring pulse signal with a further starting pulse,

Fig. 7 shows a fourth example of an overlap of an entire

Measuring pulse signal with a further starting pulse,

8 shows an example of an overlap of two measuring pulse signals with temporal references,

9 shows a parking area with several parking spaces and a vehicle to be parked, and

10a to 10c a first example of a sequence of the method according to the invention,

11 is a flowchart of the method according to the invention and

Fig. 12 shows a more detailed flow chart of the method according to the invention.

10a to 10c show the initial overlap of the measuring pulse signals of two participants in a vehicle positioning and their synchronization according to the inventive method in a first embodiment. The process is as follows:

A first vehicle wants to park, at the neighboring parking space a second vehicle is in the process of parking. The first vehicle has the identification date 7D and the associated charging station has the identification date 5A, so the first subscriber thus formed has the identification date 5A-7D. The second Participants should have the identification date B6-4F formed in the same way.

The measuring pulse signal with the identification date B6-4F of the second subscriber, which is shown in broken lines, arrives first at both mobile units. The measuring pulse signal with the identification date 5A-7D of the first participant should come 15 ms later.

The method according to the invention runs as follows in a subscriber. Communication channels should already be established between the stationary and mobile units of the two participants and the identification data should be exchanged (step A). The mobile unit of the first

The participant begins the measurement at the time of the entry of the first measuring pulse signal on the receiving antennas of the assigned vehicle plate. Since both signals are shifted by 15 ms, the received signal ends at t _E = 41.15 ms. The duration of the received signal is therefore greater than the expected signal duration of 26.15 ms.

The mobile unit of the first participant carries out a CRC check on the incoming signal and receives a positive result (step C -> step E). She reads in the complete identification date (charging station + vehicle) and realizes that it is not her identification date (5A-7D). So it does not carry out a shift and starts a measurement again (step K -> step B).

The mobile unit of the second subscriber also carries out the method according to the invention, in which measuring pulses have already been sent (step C -> step E -> step F -> step H), on the other hand sees its identification date (B6-4F) and detects and initiates faulty measuring pulses the shift function (step C -> step E -> step F -> step H -> step J).

The second participant's mobile unit checks whether there is still room for its measuring pulse signal within the set period T, which is designed for four participants, or based on the received signal length, how many participants are currently active.

However, it only recognizes its own measuring pulse signal and another that interferes with the measuring pulses. So it does not initiate a period adjustment.

Since the mobile unit of the second subscriber could clearly read its identification date, no random time delay is determined, but only the necessary shift is calculated using a formula. With the shift formula, t _shift = 41.15 ms + 5 ms = 46.15 ms. The stationary unit is informed of this delay via the second interface. The time reference according to FIG. 10b results. In the next measuring pulse signal transmission cycle, the start of the first measuring pulse signal is again assumed to be zero in accordance with FIG. 10c. Due to the current setting for four participants, a period would be twice as long as the duration of the two successive and synchronized measuring pulse signal durations shown. The disturbance is thus eliminated in the next measurement of a measuring pulse signal in both participants by independent and parallel execution of the method according to the invention in both participants. The then synchronized sequence follows the steps shown in bold in FIG. 12 in all participants.

In addition, the repetition rate is optimized in time after the successful synchronization.

Some additional measurements and settings are carried out below. The mobile unit of the first participant with the identification data 5A-7D also receives the measuring pulse signal of the second participant with the identification data B6-4F and remembers the part of the charging station (B6) but not that of the currently participating vehicle, and that Field strength. The charging station of the first participant had not previously received a measuring pulse signal from this charging station.

The mobile unit of the first subscriber observes this measuring pulse signal until it ends and stores the received field strengths or at least overwrites them with the last received one. Since the last received stored measurement pulse signal from the charging station of the second participant with the identification date B6-4F has a field strength with a value much greater than zero, this charging station is assumed to be in the vicinity and accordingly in a database of the charging station of the first participant saved.

FIG. 12 shows an expanded flow chart by means of which further advantageous functionalities of the method according to the invention are to be explained. Here, too, a connection is established via the second interface, in particular a WLAN connection, after the start in an initialization process Init, and the vehicle and charging station identification data are exchanged. In addition, the initial period T is exchanged.

In the subsequent step a, a measuring pulse signal is received in the mobile unit and it is determined whether this received measuring pulse signal is larger than a measuring pulse. If not, the process returns to the beginning of step a and if so, a time measurement with the period T is started. The received signals are then recorded and continuously checked in a step d whether the period T has expired. If this is not the case, incoming signals will continue to be recorded. If the period T has expired, it is checked in a step e whether at least one error-free start pulse has been received.

If this is not the case, it is checked in a step m whether a large part of the period T was blocked by disturbances. If not, in a step o from the mobile unit to the stationary unit via the second interface communicates that there should be a random delay when the next measuring pulse signal is transmitted.

If a large part of the period T was blocked by disturbances, the period T is first increased in a step k by the duration of a measuring pulse signal plus a safety margin and this information is transmitted to the stationary unit via the second interface. Then also in step o on the second

Interface communicated from the mobile to the stationary unit that there should be a delay of a randomly selected period.

If at least one error-free start pulse was received in step e, a check is then carried out in a subsequent step f as to whether the own identification data are contained in this error-free start pulse. This is done with the help of the checksum. If this is not the case, a step q checks whether measuring pulses, ie a complete measuring pulse signal, have also been sent together with an undisturbed start pulse.

If this is the case, a step r checks whether there are faults in the measuring pulses of this measuring pulse signal with an error-free starting pulse. If this is the case, the process returns to step a. If this is not the case, it is checked in a step t whether the period T is long enough for signals from this undisturbed measuring pulse signal and signals from two further participants to be recorded. If this is the case, the process returns to step a. If not, it is checked again in a step t whether the period T is long enough to be able to record at least the signals from three participants. Then in a step s the period T is increased by the duration of a measuring pulse signal plus a safety distance and the signal is delayed by a period of time with a randomly selected value, so that it lies outside the undisturbed measuring pulse signal. Then the process returns to step a. If it is recognized in step f that the own identification data is contained in the error-free start pulse, in a subsequent step g it is checked whether measuring pulses with this undisturbed start pulse were also sent. If this is not the case, in one step n is over the second

Interface to the associated stationary unit of the receiving mobile unit via the second interface transmits the information that the measuring pulses are to be sent with the start pulse in the next cycle. Then in a step p it is checked whether other disturbances have occurred during the measurement. If this is not the case, the process returns to step a. If this is the case, a step t checks whether the period T is large enough to receive signals from the undisturbed start pulse and signals from two other participants. If this is the case, the process returns to step a. If not, in a step k the period T is increased by the duration of a measuring pulse signal plus a safety distance and this information is transmitted from the mobile to the stationary unit of a subscriber via the second interface and then returned to step a.

If it is determined in step g that measuring pulses with the start pulse, which contains the own identification data, have also been sent, a check is carried out in a step h to determine whether the measuring pulses are disturbed in this measuring pulse signal. If they are disturbed, the starting point and the duration of the disturbance are determined in step i and subsequently checked in step j whether there is sufficient space in the current period T to be able to shift the signal. If this is the case, the calculated delay is transmitted in a step 1 from the mobile to the stationary unit of the subscriber via the second interface. If there is not enough space, the period T is increased in step k by the duration of a measuring pulse signal plus a safety distance and this information is transmitted from the mobile to the stationary unit of the subscriber via the second interface. Subsequently the calculated delay is again transmitted in a step 1 via the second interface from the mobile to the stationary unit of the subscriber. Then return to step a to restart the cycle.

If it is determined in step h that the measuring pulses of the received measuring pulse signal are not disturbed, a check is carried out in a step p to determine whether there are any other faults and, if this is not the case, return to step a in order to start the cycle again. If other disturbances are present, a check is carried out in a step t to determine whether the period T is long enough to receive signals from the undisturbed start pulse and signals from two other participants. If this is the case, the cycle is also started again at step a. If not, in a step k the period T - as already described - is increased by the duration of a measuring pulse signal plus a time safety margin and this information is sent from the mobile unit to the stationary unit of the received subscriber. Then the cycle is restarted at step a.

Insofar as steps in different loops of the flow chart have been designated with the same letters, this is only intended to identify the same process sequence but not a jump into another loop.

Claims

1. Method for synchronizing measuring pulse signals (SP; SP, MP1, MP2, MP3, MP4) of at least two participants of a vehicle positioning system,

in which each participant has a stationary unit (3) for sending a measuring pulse signal (SP; SP, MP1, MP2, MP3, MP4) of defined strength via a first wireless interface and for receiving information about the strength of the measuring pulse signal (SP; SP, MP1 , MP2, MP3, MP4) at the location of a mobile unit (6, 7) via a second wireless interface

and a mobile unit (6, 7) for receiving the measuring pulse signal (SP; SP, MP1, MP2, MP3, MP4) via the first wireless

Interface and for sending the information about the strength of the measuring pulse signal (SP; SP, MP1, MP2, MP3, MP4) at the location of the mobile unit (6, 7) via the second wireless interface, the measuring pulse signal (SP; SP, MP1 , MP2, MP3, MP4) consists of at least one start pulse (SP) and is transmitted at a repetition rate that is inversely proportional to a period,

and the start pulse (SP) an identification date (Station_ID) of the stationary (3, 4) and an identification date (Auto_ID) of the mobile unit (6, 7), information about the period (T) and a checksum (CRC) for checking the Has integrity of the start pulse (SP),

wherein the period (T) is selected such that both a start pulse (SP) and measuring pulses (MP1, MP2, MP3, MP4) comprising measuring pulse signals (SP; SP, MP1, MP2, MP3, MP4) also at least one neighboring participant of the Vehicle positioning system have space in a row,

the following steps for the synchronization of all measuring pulse signals (SP; SP, MP1, MP2, MP3, MP4) that can be received by a subscriber are carried out by each subscriber of the vehicle positioning system:

A A communication channel is established between the stationary unit (3, 4) of a subscriber and his mobile unit (6, 7) via the second wireless interface and an identification date (station ID) of the stationary one Unit (3, 4) from the stationary (3, 4) to the mobile unit (6) and an identification date (Auto_ID) of the mobile unit (3, 4) from the mobile (3, 4) to the stationary unit (6) transmitted, and information about the period was exchanged;

B The stationary unit (3, 4) sends a measuring pulse signal (SP; SP, MP1, MP2, MP3, MP4) with at least one start pulse (SP) cyclically at the repetition rate;

C All starting pulses (SP) received during the period (T) are checked by the mobile unit (6, 7) on the basis of the checksum (CRC) whether they are error-free;

D If the check shows that no start pulse (SP) is error-free, the stationary unit (3, 4) is informed via the second interface that the start of the start pulse (SP) should be shifted by a randomly selected period, including a complete measuring pulse signal (SP, MP1, MP2, MP3, MP4) must still be within the period (T); then the procedure is started again at B;

E If the verification is received in at least one

Start pulse (SP) does not result in an error, the mobile unit (6, 7) uses the identification date of the stationary unit (3, 4) (Station_ID) to check whether an undisturbed start pulse (SP) with the identification date (Station_ID) of the stationary unit Unit (3, 4) was received;

F If an undisturbed start pulse (SP) with the

Identification date (Station_ID) of the stationary unit (3, 4) was received, the length of the measuring pulse signal (SP; SP, MP1, MP2, MP3, MP4) is used to check whether measuring pulses (MP1, MP2, MP3, MP4) were also received ;

G If no measuring pulses (MP1, MP2, MP3, MP4) have been received, use the second one

Interface from the mobile (6, 7) to the stationary unit (3, 4) the information about a correctly received start pulse (SP) is sent, whereupon the stationary unit (3, 4) in next cycle sends the entire measuring pulse signal (SP, MP1, MP2, MP3, MP4), including measuring pulses (MP1, MP2, MP3, MP4) of defined strength and sequence; then the procedure is started again at B;

H If measuring pulses (MP1, MP2, MP3, MP4) have been received, it is checked whether the measuring pulses (MP1, MP2, MP3, MP4) are undisturbed;

I If the measuring pulses (MP1, MP2, MP3, MP4) are undisturbed, the process is started again at B and the measuring pulse signal (SP, MP1, MP2, MP3, MP4) is sent periodically until the process is completed;

J If the measuring pulses (MP1, MP2, MP3, MP4) are disturbed, the time of the disturbance is determined and the start of the starting pulse (SP) is delayed by a time that corresponds to the duration of a measuring pulse signal (SP; SP, MP1, MP2, MP3 , MP4) plus a break plus that

Corresponds to the time of the start of the fault, postponed; then the procedure is started again at B;

K If no start pulse (SP) with the identification date (Station_ID) of the stationary unit (3, 4) was received, the procedure is started again at B.

2. The method according to claim 1, wherein the mobile unit is a secondary coil module of a vehicle (2) for inductive energy transmission and the stationary unit is a primary coil module in a base plate (3) connected to a charging station (4).

3. The method according to any one of claims 1 to 2, wherein the second interface is a WLAN interface.

4. The method according to any one of claims 1 to 3, in which a variable period (T) is provided, of which mobile unit (6, 7) the temporal length of the received measuring pulse signal (SP; SP, MP1, MP2, MP3, MP4) is measured and the number of stationary units (3, 4) measuring pulse signals (SP; SP, MP1, Send MP2, MP3, MP4) and check whether the period (T) is long enough to include all measuring pulse signals (SP; SP, MP1, MP2, MP3, MP4) or is too long, and if there is no match , to the stationary unit (3, 4) the information is transmitted as to how long the period (T) should be.

5. The method according to any one of claims 1 to 4, in which, if the mobile unit (6, 7) of a participant at least one further start pulse (SP) of another participant with an identification date belonging to the stationary unit (3, 4) (Station_ID ) is recognized, the identification date (Station_ID) is changed and the stationary unit (3, 4) is communicated via the second interface.

6. The method according to claim 5, wherein the new identification date (Station_ID) is randomly selected from a data record with free identification data.

7. The method according to any one of claims 1 to 6, in which, if from the mobile unit (6, 7) of a participant at least one further start pulse (SP) of another participant with an identification date belonging to the stationary unit (3, 4) (Station_ID ) is recognized, corresponding information of the stationary unit (3, 4) is communicated via the second interface.

8. The method according to any one of claims 1 to 7, in which, if a participant identifies an identification date (Station_ID) in a start pulse (SP) that does not correspond to the identification date (Station_ID) of the stationary unit (3, 4) of the participant , and after receiving the start pulse (SP) containing this identification date (Station_ID)

Measuring pulse signal (SP; SP, MP1, MP2, MP3, MP4) is measured with additional measuring pulses (MP1, MP2, MP3, MP4) that go with this Identification date (Station_ID) belonging to the stationary unit (3, 4) is classified as adjacent and is accordingly identified in a memory.

9. The method according to claim 8, in which a subscriber in the mobile unit for receiving the measuring pulse signals (SP; SP, MP1, MP2, MP3, MP4) has at least two receiving antennas, with different strengths of the measuring pulse signals (SP ; SP, MP1, MP2, MP3, MP4) of a neighboring subscriber whose neighborhood ratio is determined as a function of the respective strength in the receiving antennas.

10. The method according to any one of claims 4 to 9, in which, in the event that no start pulse (SP) can be recognized in a signal measured first, the period by at least the duration of a measuring pulse signal (SP; SP, MP1, MP2, MP3 , MP4) is extended.

11. The method according to any one of claims 1 to 10, wherein the stationary unit of a participant has a receiving unit (10) with which measuring pulse signals (SP; SP, MP1, MP2, MP3, MP4) of other participants can be received and, if so the case is, the measuring pulse signals (SP; SP, MP1, MP2, MP3, MP4) of the currently sending participants are synchronized.