DE102018216468B3 - Method for synchronizing measuring pulse signals of at least two participants in a vehicle positioning system - Google Patents

Abstract

The invention relates to a method for synchronizing measuring pulse signals (SP; SP, MP1, MP2, MP3, MP4) of at least two participants in a vehicle positioning system, in which a measuring pulse signal (SP; SP, MP1, MP2, MP3, MP4) represents a start pulse (SP). with at least one identification date of a subscriber unit and systematically successive measuring pulses (MP1, MP2, MP3, MP4), whereby a defined time shift is detected by detecting a start pulse (SP) disturbed by neighboring subscribers or a distorted measuring pulse (MP1, MP2, MP3, MP4) the sending of the measuring pulse signal is initiated within a period of a repetition rate in each participant. As a result, the (SP, MP1, MP2, MP3, MP4) of the individual participants are arranged one after the other in a period and can be sent synchronized.

Description

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

The energy is transferred according to the schematic representation in the 1 from a primary coil in a so-called bottom plate 3 is installed and in or on the floor of a parking lot 1 is mounted to a secondary coil 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 floor and the vehicle plate 3 . 6 have no mechanical contact and the energy is transferred via the air gap between the coils or plates.

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

In inductive charging, the positioning of the vehicle plate above the base plate plays a crucial role in enabling energy to be transferred. Energy transfer with sufficient efficiency is only possible if the two plates are positioned one above the other with a tolerance of a few centimeters. Because the poorer the two coils are on top of each other, the worse the energy transmission 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.

US 2017/0 351 587 A1 discloses, among other things, a method for parking a vehicle in a parking lot by means of wireless information transmission.

WO 2016/173 822 A1 describes a method for assigning communication time slots which are contained in repetitive frames for communication between an inductive wireless power transmitter and at least two inductive wireless power receivers, the power transmitter and the power receivers being arranged to use modulation and demodulation to communicate an inductive power signal. The transmitter sends synchronization messages marking the start of the communication time slots and the frames, and messages indicating whether a time slot is not allocated. A receiver can send a message to the transmitter during an unassigned time window to request the assignment of the unassigned communication time window. The sender then sends messages to indicate whether the communication was successfully received and whether the assignment request was granted.

In the US 9,759,575 B2 describes a method for assisting a driver in the positioning of a motor vehicle for charging an electrical energy store of the motor vehicle, in which a charging device for charging the energy store located in the vehicle surroundings is determined and its relative position with respect to the motor vehicle is determined. A display device of the motor vehicle can be operated in a plurality of display modes, at least one of the display modes being a positioning mode in which the display device displays information relating to the positioning of the motor vehicle with respect to the charging device. It is determined whether the charging device is in an activation area defined with respect to the motor vehicle, this being dependent both on the distance of the Charging device depends on a reference point fixed in the vehicle and on the direction in which the charging device is located with respect to the reference point, after which it is determined, depending on whether the charging device is in the activation area, whether the display device is operated in the positioning mode.

The US 9 693 196 B2 discloses techniques for locating a power transmission unit (PTU) in a system, method, and apparatus. For example, a device may include a power detector to detect a low battery condition of the device. The device may also include a PTU locator to perform a PTU scan in response to the low battery condition, the PTU scan identifying a position of the PTU. The device may further include a PTU position indicator to indicate a position of the PTU based on the results of the PTU scan.

In the DE 10 2007 042 140 A1 describes a method for radio transmission of data from a plurality of measuring devices to a common central data collector, the measuring devices periodically going to receive for a certain period of time after a predetermined time interval in which they are not ready to receive, the data collector for the Duration of the specified time interval or somewhat longer transmits data telegrams, which are received by all measuring devices simultaneously, whereby all measuring devices are set to a common zero point in time by the receipt of the data telegrams, and starting from this zero point in time, the measuring devices successively transmit their data signals to the at different times Send out data collector.

US 2013/0 272 278 A1 discloses a method, systems and devices that are encoded on computer-readable media and configured to receive monitoring data from an electricity meter. A data stream is created based on the monitoring data. The data stream is spread with a common pseudo-noise code (PN code), which is used by several nodes in communication with an access point. The spread data stream is transmitted at a first point in time based on a slot start time and a first randomly selected time offset. The spread data stream is transmitted while at least a portion of a second spread data stream is transmitted at a second time based on the slot start time and a second randomly selected time offset. The second spread data stream is spread with the common PN code.

The object of the invention is therefore to specify 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 specified in the subclaims.

• A Es wird ein Kommunikationskanal zwischen der stationären Einheit eines Teilnehmers und dessen mobiler Einheit über die zweite drahtlose Schnittstelle hergestellt und ein Identifikationsdatum der stationären Einheit von der stationären an die mobile Einheit und ein Identifikationsdatum der mobilen Einheit von der mobilen an die stationäre Einheit übermittelt, sowie eine Information über die Periodendauer ausgetauscht;
• B Es wird von der stationären Einheit zyklisch mit der Wiederholrate ein Messpulssignal mit zumindest einem Startpuls gesendet;
• C Es werden von der mobilen Einheit alle während der Periodendauer empfangenen Startpulse anhand der Checksumme überprüft, ob sie fehlerfrei sind;
• D Falls die Überprüfung ergibt, dass kein Startpuls fehlerfrei ist, wird der stationären Einheit über die zweite Schnittstelle mitgeteilt, dass der Beginn des Startpulses um eine zufällig gewählte Zeitspanne verschoben werden soll, wobei auch ein vollständiges Messpulssignal noch innerhalb der Periodendauer liegen
• muss; danach wird das Verfahren wieder bei B begonnen; E Falls die Überprüfung in zumindest einem empfangenen Startpuls keinen Fehler ergibt, wird in der mobilen Einheit anhand des Identifikationsdatums der stationären Einheit überprüft, ob ein ungestörter Startpuls mit dem Identifikationsdatum der stationären Einheit empfangen wurde;
• F Falls ein ungestörter Startpuls mit dem Identifikationsdatum der stationären Einheit empfangen wurde, wird anhand der Länge des Messpulssignals überprüft, ob auch Messpulse empfangen wurden;
• G Falls keine Messpulse empfangen wurden, wird über die zweite Schnittstelle von der mobilen an die stationäre Einheit die Information über einen korrekt empfangenen Startpuls gesandt, worauf die stationäre Einheit im nächsten Zyklus das gesamte Messpulssignal also einschließlich von Messpulsen definierter Stärke und Reihenfolge sendet; danach wird das Verfahren wieder bei B begonnen;
• H Falls Messpulse empfangen wurden, wird überprüft, ob die Messpulse ungestört sind;
• I Falls die Messpulse ungestört sind, wird das Verfahren wieder bei B begonnen und das Messpulssignal periodisch bis zur Beendigung des Verfahrens versandt;
• J Falls die Messpulse gestört sind, wird der Zeitpunkt der Störung ermittelt und der Beginn des Startpulses wird um eine Zeitspanne, die der Dauer eines Messpulssignals plus einer Pause plus dem Zeitpunkt des Beginns der Störung entspricht, verschoben; danach wird das Verfahren wieder bei B begonnen;
• K Falls kein Startpuls mit dem Identifikationsdatum der stationären Einheit empfangen wurde, wird das Verfahren wieder bei B begonnen.

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 transmitting 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 for checking has the integrity of the start pulse,
the first period being selected such 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,
the following steps for the synchronization of all measuring pulse signals receivable by one participant are carried out by each participant of the vehicle positioning system:

• 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 from the mobile to the stationary unit, as well as a Exchanged information about the period;
• B The stationary unit sends a measuring pulse signal with at least one start pulse cyclically at the repetition rate;
• C All received during the period are received by the mobile unit Startpulses checked against 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 is still within the period
• got to; after that, the procedure is back at B began; e If the check does not result in an error in at least one received start pulse, 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 was received with the identification date of the stationary unit, the length of the measuring pulse signal is used to check whether measuring pulses have also been 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 a defined strength and sequence; after that, the procedure is back at B began;
• H If measuring pulses have been received, it is checked whether the measuring pulses are undisturbed;
• I If the measuring pulses are undisturbed, the procedure is again at B started and the measuring pulse signal sent periodically until the end of the procedure;
• J If the measuring pulses are disturbed, the time of the disturbance is determined and the start of the start pulse is shifted by a time period which corresponds to the duration of a measuring pulse signal plus a pause plus the time of the start of the disturbance; after that, the procedure is back at B began;
• K If no start pulse with the identification date of the stationary unit has been received, the procedure is again at B began.

This process is in the 11 shown 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 via the second interface is used.

On the basis of the measured magnetic field strengths, the position between the vehicle and the base plate and thus between the primary and the secondary coil of the energy transmission transformer can then be determined in the mobile unit - that is to say in the vehicle.

The transmitting antennas do not generate their magnetic fields at the same time but one after the other. The measuring pulse signal exists according to 2 from a start pulse SP and four measuring pulses MP1 . MP2 . MP3 . MP4 if four transmit 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.

Would only the measuring pulses MP1 . MP2 . MP3 . MP4 sent, it would not be possible for the mobile unit to find out which signals are intended for it 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.

Therefore the measuring pulses MP1 . MP2 . MP3 . MP4 preceded by a start pulse SP, which is used by the mobile unit to identify the origin of the measurement pulse signals received.

The starting pulse SP , often called "header" in English, 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. Does not match the remaining bits of the start pulse SP , it must be assumed that there was an overlap or other errors during the reception of the start pulse. In addition, information about the length of the period is shown in the start pulse T the repetition frequency of the measuring pulse signals. The start pulse also has a start and a stop bit. This is in the 3 shown. The starting 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 a superimposition 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 their 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, a communication channel (eg 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, is already present before the parking process, open. If a vehicle registers at a charging station, the charging station informs the vehicle of its identification date, Station_ID. In addition, the vehicle can also inform the station of its identification date Auto_ID. This vehicle identification date can be predetermined or can be selected by 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 at the same time, neither the vehicles, i.e. the mobile units, are synchronized with each other, nor are the charging stations, i.e. the stationary units, synchronized with one another. The result 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 in such a way 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 in 2 and 3 is shown is the start pulse SP longer than a measuring pulse MP1 . MP2 . MP3 . MP4 plus a break. In the 4 to 7 different cases of mutual influence of the measuring pulse signals of two participants are shown. For the sake of simplicity, the 4 to 7 on the measuring pulses of the charging station B waived. The measuring pulse signal of the charging station A is drawn with a solid line while the measuring pulse signal of the charging station B is drawn in dashed lines.

The start pulse SP_B one charging station at the same time as the measuring pulses MP1 . MP2 . MP3 . MP4 sent to the other charging station, this start pulse overlaps SP_B consequently always with at least one of the pause times between the measuring pulses MP1 . MP2 . MP3 . MP4 , Is it ensured by appropriate coding (eg Manchester code) that a start pulse within the duration of a Break time cannot permanently assume the value zero, there is consequently a measurable difference to the undisturbed break time.

1. 1. Ein Startpuls ist lesbar und der zweite Startpuls liegt in den Messpulsen des ersten Messpulssignals.
2. 2. Beide Startpulse überlappen und ggf. alle Messpulse.

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 for this.

1. 1. A start pulse is readable and the second start pulse lies in the measuring pulses of the first measuring pulse signal.
2. 2. Both start pulses overlap and, if necessary, all measurement pulses.

In the first case, which in the 5 to 7 in conjunction with 8th is shown is the start pulse SP A the charging station A readable. The starting pulse SP_B the charging station B is by at least one measuring pulse of the charging station A disturbed and can therefore not be assigned to any station.

Because the charging station A the measurement information transmitted by the vehicle assigned to it via the second interface, however, knows when the fault by the charging station B t _overlap has occurred), the time difference between the two overlapping measuring pulse signals is known. The length (t _signal ) of the interference signal is also known or can be measured. Since both measuring pulse signals change cyclically with the period T repeat and this is known, the charging station A calculate how much your measuring pulse signal has to be delayed, not by that of the charging station B to collide. This enables the measuring pulse signal of the charging station A be delayed accordingly once in the next cycle. So the charging stations send A and B synchronized with 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, the one in 4 is shown, the measuring pulse signals from the charging station overlap A and charging station B already in their two starting pulses SPA . 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 greater 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 whole 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 in parking spaces in which vehicles also want to park, although the actual positioning process cannot yet begin.

In order to avoid this early disturbance, according to the invention initially only the start pulse of the measuring pulse signal is sent. Only when a vehicle belonging to a charging station detects this start pulse and communicates this to the charging station via the second interface, are the measuring pulses also sent. 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 out 8th that the measuring pulse signal B is not readable because the measuring pulse signal A cannot be delayed, cannot occur according to the inventive method. The starting pulse of the measuring pulse signal of the charging station A could only be the start pulse of the measuring pulse signal of the charging station B or disturb their measuring pulses. Would the starting pulse of the measuring pulse signal from the charging station B disturbed, the measuring pulse signals from both the charging station B as well as the charging station A randomly delayed. As the measuring pulse signal of the charging station A cannot be delayed by the charging station B however, the problem is solved. Is the start pulse of the measuring pulse signal of the charging station A in the measuring pulses of the measuring pulse signal of the charging station from B , is the starting pulse of the measuring pulse signal of the charging station B readable and the measuring pulse signal of the charging station B could be postponed by the measured time.

According to a development of the method according to the invention, a changeable period duration is provided, with the time length of the received signal being determined by the mobile unit measuring pulse signals contained therein is measured and it is determined from this how many stationary units send measuring pulse signals and it is checked whether the period is long enough to include all measuring pulse signals or is too long, and if there is no match, the information to the stationary unit 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's performance would be wasted unnecessarily. Especially since this case should occur extremely rarely. In reality, according to 9 six adjacent parking spaces A to F be equipped with charging stations and base plates 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. For this, according to 3 in the starting pulse SP also a few bits of data T intended for the period.

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 must be T be increased at least to such an extent that both measuring pulse signals including a safety distance 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. With 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 can thus recognize how many participants are currently carrying out position procedures and can possibly interfere with one another.

In the same way, the period is reduced again if, after successful positioning, a subscriber is omitted and the time slot previously reserved for him would now keep the repetition rate for the remaining subscribers at a lower than required value. 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 recognized 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 is added, his measuring pulse signal can disturb 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 Stations_ID changed.

It can happen that a newly installed charging station happens to have the same preprogrammed identification data Station_ID as a neighboring station. The adaptive algorithm according to the invention recognizes the identification data of the neighboring stations and can adapt its own identification data Station_ID based on the findings if this is 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.

The use of a random vehicle identification date in the starting pulse enables identification 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 available on the parking area, a recognition can also 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 determined, is thus specifically assigned. This is done via the field strengths of the measuring pulse signals, which are measured in 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 take this into account when reassigning its identification date. The disadvantage here is that the measurement of adjacent identification data is only possible if a vehicle is parked at the same time.

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

For example, like in 9 illustrated the vehicle in the parking lot B park and the charging station in the parking lot D also sends measuring pulse signals, this can lead to the following problem: the charging station in the parking lot B is too far away with its receiving unit 10 the signals of the charging station in the parking lot D to recieve. The vehicle, on the other hand, measures in the parking lot due to its physical proximity to the charging station D its measuring pulse signals very well. The charging station must therefore be parked using the procedure described above B with the charging station in the parking lot D be synchronized.

It is also possible to store the field strengths of the measuring pulse signals from external charging stations in comparison to the calculated vehicle position. Positions the vehicle in 9 , for example, as shown in the parking lot B and the charging station in the parking lot D If it is active in the meantime, its position can best be determined by, for example, a maximum search. Is the vehicle in the in 9 shown position and knows its relative position compared to the floor unit at the parking lot B , the further course of the journey can provide information about the position of the charging station in the parking lot D give. As the car travels across the parking lots, it gets level with the parking lot D a maximum of the amplitude of the charging station in the parking lot D to register. This makes it known that the transmitter is at the same level as the parking lot A and D have to be. Stores the charging station in the parking lot B Now the position and height of the amplitude, this already knows that the disturbing signal from the charging station in the parking lot D is potentially to the left of this (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. The correct parking space can therefore be compared by comparing the two maximum values D can be assigned to the charging station which 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 will be shifted randomly. The random shift when the measuring pulse signals meet for the first time can serve as the basis for the next incident.

• 1 einen Teilnehmer eines Fahrzeugpositionierungssystems mit einem Fahrzeug und einer Ladestation mit damit verbundener Bodenplatte nach dem Stand der Technik,
• 2 ein schematisches Messpulssignal,
• 3 einen detaillierteren Startpuls,
• 4 ein erstes Beispiel einer Überlappung eines gesamten Messpulssignals mit einem weiteren Startpuls,
• 5 ein zweites Beispiel einer Überlappung eines gesamten Messpulssignals mit einem weiteren Startpuls,
• 6 ein drittes Beispiel einer Überlappung eines gesamten Messpulssignals mit einem weiteren Startpuls,
• 7 ein viertes Beispiel einer Überlappung eines gesamten Messpulssignals mit einem weiteren Startpuls,
• 8 ein Beispiel einer Überlappung zweier Messpulssignale mit zeitlichen Bezügen,
• 9 ein Parkareal mit mehreren Parkplätzen und einem zu parkenden Fahrzeug, und
• 10a bis 10 c ein erstes Beispiel eines Ablaufs des erfindungsgemäßen Verfahrens,
• 11 ein Flussdiagramm des erfindungsgemäßen Verfahrens und
• 12 ein detaillierteres Flussdiagramm des erfindungsgemäßen Verfahrens.

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

• 1 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 a schematic measuring pulse signal,
• 3 a more detailed start pulse,
• 4 a first example of an overlap of an entire measuring pulse signal with a further starting pulse,
• 5 a second example of an overlap of an entire measuring pulse signal with a further starting pulse,
• 6 a third example of an overlap of an entire measuring pulse signal with a further starting pulse,
• 7 a fourth example of an overlap of an entire measuring pulse signal with a further starting pulse,
• 8th an example of an overlap of two measuring pulse signals with temporal references,
• 9 a parking area with several parking spaces and a vehicle to be parked, and
• 10a to 10 c a first example of a sequence of the method according to the invention,
• 11 a flowchart of the inventive method and
• 12 a more detailed flow chart of the method according to the invention.

The 10a to 10 c 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, a parking process for a second vehicle is in progress at the neighboring parking space. The first vehicle has the identification date 7D and the associated charging station the identification date 5A , the first participant thus formed has the identification date 5A-7D , The second participant should use the identification date created in the same way B6-4F to have.

The measuring pulse signal with the identification date B6-4F the second participant, who is drawn with a broken line, arrives first on both mobile units. The measuring pulse signal with the identification date 5A-7D the first participant should come 15ms 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 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 the complete identification date (charging station + vehicle) and notices that it does not have her identification date ( 5A-7D ) is. 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, wherein measurement pulses have already been sent (step C -> step E -> step F -> step H), but sees its identification date ( B6-4F ) and detects disturbed measuring pulses and initiates 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 in 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 is determined according to 10b , In the next measuring pulse signal transmission cycle, according to 10c the beginning of the first measuring pulse signal is assumed to be zero time. Due to the current setting for four users, 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 that in all participants 12 bold steps.

In addition, the temporal optimization of the repetition rate will advantageously take place after the successful synchronization.

Some additional measurements and settings are carried out below. The first subscriber's mobile unit with the identification date 5A-7D also receives the measuring pulse signal of the second participant with the identification date B6-4F and remembers the part of the charging station ( B6 ) but not that of the currently participating vehicle and the 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 participant 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 measuring 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 is accordingly stored in a database of the charging station of the first subscriber.

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

In the following 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 is carried out T began. Then the received signals are 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 in step e it is checked whether at least one error-free start pulse has been received.

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

If much of the period T was blocked by interference, first in one step k the period T increased by the duration of a measuring pulse signal plus a time safety margin and and this information is transmitted to the stationary unit via the second interface. Subsequently, in step o, it is also transmitted from the mobile to the stationary unit via the second interface that a delay should occur by a randomly selected period of time.

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

If so, do one step r checks whether there are any faults in the measuring pulses of this measuring pulse signal with an error-free start pulse. If this is the case, the process returns to step a. If this is not the case, one step t checks whether the period T is large enough to receive signals from this undisturbed measuring pulse signal and signals from two other participants. If this is the case, the process returns to step a. If not, again in one step t checks whether the period T is large enough to be able to record at least the signals from three participants. Then in one step s the period T increased by the duration of a measuring pulse signal plus a safety distance and the signal delayed by a period of time with a randomly selected value so that it lies outside the undisturbed measuring pulse signal. Then the step a returned.

If in step f it is recognized that the own identification data are contained in the error-free start pulse, in a subsequent step G checks whether measuring pulses with this undisturbed start pulse were also sent. If this is not the case, one step n Via the second interface to the associated stationary unit of the receiving mobile unit, the information is transmitted via the second interface that the measuring pulses are to be sent with the start pulse in the next cycle. After that, in one step p checks whether other faults have occurred during the measurement. If this is not the case, the step becomes a returned. If this is the case in one step t checks whether the period duration T is large enough to receive signals from the undisturbed start pulse and signals from two other participants. If so, go to step a returned. If not, one step k the period T increased by the duration of a measuring pulse signal plus a safety distance and this information is sent from the mobile to the stationary unit of a subscriber via the second interface and then returned to step a.

If in step G It is determined that measuring pulses with the start pulse, which contains the own identification data, were also sent, a step h checks whether the measuring pulses are disturbed in this measuring pulse signal. If they are disturbed, one step i the starting point and the duration of the fault are determined and subsequently in one step j checks whether there is enough space in the current period T is to be able to shift the signal. If so, do one step 1 the calculated delay is transmitted from the mobile to the stationary unit of the subscriber via the second interface. If there is not enough space, in one step k the period T increased by the duration of a measuring pulse signal plus a safety distance and transmits this information from the mobile to the stationary unit of the subscriber via the second interface. Then again in one step 1 the calculated delay is transmitted from the mobile to the stationary unit of the subscriber via the second interface. Then it becomes a step a returned to restart the cycle.

If in the step H It is determined in one step that the measuring pulses of the received measuring pulse signal are not disturbed p checks to see if there are any other faults, and if not, returned to step a to begin the cycle again. If there are other malfunctions in one 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 cycle is also started again at step a. If not, one step k the period T - As already described - increased by the duration of a measuring pulse signal plus a time safety margin and this information is transmitted from the mobile to the stationary unit of the received subscriber. Then the cycle at step a restarted.

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 (11)

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 ) 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) consisting of at least one start pulse (SP) and with a repetition rate that results in a period is inversely proportional is sent, 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 integrity of the start pulse (SP), the period (T) being selected such that both a start pulse (SP) and measurement pulses (MP1, MP2, MP3, MP4) comprising measurement pulse signals (SP; SP, MP1, MP2, MP3, MP4) also have space in time for at least one neighboring participant of the vehicle positioning system, with each participant of the vehicle positioning system following steps for the synchronization of all measuring pulse signals (SP; SP, MP1, MP2, MP3, MP4): A A communication channel is established between the stationary unit (3, 4) of a subscriber and their mobile unit (6, 7) via the second wireless interface and an identification date (Station_ID) of the stationary unit (3, 4) transmitted 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), as well as information about exchanged the period; 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 The mobile unit (6, 7) checks all start pulses (SP) received during the period (T) based on 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 check does not result in an error in at least one received start pulse (SP), 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 (3, 4) was received; F If an undisturbed start pulse (SP) with the identification date (Station_ID) of the stationary unit (3, 4) has been 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 received; G If no measuring pulses (MP1, MP2, MP3, MP4) were received, the information about a correctly received start pulse (SP) is sent from the mobile (6, 7) to the stationary unit (3, 4) via the second interface. whereupon the stationary unit (3, 4) in the next cycle sends the entire measuring pulse signal (SP, MP1, MP2, MP3, MP4), including measuring pulses (MP1, MP2, MP3, MP4) of a 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 the time of a measuring pulse signal (SP; SP, MP1, MP2, MP3 , MP4) plus a pause plus the time at which the fault started, 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. Procedure 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). Procedure according to one of the Claims 1 to 2 , in which the second interface is a WLAN interface. Procedure according to one of the Claims 1 to 3 , in which a variable period (T) is provided, the mobile unit (6, 7) measuring the length of time of the received measuring pulse signal (SP; SP, MP1, MP2, MP3, MP4) and determining how many send stationary units (3, 4) measuring pulse signals (SP; SP, MP1, MP2, MP3, MP4) and check whether the period (T) is long enough to transmit all measuring pulse signals (SP; SP, MP1, MP2, MP3, MP4) or is too long, and if there is no match, the information is transmitted to the stationary unit (3, 4) how long the period (T) should be. Procedure according to one of the Claims 1 to 4 , in which, if the mobile unit (6, 7) of one subscriber detects at least one further start pulse (SP) of another subscriber with an identification date (Station_ID) belonging to the stationary unit (3, 4), the identification date (Station ID) changed and the stationary unit (3, 4) is communicated via the second interface. Procedure according to Claim 5 , in which the new identification date (Station_ID) is selected randomly from a data record with free identification data. Procedure according to one of the Claims 1 to 6 , in which if the mobile unit (6, 7) of a subscriber detects at least one further start pulse (SP) of another subscriber with an identification data (Station_ID) belonging to the stationary unit (3, 4), corresponding information from the stationary unit (3, 4) is communicated via the second interface. Procedure according to one of the Claims 1 to 7 , in which, if a participant recognizes 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) a measuring pulse signal (SP; SP, MP1, MP2, MP3, MP4) containing this identification data (Station_ID) is measured with additional measuring pulses (MP1, MP2, MP3, MP4), the stationary unit (3, 4 ) classified as neighboring and marked accordingly in a memory. Procedure 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. Procedure according to one of the Claims 4 to 9 , in the event that no start pulse (SP) can be recognized in a signal measured first, the period is extended by at least the duration of a measuring pulse signal (SP; SP, MP1, MP2, MP3, MP4). Procedure according to one of the Claims 1 to 10 , in which the stationary unit of a subscriber has a receiving unit (10) with which measuring pulse signals (SP; SP, MP1, MP2, MP3, MP4) of other subscribers 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.

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