CN112776752A

CN112776752A - Method for activating a remote control function of a motor vehicle and system for carrying out such a method

Info

Publication number: CN112776752A
Application number: CN202011215136.6A
Authority: CN
Inventors: C-P·布吕克纳
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2019-11-04
Filing date: 2020-11-04
Publication date: 2021-05-11
Anticipated expiration: 2040-11-04
Also published as: DE102019216947B4; CN112776752B; DE102019216947A1

Abstract

A method of activating a remote control function of a motor vehicle and a system for performing such a method. The invention relates to a method, a system and a motor vehicle for activating a remote control function of a motor vehicle by means of a mobile control device. In this case, the distances between the individual transceivers of the motor vehicle and the control unit of the control unit are first periodically repeatedly ascertained by means of a transit time measurement. If at least two distances are ascertained in this case, the current relative position of the control device relative to the motor vehicle and the current distance are determined. If the current spacing is outside the range of spacing values, a recalculation is performed. If only one single recalculated distance value is then determined, the predicted relative position is determined with the application of the position estimation criterion. Starting from the predicted relative position, a predicted distance is determined. The remote control function is activated only if the determined predicted distance is within the range of distance values.

Description

Method for activating a remote control function of a motor vehicle and system for carrying out such a method

Technical Field

The present invention relates to a method for activating a remote control function of a motor vehicle by means of a mobile control device, a system for performing such a method, and a motor vehicle comprised by such a system.

Background

Motor vehicles often have a function which is remotely controlled by means of a mobile control device. An example of such a remote control function is a remote control car key, by means of which the motor vehicle can be unlocked without the car key being actively used. For this purpose, the vehicle key in the outer region of the motor vehicle is located by means of a periodically performed distance measurement, which is implemented, for example, as a Time-of-Flight (Time-of-Flight) measurement. Typically, each range measurement is based on the exchange of Ultra-Wideband (UWB) technology data (UWB stands for Ultra-Wideband). The UWB data exchange takes place between the corresponding transmitting and receiving unit of the vehicle key and a plurality of transmitting and receiving units arranged inside and outside the motor vehicle. The transceiver unit of the motor vehicle can be arranged, for example, on the body of the motor vehicle and there in the region of the bumper at the respective corner of the motor vehicle. The current distance of the vehicle key from the motor vehicle can thus be calculated finally by means of known methods, such as bilateral measurement and/or trilateration, the current distance referring to the shortest connection between the vehicle key and the vehicle body. Finally, it is decided whether a preferably automatic unlocking of the door lock system takes place or not, depending on the calculated spacing. The activation of the remote control function is therefore based on a distance measurement between the vehicle key and the motor vehicle.

DE 102018102405 a1 shows a communication system of a vehicle, which is designed to communicate with a portable ID transmitter of an operator, which is set up for UWB communication, for example, by means of a UWB transceiver. In this case, the two UWB antennas of the UWB receiver of the motor vehicle are arranged on the vehicle at a distance from one another.

WO 2016/146617 a1 shows a method for determining the location of a mobile device using a positioning network. The method is based on measurements of the respective signal exchanges between the mobile device and the communication interface of the positioning network.

WO 2019/149748 a1 shows an object locating system in which the position of an object is determined by means of position signals of emitters of the object. In this case, the time window is determined using movement data of a sensor arranged on the object. Based on the determined time window, the at least one position signal and/or position data derived from the at least one position signal is processed. Not only the emitter but also the sensor may be integrated into a component arranged on the object itself.

Disclosure of Invention

The object of the present invention is to provide a solution by means of which the remote control function of a motor vehicle can be reliably activated by means of a mobile control device.

This object is achieved by the subject matter of the independent patent claims. Advantageous embodiments of the invention with suitable and important embodiments are described in the dependent claims, the following description and the drawings.

The method according to the invention for controlling a remote control function of a motor vehicle by means of a mobile control device is based on: the motor vehicle has a first transceiver unit and at least one second transceiver unit arranged spatially separated from the first transceiver unit. The mobile control device has a control device transmission/reception unit. The mobile control device is, for example, a car key or a mobile terminal device, such as a smartphone. The respective transceiver unit and the control device transceiver unit are each a transceiver which is designed to carry out signal transmission by means of radio technology. The respective transceiver unit of the motor vehicle and the control unit transceiver unit may be configured, for example, in each case as: data in the Ultra-Wideband range, that is to say Ultra-Wideband (UWB) signals (UWB stands for Ultra-Wideband), are exchanged.

The invention is based on the recognition that: when a user approaches with a vehicle key as a mobile control device for a motor vehicle, the respective distance measurement data from a plurality of transmitting and receiving units of the motor vehicle often do not exist at every measurement time. However, if only one distance value exists, which describes the distance between one of the transceiver units of the motor vehicle and the transceiver unit of the control device, the remote control function of the motor vehicle cannot be reliably activated by means of the mobile control device, since a reliable distance of the mobile control device from the motor vehicle cannot be determined. This is the case, for example, when a reliable distance value to the motor vehicle cannot be determined in each measurement cycle on the basis of distance measurements from at least two or more transmitting and receiving units due to signal attenuation caused by the human body when it approaches the motor vehicle. Because conventional ranging methods are always based on: distance data from at least two transmitting/receiving units of the motor vehicle are available. This results, for example, in: the remote control function is in some cases not activated by means of the mobile control device, but remains inactive even if the user with the mobile control device stands, for example, directly in front of the motor vehicle, since a distance measurement is not possible. Thus, a method for activating a remote control function by means of a mobile control device should provide a reliable distance estimation, so that the remote control function of a motor vehicle can be reliably activated even if the distance is not reliably detected.

The method according to the invention comprises the following steps: first, according to step a), for each transceiver unit of the motor vehicle, for which a predefined signal exchange with the transceiver unit of the control device is established, a distance value describing the distance of the transceiver unit from the transceiver unit of the control device is ascertained periodically and repeatedly. This ascertainment of the distance is achieved by evaluating the signal transit time of a predefined signal exchange between the transceiver unit and the control device transceiver unit. In the case of this predefined handshake, the signal transit time required for the handshake is primarily analyzed. That is, the time-of-flight measurements are made on the signals exchanged between the transceiver unit and the control device transceiver unit, so that the distance between the transceiver unit and the control device transceiver unit is determined, for example, on the basis of conventional time-of-flight measurement methods. The individual transceiver units of the motor vehicle are fixedly built into the motor vehicle and are therefore arranged at fixedly predefined positions. Preferably, for example, at least four transmitting/receiving units, more precisely a first transmitting/receiving unit and three second transmitting/receiving units are present in the motor vehicle. The respective transceiver units are arranged on the body at the respective corners of the motor vehicle, usually below the bumper of the motor vehicle. In this way, the surroundings of the motor vehicle can be detected around the motor vehicle within the range of the respective transceiver unit. For all transmitting and receiving units participating in step a), the distance is ascertained at the same time in each ascertaining period, taking into account a predefined time tolerance interval.

In a further step b), whenever at least two distance values are ascertained, the current relative position of the control unit transceiver unit with respect to the motor vehicle is determined by applying a relative position determination criterion to the respective ascertained distance values. If, for example, a person approaches the motor vehicle from a predetermined direction, which corresponds, for example, to the direction of a diagonal between, for example, the front right transceiver and the rear left transceiver, for example, and carries the vehicle key with him as a mobile control device, a signal exchange with the control device transceiver of the vehicle key can be established first for the three transceivers of the motor vehicle, to be precise for the front left, rear left and rear right transceivers. In this case, the positional specification is specified with respect to a vehicle longitudinal direction pointing in the forward direction and a vehicle transverse direction arranged perpendicularly thereto. Based on the three ascertained distance values, the current relative position of the user with the vehicle key can first be determined according to the relative position determination criterion. To this end, the relative position determination criteria may include provisions according to which trilateration and/or bilateral measurement can be performed. The application of the relative position determination criterion thus enables the positioning of a mobile control device having a control device transceiver unit in the surroundings of the motor vehicle.

In relation to the at least two ascertained distance values, a distinction is made between the first distance value and the at least one second distance value. The first distance value describes the distance of the first transceiver unit from the transceiver unit of the control device, and the at least one second distance value describes the distance of the at least one second transceiver unit from the transceiver unit of the control device. In the above example, the first distance value is determined, for example, by means of the front left transmitting and receiving unit, while the second distance value is determined by means of the rear left and rear right transmitting and receiving units, respectively.

In addition, a current distance between the determined current relative position and the surface of the body of the motor vehicle is determined when the distance measurement criterion is applied. That is, from the current relative position, the actual distance from the vehicle body can be calculated. For this purpose, the distance measurement criteria include, for example, detailed information about the configuration and shape of the motor vehicle and the positioning of the transceiver unit on the vehicle. This distance is always the shortest connection between the determined current relative position and the surface of the body. Thus, by applying the ranging criterion, the actual distance of the current relative position from the body of the motor vehicle can be estimated. The described definition of the spacing is based on the recognition that: in general, the vehicle center of a motor vehicle is not a reasonable starting point for the distance measurement of the mobile control device from the motor vehicle, but in this context the distance from the outer edge of the motor vehicle, that is to say from the surface of the vehicle body, is of interest. Since a large number of remote control functions, such as the remote control car keys already mentioned above, each take into account at least one specific limit value with respect to the distance, which must be observed with respect to the outer surface of the vehicle body and not with respect to the vehicle center. The reason for this may be: the safety requirements relevant to the vehicle key function are established with respect to the vehicle exterior surface of the motor vehicle and thus with respect to the surface of the vehicle body.

In a next step c), it is checked whether the determined current distance is within a predefined distance value range. For remote control car keys, for example, provision is made for: the vehicle key activates automatic unlocking of a door lock system of a motor vehicle when the distance from the surface of the vehicle body is usually less than or equal to one meter. That is, the remote control function for the vehicle should be activated within a range of spacing values between greater than zero meters and one meter. In this context, a tolerance range can also be specified, which is specified, for example, on the basis of the safety requirements relevant for the vehicle key function and extends up to a distance of two meters from the vehicle body. Within this tolerance, the remote control function can already be activated, but this is still not desirable within the scope of the described method.

If the current distance determined as described is outside the predefined distance value range, a recalculation of the distance of the transceiver from the control unit transceiver is carried out as step d) for each of the transceivers for which a predefined exchange of signals with the control unit transceiver is established. If, for example, a user approaching the motor vehicle from diagonally behind as described above is at a current distance of 1.5 meters from the vehicle body at the point in time of step a), the motor vehicle is not unlocked, but the distance between the transceiver unit and the transceiver unit of the control device is recalculated for each transceiver unit possible for it. I.e. re-performing the transit time measurement, with the aim of: the current relative position and the distance between the current relative position and the surface of the vehicle body are re-determined.

The next step e) takes place if only one recalculated distance value is now ascertained with the recalculation being carried out. This is the case, for example, whenever the user turns away from the motor vehicle during his approach such that, for example, only one of the transceiver units of the motor vehicle can remain in signal communication with the transceiver unit of the control unit. This one transceiver unit is, for example, the left front transceiver unit. Suppose that: the recalculated distance value is the recalculated first distance value, i.e. the recalculated distance value is determined by the first transceiver unit. Furthermore, when, for example, a plurality of persons walk toward the motor vehicle and, due to the relative arrangement of one of these persons with respect to the user, the exchange of signals between the control device transceiver unit of the mobile control device of the user and the respective control device transceiver unit of the motor vehicle is masked, this may be the case for the ascertainment of only one recalculated distance value. In step e), the predicted relative position of the control unit transmitter receiver unit with respect to the motor vehicle is determined. This is achieved if the position estimation criterion is applied to the recalculated first distance value, the second distance value and the current relative position. That is, it is estimated to which expected position the mobile control device has been moved, that is to which predicted relative position, based on at least two distance values assigned to the current relative position. For this purpose, a distance change of the first distance value is taken into account, which is derived from the difference between the first distance value and the recalculated first distance value. The location estimation criteria include the specifications and criteria upon which the estimation is based. In other words, the first distance value detected in steps a) and d), which is determined, for example, by the transceiver unit in front of the left of the motor vehicle, the two second distance values detected in step a) from the transceiver units in the rear left and rear, and the current relative position determined in step b) are summed with one another, so that an expected value or at least one expected value range for the relative position is determined.

In a next step f), a predicted distance of the control device transmitter receiver unit from the surface of the body of the motor vehicle is determined. This is achieved if a ranging criterion is applied to the predicted relative position. Similarly to the determination of the current relative position, the distance expected at the recalculated point in time is determined as the predicted distance by means of the application of the above-mentioned distance measuring criteria.

If the determined predicted distance is within the predefined distance value range, a remote control function of the motor vehicle is activated in step g). Even if, in the recalculation, only the distance between the mobile control device and the motor vehicle can be measured and the relative position cannot be unambiguously determined, it is still possible to indicate with high reliability whether the mobile control device has moved within a predetermined surroundings (which are arranged, for example, within one meter of the distance from the motor vehicle) and therefore, for example, whether a remote-control door lock system as a remote control function should be activated.

The described activation of the remote control function is particularly convenient for the user of the motor vehicle, since the user can reassure that: even in the case of a signal exchange between the transmission and reception unit of the shielding control device and the corresponding transmission and reception unit of the motor vehicle, operation is possible, if: there is a distance measurement of one of the transceiver units of the motor vehicle from the transceiver unit of the control device. Since the distance of the mobile control device from the motor vehicle can be reliably predicted, the usability and robustness of the remote control function is increased. Overall, a reliable distance estimation is always provided despite the occlusion of the individual handshakes.

In the example described so far, remote unlocking of the door locking device of the motor vehicle can occur if the determined predicted distance is within a distance value range of less than or equal to one meter from the vehicle body. Alternatively or in addition thereto, other predefined spacing value ranges can be provided. For example, in the case of locking the door as a remote control function, a range of spacing values of less than or equal to 1.5 meters may be specified. Other remote control functions may be allowed within a range of spacing values up to 6 meters. The remote control function of the motor vehicle can also be controlled after it has been activated in accordance with the control commands of the mobile control device. This is useful, for example, when the convertible is used as a motor vehicle for remote-controlled control of windows, sunroofs and/or roofs, wherein control commands for the functions of the motor vehicle are provided, for example, by means of an operating device of a vehicle key and/or an application on a user's mobile terminal.

The invention also includes design forms that result in additional advantages.

According to a particularly advantageous embodiment, provision is made for: if only one recalculated distance value is ascertained when the recalculation is performed, the following steps are performed: in step a), it is first checked whether the determined current distance is within a predefined tolerance range. The tolerance range includes a range around the vehicle body that is larger than the range of pitch values. Typically, the tolerance range limit is two meters from the body. That is, the range of pitch values is fully encompassed by the tolerance range. The tolerance range is specified, for example, on the basis of insurance requirements relevant for the vehicle key function. If, for example, a distance of 1.5 meters from the vehicle body is determined as the current distance, the current relative position is within the tolerance range described in the example.

If the determined current distance is within a predefined tolerance range, the expected length of time for moving from the determined current relative position to the tolerance range limit of the tolerance range at a predefined standard speed is determined in step b). In this example, the distance between the current relative position and the tolerance range limit is 50 centimeters. In the case of a typical speed of a person of 1.5 meters per second (which is assumed to be a standard speed, for example), the expected duration is therefore about 330 milliseconds. That is, if the user with the mobile control device is far from the motor vehicle, the tolerance range limit is expected to be reached after three to four ascertaining cycles, in the case of a typical ascertaining cycle duration of 100 milliseconds, i.e. the ascertaining of the distance between the respective transceiver unit and the control device transceiver unit is repeated every 100 milliseconds.

In step c), a corresponding subsequent recalculation of the distance of the transceiver unit from the transceiver unit of the control device is then carried out for each of the transceiver units for which a predefined handshake with the transceiver unit of the control device is established, up to the expiration of the expected time period. Here, in the case of recalculation, only one distance value has been determined after the current relative position has been determined. The only one distance value is determined, for example, after 100 milliseconds and the method described initially is carried out immediately thereafter in accordance with steps e) to g). If the remote control function is not activated on the basis of this recalculation, the ascertained distance value after 100 milliseconds is analyzed analogously thereto. That is, the later ascertained distance value is determined 200 milliseconds after the ascertained event within the framework of which the current relative position has been determined. That is, in step d), the further recalculated distance values determined in the case of the respective subsequent recalculation are analyzed for determining the recalculated distance or the further predicted distance accordingly. If this later ascertained distance value is also only a single value and steps e) to g) likewise do not lead to a triggering of the activation, a further ascertaining cycle is also carried out, so that at least one distance value is present 300 milliseconds after the determination of the current relative position.

Step e) provides for: as soon as the determined recalculated distance or one of the determined other predicted distances is within the distance value range, a remote control function of the motor vehicle is activated. If all the distance values after 100, 200 and 300 milliseconds indicate: if the corresponding predicted distance value is not within the distance value range and if, in addition, the new current relative position is not unambiguously determined, it can no longer be unambiguously ruled out that the user with the movement control device has moved away from the tolerance range. I.e. if the distance ascertainment performed within 300 milliseconds does not allow an unambiguous relative position determination similar to the initially described method steps a) to c) and/or does not trigger the activation of the remote control function in dependence on the predicted distance, no further evaluation of the predicted relative position and/or the predicted distance based on the current relative position takes place.

Thereby ensuring that: the predicted relative position is not taken into account for any significant time in triggering the activation of the remote control function. By selecting the tolerance range limit as the maximum tolerance limit for further estimation of the predicted relative position and the predicted separation, it is achieved that: an undesirable unlocking of the door lock system as a remote control function does not occur outside the tolerance range. The idea here is: although the method described at the outset makes it possible to determine a predicted distance which is not in the distance value range itself but is at least reliably within the tolerance range for this purpose, a new initialization, that is to say a new current relative position determination, is required if the probability of a possible departure from the tolerance range is too high. By this, the method becomes particularly reliable and trustworthy.

An additional design form provides for: the method described initially with steps a) to g) is always executed anew if, at the expiration of the expected period of time, it is not determined that the recalculated distance or the other predicted distance lies within the range of distance values. That is, the ascertaining period for ascertaining the distance value continues to be executed even if the expected duration expires. I.e. no interruption of the activation of the remote control function occurs, but only a successful, reliable initialization, i.e. a renewed determination of the current relative position, is required, and the remote control function is then automatically activated on the basis of the predicted distance. This results in a particularly high reliability of the method.

According to a particularly advantageous embodiment, provision is made for: if only one recalculated distance value is ascertained when the recalculation is performed, the following steps are performed: checking in step a): if at least one temporally preceding ascertainment of the distance of the transceiver unit from the control unit transceiver unit is made, it is determined whether a corresponding temporally preceding relative position of the control unit transceiver unit with respect to the motor vehicle has already been established. Namely, checking: the control device is provided with a control device transmitting and receiving unit, and whether historical data exists or not, and the previous relative position of the mobile control device with the control device transmitting and receiving unit relative to the motor vehicle is provided according to the historical data.

If at least one temporally preceding relative position is determined, in step b) the direction of movement of the control device transmitting and receiving unit is determined by analyzing the at least one temporally preceding relative position and the current relative position. That is, if there is other data recorded with, for example, the distances between the control device transmitting and receiving unit and the surface of the vehicle body of 1.7, 1.9, and 2.1m, there are three other relative position values, and the movement trajectory up to now of the user carrying the movement control device with him can be finally traced back on the basis of the differences between the three other relative position values. The trajectory is analyzed for determining the direction of movement of the transmitting and receiving unit of the control device.

In a next step c), the predicted relative position of the control unit transmitter receiver unit with respect to the motor vehicle is determined. This is achieved if a position estimation criterion is applied, wherein in addition to the above-mentioned variables the determined direction of movement is taken into account in the case of this application. I.e. the at least one recalculated first distance value, the at least one second distance value, the current relative position and the determined direction of movement are analyzed in order to determine the predicted relative position. Namely, it is assumed that: the user continues to move toward the vehicle in the previously ascertained direction of movement. In the assumed case, starting from the determined current relative position (which was already determined before the recalculation was performed) and taking into account the recalculated first distance value ascertained at the time of the recalculation, it can be predicted at which position the user is expected to be located at the point in time of the recalculation. In this case, the following should be considered: the distance values calculated during the recalculation allow the following conclusions: all possible relative positions lie on a circular trajectory around the corresponding control device transceiver unit whose radius has the value of the recalculated distance value, since all relative positions lying on this circular trajectory each have a recalculated distance from the corresponding transceiver unit. Since the current relative position is known in a fixed manner and the direction of movement is also assumed, the predicted relative position and, as a result, the predicted distance of the control unit from the surface of the vehicle body can be calculated relatively accurately and reliably.

In addition, one embodiment of the invention provides for: by analyzing at least one temporally preceding relative position and the current relative position, a current speed of the mobile control device is determined, which current speed is taken into account in the determination of the desired time period. The current speed of the mobile control device usually corresponds to the speed of movement of the user carrying the mobile control device with him. That is, instead of a predefined standard speed, which is typically 1.5 meters per second, the actual speed at which a user, for example with a vehicle key as a movement control device, moves towards the motor vehicle can be determined from historical data. This is possible because the detection time points are known in each case with regard to the respective relative positions, so that the speed of the user can be reliably determined as a function of the position difference between the temporally preceding relative position and the current relative position and the time period between the respective distance measurements based on these relative positions. In this way, the accuracy of the estimation of the predicted distance is additionally increased, so that it can ultimately be recognized particularly reliably whether the mobile control device is within the distance value range with a high probability after the expected duration.

According to a particularly advantageous embodiment, provision is made for: after performing the recalculation, in which only one recalculated distance value is ascertained, the following steps are performed. First, in step a), a desired travel time length is determined, within which the determined current relative position is moved in the determined direction of movement at a predetermined reference speed to a predetermined target position within a predetermined range of distance values. I.e. to calculate how long a user with a mobile control device will expect to move from a known current relative position into an area surrounding the vehicle in which it is prescribed that the remote control function of the vehicle is activated. Instead of the standard speed, a current speed of the mobile control device determined as described above may be assumed. In the above example (where the relative position is accurately determined from a plurality of distance values in the case of a distance of 1.5 meters from the vehicle), it may be the case that: the user has for example moved towards the vehicle, shortening the distance by 50 cm. Within the framework of the recalculation, however, only one recalculated distance value of more than two meters is ascertained due to the lack of signal exchange with a plurality of transceiver units of the motor vehicle. In this example, a travel time period can now be determined, after which the user can be expected to enter the surroundings of the range of distance values of the motor vehicle. For this reason, it can be assumed that the standard speed is typically 1.5 meters per second. With these assumptions, the user would walk 50 centimeters in a duration of about 330 milliseconds. In the case of a typical time interval of 100 milliseconds between two ascertainment periods for the distance, this distance shortening is achieved after three to four measurement periods. After the expected travel time has elapsed since the time at which the distance value based on the current relative position was detected, the movement control device is moved with a high probability into the surroundings range of the motor vehicle corresponding to the range of distance values, assuming that the determined movement direction is maintained.

Thus, at least after the expected travel time, in step b), the subsequent recalculation of the distance of the transceiver unit from the control device transceiver unit is evaluated for each of the transceiver units for which a predefined handshake with the control device transceiver unit is established. In this case, the travel time length is to be regarded as being in terms of the distance measurement in which the current distance from the vehicle body is ultimately determined. The subsequent recalculation, which is now analyzed, is carried out, for example, 300 ms after the first distance finding, i.e., in this case the third finding period of the distance of the transceiver unit from the transceiver unit of the control unit after the determination of the current relative position and the current distance is analyzed. In addition to this, the remaining ascertainment periods after the determination of the current relative position can likewise be correspondingly evaluated.

In general, it is preferred that for each of the transceivers for which a predefined signal exchange with the transceiver of the control device is established, the distance of the transceiver from the transceiver of the control device is ascertained every 100 milliseconds and is therefore recalculated. However, in connection with the determination of the expected stroke length, special consideration and analysis are made of the results of the recalculations performed after the expected stroke length. In the following, the term "recalculation" relates to a recalculation that is performed after the expected stroke duration.

If only one further recalculated distance value is ascertained in the case of the analysis of the subsequent recalculation, this further recalculated distance value is taken into account in the determination of the predicted relative position in the case of the application of the position estimation criterion. I.e. it is checked whether the user has actually moved into the range of pitch values within 300 ms or whether he may not have done so. If, for example, a distance of four meters is detected as a further recalculated distance value, it is assumed that the mobile control device has moved away from the motor vehicle again. However, if a distance of less than two meters is detected as the other recalculated distance value, it is determined that the movement control apparatus has continued to move toward the motor vehicle. The precondition is that: the two distance values are determined with respect to the same transceiver unit, i.e. the two distance values are the respective first distance values. If this is the case, as already described above, the remote control function of the motor vehicle is activated if the determined predicted distance lies within the predefined distance value range. Even if only one corresponding distance value between the mobile control device and the motor vehicle is always present after the current position data is determined, so that no further distance measurement is possible, the availability of the remote control function can still be present, so that it is activated reliably on the basis of the predicted distance. This is particularly convenient for the user of the motor vehicle, since the user is now generally not standing in front of the motor vehicle without unlocking the motor vehicle by means of the remote control function during his approach to the motor vehicle.

It has been described so far that the expected stroke length is preferably always determined within the framework of the recalculation performed and then the other recalculated distance values are additionally taken into account when determining the predicted distance. The detailed calculation rule for this is registered in the distance estimation criterion. In an alternative embodiment, provision is made for: whenever the determined predicted distance lies outside the predefined distance value range, i.e. at least when the determined predicted distance in the framework of the recalculation indicates that the mobile control device is not within the distance value range, the following steps are carried out: in a first step a), a desired travel time length is determined, within which the determined current relative position is moved in the determined direction of movement at a predetermined reference speed to a predetermined target position within a predetermined range of distance values. This step a) corresponds to step a) described directly above. Next, in step b), the subsequent recalculation of the distance of the transceiver unit from the control device transceiver unit is analyzed for each of the transceiver units at least after the expected travel time length. This step b) corresponds to step b) described directly above.

However, if only one other recalculated distance value is ascertained during the analysis of the subsequent recalculation, then in step c) in contrast to the procedure described directly above, the other predicted relative positions are determined with the application of the position estimation criterion and the other predicted distances are determined with the application of the distance estimation criterion. In this case, the location estimation criterion takes into account the other recalculated distance values. I.e. determining the second predicted distance. If, for example, the recalculated distance value indicates that the mobile control device is not yet within the range of distance values, at least one subsequent recalculation is performed, wherein the results of the two recalculations may be taken into account for determining further predicted distances. In step d), the remote control function of the motor vehicle is activated only if the other determined predicted distance lies within the predetermined distance value range.

That is, if it is ascertained, for example, when performing the recalculation that it should be assumed that the user with the movement control device has not moved into the range of distance values within the time period between the determination of the current relative position and the recalculation, for example because the following recalculation takes place 100 milliseconds after the first distance finding and it cannot be expected that the user moved more than half a meter into the motor vehicle within 100 milliseconds, the above-described steps are additionally performed. I.e. the following recalculation takes place in this case. In this case, the travel time length and therefore the further recalculated distance value are only taken into account whenever a relative position is predicted on the basis of the recalculated first distance value, the at least one second distance value and the current relative position, on the basis of which a distance is predicted on the basis of which it cannot be assumed that the user with the mobile control device has moved within the range of distance values. In this way, a particularly time-saving, energy-saving and simple method is provided, since the above-described steps, which are otherwise always performed, for example, after a recalculation has been performed, with regard to the determined travel time and its consequences, are only performed in these special cases.

Alternatively, it may be provided that: the steps described within the framework of the design are only carried out if the determined predicted distance lies outside a predefined distance value range.

Alternatively or in addition thereto, it can be provided that: if the determined predicted distance and/or the determined other predicted distances lie outside the predefined distance value range, the initially described method according to the invention with steps a) to h) is executed anew, as was already described above initially. This method is not one of the two methods described later, and within the framework of these two methods, the expected stroke length plays an important role. If, in the case of the subsequent recalculation, the determined predicted distance lies outside the predefined distance value range, the respective distance of the control unit transceiver from each of the transceivers, which establishes the predefined signal exchange with the control unit transceiver, is ascertained again until a further current distance between the determined further relative position and the surface of the vehicle body is determined. If the other current distances determined in this way lie outside the predefined distance value range, a recalculation of the distance of the transceiver unit from the transceiver unit of the control device is carried out, a described determination of the predicted relative position is carried out, a determination of the predicted distance of the transceiver unit of the control device from the surface of the vehicle body is carried out, and, if necessary, an activation of a remote control function of the motor vehicle is carried out. That is, whenever the predicted distance and/or other predicted distances do not allow a reliable conclusion about the current position of the mobile control device and/or indicate that the user has unexpectedly not moved into the range of distance values, the method is started from the beginning again until the reinitialization is successful according to the initially described steps a) to c). In the case of successful initialization, the other current relative positions and the other current spacings are determined. Then, the pitch may be re-predicted based on the re-calculation result. This avoids: even if the mobile control device is not arranged within the range of distance values, the remote control function is erroneously activated because the ascertained events for determining the current distance are temporally and/or spatially far apart. That is, the method is guaranteed against inaccuracies in analyzing the predicted spacing and/or other predicted spacings.

In a further embodiment, provision is made for: if the current distance is already within the predefined distance value range, a remote control function of the motor vehicle is activated. That is, if after one of the first method steps, that is to say in the case of the checking step c) of the initially described method, it has been checked that the determined current distance indicates that, for example, the user is already located one meter from the motor vehicle or is still closer to the motor vehicle, this can already be used as a trigger condition for activating the remote control function of the motor vehicle. Then, it is no longer necessary to perform a recalculation and the following further method steps d) to h). In general, whenever a distance value is determined which indicates that the mobile control device is already within the distance value range, further method steps can be omitted and the remote control function of the motor vehicle can be activated immediately. In this case, the remote control function of the motor vehicle is also ensured by means of the mobile control device in the case in which a signal exchange with the transceiver unit of the control device can be established for all or a plurality of transceiver units of the motor vehicle and thus a plurality of distance measurements are available.

In addition, one embodiment of the invention provides for: the ranging criteria include: the current distance is determined by evaluating the determined current relative position, taking into account vehicle data describing the layout of the transceiver unit in the motor vehicle and vehicle stretch data describing the vehicle stretch of the motor vehicle. In order to be able to determine the current distance of the determined current relative position from the surface of the body of the motor vehicle, details are available on the one hand with regard to the positioning of the individual transceiver units of the motor vehicle within the motor vehicle and/or outside the motor vehicle. That is, the vehicle data describe, for example, the exact positions of the transmitting and receiving unit at the respective four corners of the motor vehicle, i.e., the front left, front right, rear left and rear right (with respect to the vehicle longitudinal direction in the direction of travel and the vehicle transverse direction arranged perpendicularly thereto, respectively). The vehicle stretch data in turn contains information about what stretch size the motor vehicle has and/or what shape the body has. From these data, the actual current distance can be calculated from the respective determined relative positions. For this purpose, vehicle data and vehicle stretch data are registered, for example, in a memory device of the motor vehicle, wherein these data can be used when executing the method for activating a remote control function of the motor vehicle by means of the mobile control device. In this way, the actual current distance can be determined with high accuracy.

Another design form provides for: the relative position determination criteria include: if, when the distances of at least two of the first transceiver unit and the second transceiver unit are determined accordingly, the respective distance values from the transceiver unit of the control device are each determined, then exactly one current relative position of the transceiver unit of the control device relative to the motor vehicle is determined by means of trilateration. Thus, in the case of at least three existing detected distance values, a general method for locating the point, here the position of the transmitting and receiving unit of the control device, can be used. In this way, a particularly reliable initialization is provided, within the framework of which at least one unambiguously determined position of the movement control device relative to the motor vehicle is provided, on the basis of which a prediction of the predicted distance can ultimately be achieved.

In addition, another embodiment of the invention provides for: the relative position determination criteria include: if, when the distances of the first transceiver unit and only one second transceiver unit are determined accordingly, the respective distances to the transceiver unit of the control device are determined, in each case, in step a) two possible relative positions of the transceiver unit of the control device relative to the motor vehicle are determined by means of bilateral measurement. If there are exactly two distance values in total, these respective distance values can be assigned two relative positions first. The reason for this is that: if a circle having a radius corresponding to the distance determined by the transceiver unit is drawn around the first transceiver unit and a circle having a radius corresponding to the distance determined by the transceiver unit is drawn around the second transceiver unit, the two circles intersect at two intersection points that are spatially separated from each other. Now, in step b), the rationality criterion is applied to the two determined relative positions. This is used to generate a plausibility value for each of the determined relative positions. The corresponding rationality values represent: the respective calculated relative position is assumed to be how reasonable the actual relative position of the transmitting and receiving unit of the control device is in relation to the motor vehicle. Next, in step c) the relative position with the highest plausibility value is selected as the plausible relative position, and in step d) the current distance is determined taking into account the plausible relative position. That is, even if only two transceiver units can be exchanged, the current position of the mobile control device relative to the motor vehicle can still be determined precisely by means of plausibility criteria. For this purpose, the known least-squares method is first used. In this case, the method described above can be initiated reliably and subsequently continued for only two existing distance values, both for three existing distance values, since in both cases a reliable current distance is finally determined, on the basis of which the following method steps are carried out. The method can therefore be used particularly variously, provided that: at least two handshakes take place, i.e. at least distance values from two transmitting and receiving units are present.

In an advantageous embodiment, provision is furthermore made for: the rationality criterion takes into account vehicle data, vehicle stretch data and the masking of the signal exchange of the motor vehicle. From these data, it can be estimated that: in which relative arrangement of the mobile control device with respect to the motor vehicle, for example due to occlusion of at least one component of the motor vehicle, the signal exchange is completely possible and in which relative arrangement the signal exchange is completely impossible. That is, the rationality criterion is based on: how precisely a motor vehicle is constructed and the location of the respective transceiver unit of the motor vehicle in the motor vehicle. It is also assumed that: the signal exchange is shielded by the motor vehicle. This is the case, for example, when the handshake is based on UWB signals. Since such signal exchanges can be shielded particularly easily and even completely by the vehicle body due to the damping properties of the vehicle body. In this way, it is possible, for example, to determine which of these relative positions is possible by directly comparing the two determined relative positions, since the detection of the relative position on the basis of the signal exchange at least partially through the body and thus through the motor vehicle is not reasonable and can therefore be directly ruled out. The plausibility criterion is therefore based on all characteristic data, from which plausibility values can be determined for the respective relative position on the basis of the design of the motor vehicle. This additionally increases the accuracy of the method.

Another design form provides for: the respective signals of the handshake are transmitted and/or received as ultra wideband technology data, respectively. The used frequency of these signals is in the range of typically 6 to 10 gigahertz with a bandwidth of at least 500 megahertz. However, in the case of suitable semiconductor hardware, other frequency ranges as well as other bandwidths may in principle be used instead of or in addition to this. In the case of using UWB data as the corresponding signal, there are the following advantages: it has not been known to date how such data can be manipulated within the framework of a transit time measurement to make it no longer possible to carry out a reliable check of the positional proximity between the motor vehicle and the control device. In the case of the use of UWB technology for the exchange of signals, the transmission of vehicle-to-X (Car-to-X) data between the mobile control device and the motor vehicle for activating and, if appropriate, for transmitting control commands from the mobile control device to the remote control function can therefore be reliably protected, since in general the proximity of the position between the motor vehicle and the control device can thus be reliably ascertained by means of the transit time measurement.

Provision is also made for: the exchange of signals between each transceiver unit, which establishes a connection to a transceiver unit of a control unit, in a transceiver unit of a motor vehicle and the transceiver unit of the control unit comprises the following steps: first, an interrogation signal is emitted by means of the transceiver unit. The received signal is then received by means of the control device transmit-receive unit. In a further step, a response signal is emitted by means of the control device transceiver unit which receives the interrogation signal, and the emitted response signal is received by means of the transceiver unit. Subsequently, the time interval between the emission of the interrogation signal and the reception of the response signal is calculated as the signal transit time of the handshake. In this case, the respective reaction time and/or the respective processing time of the respective transceiver unit or of the control device transceiver unit are also taken into account. By this, it is clearly shown that: for example, the time-of-flight measurement can be reliably carried out on the basis of the exchange of UWB data between the respective transceiver unit of the motor vehicle and the transceiver unit of the control unit.

Alternatively or in addition thereto, provision is made for: only after the communication connection between the vehicle communication interface of the motor vehicle and the control device communication interface of the mobile control device has been established is a predefined exchange of signals activated between the respective transceiver unit of the motor vehicle and the control device transceiver unit. The communication link is designed as a Low-Energy radio link, in particular as a Bluetooth Low Energy (BLE) link. BLE is a radio technology by which devices within an ambient environment of about ten meters around a corresponding communication interface can be networked. BLE has significantly lower power consumption and therefore lower cost than traditional bluetooth, however, communication range is limited. BLE is often alternatively referred to as Bluetooth Smart. By selecting the BLE technology for the communication link, it is possible, in particular in the case of the previously described use of UWB data for the exchange of signals between the respective transceiver unit of the motor vehicle and the transceiver unit of the control device, to: for example, a further data exchange between the mobile control device and the motor vehicle via the communication connection can be designed to be significantly more energy-saving than a signal exchange for checking the proximity of a location. Since, for example, in order to establish a communication link between the motor vehicle and the control device: issuing a corresponding acceptance contact signal based on the establishment contact signals continuously issued by the corresponding other devices, may be achieved by using BLE techniques: whenever there is no motor vehicle in the vicinity of the mobile control device at all, the respective transceiver unit of the motor vehicle and/or the control device transceiver unit does not emit an interrogation signal which results in a higher energy consumption, but only emits a BLE establishment contact signal which is significantly less energy-consuming and therefore more energy-efficient.

Within the framework of the communication connection, the interrogation signal is first emitted, for example, by means of a control device communication interface or a vehicle communication interface. Correspondingly, the other communication interface receives the request signal and, if necessary, checks whether a response signal is provided for the received request signal. If, for example, the vehicle communication interface receives an interrogation signal from the control device communication interface, it is checked in the motor vehicle whether a response signal is provided for the received interrogation signal. The response signal can be provided, for example, in a memory unit of the motor vehicle. If a response signal is provided, the response signal is emitted by means of the vehicle communication interface. This can likewise be achieved, if necessary, by means of a control device communication interface. The emitted response signal is then received by means of the control device communication interface or the vehicle communication interface. Subsequently, a reception confirmation signal for the received response signal is emitted by means of the communication interface which received the response signal. The reception confirmation signal is then received by means of a corresponding further communication interface, that is to say in the example mentioned here, for example by means of a vehicle communication interface. Only when this handshake has occurred is a predefined handshake activated between the respective transceiver unit of the motor vehicle and the transceiver unit of the control unit activated. Thereby ensuring that: for example, only for a vehicle key that is permissible for a motor vehicle as a mobile control device is it possible to completely exchange signals via the corresponding transceiver or control device transceiver. In this way, by using a more energy efficient BLE technique, an energy efficient pre-initialization of the true handshake based on the UBW technique is provided.

The system according to the invention for controlling a remote control function of a motor vehicle by means of a mobile control device is based on: the system includes the motor vehicle and the motion control device. The motor vehicle has a first transceiver unit and at least one second transceiver unit arranged spatially separated from the first transceiver unit. The control device has a control device transmitting and receiving unit. Each of the transmitting and receiving units of the motor vehicle, which transmit and receive the predetermined signal exchange with the transmitting and receiving unit of the control device, is designed to: the distance between the transceiver and the transceiver of the control device is ascertained periodically and repeatedly by evaluating the signal transit time of a predefined signal exchange between the transceiver and the transceiver of the control device. Furthermore, a control device of a motor vehicle, for example a motor vehicle, is configured to: the current relative position of the control unit transmitter-receiver unit with respect to the motor vehicle and the current distance between the determined current relative position and the surface of the body of the motor vehicle are determined. This is achieved if relative position determination criteria are applied to the respective distances ascertained and/or if distance measurement criteria are applied. The motor vehicle is also designed to check whether the determined current distance is within a predefined distance value range. The system is configured to: only if the determined current distance lies outside the predefined distance value range, however, a recalculation of the distance of the transceiver unit from the control unit transceiver unit is carried out for each of the transceiver units for which a predefined exchange of signals with the control unit transceiver unit is established. The system is further configured to: if only one recalculated distance value is ascertained when the recalculation is carried out, which distance value is the recalculated first distance value, the predicted relative position of the control device transceiver unit with respect to the motor vehicle is determined if the position estimation criterion is applied to the recalculated first distance value, the at least one second distance value and the current relative position, and the predicted distance of the control device transceiver unit from the surface of the vehicle body is determined if the distance measurement criterion is applied to the predicted relative position. The system is further configured to: the remote control function of the motor vehicle is activated only if the determined predicted distance lies within a predetermined distance value range. The advantageous embodiments and advantages thereof described in connection with the method according to the invention correspondingly apply as far as they can be applied to the system according to the invention. For this reason, a corresponding design of the system according to the invention is not described again here.

In one embodiment, the system can also be designed such that after activation of a remote control function of the motor vehicle, control commands are transmitted from the mobile control device to the motor vehicle. The control command can be implemented, for example, by a communication link existing in addition to the signal exchange between the vehicle communication interface and the control unit communication interface.

The invention also relates to a motor vehicle having a first transceiver unit and at least one second transceiver unit arranged spatially separated from the first transceiver unit. The motor vehicle is constructed as a component of the system described above. The invention also relates to the design of a motor vehicle according to the invention, which has the features already described in connection with the design of the method according to the invention. For this reason, a corresponding embodiment of the motor vehicle according to the invention is not described again here.

The invention also relates to a control device for a motor vehicle. The control device has a processing device which is designed to carry out steps which can be carried out by the motor vehicle according to the embodiment of the method of the invention. For this purpose, the processing device can have at least one microprocessor and/or at least one microcontroller and/or at least one FPGA (Field Programmable Gate Array) and/or at least one DSP (Digital Signal Processor). The processing device can also have a program code which is designed to carry out the steps of the method according to the invention, which steps can be carried out by the motor vehicle, when the steps are carried out by the processing device. The program code may be stored in a data memory of the processing device.

The invention also comprises a combination of features of the described design forms.

Drawings

An embodiment of the present invention is described below. Therefore, the method comprises the following steps:

FIG. 1 shows a schematic diagram of a user approaching a motor vehicle, where three distance values exist for initialization;

FIG. 2 shows a schematic diagram of a user approaching a motor vehicle, where only two distance values exist for initialization;

fig. 3 shows a signal flow diagram of a method for activating a remote control function of a motor vehicle by means of a mobile control device in a schematic representation.

Detailed Description

The example set forth below is a preferred embodiment of the invention. In this exemplary embodiment, the described components of the exemplary embodiments are in each case individual features of the invention which are to be considered independently of one another, which in each case also extend the invention independently of one another and can thereby also be considered as components of the invention, alone or in other combinations than those shown. Furthermore, the described embodiments can also be supplemented by other of the already described features of the invention.

In these figures, functionally identical elements are provided with the same reference numerals.

In fig. 1, a motor vehicle 10 is depicted: the motor vehicle 10 comprises a remote control function 12, which is designed as a door lock system 12. The door lock system 12 is configured to unlock or lock various door locks of the motor vehicle 10. The motor vehicle 10 also has a plurality of transceiver units 14, 16, specifically a first transceiver unit 14, which is arranged in the region of the bumper at the left front corner of the motor vehicle 10, and three second transceiver units 16, which are arranged on the motor vehicle 10 at the left and right, right rear and right front of the motor vehicle 10, which are arranged at a spatial distance from the first transceiver unit 14. In this case, the designations left, right, front and rear relate to a longitudinal direction of the vehicle pointing in the forward direction and a transverse direction of the vehicle arranged perpendicularly thereto. The individual transceiver units 14, 16 are arranged in the region of the bumper of the motor vehicle 10. Further second transceiver units 16 may be arranged in the rear region, the front region and/or in the respective side regions of the motor vehicle 10. The motor vehicle 10 also has a control device 18, a memory device 20, and a vehicle communication interface 22. The motor vehicle 10 is bounded towards the outside by a body 24, which is oriented with a surface 26 facing the surroundings of the motor vehicle 10.

The user 30 is approaching the motor vehicle 10, wherein four different positions of the user 30 on its path to the motor vehicle 10 are depicted in fig. 1, in which the user 30 is located in sequence over time. In this case, the user moves from a position farthest from the vehicle 10 to a position closest to the vehicle 10. In this approach to the motor vehicle 10, a co-worker 32 accompanies the user 30, which co-worker likewise moves along a co-worker path of movement 33 toward the motor vehicle 10. During their approach to the motor vehicle 10, the user 30 and the accompanying person 32 pass through three different ambient regions of the motor vehicle. From the motor vehicle 10, a distance value range 46 is used as a first ambient region, which extends from the surface 26 of the vehicle body 24 up to a distance value range limit 47. The spacing value range limit 47 is typically one meter from the surface 26. Within the range of distance values 46, the remote control function 12, that is to say the door locking system 12, is activated. Immediately adjacent to the range of spacing values 46 is a tolerance range 48, which is bounded by a tolerance range limit 49. The tolerance range limit 49 is typically spaced two meters from the surface 26. Within the tolerance range limit 49, activation of the remote control function 12, that is to say the door lock system 12, is permissible per se, but is not explicitly desired. Also extending around the motor vehicle 10 is a range 50 of the vehicle communication interface 22, the range limit 51 of which is also depicted. The range limit 51 is typically ten meters from the surface 26.

The user 30 carries with him a mobile control device 40, which is designed here as a mobile terminal in the form of a smartphone. Alternatively, the movement control device 40 may be a vehicle key for the motor vehicle 10. The movement control device 40 includes a control device transmitting-receiving unit 42 and a control device communication interface 44. Generally, the system 11 is provided by means of a motor vehicle 10 and a movement control device 40.

If the user 30 is approaching the motor vehicle 10, a communication connection 52 is established between the control device communication interface 44 and the vehicle communication interface 22 once the user 30 is within the range 50. The communication link 52 is designed as a low-energy radio link, that is to say as a bluetooth low-energy link, and establishes a first contact between the mobile control device 40 and the motor vehicle 10. Within the framework of the establishment of this communication connection 52, for example, digital keys can be exchanged and/or manipulated, so that the authentication of any subsequent exchange between the mobile control device 40 and the motor vehicle 10 is checked as follows: only the user 30 with the matching movement control device 40 is allowed to enter the motor vehicle 10.

After the communication connection 52 has been established, the handshake 54 is established for each of the transceiver units 14, 16 of the motor vehicle 10 for which no obstacles prevent the handshake 54. The handshake 54 is based on signals which are here sent out and/or received as Ultra-Wideband (UWB) technology data (UWB stands for Ultra-Wideband). Alternatively, for the time-of-flight measurement or the quasi time-of-flight measurement based on the phase difference measurement, other radio frequency bands can be used, such as a wireless local area network at 60 gigahertz or a radio frequency band at 2.4 gigahertz. By means of the signal exchange 54, distance measurements can be carried out, more precisely based on time-of-flight measurements. That is, the handshake 54 ultimately allows time of flight measurements. However, as soon as a person, such as a fellow passenger 32, a part of the body 24 or another object, is located between the respective transceiver unit 14, 16 of the motor vehicle 10 and the control device transceiver unit 42, the signal exchange 54 is not possible and a shielding of the mobile control device 40 from the respective transceiver unit 14, 16 takes place. Thus, in fig. 1, a corresponding signal exchange 54 between the three transmit/receive units 14, 16 of the motor vehicle, more precisely two of the first transmit/receive unit 14 and the second transmit/receive unit 16, and the control unit transmit/receive unit 42 takes place first. However, at a position which is then occupied by the user 30 over time, shielding of the user 30 with respect to the second transmitting-receiving unit 16 occurs due to the accompanying person moving trajectory 33 of the accompanying person 32.

For each of the transceivers 14, 16 of the motor vehicle for which a predefined handshake 54 with the control device transceiver 42 is established, the distance 56 of the transceiver 14, 16 from the control device transceiver 42 is then periodically repeatedly ascertained in a step S1. This is achieved by correspondingly evaluating the respective duration of the respective predefined handshake 54, i.e. by means of a transit time measurement. Three distances 56 are ascertained here. More precisely a first distance 56 and two second distances 56'. The first distance 56, specifically the first distance value, describes the distance 56 of the first transceiver unit 14 from the control unit transceiver unit 42, while the second distance 56', that is to say the second distance value 56', describes the distance 56' of the respective second transceiver unit 16 from the control unit transceiver unit 42.

In step S2, if at least two distance values 56, 56 'are ascertained for the respective distance 56, 56', the current relative position 58 of the control unit transceiver unit 42 relative to the motor vehicle 10 is determined. This is achieved if so-called relative position determination criteria are applied to the ascertained distances 56. The relative position determination criteria include: the current distance 60 is determined by evaluating the determined current relative position 58, taking into account vehicle data describing the layout of the transceiver units 14, 16 of the motor vehicle 10 and vehicle stretch data describing the vehicle stretch of the motor vehicle 10. In addition, a current spacing 60 between the determined current relative position 58 and the surface 26 of the body 24 is determined, with the ranging criteria applied. In this case, it is ascertained that the motor vehicle 10 is currently about 2.5 meters from the surface 26 of the body 24. In a next step S3, it is checked whether the determined current distance 60 is within the predefined distance value range 46. Here, this is obviously not the case. For this reason, the door lock system 12 of the motor vehicle 10 is not activated as long as the user 30 is in the current relative position 58.

Thus, in step S4, a recalculation of the distance 56 of the transceiver 14, 16 from the control device transceiver 42 is now carried out for the transceiver 14, 16 for which it is possible. However, this step S4 is only performed if the determined current distance 60 is outside the predefined distance value range 46.

This recalculation may be performed in the next acquisition period for acquiring distance 56, which is typically repeated every 100 milliseconds. Here, the recalculation is performed when the user 30 is already within the tolerance range 48. The following now occurs: when a recalculation is performed, only the recalculated distance 62 in the form of the recalculated distance value, which is the recalculated first distance value, is ascertained. If, when the recalculation is carried out, only one recalculated distance value is ascertained which describes the recalculated distance 62, in step S5, the predicted relative position 68 of the control device transceiver unit 42 relative to the motor vehicle 10 is determined, with the position estimation criterion being applied to the recalculated first distance value, the two second distance values 56 and the current relative position 68.

Next, in step S6, the control device determines the predicted distance 70 of the transceiver unit 42 from the surface 26 of the body 24 of the motor vehicle 10, with the ranging criterion being applied to the predicted relative position 68. Only if the determined predicted distance lies within the predefined distance value range 46 is the remote control function 12 of the motor vehicle 10 activated in step S7.

Furthermore, if only one recalculated distance 62 is ascertained when performing the recalculation, it can be checked: if at least one temporally preceding ascertainment of the distance 56 of the transceiver units 14, 16 from the control unit transceiver unit 42 is made, it is determined whether a corresponding temporally preceding relative position 64 of the control unit transceiver unit 42 relative to the motor vehicle 10 has already been established. This is assumed to be the case, i.e. at least one temporally preceding relative position 64 is determined. Thus, by analyzing at least one temporally preceding relative position 64 and the current relative position 58, the direction of movement 66 of the control device transceiver unit 42 can be determined. In fig. 1, the determined movement direction 66 is depicted in the form of a line with an arrow symbol, which extends as far as a final target position 67 within the range of the door of the motor vehicle 10.

If only one recalculated distance value is ascertained when the recalculation is carried out, it is checked whether the determined current spacing 60 lies within the predefined tolerance range 48 (not illustrated in fig. 1). If this is the case, the expected length of time to move from the determined current relative position 58 to the tolerance range limit 48 at the predefined standard speed is determined. At most until the expiration of the expected time period, for each of the transceivers 14, 16 for which a predefined handshake 54 with the control device transceiver 42 is established, a corresponding subsequent recalculation of the distance 56 of the transceivers 14, 16 from the control device transceiver 42 is carried out. Subsequently, the further recalculated distance values determined in the case of the respective subsequent recalculation are analyzed for the corresponding determination of the recalculated distance or of the further predicted distance 70, which distance values describe the respective further recalculated distance 72. As soon as one of the distance values is within the distance value range 46, the remote control function 12 of the motor vehicle 10 is activated.

Next, a predicted distance 70 of the control device transceiver unit 42 from the surface 26 of the body 24 can be determined, taking into account the determined direction of movement 66. I.e. in this case it is assumed that: the user 30 continues to move toward the motor vehicle 10 in accordance with the previously ascertained direction of movement 66. By means of this assumption it can be predicted where the user 30 with the movement control device 40 is expected to be at the recalculated point in time. In this case, the following should be considered: the distance values recalculated during the recalculation allow the following conclusions: all possible positions are on a circular trajectory around the radius of the first transceiver unit 14 with the value of the recalculated distance value 62, since all possible relative positions located at this circular trajectory have the recalculated distance 62 from the control device transceiver unit 42, respectively. Thus, by applying the position estimation criterion, the predicted relative position 68 of the control device transceiver unit 42 with respect to the first transceiver unit 14 is first determined for more accurately determining the predicted separation 70.

It is also possible to determine a desired travel time within which the determined position of the movement control device 40, i.e. the determined current relative position 58, is moved in the determined direction of movement 66 at a predetermined standard speed to a predetermined target position 69 within the predetermined range of distance values 46. A speed of 1.5 meters per second is generally assumed as the standard speed of the user 30. Then, it is possible to realize: at least after the expected travel time, a subsequent recalculation of the distance 56 of the transceivers 14, 16 from the control device transceiver 42 is carried out for each of the transceivers 14, 16, which can establish a signal exchange 54 with the control device transceiver 42. In general, the recalculation is performed every 100 milliseconds.

If only one other recalculated distance value, that is to say only one other recalculated distance 72, is ascertained when the subsequent recalculation is performed, a more accurate determination of the predicted distance 70 can be provided as described above. This is achieved by: this other recalculated distance value is considered when applying the position estimation criterion to determine the predicted relative position 68. That is, the determined predicted distance 70 may then ultimately be determined based on the recalculated distance value, the other recalculated distance values, the determined current distance 60, and the determined direction of movement 66.

Here, the current relative position 58 is at a distance of about 2.5 meters from the body 24, i.e. at a current distance 60 of about two meters. Then, within the tolerance range 48, a new distance measurement is performed, wherein however only the recalculated distance value is determined and not the recalculated pitch value. At this location, the determination based on the predicted separation 70 may indicate: the user 30 with the movement control device 40 is currently still outside the range of separation values 46. Thus, activation of the door lock system 12 does not occur first. According to step S7, the remote control function 12 is activated only if the determined predicted distance 70 is within the predefined distance value range 46.

In such a case, where the door lock system 12 is not activated, the expected stroke length is determined. However, if only one further recalculated distance value is ascertained when the subsequent recalculation is carried out, then, in contrast to the previously described procedure, a further predicted distance 74 of the control device transceiver unit 42 from the surface 26 of the body 24 is now determined by applying the position estimation criterion and the subsequent distance estimation criterion. I.e. a second predicted distance is determined as the further predicted distance 74. If, for example, the recalculated distance value already clearly indicates that the movement control device 40 is still not within the distance value range 46, at least one of the described subsequent recalculations is carried out, the results of the two recalculations being taken into account for determining the further predicted distance 74. The remote control function 12 of the motor vehicle 10 is activated, i.e. step S7 is executed, only if the determined further predicted distance 74 is within the predefined distance value range 46.

If, in the case of one of these recalculations, a value outside the distance value range 46 is determined as the predicted distance 70 and/or as the further predicted distance 74, the method steps described above are repeated from step S1. I.e., awaits a new successful initialization in which the current relative position 58 is determined to be updated. Starting from this determined current relative position 58, the door locking system 12 can be finally activated even with only one recalculated distance value.

By evaluating the relative position 64 that precedes in time and the current relative position 58, it is also possible to determine the current speed of the control device transceiver unit 42, that is to say of the user 30 with the mobile control device 40, which is taken into account when determining the desired time.

If the current distance 60 is already within the distance value range 46, the door locking system 12 is directly activated.

In the case of three distances 56, the current relative position 58 is determined by means of trilateration. In fig. 2, a situation is depicted in which for the first time there are only two distance measurements and thus only two distances 56. For this purpose, a corresponding handshake 54 between the control device transceiver unit 42 and one of the first transceiver unit 14 or the second transceiver unit 16 is depicted in fig. 2. In the following, a first distance 56 between the first transceiver unit 14 and the control device transceiver unit 42 and a second distance 56' between the second transceiver unit 16 and the control device transceiver unit 42 are distinguished. Since only two distances 56, 56 'are present, it is not possible to unambiguously determine the current position of the control unit transceiver unit 42 relative to the motor vehicle 10, i.e. the determination of the current relative position 58 is more expensive than in the case of three distances 56, 56'. Now using bilateral measurement. To clarify this, a first circle 81 with a radius according to the first distance 56 around the first transceiver unit 14 and a second circle 83 with a radius according to the second distance 56' around the second transceiver unit 16 are depicted in fig. 2. The two circles 81, 83 intersect at a total of two locations in the surroundings of the motor vehicle 10. This results in: there are two possible relative positions, namely the current relative position 58 and an alternative relative position 84.

Thus, the following subsequent method steps are carried out. First, in step S15, two possible

relative positions

58, 84 of the control unit transceiver unit 42 relative to the motor vehicle 10 are determined by means of the least squares method. In a next step S16, a rationality criterion is applied to the determined

relative positions

58, 84 for generating a rationality value for each of the determined

relative positions

58, 84. The corresponding rationality values represent: the respective calculated

relative position

58, 84 is assumed to be how reasonable the current relative position 58 is. In step S17, the

relative position

58, 84 with the highest rationality is selected as the reasonable relative position, wherein the reasonable relative position is the current relative position 58. In step S18, the current distance 60 is determined taking into account the plausible relative position and thus the current relative position 58.

The reason why the alternative relative position 84 is not reasonable, that is to say has only a slight plausibility value, is that: with the positioning of the movement control device 40 at the alternative relative position 84, the signal exchange 54 between the second transceiver unit 16 and the control device transceiver unit 42 must take place through the motor vehicle 10. However, this is not possible due to the shielding properties of the vehicle body 24. Thus, the user 30 with the movement control device 40 must be at the current relative position 58 rather than at the alternative relative position 84. Thus, the rationality criteria take into account vehicle data, vehicle stretch data, and the shielding of the signal exchange 54 by the vehicle 10.

In fig. 3, the individual method steps of the described method for activating a remote control function 12, here a door lock system 12 of a motor vehicle 10, by means of a mobile control device 40 are depicted. First, in step S1, distance 56 is periodically repeatedly ascertained. In this regard, in a decision step E1 it is ascertained or checked whether the distances 56 to the plurality of transceivers 14, 16 have been determined. If this is not the case, step S1 is re-performed. However, if there are a plurality of distance values 56, it is checked in a second decision step E2 whether there are two or three distances 56. If there are three distances 56, the current relative position 58 and the current distance 60 are determined in step S2 by means of trilateration. However, if only two distances 56, that is to say distances 56, 56', are present, steps S15 to S18 follow, that is to say the distance measurement for determining the current relative position 58 is checked for plausibility and the current distance 60 is determined, taking into account this plausible relative position as the current relative position 58. This has been described in connection with fig. 2.

After step S2 or S18 (depending on the result of the decision step E2), a transition is made to step S3, which step S3 is precisely the same decision step. In step S3, it is checked whether the determined current spacing 60 is within the spacing value range 46. If an affirmative answer is directly made, a transition is made directly to step S8, that is to say the remote control function 12 is activated. In step S19, the vehicle function 12 is then controlled in accordance with a control signal of the movement control device 40, which is transmitted to the motor vehicle 10, for example, via the communication link 52.

However, if in step S3 it is ascertained that the current distance 60 lies outside the predefined distance value range 46, in step S4 a recalculation of the distance 56 is carried out, within the framework of which recalculation at least one recalculated distance value is determined. After the recalculation has been carried out, it is checked in a decision step E3 whether only one recalculated distance value was ascertained in the case of this recalculation. If this is not the case, the method returns to decision step E2. However, if only one recalculated distance value is determined, in step S5 the predicted relative position 68 is determined with the position estimation criterion applied to the recalculated first distance value, the at least one second distance value and the current relative position 68. Next, in step S6, the predicted distance 70 is determined with the ranging criterion applied to the predicted relative position.

Following the step S6 is a renewed decision step E4, that is to say a check is made as to whether the predicted distance 70 can conclude that the user 30 is within the distance value range 46. If an affirmative decision is made, a transition is made to step S7. The judgment step E4 is substantially very similar to the step S3. If the predicted separation 70 is not within the separation value range 46, it may be reused in the form of a subsequent recalculation in step S1 or in step S4.

The individual method steps described can be carried out by the control device 18. The data, standards and/or specifications required for this can be registered in the memory device 20.

In general, whenever the predicted spacing 70 or other predicted spacing 74 is not reasonable, an interruption of the current part of the method occurs and the process returns again to step S1, that is to say the initialization is re-executed. Such irrationality may occur, for example, due to too few distance measurements, too large a temporal or spatial separation of the distance measurements to the current relative position 58, and/or such unreasonable values measured after that period of time.

In general, this example shows: how by the invention a method is provided for improving the accuracy, robustness and usability of the positioning of a car key in a passive access system using time-of-flight measurements. Here, the passive access system is a remote control function 12 of the motor vehicle 10. Alternatively, it can be provided that: the described method is used to control the remote opening or closing of the roof, the locking function of the motor vehicle 10 and/or the ambient lighting of the motor vehicle 10. The precondition is that: the range of pitch values 46 is selected accordingly. When the motor vehicle 10 is locked, it can be situated, as seen from the body 24, in a distance value range 46 of between 1.5 and 2 meters.

The preconditions for positioning, that is to say determining, the current distance 60 of the vehicle body 24 are: there are at least two distances 56 from the different transceiver units 14, 16 of the motor vehicle 10. In the case of position determination by means of the least squares method, two possible

relative positions

58, 84 are obtained, that is to say the current relative position 58 and an alternative relative position 84. Which of these positions is the vehicle key, that is to say the actual position of the movement control device 40, is checked for plausibility as an assumption that the damping behavior of the vehicle body 24 is included, that is to say, in method steps S15 to S17, this is determined taking into account plausibility criteria.

In the following process, the recalculation can be carried out as a function of the periodically arriving measured values, even if only one recalculated distance value from one of the transceiver units 14, 16 of the motor vehicle 10 is present. The recalculated distance value 62 can be checked for plausibility on the basis of a history of these measured values, i.e. taking into account the temporally preceding relative position 64 and the movement direction 66 determined therefrom. Furthermore, tolerance calculations for possible position changes of the user 30 with the movement control device 40 can be taken into account in dependence on the assumed movement speed, that is to say for example in dependence on a standard speed of 1.5 meters per second.

If a time-out (Timeout) time, that is to say an expected duration, is determined, a change back to the beginning of the method takes place, that is to say a reinitialization of the method from step S1 takes place, if no further recalculated distances 72 are determined on the next recalculation and/or no recalculated distances 62 are determined on the recalculation (which can conclude that the mobile control device 40 is within the range of distance values 46). This occurs even if no new distance value is detected within the determined time period.

List of reference numerals

10 Motor vehicle

11 system

12 door lock system/remote control function

14 first transmitting and receiving unit

16 second transmitting and receiving unit

18 control device

20 storage device

22 vehicle communication interface

24 vehicle body

26 surface of

30 users

32 accompanying person

33 accompanying person moving track

40 movement control device

42 control device transmit receive unit

44 control device communication interface

46 range of pitch values

47 pitch value range limit

48 tolerance range

49 limit of tolerance range

50 distance of action

51 distance limit of action

52 communication connection

54 handshake

56 distance/first distance

56' second distance

58 current relative position

60 current pitch

62 recalculated distance

64 relative position preceding in time

66 direction of movement

67 final target position

68 predicted relative position

69 target position

70 predicted pitch

72 other recalculated distances

74 other predicted intervals

81 first circle

83 second circle

84 alternative relative positions

S1-S7 steps

S15-S19 steps

E1-E4 judgment steps

Claims

1. A method for activating a remote control function (12) of a motor vehicle (10) by means of a mobile control device (40), wherein the motor vehicle (10) has a first transceiver unit (14) and at least one second transceiver unit (16) which is arranged spatially spaced apart from the first transceiver unit (14), and the mobile control device (40) has a control device transceiver unit (42), comprising the following steps:

a) for each of the transmitting and receiving units (14, 16) of the motor vehicle (10) for which a predefined signal exchange (54) with the control device transmitting and receiving unit (42) is established, periodically and repeatedly ascertaining a distance value (S1) that describes a distance (56) of the transmitting and receiving unit (14, 16) from the control device transmitting and receiving unit (42) by evaluating a signal transit time of the predefined signal exchange (54);

b) if at least two distance values are detected, of which a first distance value describes a distance (56) of a first transceiver unit (14) from the control unit transceiver unit (42) and at least one second distance value describes a distance (56') of at least one second transceiver unit (16) from the control unit transceiver unit (42), a current relative position (58) of the control unit transceiver unit (42) relative to the motor vehicle (10) is determined if a relative position determination criterion is applied to the detected distance values, and a current distance (60) between the determined current relative position (58) and a surface (26) of a body (24) of the motor vehicle (10) is determined if a distance measurement criterion is applied (S2);

c) checking (S3) whether the determined current distance (60) is within a predefined distance value range (46);

d) if the determined current distance (60) is outside the predefined distance value range (46), a recalculation (S4) of the distance (56) of the transceiver unit (14, 16) from the control unit transceiver unit (42) is carried out for each of the transceiver units (14, 16) for which a predefined signal exchange (54) with the control unit transceiver unit (42) is established;

e) if, if a recalculation is carried out, only one recalculated distance value is ascertained which describes the recalculated distance (62), which is the recalculated first distance value, the predicted relative position (68) of the control unit transceiver unit (42) relative to the motor vehicle (10) is determined if a position estimation criterion is applied to the recalculated first distance value, the at least one second distance value and the current relative position (68), wherein a distance change of the first distance value is taken into account, which is derived from the difference between the first distance value and the recalculated first distance value (S5);

f) determining a predicted distance (70) of the control device transceiver unit (42) from a surface (26) of a body (24) of the motor vehicle (10) if the distance measurement criterion is applied to the predicted relative position (68) (S6);

g) activating a remote control function (12) of the motor vehicle (10) only if the determined predicted distance (70) is within the predefined distance value range (46) (S7).

2. Method according to the preceding claim, wherein if only one recalculated distance value is ascertained when performing the recalculation, the following steps are performed:

a) checking whether the determined current distance (60) lies within a predetermined tolerance range (48) that includes a greater range around the vehicle body (24) than the distance value range (46);

b) determining an expected length of time for moving from the determined current relative position (58) at a predetermined standard speed to a tolerance range limit (49) of the tolerance range (48) if the determined current distance (60) lies within the predetermined tolerance range (48);

c) at most until the expiration of the expected duration, for each of the transceivers (14, 16) for which a predefined signal exchange (54) with the control device transceiver (42) is established, a respective subsequent recalculation of the distance (56) of the transceiver (14, 16) from the control device transceiver (42) is carried out;

d) analyzing the further recalculated distance values determined in the case of the respective subsequent recalculation describing the respective further recalculated distances (72) for determining a recalculated or further predicted distance (70) accordingly;

e) activating a remote control function (12) of the motor vehicle (10) as soon as the determined recalculated distance or the determined other predicted distance (74) is within the distance value range (46).

3. The method according to the preceding claim, wherein the method according to claims 1 a) to g) is re-executed if it is not determined that the recalculated or other predicted spacing (74) is within the range of spacing values (46) at the expiration of the expected duration.

4. Method according to one of the preceding claims, wherein if only one recalculated distance value is ascertained when performing the recalculation, the following steps are performed:

a) and (4) checking: in the event of at least one temporally preceding detection of a distance (56) of the transceiver (14, 16) from the control unit transceiver (42), whether a corresponding temporally preceding relative position (64) of the control unit transceiver (42) relative to the motor vehicle (10) has already been determined;

b) determining a direction of movement (66) of the control device transmit receive unit (42) by analyzing the at least one temporally previous relative position (64) and the current relative position (58) if at least one temporally previous relative position (64) is determined;

c) when determining the predicted relative position (68) applying the position estimation criterion, the determined direction of movement (66) is taken into account.

5. Method according to the preceding claim, wherein the current speed of the control device transceiver unit (42) is determined by analyzing the at least one temporally preceding relative position (64) and the current relative position (58), said current speed being taken into account in determining the expected duration.

6. The method according to any one of claims 4 or 5, wherein after performing the recalculation in which only one recalculated distance value is ascertained, the following steps are always performed:

a) determining a desired travel time period within which the determined current relative position (58) is moved in the determined direction of movement (66) at a predetermined reference speed to a predetermined target position (69) within the predetermined range of distance values (56);

b) at least after the expected travel time, for each of the transceiver units (14, 16) for which a predefined signal exchange (54) with the control device transceiver unit (42) is established, a subsequent recalculation of the distance (56) of the transceiver unit (14, 16) from the control device transceiver unit (42) is evaluated;

c) if only one other recalculated distance value is ascertained in the case of the analysis of the subsequent recalculation, said other recalculated distance value is taken into account in the determination of the predicted relative position (68).

7. Method according to one of claims 1 to 5, wherein the following steps are carried out whenever the determined predicted distance (70) lies outside the predefined distance value range (46):

a) determining a desired travel time period within which the determined relative position (58) is moved in the determined direction of movement (66) at a predetermined reference speed to a predetermined target position (69) within the predetermined range of distance values (46);

c) if only one other recalculated distance value is ascertained in the event of the analysis of the subsequent recalculation, determining other predicted relative positions in the event of the application of position estimation criteria and further predicted distances in the event of the application of distance estimation criteria (74), wherein the position estimation criteria are applied taking into account the other recalculated distance values;

d) activating a remote control function (12) of the motor vehicle (10) only if the determined further predicted distance (74) is within the predefined distance value range (46).

8. Method according to one of the preceding claims, wherein a remote control function (12) of the motor vehicle (10) is activated if the current distance (60) is already within the predefined distance value range (46).

9. The method of any preceding claim, wherein the ranging criteria comprises: the current distance (60) is determined by evaluating the determined current relative position (58) while taking into account vehicle data describing the layout of the transceiver units (14, 16) in the motor vehicle (10) and vehicle stretch data describing the vehicle stretch of the motor vehicle (10).

10. The method of any preceding claim, wherein the relative position determination criteria comprise: if, when the distances (56) to at least two of the first transceiver unit (14) and the second transceiver unit (16) are respectively ascertained, the respective distance values (56) to the control unit transceiver unit (42) are respectively ascertained, exactly one current relative position (58) of the control unit transceiver unit (42) relative to the motor vehicle (10) is determined by means of trilateration.

11. The method of any preceding claim, wherein the relative position determination criteria comprise: if, when the distances (56) from the first transceiver (14) and only one second transceiver (16) are determined in each case, a respective distance value (56) from the control device transceiver (42) is determined, then:

a) determining two possible relative positions (58, 84) of the control device transceiver unit (42) relative to the motor vehicle (10) by means of bilateral measurement (S15);

b) applying a rationality criterion to the determined relative positions (58, 84) for generating a rationality value for each of the determined relative positions (58, 84), wherein a respective rationality value represents: assuming the respective calculated relative position (58, 84) as how reasonable the control device transmits the current relative position (58) of the receiving unit (42) to the motor vehicle (10) (S16);

c) selecting the relative position (58, 84) with the highest rationality value as a rational relative position (S17); and also

d) Determining the current spacing (60) taking into account the reasonable relative position (S18).

12. Method according to the preceding claim, wherein said rationality criterion takes into account said vehicle data, said vehicle stretch data and the shielding of said signal exchange (54) by said motor vehicle (10).

13. The method according to any of the preceding claims, wherein respective signals of the handshake (54) are emitted and/or received, respectively, as ultra wideband technology data.

14. A system (11) for activating a remote control function (12) of a motor vehicle (10) by means of a mobile control device (40), wherein the system (11) has the motor vehicle (10) with a first transceiver unit (14) and at least one second transceiver unit (16) arranged spatially separated from the first transceiver unit (14), and the mobile control device (40) with a control device transceiver unit (42), and is designed to carry out the method according to one of the preceding claims.

15. A motor vehicle (10) having a first transceiver unit (14) and at least one second transceiver unit (16) arranged spatially separated from the first transceiver unit (14), wherein the motor vehicle (10) is designed to be comprised by a system (11) according to the preceding claim.