DE102019215535A1 - Vehicle, comprising a radio device for a radio-based vehicle unlocking system, radio device for a vehicle and method for operating a vehicle - Google Patents

Abstract

The invention relates to a vehicle (1) comprising a radio device (2) for a radio-based vehicle unlocking system. The radio device (2) has at least two transceiver units (4, 5) which are each set up to receive radio signals (8). The radio device (29) is designed to use a predetermined distance determination method to determine a respective distance (r1, r2) from an original location (P) of a radio signal (8) to the respective transceiver units (4, 5), and from the at least two distances (r1, r2) to determine the original location (P) according to a predetermined locating method. The invention provides that in the radio device (2) for at least one pair, consisting of two of the transceiver units (4, 5), a respective ellipse ( 10) is assigned, wherein a predetermined minor axis length (bf) is defined for the respective ellipse (10) and positions (Pa1, Pa2) of the transceiver units (4, 5) are defined as focal points of the respective ellipse (10), and the Radio device (2) is set up to unlock the vehicle (1) only when it is determined by the radio device (2) that the original location (P) of the radio signal (8) is on or within the respective ellipse (10) of the at least one pair is located.

Description

The invention relates to a vehicle, comprising a radio device for a radio-based vehicle unlocking system, a radio device for a vehicle and a method for operating a vehicle.

Radio-based vehicle unlocking systems also have radio keys in addition to mechanical keys. A vehicle is unlocked here by actuating an actuating element of the radio key, whereupon a radio signal is sent out by the radio key. The vehicle unlocking system of the vehicle then unlocks a door of the vehicle, for example. The disadvantage of using radio keys of the type described, however, is that manual actuation of the actuating element of the radio key is required in order to unlock the vehicle. For this reason, vehicle unlocking systems with radio keys have become established that enable the vehicle to be unlocked without manual intervention by the driver. The ultra-broadband process is particularly widespread here.

In these vehicle unlocking systems, it is provided for reasons of security that an origin of the radio signal received by the vehicle unlocking system is located. The vehicle is only unlocked when the origin of the radio signal is located in a predetermined area in the vicinity of the vehicle. This is to ensure that the vehicle can only be opened by people who have the remote control key with them.

However, some of these vehicle unlocking systems can be attacked by so-called relay attacks, whereby unauthorized third parties can gain access to the vehicle. Said relay attack is based on the transmission of the radio signal by an unauthorized third party in order to simulate an origin of the radio signal in the predetermined area of the vehicle. Here, a radio device is arranged between the vehicle and the radio key. The attacker uses the radio device to switch between the communication of the radio key and the vehicle unlocking system and forwards the radio signals while he is in the vicinity of the vehicle. The presence of the radio key in the access area of the vehicle can thus be simulated.

As a countermeasure against these attacks, it is common to monitor the running times of radio signals between the radio key and the vehicle unlocking system. A forwarding of the radio signals by a third party can be recognized as part of this countermeasure on the basis of an increased transit time of the radio signals.

The disadvantage of the known prior art is the way in which the areas from which the vehicle can be opened are defined. These areas are usually defined by a maximum distance between the radio key and an individual transceiver unit of the vehicle unlocking system. As a result, the areas have circular areas which are arranged around the transceiver units. If several of the transceiver units are used, this can result in areas which may not appear intuitive to a driver.

It is an object of the invention to provide a method that provides a more intuitive provision of an area for ultra-wideband vehicle unlocking systems.

The object is achieved by the subjects of the independent claims. Advantageous developments of the invention result from the features of the dependent claims, the following description and the figures.

The invention comprises a vehicle that comprises a radio device for a radio-based vehicle unlocking system. It is provided that the radio device has at least two transceiver units, each of which is set up to receive radio signals. In other words, the invention relates to a vehicle equipped with the radio device for the radio-based vehicle unlocking system. Provision is made for the radio device which has the at least two transceiver units to be provided for contactless unlocking of the vehicle. These are set up to receive the radio signals sent by a radio key. The radio device is set up to use a predetermined distance determination method to detect a respective distance from an original location of the radio signal to the respective transceiver units and to determine the original location of the radio signal from the at least two distances according to a predetermined location method. In other words, the radio device is set up to determine the respective distances by means of the predetermined distance determination method in which the original location of the radio signal to the respective transceiver units is located. The radio device is set up to determine the original location from which the radio signal was sent in the subsequent locating process based on the respective distances which were recorded during the distance determination process. In the A respective ellipse is assigned to the radio device for at least one pair, which consists of two of the transceiver units. A predetermined minor axis position is defined for the respective ellipse and the positions of the transceiver units are defined as focal points of the respective ellipse. In other words, it is provided that a predetermined area is defined for the pair of the two transceiver units, which area has the shape of an ellipse in a horizontal plane. To delimit the ellipse, the positions of the two transceiver units are provided as respective focal points of the ellipse. Furthermore, the minor axis length is defined in the radio device for the respective ellipse. The radio device is set up to unlock the vehicle only when it is determined by the radio device that the original location of the radio signal is on or within the respective ellipse of the at least one pair. In other words, the vehicle will only unlock if it is determined during the predetermined locating method that the original location of the radio signal lies within the at least one ellipse.

The invention has the advantage that an area perceived as natural is defined for unlocking a vehicle.

The invention also includes optional developments which result in further advantages.

A further development of the invention provides that the radio device is set up to unlock the vehicle only when one of the respective distances between the original location of the radio signal and one of the respective transceiver units is less than a predetermined threshold value. In other words, it is provided that the radio device also unlocks the vehicle if the original location of the radio signal lies in a respective circle which is arranged around a respective transceiver unit and has a predetermined threshold value as a radius. It is therefore provided that the vehicle is also unlocked when the radio key is either located within one of the ellipses or within a circle around one of the transceiver units. This has the advantage that both the elliptical shape and the known circular shape are provided to enable unlocking.

A further development of the invention provides that at least one of the pairs, which consists of two of the transceiver units, is arranged along a longitudinal direction of the vehicle. It can be provided, for example, that at least one of the pairs has a transceiver unit in a rear area of the vehicle and a transceiver unit in the front of the vehicle. This provides an ellipse, the longitudinal axis of which is aligned parallel to the longitudinal direction of the vehicle. The further development results in the advantage that the ellipse covers a large area of the vehicle.

A further development of the invention provides that at least one of the pairs consisting of two of the transceiver units is arranged along a transverse direction of the vehicle. In other words, the two transceiver units of the pair are arranged on a transverse axis of the vehicle. This has the advantage that a separate zone can be provided for unlocking a tailgate or a motorized flap. It can be provided, for example, that the two transceiver units are arranged on different sides of a tailgate, as a result of which the ellipse encompasses a space in front of the tailgate.

A further development of the invention provides that the predetermined distance determination method includes a transit time measurement. In other words, it is provided that the radio device is set up to determine a runtime of the radio signal, which describes a period of time, starting from a point in time when the radio signal was sent by the radio key and the point in time when the radio signal was received by the respective transceiver unit . The travel time can then be used to calculate the path that the radio signal has covered from the original location to the respective transceiver unit. The further development results in the advantage that relay attacks can be detected by means of the transit time measurement, because the transmission of the radio signal via a relay increases the transit time of the signal.

A further development of the invention provides that the predetermined distance determination method includes a power measurement. In other words, the distance determination method is based on a determination of a decrease in level of the radio signal on its way from the original location to the respective transceiver unit. It can be provided, for example, that for the distance determination method it is assumed that the radio signal is transmitted by a radio key defined as a point source and that a power density of the radio signal decreases with increasing distance, starting from the original location. This has the advantage that the problem of synchronization, which exists with time-based methods, can be avoided.

A further development of the invention provides that the radio device is set up to receive the radio signal by means of an ultra-broadband method. In other words, that's based Radio-based vehicle unlocking system based on the transmission of radio signals using the ultra-broadband method. This has the advantage that a pulsed transmission of radio signals is made possible.

The invention also includes a radio device for a vehicle.

The invention also includes a method for operating a vehicle. The vehicle comprises a radio device for a radio-based vehicle unlocking system. It is provided that a radio signal is received by at least two transceiver units of the radio device. In other words, one and the same radio signal that was sent by a radio key of the radio-based vehicle unlocking system is received by the at least two transceiver units. By means of a predetermined distance determination method, the radio device determines a respective distance between an original location of the radio signal and the respective transceiver units. In other words, the radio device determines the distances at which the origin of the radio signal is from the respective transceiver units. The radio device determines the original location of the radio signal from the at least two distances using a predetermined locating method. In other words, the location of the transceiver units and the respective distances are used to determine from which original location the radio signal was sent. The place of origin can be specified relative to the positions of the transceiver units. It is provided that the vehicle is only unlocked by the radio device when it is determined by the radio device that the original location of the radio signal is on or within the ellipse. In other words, it is provided that the vehicle is only unlocked by the radio device if the original location of the radio signal is in an area which is defined by an ellipse.

The ellipse is defined by a predetermined minor axis length and the positions of the transceiver units of the pair as focal points. In other words, the area of the ellipse is defined by the position of the transceiver units and a predetermined minor axis length. The minor axis length can be stored in the radio device, for example. The positions of the transceiver units can be determined as foci of the ellipse.

The invention also includes further developments of the radio device according to the invention and the method according to the invention which have features as they have already been described in connection with the further developments of the vehicle according to the invention. For this reason, the corresponding developments of the radio device according to the invention and the method according to the invention are not described again here.

The invention also includes the combinations of the features of the described embodiments.

• 1 ein Fahrzeug;
• 2 den Zugangsbereich welcher durch die Kreisflächen der Sende-Empfängereinheiten vorgegeben ist;
• 3 den Zugangsbereich welcher durch die Ellipsen der Sende-Empfängereinheiten vorgegeben ist;
• 4 die Kombination der beiden Zugangsbereiche; und
• 5 einen möglichen Ablauf eines Verfahrens zum Betreiben des Fahrzeugs.

An exemplary embodiment of the invention is described below. This shows:

• 1 a vehicle;
• 2 the access area which is predetermined by the circular areas of the transceiver units;
• 3 the access area which is given by the ellipses of the transceiver units;
• 4th the combination of the two access areas; and
• 5 a possible sequence of a method for operating the vehicle.

The exemplary embodiment explained below is a preferred embodiment of the invention. In the exemplary embodiment, the described components of the embodiment each represent individual features of the invention that are to be considered independently of one another, which also develop the invention independently of one another and are therefore also to be regarded as part of the invention individually or in a combination other than the one shown. Furthermore, the described embodiment can also be supplemented by further features of the invention already described.

In the figures, functionally identical elements are each provided with the same reference symbols.

1 shows a vehicle 1 . The vehicle 1 can be a radio device 2 for a radio-based vehicle unlocking system. The radio device 2 can be a control unit 3 have, which can be a microcontroller or a microprocessor. The radio device can have four transceiver units 4th , 5 , 6th , 7th have in different positions on the vehicle 1 can be arranged. The transceiver units 4th , 5 , 6th , 7th can be set up to use radio signals 8th to send and / or receive. The radio signals 8th can for example be ultra-wideband signals, which are transmitted by a radio key 9 of the radio-based vehicle unlocking system. The transceiver units 4th , 5 , 6th , 7th can in the radio device 2 be grouped together as pairs. One respective pair of transceiver units 4th , 5 , 6th , 7th can be a respective ellipse 10 , 11 , 12th , 13th be assigned. The ellipses 10 , 11 , 12th , 13th can define areas from which a driver is allowed to enter the vehicle using a remote control key 9 to unlock. The faces of the ellipses 10 , 11 , 12th , 13th can be defined by the location of the transceiver units 4th , 5 , 6th , 7th as coordinates of focal points of the ellipses 10 , 11 , 12th , 13th be used. The transceiver units 4th and 5 can be parallel to a transverse direction Y of the vehicle 1 be arranged and a distance of two linear eccentricities cs , cf. have to each other. The transceiver units can also 6th , 7th be a pair which is an ellipse 12th provides whose main axis is aligned parallel to the transverse direction Y of the vehicle. The respective ellipses can also be defined by predetermined minor axis lengths bf , bs be defined. The transceiver units 4th and 6th as 5 and 7th can use the ellipses 13th and 11 form which are parallel to a longitudinal direction X of the vehicle 1 can be aligned. The ellipses 10 , 11 , 12th , 13th may have areas that overlap and a total area as the access area 14th form. It can be provided that there is only a driver within the access area 14th can be made possible by the vehicle 1 by sending the radio signal 8th through his remote control key 9 to unlock. Thus a location of a place of origin P. of the radio key 9 can be determined, it can be provided that the transmitted radio signal 8th by at least two of the transceiver units 4th , 5 must be received. The control unit 3 can be set up to include a transit time or a change in level of the radio signal 8th to determine. The control unit 3 can be set up to determine a respective distance by means of a predetermined distance determination method r1 , r2 of the place of origin P. of the radio signal 8th to the transceiver units 4th , 5 according to a predetermined distance determination method. From the two distances r1 , r2 can the control unit 4th the place of origin according to a predetermined locating method P. of the radio signal 8th determine. The control unit 3 can be set up, for example, to set time intervals between the reception times of the radio signal 8th at the transceiver units 4th , 5 evaluate to the place of origin P. of the radio signal 8th to determine.

The radio device 2 can be set up to the vehicle 1 can only be unlocked if the determined place of origin P. of the radio signal 8th within the access area 14th is arranged. Is the place of origin P. of the radio signal 8th outside the access area 14th , can unlock the vehicle 1 through the radio device 2 be denied. It can be provided that a respective ellipse 10 , 11 , 12th , 13th at least one respective vehicle door or flap 15th of the vehicle 1 assigned. It can be provided, for example, that the respective door or flap 15th of the vehicle 1 through the radio device 2 is unlocked when the driver uses the remote control key 9 and thus the place of origin P. of the radio signal 8th is located in the assigned ellipse. The ellipses 10 , 11 , 12th , 13th can be intersections of a horizontal plane with ellipsoids.

2 shows the access area 14th , which by the circular areas 16 , 17th , 18th , 19th the transceiver units 4th , 5 , 6th and 7th is given. The circular areas 16 , 17th , 18th , 19th can be formed by a predetermined radius R, which the circular surfaces 16 , 17th , 18th , 19th the respective positions of the transceiver units 4th , 5 , 6th and 7th delimits. The access area thereby provided 20th can with the commonly used access area 20th correspond to the state of the art. Disadvantageous when using the access area shown 20th can be a presence of void areas 21 between two of the circular areas 16 , 17th , 18th , 19th which are outside the access area 20th lie

3 shows the access area 14th which by the ellipses 4th , 5 , 6th , 7th the transceiver units 4th , 5 , 6th and 7th is given.

4th shows the combination of the two access areas 14th and 20th . What is noticeable here is that the in 2 area shown 21 in 4th through the access area 14th is covered.

5 shows a possible sequence of a method for operating the vehicle 1 including the radio device 2 for a radio-based vehicle unlocking system. In a first step S1 of the method, a radio signal 8th by at least two transceiver units 4th , 5 the radio device 2 be received. The radio signal 8th can for example be a radio signal 8th be in the ultra-wideband range or a bluetooth signal.

In a step S2, the radio device 2 of the vehicle 1 the respective distance R1, R2 the original location by means of the predetermined distance determination method P. to the respective transceiver units 4th , 5 be determined. The determination can be made, for example, by determining the transit time of the radio signal 8th respectively. The predetermined distance determination method can, for example, be used in the control unit 3 the radio device 2 be performed. For this purpose, for example, time stamps of the radio signal 8th or further information of the radio signal by the transceiver units 4th , 5 to the control unit 3 be transmitted.

In a step S3, the control unit 3 the radio device 2 the place of origin from the at least two distances R1, R2 according to the predetermined locating method P. be determined.

In a step S4, for example, by the control unit 3 the radio device 2 the determined place of origin P. with the coordinates of the ellipses 10 , 11 , 12th , 13th enclosed areas are compared in order to determine whether the place of origin P. and thus the key 9 within the access area 14th is located. Method step S4 provides that the vehicle 1 through the radio device 2 is unlocked when the determined place of origin is within the access area 14th is located. Otherwise the vehicle will be unlocked 1 refused. Unlocking the vehicle 1 can, for example, actuate a lock on a door or flap 15th of the vehicle 1 include.

The invention deals with the problem of relay attacks on vehicles with LF / RF comfort access systems. In the event of a relay attack, this locking system is led to believe that there is an authorized radio key 9 in the vicinity of the vehicle is around the vehicle 1 to open. This is done using the radio signal 8th of the radio key 9 extended. One possibility of defense is a so-called relay attack defense. A static attack on a locking system of a vehicle takes place in a state in which the remote control key 9 is motionless, this can for example be in a house or apartment. An attack on this radio key 9 can be avoided by using a motion sensor in the remote control key. Opening the vehicle 1 is only possible if the remote control key 9 is moved and in the area around the vehicle 1 is located by the radio device.

One possibility to prevent the relay attack on a locking system based on UWB is to carry out a Time of Flight (ToF) measurement by an Ultra Wideband (UWB) system in addition to the LF / RF signal. In this way it can be validated that the remote control key is 9 in the immediate vicinity of the vehicle 1 is located. This is done by a distance from a transceiver unit 4th (UWB transceiver) to the radio key 9 calculated and compared with a threshold value (Dm ≥ r1). This creates four circles in which the remote control key 9 can be recognized as legitimate. In the example shown, a vehicle 1 assumed the four UWB transceivers as transceiver units 4th , 5 , 6th , 7th which is installed at the four corners of the vehicle 1 are located.

The approach shown uses the following equation to identify whether there is a remote control key 9 is in the area of the circles or not.

If one considers the state of the art, the gap areas fall 21 between the circular areas 16 , 17th , 18th , 19th on where the remote control key 9 cannot be recognized as "in the vicinity of the vehicle" because the place of origin P. outside the access area 20th lies. The size of the circular areas 16 , 17th , 18th , 19th depends on the distances between the transceiver units 4th , 5 , 6th , 7th from each other. The further the circle centers and thus the transceiver units 4th , 5 , 6th , 7th are apart, the more pronounced the gap areas are 21 . The threshold value for recognizing the permitted access area 20th Cannot be enlarged at will, as this also includes areas of the access area 20th assigned from which to open the vehicle 1 should not be allowed. Around circular areas 16 , 17th , 18th , 19th no additional transceiver units should be covered either 4th , 5 , 6th , 7th be used as this would further increase the cost of the locking system. The problem is in the most uniform possible area around the vehicle 1 the remote control key 9 as authorized to open to see what also the circular areas 16 , 17th , 18th , 19th includes.

By forming the ellipses 10 , 11 , 12th , 13th can be used for those in the specified access area 14th determine whether the remote control key is 9 is located in the permitted access area 14 around the vehicle. This is given by the width of the respective ellipses 10 , 11 , 12th , 13th can be adjusted. For the overall system, the state of the art (application of threshold values to individual distance measurements) is combined with the new approach using ellipses. Thus, both the access area 20th , based on circular areas 16 , 17th , 18th , 19th , as well as the access area 14th , based on that of the ellipses 10 , 11 , 12th , 13th for opening the vehicle 1 through the remote control key 9 be defined as admissible.

By forming ellipses 10 , 11 , 12th , 13th Areas can be covered so that in an access area shaped as a homogeneous surface 14th around the vehicle 1 a radio key 9 can be reliably recognized, as can also be required, for example, by insurance companies and automobile manufacturers.

Around the homogeneous access area 14th around the vehicle 1 to be able to represent, should in addition to the circular areas 16 , 17th , 18th , 19 about the positions of the transceiver units 4th , 5 , 6th , 7th Ellipses 10 , 11 , 12th , 13th by two positions of the transceiver units 4th , 5 , 6th , 7th be placed. This allows the faces of the ellipses 10 , 11 , 12th , 13th to be covered.

From the simulations it is evident that the exact ones described in the problem definition Gap areas 21 can be covered if both methods are used.

Berechnung von a: $$\begin{array}{l}{\text{c}}^2+{\text{b}}^2={\text{a}}^2\\ \text{a}=\text{sqrt}\left({\text{c}}^2+{\text{b}}^2\right)\end{array}$$

Berechnung von cs: $$\text{cs}=\left(\left|\text{Pa}4-\text{Pa}2\right|\right)\text{/}2$$

Berechnung von cf: $$\text{cf}=\left(\left|\text{Ya1}-\text{Ya}2\right|\right)\text{/}2$$

The following is the approach to designing the ellipses 10 , 11 , 12th , 13th and the resulting test for the relay attack Test: Ellipses design: The given parameters are the focus points Pa1 , Pa2 , Pa3 , Pa4 showing the positions of the transceiver units 4th , 5 , 6th , 7th are. The lengths b can be used as design parameters, which determine the size of the permitted area (access area 14th ) should determine from where the vehicle is coming from 1 can be opened. The parameter bs supposed for the ellipses 13th , 11 be used via the two pairs consisting of the receiver units 4th , 6th and 5 , 7th be stretched on the left or right side of the vehicle 1 are located. The parameter bf will for the ellipses 10 , 12th at the front or rear of the vehicle 1 used by the pairs of the receiving units 4th , 5 and 6th , 7th be stretched. The decision as to whether the place of origin P. of the radio signal 8th and thus the radio key 9 inside the ellipses 10 , 11 , 12th , 13th depends on the fulfillment of the following conditions: $$\begin{array}{l}\text{r}1+\text{r}2\le 2\text{af}\\ \text{r}1+\text{r3}\le 2\text{af}\\ \text{r3}+\text{r4}\le 2\text{af}\\ \text{r4}+\text{r}2\le 2\text{af}\end{array}$$

Calculation of a: $$\begin{array}{l}{\text{c}}^2+{\text{b}}^2={\text{a}}^2\\ \text{a}=\text{sqrt}\left({\text{c}}^2+{\text{b}}^2\right)\end{array}$$

Calculation of cs: $$\text{cs}=\left(\left|\text{Pa}\mathrm{4th}-\text{Pa}2\right|\right)\text{/}2$$

Calculation of cf: $$\text{cf.}=\left(\left|\text{Ya1}-\text{Ya}2\right|\right)\text{/}2$$

oder $$\text{r}1+\text{r}2\le 2\text{af}\Vert \text{r}1+\text{r3}\le 2\text{as}\Vert \text{r3}+\text{r4}\le 2\text{af}\Vert \text{r4}+\text{r}2\le 2\text{as}$$

The resulting equation for recognizing whether an ID is in the permitted area around the vehicle is shown below (line 1 : Approach via the threshold value formation, line 2: Approach through ellipse formation): $$\text{R.}1\le \text{Dm}\Vert \text{r}2\le \text{Dm}\Vert \text{<figure-callout id="3" label="r" filenames="DE102019215535A1\_0007.png" state="{{state}}">r</figure-callout>}3\le \text{Dm}\Vert \text{r}\mathrm{4th}\le \text{Dm}$$

or $$\text{r}1+\text{r}2\le 2\text{af}\Vert \text{r}1+\text{r3}\le 2\text{as}\Vert \text{r3}+\text{r4}\le 2\text{af}\Vert \text{r4}+\text{r}2\le 2\text{as}$$

Overall, the example shows how the invention can provide an improvement in the coverage of the access area for ultra-broadband-based relay attack defense.

List of reference symbols

1

vehicle

2

Radio device

3

Control unit

4th

Transceiver unit

5

Transceiver unit

6th

Transceiver unit

7th

Transceiver unit

8th

Radio signal

9

Remote control key

10

ellipse

11

ellipse

12th

ellipse

13th

ellipse

14th

Access area

15th

flap

16

Circular area

17th

Circular area

18th

Circular area

19th

Circular area

20th

Access area

21

Gap areas

P

Place of origin

bs

Minor axis length

bf

Minor axis length

it

linear eccentricity

cf.

linear eccentricity

r1

Distance from the original location to the transceiver unit 4

r2

Distance from the original location to the transceiver unit 5

r3

Distance from the original location to the transceiver unit 6

r4

Distance from the original location to the transceiver unit 7

Dm

Threshold

Pa1

Position of the sender / receiver unit 4

Pa2

Position of the sender / receiver unit 5

Pa3

Position of the sender / receiver unit 6

Pa4

Position of the sender / receiver unit 7

Claims (9)

Vehicle (1), comprising a radio device (2) for a radio-based vehicle unlocking system, the radio device (2) having at least two transceiver units (4, 5), each of which is set up to receive radio signals (8) is set up to determine a respective distance (r1, r2) from an original location (P) of a radio signal (8) to the respective transceiver units (4, 5) by means of a predetermined distance determination method, and from the at least two distances (r1, r2) to determine the original location (P) according to a predetermined locating method, characterized in that a respective ellipse (10) is assigned in the radio device (2) for at least one pair consisting of two of the transceiver units (4, 5), wherein a predetermined minor axis length (bf) is defined for the respective ellipse (10) and positions (Pa1, Pa2) of the transceiver units (4, 5) are defined as focal points of the respective ellipse (10), and - the radio device (2) is set up to unlock the vehicle (1) only when it is determined by the radio device (2) that the origin (P) of the radio signal (8) is on or within the respective ellipse ( 10) of the at least one pair is located. Vehicle (1) after Claim 1 , characterized ur ch that the radio device (2) is set up to unlock the vehicle (1) only when one of the respective distances (r1, r2) of the origin (P) of the radio signal (8) to one of the respective Transceiver units (4, 5) is smaller than a predetermined threshold value (Dm). Vehicle (1) according to one of the preceding claims, characterized in that at least one of the pairs consisting of two of the transceiver units (4, 6) is arranged along a longitudinal direction (X) of the vehicle (1). Vehicle (1) according to one of the preceding claims, characterized in that at least one of the pairs consisting of two of the transceiver units (4, 5) is arranged along a transverse direction (Y) of the vehicle (1). Vehicle (1) according to one of the preceding claims, characterized in that the predetermined distance determination method comprises a transit time measurement of the radio signal (8). Vehicle (1) according to one of the preceding claims, characterized in that the predetermined distance determination method comprises a power measurement of the radio signal (8). Vehicle (1) according to one of the preceding claims, characterized in that the radio device (2) is set up to receive the radio signal (8) by means of ultra-broadband methods. Radio device (2) for a vehicle (1) according to one of the preceding claims. A method for operating a vehicle (1) comprising a radio device 2 for a radio-based vehicle unlocking system, wherein - a radio signal (8) is received by at least two transceiver units (4, 5) of the radio device (2), - by the radio device (2) , a respective distance (r1, r2) from an original location (P) of the radio signal (8) to the respective transceiver units (4,5) is determined by means of a predetermined distance determination method, and - from the at least two distances (r1, r2) according to the original location (P) is determined using a predetermined locating method, characterized in that the vehicle (1) is only unlocked by the radio device (2) when it is determined by the radio device (2) that the original location (P) of the Radio signal (8) is located on or within a respective ellipse (10) assigned to a respective pair consisting of two of the transceiver units (4, 5), wherein - for the respective ellipse (1 0) a predetermined minor axis length (bf) is defined and positions (Pa1, Pa2) of the transceiver units (4, 5) are defined as focal points of the respective ellipse (10).

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