DE102019132627A1 - Device and method for searching for a vehicle key - Google Patents

Abstract

A portable search device (200) for obtaining information relating to a position of a vehicle key (120) is described. The search device (200) is set up to send out a request signal which is aimed at causing a vehicle key (120) located within range of the request signal to send out one or more response signals. The search device (200) is also set up to check whether at least one response signal is received at the search device (200) in response to the transmitted request signal. In addition, the search device (200) is set up to output information relating to a detected vehicle key (120) via a user interface (205, 206) when at least one response signal is received at the search device (200).

Description

The invention relates to a device and a method which are designed to support a user in the search for a misplaced vehicle key.

Vehicles today often have radio keys that enable a user to control functions of a vehicle remotely. It can happen that a user has misplaced his vehicle key and has to search for it. The search for a (relatively small) vehicle key can take a relatively long time and may be unsuccessful, so that the vehicle key has to be replaced, which is associated with costs for the user.

The present document deals with the technical task of supporting a user of a vehicle in their search for a radio-based vehicle key.

The problem is solved by each of the independent claims. Advantageous embodiments are described, inter alia, in the dependent claims. It is pointed out that additional features of a patent claim dependent on an independent patent claim without the features of the independent patent claim or only in combination with a subset of the features of the independent patent claim can form a separate invention independent of the combination of all features of the independent patent claim, which can be made the subject of an independent claim, a divisional application or a subsequent application. This applies equally to technical teachings described in the description, which can form an invention that is independent of the features of the independent patent claims.

According to one aspect, a portable (in particular portable) search device for determining information relating to the position of a misplaced vehicle key or radio key is described. The search device can, for example, have the size of a smartphone. Exemplary dimensions of the search device are: a length of 15 cm or less, a width of 10 cm or less and / or a thickness of 5 cm or less. The search device can comprise an electrical energy store (in particular an electrochemical energy store). The search device can thus be battery-operated. It can thus be made possible for a user to conveniently move the search device to different positions and / or to different areas when searching for a vehicle key.

The search device can be set up to send out a request signal which is aimed at causing a vehicle key located within range of the request signal to send out one or more response signals. The transmitted request signal can, for example, have a range of up to 10m or up to 100m.

Furthermore, the search device can be set up to check whether at least one response signal is received at the search device in response to the transmitted request signal. For example, it can be checked whether a response signal is received from a vehicle key on the search device within a defined time interval after the request signal has been sent out. If this is the case, it can be concluded that a vehicle key is located within the range of the request signal around the search device.

The search device can also be set up to output information relating to a detected vehicle key via a user interface (e.g. on a screen and / or via a loudspeaker) when at least one response signal is received at the search device. In particular, a user of the search device can be shown that a vehicle key has been detected. The user then knows that a vehicle key is within range of the request signal. In this way, the search for the vehicle key can be localized so that the user is supported in the search for a misplaced vehicle key.

The request signal can be directed towards it and / or can be designed to wake up a vehicle key. Furthermore, the request signal can be directed and / or designed to put the vehicle key into a recognition mode in which the vehicle key repeatedly, in particular periodically, sends out response signals. A particularly reliable search can thus be made possible, in particular since the quality of the localization of the vehicle key by the search device can be increased on the basis of the response signals that are repeatedly sent out.

The search device can be set up to determine position information in relation to the distance between the search device and the detected vehicle key on the basis of the received response signal and / or on the basis of a sequence of received reply signals and / or to determine position information in relation to the direction in which is the detected vehicle key based on the search device.

In particular, the search device can be set up to determine information relating to the intensity and / or the running time of the request signal received from the detected vehicle key on the basis of a received response signal. This information can be determined, for example, from the vehicle key and sent back to the search device within a response signal. As an alternative or in addition, information relating to the intensity and / or the transit time of the received response signal can be determined. This information can, if necessary, be determined directly by the search device.

Based on the above information, position information relating to the distance from the vehicle key and / or relating to the direction in which the vehicle key is located, starting from the search device, can then be determined in a precise manner.

The search device can be set up to receive a sequence of successive response signals while the search device is moved to different positions. If necessary, the different response signals can each have been sent by the vehicle key in response to a request signal sent by the search device. The sequence of response signals can thus be associated with a corresponding sequence of query signals.

The request signals and / or the response signals can thus each have covered different transmission paths from the vehicle key to the search device. The search device can be set up to determine for each of the response signals information relating to an intensity and / or a running time of the request signal received from the detected vehicle key, and / or information relating to an intensity and / or a running time of the received response signal.

Based on the change in intensity and / or the transit time resulting from the sequence of successive response signals, position information relating to the direction of the vehicle key can then be determined in a particularly precise manner.

The position information can be output via the user interface of the search device. In particular, the search device can be set up to output position information relating to the direction of the detected vehicle key via the user interface. The direction can be indicated by a direction indicator on the screen of the search device. Alternatively or additionally, the direction can be displayed or output by changing the signal frequency (i.e. the pitch) and / or the repetition frequency of a signal tone output via the loudspeaker of the search device when the position of the search device changes. As an alternative or in addition, a linguistic reference to the determined direction and / or the determined distance can be output. For example, a verbal indication (for example “30 ° to the right” and / or “3 meters straight ahead”) can be output which is designed to inform the user of the search device on the basis of the determined direction and / or on the basis of the determined distance to the detected one To direct vehicle keys. This enables a particularly convenient and reliable search for a misplaced vehicle key.

The vehicle key can be configured to communicate with a vehicle using a radio communication method. The vehicle key can in particular be designed for a keyless access function to a vehicle.

The search device can be configured to communicate with the vehicle key using the radio communication method. In particular, the search device can be set up to transmit the request signal in accordance with the radio communication method. As an alternative or in addition, the search device can be set up to receive a response signal which is transmitted by the vehicle key and is designed according to the radio communication method.

In a preferred example, the search device can be designed to transmit a request signal in a low frequency, LF for short, frequency band and / or in a frequency band between 20-140 kHz, in particular at 125 kHz. Alternatively or in addition, the search device can be designed to receive a response signal in a high frequency, or HF for short, frequency band and / or in a frequency band between 400 MHz and 900 MHz, in particular at 433 MHz and / or at 863 MHz.

In an alternative example, frequencies in the range of 2.4 GHz (in particular in the Bluetooth Low Energy frequency band) and / or in the Ultra Wide Band (UWB) frequency band can be used for a request signal and / or for a response signal.

By using the radio technology built into a vehicle key, a particularly reliable and efficient search for a vehicle key can be made possible.

The vehicle key can be designed to send identification and / or authentication information within a response signal to the vehicle as part of a communication with a vehicle (which, for example, enables the vehicle to be unlocked with the vehicle key and / or the engine of the vehicle based on start the radio-based authentication using the vehicle key).

The query signal transmitted by the search device can be designed to cause a vehicle key to transmit a response signal that does not include the identification and / or authentication information intended for a vehicle. In this way, misuse of the search device (e.g. for listening to identification and / or authentication information) can be avoided in a reliable manner.

According to a further aspect, a vehicle key and / or a radio key is described which is designed to be searched for and possibly found with the search device described in this document.

The vehicle key can be set up to communicate with a vehicle using a radio communication method, in particular to enable a user to access the vehicle (in particular a motor vehicle). Furthermore, the vehicle key can be designed to receive a request signal designed according to the radio communication method from a search device described in this document. The request signal can be aimed at putting the vehicle key into a recognition mode.

The vehicle key can also be set up, in response to the receipt of a request signal, to put the vehicle key into the recognition mode in which response signals are repeatedly, in particular periodically, transmitted by the vehicle key. The response signals can each be designed according to the radio communication method. By providing a vehicle key with a recognition mode, an efficient search for the vehicle key can be made possible.

As already explained above, the vehicle key can be designed to send identification and / or authentication information within a response signal to the vehicle in the context of communication with a vehicle. Furthermore, the vehicle key can be designed to send out response signals in the recognition mode that do not include the identification and / or authentication information intended for a vehicle. In this way, a vehicle key can be provided which can be searched for in a particularly data-secure manner using a search device.

According to a further aspect, a system is described which comprises the search device described in this document and one or more of the vehicle keys described in this document.

According to a further aspect, a (computer-implemented) method for determining information relating to a position of a misplaced vehicle key (in particular a key for a motor vehicle, for example for a passenger car, a truck, a bus or a motorcycle) by means of a portable search device .

The method comprises the transmission of a request signal which is aimed at causing a vehicle key located within range of the request signal to send out one or more response signals. Furthermore, the method comprises checking whether at least one response signal is received at the search device in response to the transmitted request signal. The method further comprises the outputting of information relating to a detected vehicle key when at least one response signal is received at the search device.

According to a further aspect, a software (SW) program is described. The SW program can be set up to be executed on a processor and thereby to execute the method described in this document.

According to a further aspect, a storage medium is described. The storage medium can comprise a software program which is set up to be executed on a processor and thereby to execute the method described in this document.

It should be noted that the methods, devices and systems described in this document can be used both alone and in combination with other methods, devices and systems described in this document. Furthermore, any aspects of the methods, devices and systems described in this document can be combined with one another in diverse ways. In particular, the features of the claims can be combined with one another in diverse ways.

• 1a ein beispielhaftes Fahrzeug mit einer Zugangs- und/oder Aktivierungsfunktion;
• 1b einen beispielhaften Fahrzeugschlüssel;
• 2a eine beispielhafte Suchvorrichtung;
• 2b ein beispielhaftes System mit einer Suchvorrichtung und einem Fahrzeugschlüssel; und
• 3 ein Ablaufdiagramm eines beispielhaften Verfahrens zum Suchen eines Fahrzeugschl üssel s.

The invention is described in more detail below on the basis of exemplary embodiments. Show it

• 1a an exemplary vehicle with an access and / or activation function;
• 1b an exemplary vehicle key;
• 2a an exemplary search engine;
• 2 B an exemplary system including a locator and a vehicle key; and
• 3rd a flowchart of an exemplary method for searching for a vehicle key.

As stated at the outset, the present document deals with the efficient and reliable search for a vehicle key that has been misplaced by a user. The vehicle key can be part of an access and / or activation system for a (motor) vehicle. 1a shows an exemplary vehicle 100 and 1b shows an exemplary vehicle key 120 which provide a keyless access and / or activation function or which together form an access and / or activation system. A keyless entry and / or activation function allows a driver of a vehicle 100 without using the key-lock principle, a vehicle door 110 to open and / or the engine of the vehicle 100 to start. To open the door 110 the driver grabs the door handle 111 . A proximity sensor 112 on or near the door handle 111 captures this movement. A specific radio signal (eg in the LF, Low Frequency, range or with a Bluetooth Low Energy, BLE, or an Ultra Wideband (UWB) radio protocol) is then sent via one or more transmitter units 101 of the vehicle 100 shipped. This radio signal can also be referred to as a request signal or request message. In other words, the one or more transmission units 101 of the vehicle 100 can be set up to send out an electromagnetic signal, ie the request signal or the request message. Exemplary transmission frequencies of the one or more transmission units 101 are in the frequency range of 20-140kHz (e.g. 20 kHz, 124kHz, 125kHz, 127 kHz, 133kHz or 135kHz). Alternatively, frequencies in the range of 2.4 GHz (e.g. when using BLE (Bluetooth Low Energy) or UWB (Ultra Wide Band)) can be used (in order to enable greater ranges and / or greater localization accuracy). Furthermore, BLE and / or UWB can be used advantageously in connection with smartphones as vehicle keys 120 be used.

The vehicle key 120 can be set up to receive request signals or request messages in the LF (Low Frequency) and / or in the UWB frequency range. In particular, a combined ability to receive LF and UWB request signals can be advantageous.

As an alternative or in addition to the localization of the vehicle key 120 in response to touching a door handle 111 can be the approach of a user to a vehicle 100 a localization of the vehicle key 120 (in particular the determination of the position coordinate of the position of the vehicle key 120 relative to the vehicle 100 ) trigger. In response to the location of the vehicle key 120 one or more functions can then be triggered and / or enabled.

That from the one or more transmitter units 101 transmitted request signal can comprise several parts. A first part of the request signal can be designed to be a receiving unit 123 in a vehicle key 120 to wake up or put into an operating mode, ie to prepare for the receipt of further information. Another part of the request signal can be information to identify the vehicle 100 and / or to uniquely identify the request signal. The different parts of the one or more transmitter units 101 The request signals sent out in each case can be sent with a time delay.

The receiving unit 123 in the vehicle key 120 is set up by the one or more transmitter units 101 to receive transmitted signals or signal parts and to determine the signal strength or field strength and / or the transit time of the signals or signal parts. A transmitter unit 121 of the vehicle key 120 responds to the request signal received with a response signal (or with a useful message). The response signal can be transmitted in a different frequency range than the one or more request signals. For example, the response signal can be transmitted with a response frequency of 433 MHz (ie in the HF (high frequency) range). Alternatively, frequencies in the range of 2.4 GHz (eg when using BLE) and / or in the range of UWB can be used.

The response signal (or the useful message) can consist of several parts. A first part of the response signal can identify the vehicle key 120 serve (for example, an authentication key can be transmitted) and a further part of the response signal can include signal strength and / or transit time information in relation to the measured signal strength and / or transit time of the request signal. One or more receiving units 104 of the vehicle 100 can do that Response signal and / or the response signal parts received and sent to a control unit 102 of the vehicle 100 hand off.

The control unit 102 of the vehicle 100 can be set up to check whether the vehicle key 120 to the vehicle 100 fits. In particular, authentication of the vehicle key can be performed 120 respectively. Furthermore, the position of the vehicle key can be determined via triangulation or trilateration or via a look-up table 120 relative to the vehicle 100 are calculated (based on the measured signal strengths and / or transit times of a large number of query signals and / or the response signal at different receiving units 104 ). Fits the estimated position of the vehicle key 120 with the position of the proximity sensor 112 (e.g. the area around the touched door 110 and / or the touched door handle 111 ) match, so will the door 110 and / or the entire vehicle 100 open.

As in 1a shown includes the vehicle 100 typically a plurality of transmitter units 101 . The transmission units 101 can be at different points (ie at different reference points) in the vehicle 100 be arranged. Each transmitter unit 101 the multitude of transmission units 101 can send a request signal or a request message (eg a signal pulse). The request signals can be offset in time and possibly have a predefined sequence. As an alternative or in addition, the request signals can have a unique identifier or a unique identifier. The vehicle key 120 and / or the receiving unit 104 of the vehicle 100 can, by means of the identifier or the identifier and / or by means of the sequence, the request signals uniquely in each case of a transmission unit 101 the multitude of transmitter units 101 assign. Thus, the respective signal strength and / or transit time of the individual request signals and thus also the respective distance between the transmission unit 101 (ie between a certain reference point) and the vehicle key 120 be determined. Since the transmitter units 101 at different locations (ie at different reference points) in the vehicle 100 are located, there is a large number of distances for the corresponding large number of transmitter units 101 . Using triangulation or trilateration methods, the relative position between the vehicle can be determined 100 and vehicle key 120 to be determined.

The above procedure for identity matching and / or position matching between a vehicle 100 and a vehicle key 120 typically takes about 100ms. In other words, the above procedure typically goes unnoticed by the driver due to the short period of time, so that the driver has to reach for the door handle 111 right the door 110 can open. An analogous procedure for identity matching / position matching typically also takes place when the vehicle is started 100 .

The procedure described above for an access and / or activation system can be used to restore a misplaced vehicle key 120 to search. 2a shows an exemplary search device 200 that can be used by a user to get a vehicle key 120 to search. The search device 200 may be at least partially related to 1a Include described vehicle-side parts of the access and / or activation system. In particular, the search device 200 a transmitter unit 201 include, which is set up to send a request signal. In this case, the request signal can include a part that is designed to be the receiving unit 123 of the vehicle key 120 to wake up. Furthermore, the request signal can optionally include a part which indicates that the request signal is from a search device (and not from a vehicle 100 ) was sent. The request signal can be repeated, in particular periodically, from the transmitting unit 201 the search device 200 be sent out.

If the vehicle key you are looking for is 120 is in the reception area of a transmitted request signal, the request signal from the receiving unit 123 of the vehicle key 120 can be received and evaluated. The transmitter unit 121 of the vehicle key 120 can then send out a response signal, which in turn comes from a receiving unit 204 the search device 200 can be received. The response signal can include information relating to the signal strength and / or the transit time of the request signal. Furthermore, the response signal can optionally be an identifier of the vehicle key 120 contain. The vehicle key 120 can be designed to send at least one response signal for each received request signal (which, for example, includes information relating to the signal strength and / or the transit time of the respective request signal).

In response to being repeated by the search device 200 Query signals sent out can be repeated in a corresponding manner by the vehicle key 120 Response signals sent out and from the search device 200 be received. A control unit 202 the search device 200 can be set up to evaluate the one or more received response signals, in particular the time sequence of received response signals. For example, on the basis of the information contained in the individual response signals in relation to the signal strength and / or transit time, the Distance between the search device 200 and the vehicle key can be determined. Furthermore, on the basis of the temporal development of the displayed signal strength and / or transit time when the position of the search device changes 200 it is determined whether the search device 200 due to the change in the position of the vehicle key 120 removed or on the vehicle key 120 moved towards. It can thus be determined information relating to the direction in which the vehicle key 120 relative to the search device 200 is arranged.

The search device 200 may include a user interface such as a screen 205 having. The control unit 202 the search device 200 can be set up to provide information relating to the position of the vehicle key 120 (e.g. in relation to the distance between vehicle keys 120 and search device 200 and / or in relation to the direction in which the vehicle key is 120 located) on the screen 205 to spend. For example, on the screen 205 an arrow 210 which indicates the direction in which the search device 200 should be moved to the finder 200 the vehicle key 120 to approach. Alternatively or in addition, the user interface can have a loudspeaker 206 include, via which an acoustic signal can be outputted, for example via the pitch and / or the pulse frequency, the distance and / or the direction of the vehicle key 120 indicates. For example, a rising pitch and / or pulse rate can indicate that the search device is in motion 200 the vehicle key 120 approaching.

The search device 200 includes an energy store 208 (e.g. a battery) with which the components of the search device 200 can be supplied with electrical energy. The search device 200 can be designed as a mobile device that can be carried by hand. Furthermore, the search device 200 a control element 207 include (e.g. a button) with which the search device 200 activated and / or used to search for a vehicle key 120 (in particular the sending of request signals) can be activated.

The search device 200 can possibly have several transmitter units 201 and / or receiving units 204 include. So the accuracy of the determined position of a vehicle key 120 increase.

It thus becomes a search device 200 described, with which a transmission mode of a vehicle key 120 can be activated. The vehicle key 120 can be designed to continuously and / or repeatedly transmit identification signals (for example response signals) for a certain period of time. Via the search device 200 can then (similar to an avalanche search device) the presence of a vehicle key on the basis of the identification signals 120 recognized and displayed. In addition, if necessary, the lost vehicle key can be located (for example at a distance of approx. 50 to 100 m).

The key electronics can, for example, be switched to a "lost" mode or recognition mode via the low-frequency interface (eg 125 kHz). Via the HF interface 433 / 863 MHz can then from the key 120 (Response) signals are sent and the location is made possible. The key 120 can be designed to only indicate (for security reasons) that the key 120 is present. If necessary, the use of identity information can be dispensed with. In particular, there is no need to send vehicle-specific data. The "lost" mode or the recognition mode can be set using software on the existing hardware of a vehicle key 120 to be provided.

A user can use the search device 200 use the area where the vehicle key 120 is suspected with the locator 200 and the sending of (response) signals by the vehicle key 120 to activate. Upon detection of one of the vehicle key 120 sent out signal can be the key 120 be located and found.

The search device 200 can for example be provided as a loaner device by a vehicle manufacturer in order to enable a user to find a misplaced vehicle key in a cost-effective manner 120 to find again.

2 B shows an exemplary system with a search device 200 which is set up to send a request signal or a sequence of successive request signals via a transmitting antenna and to receive a response signal or a sequence of response signals via a receiving antenna. The system also includes at least one vehicle key 120 which is set up to receive a request signal or a sequence of request signals via a receiving antenna and to send a response signal or a sequence of response signals via a transmitting antenna. The signal processing and / or the processing within the vehicle key 120 can through a control unit 122 of the vehicle key 120 respectively.

3rd shows a flow diagram of an exemplary method 300 for determining information relating to a position of a misplaced vehicle key 120 by means of a portable search device 200 . The procedure 200 can through a control unit 202 the search device 200 are executed.

The procedure 300 includes sending out 301 a (radio-based) request signal, which is aimed at a vehicle key located within range of the request signal 120 to cause one or more response signals to be sent out. The request signal can be sent out according to the radio communication method, which is from a vehicle key 120 for communication with a vehicle 100 is used.

The procedure 300 also includes checking 302 whether in response to the transmitted request signal at least one response signal to the search device 200 Will be received. For this purpose, a receiving unit 204 the search device 200 operated in a "listening mode" in order to receive a response signal. It can be checked whether a received response signal can actually be traced back to the transmitted request signal. In particular, it can be checked whether the response signal is received within a certain time interval after the request signal has been sent out. In this way, incorrect detections can be avoided in a reliable manner.

The method also includes 300 spending 303 of information related to a detected vehicle key 120 , (possibly only then) if at least one response signal to the search device 200 Will be received. For example, via a user interface 205 , 206 the search device 200 optically, acoustically and / or haptically indicated that a vehicle key 120 was detected. Furthermore, the distance and / or the direction of the vehicle key can be used 120 are displayed. This enables a user to find a misplaced vehicle key in a convenient and reliable manner 120 to find.

The present invention is not restricted to the exemplary embodiments shown. In particular, it should be noted that the description and the figures are only intended to illustrate the principle of the proposed methods, devices and systems by way of example.

Claims (12)

Portable search device (200) for determining information relating to a position of a vehicle key (120); wherein the search device (200) is set up, - to send out a request signal which is aimed at causing a vehicle key (120) located within range of the request signal to send out one or more response signals; - to check whether in response to the transmitted request signal at least one response signal is received at the search device (200); and - to output information relating to a detected vehicle key (120) via a user interface (205, 206) when at least one response signal is received at the search device (200). Portable search device (200) according to Claim 1 wherein - the vehicle key (120) is configured to communicate with a vehicle (100) using a radio communication method; and - the search device (200) is set up to communicate with the vehicle key (120) using the radio communication method; and / or - the search device (200) is set up to transmit the request signal in accordance with the radio communication method; and / or - the search device (200) is set up to receive a response signal which is sent out by the vehicle key (120) and is designed in accordance with the radio communication method. Portable search device (200) according to one of the preceding claims, wherein - The vehicle key (120) is designed to send identification and / or authentication information within a response signal to the vehicle (100) as part of a communication with a vehicle (100); - The request signal is designed to cause a vehicle key (120) to send out a response signal that does not include the identification and / or authentication information intended for a vehicle (100). Portable search device (200) according to one of the preceding claims, wherein the request signal is directed to and / or is designed to wake up a vehicle key (120) so that the vehicle key (120) is placed in a recognition mode in which the vehicle key (120) repeatedly, in particular periodically, sends out response signals. Portable search device (200) according to one of the preceding claims, wherein the search device (200) is designed to - send out a request signal in a low frequency, LF for short, frequency band and / or in a frequency band between 20-140kHz, in particular at 125kHz; and / or to receive a response signal in a high frequency, or HF for short, frequency band and / or in a frequency band between 400MHz and 900MHz, in particular at 433MHz and / or at 863MHz. Portable search device (200) according to one of the preceding claims, wherein the search device (200) is set up on the basis of the received response signal and / or on the basis of a sequence of received response signals with respect to position information - to determine a distance between the search device (200) and the detected vehicle key (120), and / or - To determine a direction in which the detected vehicle key (120) is located, starting from the search device (200). Portable search device (200) according to Claim 6 , wherein the search device (200) is set up, - on the basis of a received response signal, information relating to an intensity and / or a running time of the request signal received from the detected vehicle key (120), and / or information relating to an intensity and / or or to determine a transit time of the received response signal; and to determine the position information based thereon. Portable search device (200) according to one of the Claims 6 to 7th wherein the search device (200) is set up to receive a sequence of successive response signals while the search device (200) is moved to different positions; - to determine for each of the response signals information relating to an intensity and / or a transit time of the request signal received from the detected vehicle key (120) and / or information relating to an intensity and / or a transit time of the received response signal; and - based on a change in the intensity and / or the running time for the sequence of successive response signals, to determine position information in relation to the direction of the vehicle key (120). Portable search device (200) according to one of the preceding claims, wherein - The search device (200) is set up to output position information relating to a direction of the detected vehicle key (120) via the user interface (205, 206); and - the direction is output in particular, - by a direction indicator (210) on a screen (205) of the search device (200); and or - by changing a signal frequency and / or a repetition frequency of a signal tone output via a loudspeaker (206) of the search device (200) when the position of the search device (200) changes; and or - by a linguistic reference. Vehicle key (120), which is designed, - to communicate with a vehicle (100) using a radio communication method, in particular to enable a user to access the vehicle (100); - To receive a query signal formed in accordance with the radio communication method from a search device (200), the query signal being aimed at putting the vehicle key into a recognition mode; and - in response to putting the vehicle key (120) into the recognition mode in which repetitive, in particular periodically, response signals are transmitted from the vehicle key (120); wherein the response signals are each formed according to the radio communication method. Vehicle key (120) according to Claim 10 wherein - the vehicle key (120) is designed to send identification and / or authentication information within a response signal to the vehicle (100) in the context of a communication with a vehicle (100); and - the vehicle key (120) is designed to send out response signals in the recognition mode which do not include the identification and / or authentication information intended for a vehicle (100). Method (300) for determining information relating to a position of a misplaced vehicle key (120) by means of a portable search device (200); wherein the method comprises (300), - Sending (301) a request signal which is aimed at causing a vehicle key (120) located within range of the request signal to send out one or more response signals; - Checking (302) whether, in response to the transmitted request signal, at least one response signal is received at the search device (200); and - Outputting (303) of information relating to a detected vehicle key (120) when at least one response signal is received at the search device (200).

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