Method for determining the instantaneous distance between a motor vehicle and a mobile electronic identification device

Abstract

The invention relates to a method for determining the position of a mobile electronic identification device (2) relative to a motor vehicle (1) which can be unlocked using the identification device (2), which identification device (2) can communicate with the motor vehicle (1) in order to transmit data via a first wireless communication link (3a) operating according to the UWB standard and a second wireless communication link (3b) operating according to the BLE standard, the maximum range of the first communication link being smaller than the maximum range of the second communication link. The method has the following steps: a) transmission of at least one signal (S) from the motor vehicle (1) to the identification device (2) via the first communication link (3a), preferably successive transmission of a plurality of signals (S), the signals containing the time point of emission of the at least one signal (S), b) storage in the identification device (2) of the time point of emission and the time point of reception of the at least one signal (S) received by the identification device (2), and c) transmission of a data packet (D) from the identification device (2) to the motor vehicle (1) via the second communication link (3b), the data containing the time points of emission and reception stored in step a) of the signals (S) transmitted.

Description

Technical Field

[0001] The present invention relates to a method for determining the instantaneous distance between a motor vehicle and a mobile electronic identification device, and a system comprising a motor vehicle and an identification device, the system being configured / programmed to implement the method. Background Technology

[0002] Mobile electronic identification devices can replace mechanical keys for authorizing entry into motor vehicles. Communication between the identification device and the vehicle typically uses a low-frequency radio system. This allows for the wireless transmission of authentication data, particularly for verifying entry authorization. In this context, using a radio connection conforming to the so-called UWB ("Ultra-Wide-Band") standard is a well-known practice. Using this UWB-compliant communication link not only allows for the transmission of authorization data between the identification device and the vehicle, but also enables the determination of the instantaneous distance between them with relatively high accuracy.

[0003] Conventional methods, such as the so-called "polling," can be used for this purpose. The basic idea behind these methods is to determine the signal propagation time required for the transmission of the signal based on the signal sent from the identification device to the vehicle or from the vehicle to the identification device, and to calculate the distance between the vehicle and the identification device based on the signal propagation time.

[0004] This authorized method with distance measurement function is described in DE 10 2017 103 187 A1.

[0005] Its disadvantage is that, in order to determine the distance, the identification device must transmit data related to the signal propagation time of the UWB signal to the vehicle (usually in the form of so-called timestamps, which characterize the time of transmission and reception of the relevant UWB signal).

[0006] However, transmitting all these timestamps via a UWB connection can cause problems due to the size of the resulting data packets. This is because, for regulatory reasons, the "link budget" for data transmission is limited, often requiring reduced transmission power from the identification device to the vehicle. This can potentially result in incomplete data transmitted to the vehicle. Summary of the Invention

[0007] Therefore, the object of the present invention is to create an improved method that takes into account the above-mentioned problems.

[0008] This objective is achieved through the subject matter of the independent claim. The preferred embodiment is the subject matter of the dependent claim.

[0009] Accordingly, the basic idea of ​​the present invention is to measure the signal transmission time via a UWB connection between the vehicle and the identification device, and to store the time point required for the signal transmission time measurement—also referred to as a "timestamp" by those skilled in the art—in the identification device to perform the aforementioned authorization and distance determination—as is known in conventional methods.

[0010] However, the innovation of the method presented in this paper lies in the fact that, after transmitting the signal used to determine the propagation time via a UWB connection, the data packet containing the timestamp is transmitted to the vehicle via an additional available BLE connection, rather than via the UWB connection. Since this BLE connection is not subject to the aforementioned limitations of the UWB connection in terms of link budget and transmission power, the timestamp can also be securely and completely transmitted from the identification device to the vehicle in a relatively large data packet format, where it is analyzed to determine the distance. This allows for reliable and highly accurate determination of the distance between the identification device and the vehicle.

[0011] The method according to the invention is used to determine the distance of a mobile electronic identification device relative to a motor vehicle that can be unlocked with the identification device. The identification device communicates with the motor vehicle to transmit data via a first wireless communication link operating according to the UWB standard and a second wireless communication link operating according to the BLE standard. The maximum operating range of the first communication link is preferably less than the maximum operating range of the second communication link.

[0012] The method according to the present invention comprises three steps a), b), and c). In step a),

[0013] At least one signal, containing the transmission time of the signal, is transmitted from the vehicle to the identification device via a first communication link. Preferably, multiple such signals can be transmitted sequentially. In step b), the transmission and reception times of one or more signals received by the identification device are stored in the identification device. In a further step c), a data packet is transmitted from the identification device to the vehicle via a second communication link, the data packet containing the transmission and reception times of the one or more signals transmitted in step a). This information can then be used to calculate the distance between the identification device and the vehicle at the time the signal was transmitted. In principle, this can be achieved by calculating the difference between the reception time and the transmission time. This difference corresponds to the time required to transmit the signal. Based on this time, the distance between the identification device and the vehicle at the time the signal was transmitted can be easily calculated.

[0014] According to a preferred embodiment, the method according to the invention includes an additional step d) performed after step c), according to which the instantaneous distance between the identification device and the vehicle is determined based on the data packet transmitted to the vehicle in step c). Thus, the method according to the invention can determine the distance between the identification device and the vehicle with extremely high accuracy.

[0015] Using a polling method to perform steps a) and b) is preferable. This polling method allows for the convenient determination of the signal propagation time of signals transmitted between the identification device and the vehicle via the first communication link. These propagation times can then be used to determine the distance between the identification device and the vehicle.

[0016] To implement this polling method, it is particularly desirable that, in step b), the identification device sends a polling signal to the vehicle via a first communication link. In response to this polling signal, the vehicle—also via the first communication link—transmits at least one response signal to the identification device, the signal containing the time of its transmission. The identification device can store the time of receipt of the response signal. This allows both time points—the transmission time and the reception time—to be added to the data packet to be transmitted to the vehicle. Thus, the data to be transmitted by the identification device to the vehicle via a second communication link includes the transmission and reception times of the response signal.

[0017] If exactly one response signal is transmitted in response to the polling signal, this processing method is also known as the "ping-pong" method.

[0018] However, it is particularly preferred that, in step b), two or more response signals are successively transmitted to the identification device via the first communication link in response to the polling signal. In this variation, for each response signal, the transmission and reception times of the response signal are added to the data packet to be transmitted from the identification device to the vehicle via the second communication link. By transmitting two or more such response signals with relevant timestamps, the transmission time required for signal transmission from the identification device to the vehicle can then be determined with particular precision. This also allows for the calculation of the distance between the vehicle and the identification device with particular precision.

[0019] In a further design of the method according to the invention, the transmission and reception times of the polling signal can also be added to the data packet. In this way, the signal propagation time of the polling signal can also be used for subsequent distance calculation. This will further improve the accuracy of determining the distance between the identification device and the vehicle.

[0020] The transmission of the data packet via the second communication link in step c) can preferably be performed in an encrypted manner. This allows safety-critical authorization data for authorizing access to the vehicle to be added to the data packet.

[0021] The present invention also relates to a system comprising a motor vehicle and a mobile electronic identification device, the identification device communicating with the motor vehicle via or capable of communicating via a first wireless communication link conforming to the UWB standard and a second wireless communication link conforming to the BLE standard. For this purpose, the motor vehicle includes a transmitting and receiving system for wireless data transmission with the identification device via these two communication links, wherein the transmitting and receiving system is configured / programmed to implement the method according to the invention. Therefore, the advantages of the method according to the invention as described above also apply to the system according to the invention.

[0022] According to a preferred embodiment, the transmitting and receiving system includes a first transmitting and receiving device for transmitting and receiving data via a first communication link, and a second transmitting and receiving device for transmitting and receiving data via a second communication link. The first transmitting and receiving device and the second transmitting and receiving device are connected to each other in a data-transmitting manner via a suitable—preferably wired—communication link, thereby transmitting the propagation time of signals received by the second transmitting and receiving device to the first transmitting and receiving device for further processing.

[0023] According to a preferred embodiment, the electronic identification device is part of or constitutes a component of a smartphone. Such smartphones typically come standard with transmitting and receiving units based on UWB and BLE standards.

[0024] Other important features and advantages of the invention are derived from the dependent claims, the drawings, and the description of related drawings based on the drawings.

[0025] It should be understood that the above features and the features to be explained below can be used not only in their respective specified combinations, but also in other combinations or individually, without departing from the scope of the invention. Attached Figure Description

[0026] Preferred embodiments of the present invention are illustrated in the accompanying drawings, which will be explained in detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components. Figure 1 An example of the system 20 according to the invention is shown in the form of a plan view. Detailed Implementation

[0027] System 20 includes a motor vehicle 1 with doors 4 through which the interior of the vehicle 1 can be accessed. The motor vehicle 1 includes a transmitting and receiving system 10 for wireless data transmission, which is configured / programmed to implement the method according to the invention. The transmitting and receiving system 10 for wireless data transmission may be a control device connected to an existing fieldbus (e.g., LIN bus or CAN bus) in the motor vehicle 1. Furthermore, system 20 includes a mobile electronic identification device 2. The electronic identification device 2 may be part of, or constituted by, a smartphone 11. As the identification device 2 approaches the motor vehicle 1, it is able to automatically authorize entry into the motor vehicle 1. Specifically, the doors 4 can unlock upon successful authorization.

[0028] The mobile identification device 2 can communicate with the transmitting and receiving system 10 of the vehicle 1 via a first wireless communication link 3a conforming to the UWB standard and a second wireless communication link 3b conforming to the BLE standard. For this purpose, a first transmitting and receiving device 6a, as part of the transmitting and receiving system 10, can be installed in the vehicle 1. This first transmitting and receiving device can communicate with a corresponding first transmitting and receiving device 7a in the identification device 2 via the first communication link 3a. Correspondingly, a second transmitting and receiving device 6b can be installed in the vehicle 1. This second transmitting and receiving device can communicate with a corresponding second transmitting and receiving device 7b in the identification device 2 via the second communication link 3b.

[0029] In the example, the first maximum effective distance of the first communication link 3a from vehicle 1 to identification device 2, measured with vehicle 1 as the starting point, is less than the second maximum effective distance of the second communication link 3b, also measured with vehicle 1 as the starting point. The first transmitting and receiving device 6a and the second transmitting and receiving device 6b of vehicle 1 can be connected to each other in a manner capable of transmitting data via a wired communication link 8.

[0030] The following will refer to Figure 1 The method according to the present invention will be illustrated by example.

[0031] The method includes three steps a), b), and c). In step a), the motor vehicle 1 transmits multiple signals S to the identification device 2 via the first communication link 3a. Each of these signals contains the time point at which each signal S was emitted.

[0032] According to step b), the emission time points of each signal S received by the identification device 2 and the reception time points of these signals S—determined by the identification device 2—are stored in the identification device 2.

[0033] In step c), data packet D is transmitted from identification device 2 to motor vehicle 1 via second communication link 3b. The data packet contains the transmission time point and reception time point of signal S transmitted in step a) that were stored in step b).

[0034] Steps a) and b) can be performed using a so-called "polling" method. For this purpose, in step b), the first transmitting and receiving device 7a of the identification device 2 transmits a polling signal PS to the first transmitting and receiving unit 6a of the vehicle 1 via the first communication link 3a. In response to this polling signal PS, the first transmitting and receiving unit 6a of the vehicle 2—also via the first communication link 3a—successively transmits multiple response signals AS to the first transmitting and receiving unit 7a of the identification device 2. These response signals each contain a timestamp indicating the transmission of each response signal AS.

[0035] For each response signal AS, the transmission and reception times of the response signal AS are respectively added to the data packet D to be transmitted from the second transmitting and receiving unit 7b of the identification device 2 to the second transmitting and receiving unit 6b of the vehicle 1 via the second communication link 3b. Therefore, the data packet D transmitted from the identification device 2 to the vehicle 1 via the second communication link 3b contains the relevant transmission and reception times of each generated response signal AS, as well as the relevant transmission and reception times of the polling signal PS that triggers the response signal AS.

[0036] In the additional step d) following step c), vehicle 1 calculates the instantaneous distance between identification device 2 and vehicle 1 based on the data packet D transmitted to vehicle 1 in step c) which includes the transmission time and reception time. This calculation can be performed in the first transmitting and receiving unit 6a. For this purpose, the data packet D received by the second transmitting and receiving unit 6b of the transmitting and receiving system 10 of vehicle 1 can be transmitted to the first transmitting and receiving device 6a of the transmitting and receiving system 10 via the wired communication link 8, where it is further processed to calculate the searched distance between identification device 2 and vehicle 1.

[0037] The transmission of data packet D via the second communication link 3b in step c) can be encrypted. This means that security-critical authorization data can also be added to data packet D to authorize the identification device 2 to enter the vehicle 1.

Claims

1. A method for determining the instantaneous distance between a mobile electronic identification device (2) and a motor vehicle (1) that can be unlocked by the identification device (2), wherein, The identification device (2) is capable of communicating with the motor vehicle (1) to transmit data via a first wireless communication link (3a) operating according to the UWB standard and a second wireless communication link (3b) operating according to the BLE standard, wherein the method comprises the following steps: a) At least one signal (S) is transmitted from the first transmitting and receiving device (6a) of the transmitting and receiving system (10) of the motor vehicle (1) to the identification device (2) via the first communication link (3a), the at least one signal containing the time point of transmission of the at least one signal (S), b) Store the transmission time and reception time of the at least one signal (S) received by the identification device (2) in the identification device (2). c1) Transmit a data packet (D) from the identification device (2) to the motor vehicle (1) via a second communication link (3b), the data packet (D) containing the transmission time and reception time of the at least one signal (S) transmitted in step a). c2) The second transmitting and receiving device (6b) of the transmitting and receiving system (10) of the motor vehicle (1) receives the data packet (D) from the identification device (2). c3) The second transmitting and receiving device (6b) of the transmitting and receiving system (10) of the motor vehicle (1) transmits the received data packet (D) from the identification device (2) to the first transmitting and receiving device (6a) of the transmitting and receiving system (10) of the motor vehicle (1) via a wired communication link (8). d) The first transmitting and receiving device (6a) of the transmitting and receiving system (10) of the motor vehicle (1) determines the instantaneous distance between the identification device (2) and the motor vehicle (1) based on the transmission time point and the reception time point contained in the received data packet (D).

2. The method according to claim 1, Its features are, Use a polling method to perform steps a) and b).

3. The method according to claim 2, Its features are, In step b): The identification device (2) sends a polling signal (PS) to the motor vehicle (1) via the first communication link (3a). In response to the polling signal (PS), at least one response signal (AS) is transmitted from the vehicle (1) to the identification device (2) via the first communication link (3a), the at least one response signal containing the time point of transmission of the response signal (AS). The time of the transmission of the response signal (AS) and the time of reception of the response signal (AS) in the identification device (2) are added to the data packet (D) to be transmitted by the identification device (2) to the motor vehicle (1) via the second communication link (3b).

4. The method according to claim 3, Its features are, In step b), two or more response signals (AS) are successively transmitted to the identification device (2) via the first communication link (3a) in response to the polling signal (PS). For each received response signal (AS), the time of transmission and the time of reception of the response signal (AS) are added to the data packet to be transmitted by the identification device (2) to the motor vehicle (1) via the second communication link (3b).

5. The method according to claim 3, Its features are, The polling signal (PS) transmission and reception times are also added to the data packet (D).

6. The method according to any one of the preceding claims, Its features are, In step c1), the transmission of the data packet (D) is performed in an encrypted manner.

7. A system (20) comprising: A motor vehicle (1) comprising a transmitting and receiving system (10) for wireless data transmission, the transmitting and receiving system being configured / programmed to implement the method according to any one of the preceding claims. The mobile electronic identification device (2) communicates with the transmitting and receiving system (10) of the motor vehicle (1) via or is capable of communicating via a first wireless communication link (3a) conforming to the UWB standard and a second wireless communication link (3b) conforming to the BLE standard.

8. The system according to claim 7, Its features are, The transmitting and receiving system (10) includes a first transmitting and receiving device (6a) for transmitting and receiving data via a first communication link (3a), and a second transmitting and receiving device (6b) for transmitting and receiving data via a second communication link (3b). The first transmitting and receiving device (6a) and the second transmitting and receiving device (6b) are connected to each other via a wired communication link (8) in a manner that enables data transmission, thereby enabling the transmission of data packets (D) received by the second transmitting and receiving device (6b) of the transmitting and receiving system (10) to the first transmitting and receiving device (6a) for further processing.

9. The system according to claim 7 or 8, Its features are, The electronic identification device (2) is part of or constitutes a smartphone (11).

Images