Method and device for determining a quality indicator for a distance measurement

Abstract

A device (101) for determining a quality indicator for a distance value of the distance between an electronic device (110) and a first communication unit (102) of a vehicle (100) is described, wherein the vehicle (100) comprises M different communication units (102) arranged at different locations on the vehicle (100), with M ≥ 2. The device (101) is configured to determine a device distance value of the distance between the device (110) and the first communication unit (102) of the vehicle (100) based on a first communication connection (112) between the electronic device (110) and the first communication unit (102) of the vehicle (100).The device (101) is further configured to determine a vehicle distance value of the distance between the two different communication units (102) of the vehicle (100) by means of a second communication link (212) between two different communication units (102) of the vehicle (100), and to determine the quality indicator for the device distance value based on the vehicle distance value.

Description

[0001] The invention relates to a method and a corresponding device for determining a quality indicator for the quality of a distance measurement of the distance between an electronic device and a vehicle.

[0002] A vehicle may have one or more functions that can be controlled by a user of the vehicle using an electronic device, such as a smartphone. These vehicle functions may be controlled depending on the device's position relative to the vehicle, particularly its distance from the vehicle. For this purpose, a distance value between the device and the vehicle can be determined via a wireless communication connection, especially a Bluetooth Low Energy (BLE) connection. The control of the vehicle's functions can then be effected based on this distance value.

[0003] The accuracy of the distance value determined via a communication link can be affected by overloading of the frequency band used for the communication link. This document addresses the technical challenge of efficiently developing a precise quality indicator for the quality, and in particular the accuracy, of the distance value determined via a wireless communication link, specifically to enable reliable and robust remote control of one or more vehicle functions.

[0004] The problem is solved by each of the independent claims. Advantageous embodiments are described, inter alia, in the dependent claims. It should be noted that additional features of a claim dependent on an independent claim, without the features of the independent claim itself or only in combination with a subset of the features of the independent claim, can constitute a separate invention independent of the combination of all features of the independent 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 constitute an invention independent of the features of the independent claims.

[0005] According to one aspect, a device for determining a quality indicator for a distance value between an electronic device and a first communication unit of a (motor) vehicle is described. The distance value can be a measured and / or estimated value of the distance. The distance value can be determined based on a communication link between the device and the first communication unit.

[0006] The electronic device may have a digital key that can be configured according to the Car Connectivity Consortium (CCC) key standard, in particular according to CCC Release 3 or higher. The digital key can be used to authenticate the electronic device (e.g., a smart device such as a smartphone) via the communication link between the electronic device and the first communication unit for controlling one or more vehicle functions. Examples of vehicle functions include locking or unlocking the vehicle and / or starting the vehicle's engine.

[0007] The vehicle comprises M different communication units, arranged at different locations on the vehicle, with M ≥ 2. The vehicle may, for example, have one or more communication units at the front and / or one or more communication units at the rear. The relative position, in particular the distance, of the individual communication units to each other is typically known in advance. Each communication unit may be configured to establish a Bluetooth, in particular a Bluetooth Low Energy (BLE), communication connection (in pairs with each other and / or with the electronic device). The communication connection may operate in a specific frequency band, e.g., 2.4 GHz or 5 GHz.

[0008] The device can be configured to determine a device distance value, based on a first (BLE) communication link between the electronic device and the vehicle's first communication unit. This device distance value can be determined using phase-based distance measurement, in particular using the BLE channel sounding method.

[0009] Furthermore, the device can be configured to determine a vehicle distance value—the distance between two different communication units of the vehicle—using a second (BLE) communication link between them. This vehicle distance value can be determined using phase-based distance measurement, in particular using the BLE Channel Sounding method.

[0010] The device distance value can be determined at a first time point, and the vehicle distance value can be determined at a second time point, with the first and second time points preferably being as close together as possible. In particular, the first and second time points can have a time interval of 500 ms or less.

[0011] The device is further configured to determine the quality indicator for the device distance value (i.e., for the accuracy of the device distance value) based on the vehicle distance value. In particular, the device can be configured to compare the vehicle distance value with a reference distance value of the distance between the two different communication units of the vehicle. The reference distance value can be determined (in advance) during a calibration phase using a Bluetooth Low Energy (BLE) communication link between the two different communication units of the vehicle (and stored on a memory unit of the vehicle). The communication link is preferably interference-free during the calibration phase. The reference distance value can be determined using a phase-based distance measurement, in particular using the BLE Channel Sounding method.The quality indicator for the device distance value can then be determined in a particularly precise manner based on the comparison between the vehicle distance value and the reference distance value.

[0012] The device can be configured to control a vehicle function depending on the quality indicator, in particular to activate or deactivate it. For example, the vehicle function can be enabled when the quality indicator shows a quality level equal to or greater than a quality threshold. Conversely, the vehicle function can be deactivated when the quality indicator shows a quality level less than the quality threshold.

[0013] The device can be configured, in particular, to determine a possible range of values ​​for the distance between the electronic device and the vehicle's first communication unit, based on the quality indicator and the device distance value. The vehicle's function can then be controlled, in particular activated or deactivated, in a particularly reliable and robust manner depending on the determined range of values.

[0014] This document describes a device designed to verify the accuracy of a distance measurement based on a potentially impaired communication link by measuring the previously known distance between two communication units of the vehicle 100. The accuracy of the distance measurement can be taken into account when controlling one or more vehicle functions. Consequently, a particularly reliable and robust (remote) control of one or more vehicle functions can be achieved by an electronic device.

[0015] The vehicle can include M ≥ 3 different communication units. The device can be configured to use different communication units of the vehicle than the first communication unit for the second communication link used to determine the vehicle distance value. Alternatively or additionally, the device can be configured to determine the device distance value and the vehicle distance value simultaneously, in particular at the same time. This further increases the accuracy of the quality indicator for the device distance value.

[0016] The device can be configured to determine a large number of vehicle distance values, particularly sequentially, based on the second communication link between the two different communication units of the vehicle. The quality indicator can then be determined with particular precision based on this large number of vehicle distance values. The quality indicator can, for example, specify a dispersion, in particular a variance and / or a standard deviation, of the vehicle distance values ​​(and, based on this, a dispersion of the device distance value).

[0017] The distance values ​​can be determined in a multitude of different (BLE) channels, in particular in N different (BLE) channels, of the frequency band of the first and / or the second communication link, e.g. with N≥50. Due to interference with the respective communication link, it may happen that not all channels and / or only a selective selection of channels can be used to determine the distance value.

[0018] The device can be configured to determine the number and / or selection of channels in the frequency band of the first communication link used to determine the device distance value. Furthermore, the device can be configured to determine the vehicle distance value based on the determined number and / or selection of channels in the first communication link, in particular by using the same number and / or selection of channels for determining the vehicle distance value as for determining the device distance value. By taking into account the channels used to determine the device distance value when calculating the quality indicator, the accuracy of the quality indicator can be further increased.

[0019] The device can also be configured to determine a reference distance value for calculating the quality indicator, depending on the determined number and / or selection of channels in the first communication link. Prior to calibration (during the calibration phase), a reference distance value can be determined (and stored) for a multitude of different numbers and / or selections of channels, in particular for all possible numbers and / or selections. The reference distance value used to determine the device distance can then be selected for the number and / or selection of channels used. This allows for the determination of a particularly precise quality indicator.

[0020] According to another aspect, a (road) motor vehicle (in particular a passenger car or a truck or a bus or a motorcycle) is described that includes the device described in this document.

[0021] According to a further aspect, a method is developed for determining a quality indicator for a distance value (i.e., for the quality of the distance value) of the distance between an electronic device and a first communication unit of a vehicle, wherein the vehicle M comprises different communication units located at different points on the vehicle, with M ≥ 2. The method comprises determining, based on a first communication link between the electronic device and the first communication unit of the vehicle, a device distance value of the distance between the device and the first communication unit of the vehicle.Furthermore, the procedure includes determining, using a second communication link between two different communication units of the vehicle, a vehicle distance value of the distance between the two different communication units of the vehicle, and determining the quality indicator for the device distance value based on the vehicle distance value.

[0022] It should be noted that the aspects described in connection with the device, in particular the claims described in connection with the device, are also applicable to the method as corresponding process features.

[0023] Another aspect described is a software (SW) program. The SW program can be configured to run on a processor and thereby execute the procedure described in this document.

[0024] Another aspect describes a storage medium. This storage medium can include a software program configured to run on a processor and thereby execute the procedure described in this document.

[0025] 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 aspect of the methods, devices, and systems described in this document can be combined with one another in a variety of ways. In particular, the features of the claims can be combined with one another in a variety of ways. Features listed in parentheses are to be understood as optional features.

[0026] The invention will now be described in more detail using exemplary embodiments. Fig. 1a an exemplary digital access system for a vehicle; Fig. 1b an exemplary usage situation for a digital access system; Fig. 2 exemplary communication units of a vehicle; and Fig. 3 a flowchart of an exemplary procedure for determining a quality indicator for the quality, in particular for the accuracy and / or for the dispersion, of a distance value of the distance between a vehicle and an electronic device.

[0027] As stated at the outset, this document deals with the precise localization of an electronic device in and / or on a vehicle. In this context, it shows Fig. 1a an exemplary (access) system 150 comprising at least one vehicle 100 and one digital key device 110.

[0028] The digital key device 110 is typically a portable electronic (user) device, such as a smartphone or tablet PC, on which a digital key 111 is stored. The digital key 111 can be stored in a protected storage area, in particular in a so-called "secure element," of the portable electronic device.

[0029] The digital key device 110 is designed to communicate with a communication unit 102 of the vehicle 102 via one or more different wireless communication links 112. The different communication links 112 can be used for different purposes. In particular, a Bluetooth Low Energy (BLE) communication link 112 can be used to • to determine the distance and / or relative position between the digital key device 110 and the vehicle 100 (in particular based on the signal strength, especially the RSSI (Received Signal Strength Indicator), of the radio signals exchanged between the vehicle 100 and the device 110; and / or using BLE Channel Sounding (mode 2 / phase-based measurements); and / or • To exchange data between the digital key device 110 and the vehicle 100 (e.g. a control command to control a vehicle function 103, such as unlocking a door and / or opening or closing a window and / or activating or deactivating a heating function and / or activating or deactivating the drive motor of the vehicle 100).

[0030] A (control) device 101 of the vehicle 100 can be configured to control at least one vehicle function 103 of the vehicle 100 depending on the communication between the device 110 and the vehicle 100, as exemplified in Fig. 1b. In this context, the digital key 111 of the device 110 can be verified, in particular authenticated and / or validated. Furthermore, after successful authentication and / or validation, one or more vehicle functions 103 can be controlled, in particular depending on • the distance between the device 110 and the vehicle 100; • the position of the device 110 relative to the vehicle 100; and / or • a control command sent from the device 110 to the vehicle 100 via a communication link 112.

[0031] In an exemplary system 150, a BLE communication link 112 can be established between the device 110 and the vehicle 100 as soon as the distance between the device 110 and the vehicle 100 is equal to or less than a first distance threshold 121. This allows the user to remotely control one or more vehicle functions 103 using the device 110. Typically, the vehicle 100 repeatedly indicates the availability of a BLE communication link 112, for example, at a specific frequency. From the first distance threshold 121, the device 110 (which can also be referred to as "user equipment" (UE)) receives the display message from the vehicle 100, and the BLE communication link 112 can then be established between the device 110 and the vehicle 100.The first distance threshold 121 may depend on the communication capabilities of the device 110, the environment of the vehicle 100 and / or the device 110, and / or the position of the device 110 relative to the vehicle 100.

[0032] As explained above, the distance between the device communication unit of an electronic device 110 (e.g., the key fob) and a vehicle communication unit 102 (e.g., of the vehicle 100) can be determined using BLE Channel Sounding. In BLE Channel Sounding, one of the two communication units 102 is the initiator, and the other is the reflector. The initiator transmits an initiator signal with a specific amplitude over a specific BLE channel. This specific BLE channel is associated with a specific frequency of the initiator signal. The reflector measures the phase of the received initiator signal. Furthermore, the reflector sends a reflector signal back to the initiator on the same BLE channel, with the reflected signal having the measured phase of the received initiator signal.

[0033] The initiator measures the phase of the received reflector signal and compares it to the phase of the originally transmitted initiator signal. The phase difference between the phase of the received reflector signal and the phase of the originally transmitted initiator signal depends on the distance traveled by each signal (where the distance is twice the distance between the two communication units 102).

[0034] The phase measurement described above can be performed for a large number of different BLE channels, i.e., for a large number of different frequencies. Based on the large number of measured phase differences for the corresponding large number of different BLE channels (e.g., N = 72 different BLE channels), a measured value for the distance (i.e., a distance value of the distance) between the two communication units 102 can be determined in a precise manner.

[0035] The phase of the received reflector signal can be determined using an in-phase and quadrature (IQ) method. For this purpose, the received reflector signal is superimposed with an in-phase reference signal at the specified frequency of the respective BLE channel to determine the I-coordinate of an IQ data point. Furthermore, the received reflector signal is superimposed with a quadrature-phase reference signal at the specified frequency of the respective BLE channel (where the quadrature-phase reference signal is phase-shifted by 90° relative to the in-phase reference signal) to determine the Q-coordinate of the IQ data point.

[0036] The IQ data point for a BLE channel can be represented as a point in the (Cartesian) IQ coordinate system. Similarly, IQ data points can be determined for the N different BLE channels (i.e., for N different frequencies) and each represented as a point in the IQ coordinate system. Each IQ data point has an amplitude and a phase (in polar coordinates). The phase corresponds to the phase difference Δθ to be determined.

[0037] The following relationship can be established between the phase difference Δθ. n , the measured value of the distance D and the frequency f n of the respective BLE channel n, with n = 1,..., N, can be derived, Δθn=2π2Dfnc where c is the speed of light. Therefore, there is a linear relationship between the phase difference Δθ. n and the frequency f n of the respective BLE channel n.

[0038] Using BLE Channel Sounding, the distance D (i.e., a distance value of the distance) between an electronic (user) device 110 and a communication unit 102 of the vehicle 100 can thus be determined in a precise manner.

[0039] Fig. Figure 2 shows an exemplary vehicle 100 that has several communication units 102 arranged at different locations on the vehicle 100, e.g., in the front, rear, driver's side, and / or passenger's side. In the example shown, the vehicle 100 has three different communication units 102 (two in the front and one in the rear).

[0040] For each of the M different communication units 102 (especially M≥2 or M≥3) of the vehicle 100, the distance value between the device 110 and the respective communication unit 102 can be determined (using BLE channel sounding). Based on the M distance values ​​and the position of the M different communication units 102, the position of the device 110 can be determined precisely (using a triangulation method). The position of the device 110 can then be specified in the (Cartesian or polar) coordinate system of the vehicle 100.

[0041] The electronic device 110 is typically designed such that a BLE communication connection 112 can only be established and operated simultaneously with a single communication unit 102 of the vehicle 100. For the above localization method, to determine the M distance values ​​for the M different communication units 102, a communication connection 112 can be established sequentially between each of the communication units 102 and the device 110, the distance value for the respective communication unit 102 can be determined using channel sounding, and then the communication connection 112 can be terminated to allow the establishment of the communication connection 112 for the subsequent communication unit 102.

[0042] For the one or more communication links 112 between the device 110 and the one or more communication units 102 of the vehicle 100, a frequency band, such as the 2.4 GHz frequency band and / or the 5 GHz frequency band, can be used, which is also used for other communication applications, such as WLAN. Relatively intensive use of the frequency band can lead to congestion of the frequency band and, consequently, to impairment of the one or more communication links 112 between the device 110 and the one or more communication units 102 of the vehicle 100. This, in turn, can impair the quality, in particular the accuracy, of the one or more distance values ​​determined using channel sounding (and / or RSSI) over the one or more communication links 112.This document describes measures that make it possible to efficiently determine a precise quality indicator for the accuracy of a distance value determined using a wireless communication link 112.

[0043] As from Fig. As can be seen in Figure 2, the vehicle 100 has several communication units 102, which are arranged at different locations within the vehicle 100. The relative arrangement of the communication units 102 within the vehicle 100 is typically fixed. In particular, the communication units 102 are arranged in pairs at a fixed, and typically known, distance from each other.

[0044] A vehicle 100 with M communication units 102 has M*(M-1) / 2 different pairs, each with exactly two communication units 102. For one or more of the pairs, in particular for all possible pairs, a reference distance value can be determined between the two communication units 102 in a calibration phase using a communication link 212, in particular using a BLE communication link. For this purpose, the channel sounding method and / or the RSSI method described above can be used. During the calibration phase, it can be ensured that the individual communication links 212 are not disturbed by external influences (e.g., by another communication application). The calibration phase can be carried out, for example, in an anechoic chamber.

[0045] During the operation of the vehicle 100, as explained above, a distance value between the electronic device 110 and the communication unit 102 of the vehicle 100 can be determined based on at least one communication connection 112 between the electronic device 110 and a first communication unit 102 of the vehicle 100. This distance value can be referred to as the device distance value.

[0046] Furthermore, possibly simultaneously, a distance value between two (possibly different) communication units 102 of the vehicle 100 can be determined based on a communication connection 212. This distance value can be referred to as the vehicle distance value.

[0047] The vehicle distance value can be compared with the reference distance value between the two (possibly other) communication units 102 in order to determine a quality indicator for the quality of the communication-based distance measurement. The quality indicator can be determined, in particular, based on the deviation of the determined vehicle distance value from the reference distance value. The quality indicator can, for example, include a measure of the dispersion of the determined distance values.

[0048] If necessary, a large number of vehicle distance values ​​can be determined sequentially and each compared to the reference distance value. In this way, a particularly precise quality indicator can be determined based on the large number of vehicle distance values.

[0049] The quality indicator can be used as an indicator of the accuracy of the device distance value. In particular, based on the quality indicator and the device distance value, a possible range of values ​​for the distance between the device 110 and the communication unit 102 of the vehicle 100 can be determined. The range of values ​​can be limited by a minimum value and a maximum value, where the minimum value is below the device distance value by an amount dependent on the quality indicator, and where the maximum value is above the device distance value by an amount dependent on the quality indicator. The control of one or more vehicle functions 103 can then be effected depending on the determined range of values ​​for the distance between the device 110 and the communication unit 102 of the vehicle 100.

[0050] Thus, the M different communication units 102 (e.g., transceivers) of the vehicle 100 can be used, where the distance between the individual communication units 102 is known. During a calibration phase, a channel sounding method can be performed in an anechoic chamber between one or more pairs of communication units 102. The number of BLE channels used to determine the distance value can be varied if necessary. If required, different reference distance values ​​can be determined and stored for a pair of communication units 102 for different numbers and / or selections of BLE channels used.

[0051] To determine a quality indicator for the (device) distance value between a device 110 and the vehicle 100, the (vehicle) distance value of the distance between a pair of communication units 102 can be determined using the Channel Sounding method. This distance value can be compared with one or more reference distance values ​​to determine the quality indicator. The quality indicator can then be used as an indicator of the quality of the (device) distance value between the device 110 and the vehicle 100.

[0052] Based on the quality indicator, a decision can be made as to whether the determined (device) distance value can be used for the distance between device 110 and vehicle 100 or not. For example, a vehicle function 103 can be prevented from being executed if the quality indicator indicates a quality of the (device) distance value that is equal to or less than a certain quality threshold.

[0053] Fig. Figure 3 shows a flowchart of an exemplary (possibly computer-implemented) method 300 for determining a quality indicator for a distance value of the distance between an electronic device 110 and a first communication unit 102 of a (motor) vehicle 100. The device 110 may have a digital key 111 that enables the device 110 to control one or more functions 103 of the vehicle 100. The vehicle 100 may comprise M different communication units 102, arranged at different locations on the vehicle 100, with M ≥ 2. The method 300 may be executed by a control device 101 of the vehicle 100.

[0054] Method 300 comprises determining 301, based on a first (BLE) communication link 112 between the electronic device 110 and the first communication unit 102 of the vehicle 100, a device distance value of the distance between the device 110 and the first communication unit 102 of the vehicle 100. The device distance value can be determined, for example, using an RSSI-based method and / or a phase-based method (such as channel sounding).

[0055] Furthermore, the procedure 300 includes determining 302, using a second communication link 212 between two different communication units 102 of the vehicle 100, a vehicle distance value of the distance between the two different communication units 102 of the vehicle 100. The vehicle distance value can be determined using the same method as the device distance value.

[0056] The two different communication units 102 can include the first communication unit 102. The distance between the two different communication units 102 can be known and / or can have been determined beforehand. In particular, a reference distance value can exist for the distance between the two different communication units 102 (and may have been stored in a memory unit of the vehicle 100).

[0057] Procedure 300 further includes determining the quality indicator 303 for the device distance value based on the vehicle distance value. The quality indicator can be determined, in particular, by comparing the vehicle distance value with the reference distance value.

[0058] The measures described in this document enable the efficient and precise determination of the quality of a distance measurement based on a communication link 112. This allows for a particularly reliable and robust distance-based control of a function 103 of a vehicle 100.

[0059] The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and the figures are intended only to illustrate the principle of the proposed methods, devices, and systems by way of example.

Claims

[1] Device (101) for determining a quality indicator for a distance value of the distance between an electronic device (110) and a first communication unit (102) of a vehicle (100); wherein the vehicle (100) M comprises different communication units (102) arranged at different locations of the vehicle (100), with M≥2; wherein the device (101) is configured, - to determine a device distance value of the distance between the device (110) and the first communication unit (102) of the vehicle (100) based on a first communication link (112) between the electronic device (110) and the first communication unit (102) of the vehicle (100); - to determine a vehicle distance value of the distance between the two different communication units (102) of the vehicle (100) using a second communication link (212) between two different communication units (102) of the vehicle (100); and - to determine the quality indicator for the device distance value based on the vehicle distance value. [2] Device (101) according to claim 1, wherein the device (101) is configured, - to compare the vehicle distance value with a reference distance value of the distance between the two different communication units (102) of the vehicle (100); and - to determine the quality indicator for the device distance value based on the comparison. [3] Device (101) according to claim 2, wherein the reference distance value was determined during a calibration phase by means of a communication link (212) between the two different communication units (102) of the vehicle (100). [4] Device (101) according to one of the preceding claims, wherein - the vehicle (100) comprises M≥3 different communication units (102); and - the device (101) is set up, - to use different communication units (102) of the vehicle (100) than the first communication unit (102) for the second communication link (212) to determine the vehicle distance value; and / or - to determine the device distance value and the vehicle distance value in parallel with each other over time, in particular simultaneously. [5] Device (101) according to one of the preceding claims, wherein the device (101) is configured, - to determine a plurality of vehicle distance values ​​of the distance between the two different communication units (102) of the vehicle (100) using the second communication link (212) between the two different communication units (102) of the vehicle (100), in particular sequentially; and - to determine the quality indicator based on the large number of vehicle distance values. [6] Device (101) according to one of the preceding claims, wherein the device (101) is configured, - to determine a number and / or a selection of channels of a frequency band of the first communication link (112) that was used to determine the device distance value; and - to determine the vehicle distance value depending on the determined number and / or selection of channels of the first communication link (112), in particular in such a way that the same number and / or selection of channels is used for determining the vehicle distance value as for determining the device distance value. [7] Device (101) according to any of the preceding claims, wherein - the first and second communication links (112, 212) are both Bluetooth Low Energy (BLE) communication links; and / or - the device distance value and the vehicle distance value are each determined using a phase-based distance measurement, in particular using the BLE Channel Sounding method. [8] Device (101) according to one of the preceding claims, wherein the device (101) is configured to control a vehicle function (103) of the vehicle (100) depending on the quality indicator, in particular to effect or to prevent it. [9] Device (101) according to claim 8, wherein the device (101) is configured, - to determine a possible range of values ​​for the distance between the device (110) and the first communication unit (102) of the vehicle (100) based on the quality indicator and the device distance value; and - to control a vehicle function (103) of the vehicle (100) depending on the determined value range, in particular to effect or prevent it. [10] Method (300) for determining a quality indicator for a distance value of the distance between an electronic device (110) and a first communication unit (102) of a vehicle (100); wherein the vehicle (100) comprises M different communication units (102) arranged at different locations of the vehicle (100), with M≥2; wherein the method (300) comprises, - Determine (301), using a first communication link (112) between the electronic device (110) and the first communication unit (102) of the vehicle (100), a device distance value of the distance between the device (110) and the first communication unit (102) of the vehicle (100); - Determine (302), using a second communication link (212) between two different communication units (102) of the vehicle (100), a vehicle distance value of the distance between the two different communication units (102) of the vehicle (100); and - Determine (303) the quality indicator for the device distance value based on the vehicle distance value.

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