Optimized angle of incidence determination

Abstract

The invention relates to a method for determining an angle of incidence (AoA) and / or a direction of arrival (DoA) of an electromagnetic wave (W) from a mobile device (200) on a receiving unit (100), in particular on a UWB receiver, the receiving unit (100) having at least two receiving antennas (AE1, AE2), in order to determine the angle of incidence (AoA) and / or the direction of arrival (DoA), a phase difference (PDoA) between the signal responses (CIR) on the receiving antennas (AE1, AE2) is determined, the phase difference (PDoA) being determined at a position in the signal responses (CIR), said position being further prior to a respective midpoint (M) of the first signal path (LoS) in the signal responses (CIR).

Description

Technical Field

[0001] The invention relates to a method for determining the angle of arrival (AoA) and / or the direction of arrival (DoA) of electromagnetic waves from a mobile device on a receiving unit, in particular a UWB receiver. The invention also relates to a corresponding computer program product, a corresponding control unit and a corresponding receiving unit, in particular a corresponding UWB receiver, for executing the corresponding method. Background Art

[0002] Methods for determining the angle of incidence or direction from which the electromagnetic radio waves enter the receiver are known in principle. For this purpose, the receiver can be constructed, for example, with two receiving antennas. The angle of incidence can be calculated from the phase difference (English: phase difference of arrival, or abbreviated as PDoA) at the two receiving antennas. Problems arise in particular when the receiver is installed close to metal, such as is the case with receivers used for vehicle access systems, which are installed close to the vehicle body. The proximity to metal generates a signal path that is only slightly longer than the first signal path or the direct line of sight (English: line of sight, or abbreviated as LoS) of the receiver, i.e. the shortest signal path. This signal path can affect the determination of the phase difference for the shortest signal path (i.e. the signal path of interest or importance), which leads to erroneous results in terms of the phase difference and thus adversely affects the determination of the angle of incidence or the direction of arrival.

[0003] For example, the following scenario can be described. A mobile device, such as a smartphone, is to be located relative to a vehicle with the aid of a receiver, for example via UWB. It can happen here that only a single receiver receives the signal from the mobile device. This can happen when other receivers are blocked and / or the signal is weak. In this case, the receiver can measure the distance to the mobile device. If at least two antennas are arranged at a defined distance from each other (less than λ / 2) in the receiver, the phase difference of the signals on the two antennas can be determined. The angle of incidence of the signal can therefore be determined from the phase difference. This functionality can be advantageous for vehicle access systems.

[0004] In most cases, the midpoint of the first signal path of the signal is used to determine the phase difference. As mentioned above, determining the phase difference at the midpoint of the first signal path of the signal in this way may lead to erroneous results when determining the angle of incidence or the direction of arrival. The reason is that the UWB pulse is not an ideal Dirac impulse (t=0), but has a finite pulse width, for example about 2ns. As a result, a signal component in the channel impulse response (English: channel impulse response, or abbreviated as CIR) is visible, which extends over a few nanoseconds. If the UWB receiver is installed close to metal, there may now be a strong reflection path, depending on the direction of arrival, which is only a few centimeters longer than the first signal path of interest and whose signal components are superimposed on the signal components of the first signal path and are thereby distorted. Therefore, in this case, determining the phase difference at the midpoint of the first signal path is not optimal. Summary of the invention

[0005] The object of the present invention is therefore to at least partially overcome at least one of the above-mentioned disadvantages. The object of the present invention is in particular to provide a method for determining the angle of incidence and / or the direction of arrival of electromagnetic waves from a mobile device on a receiving unit, in particular a UWB receiver, which method can improve the determination of the angle of incidence and / or the direction of arrival, which has better accuracy, can improve the access function of the vehicle, increase the comfort of the customer and enhance the trust in the access system. In addition, the object of the present invention is to provide a corresponding computer program product for executing the corresponding method, a corresponding receiving unit, in particular a corresponding UWB receiver.

[0006] The present invention provides a method for determining the angle of incidence and / or direction of arrival of electromagnetic waves from a mobile device on a receiving unit, especially on a UWB receiver, having the features of an independent method claim. In addition, the present invention also provides a corresponding computer program product, a corresponding control unit and a corresponding receiving unit, especially a corresponding UWB receiver, having the features of a parallel claim. The features and details described herein in conjunction with different embodiments and / or aspects of the present invention are of course also applicable to other embodiments and / or aspects, and vice versa, so that the disclosures about the various embodiments and / or aspects always refer to each other or can refer to each other.

[0007] The present invention proposes a method for determining the angle of incidence and / or direction of arrival of electromagnetic waves from a mobile device on a receiving unit, especially on a UWB receiver. The receiving unit has at least two receiving antennas. In order to determine the angle of incidence and / or direction of arrival, the phase difference between the signal responses on the receiving antennas is determined. For this purpose, it is proposed to determine the phase difference at the following (multiple) positions in the signal response, which are also before the corresponding midpoint (M) of the (multiple) first signal path in the signal response.

[0008] The signal response in the sense of the present disclosure may also be referred to as a channel impulse response (English: channel impulse response, or abbreviated as CIR).

[0009] The first signal path or the direct line of sight (LoS) of the receiver is therefore called the shortest signal path.

[0010] The present invention recognizes that determining the phase difference at a midpoint of a first signal path of the signal is not optimal, since metallic parts on the vehicle may form reflection paths which may distort signal components of the first signal path.

[0011] The invention now proposes that the phase difference in the signal response is not calculated at the midpoint of the first signal path, but at an earlier (preferably as early as possible) position, at which the signal response exceeds a specific or purposefully set threshold value, for example.

[0012] In this way, the influence of signal components of slightly longer reflection paths, which could overlap with signal components of the first signal path and thus distort them, is reduced when determining the phase difference.

[0013] Furthermore, it can be provided that the phase difference is determined at (multiple) positions of the signal response, which exceed a specific, preferably specifically selected or calculated threshold value in the signal response. Thus, it can be achieved that the phase difference can be determined at an earlier (as early as possible) position, i.e. when the signal response has exceeded the threshold value.

[0014] Furthermore, it can be provided that the threshold value is determined such that the position at which the phase difference is determined occurs as early as possible in the signal response and is already above the noise level(s). In this way, it can be achieved that the phase difference can be determined as early as possible, i.e. when the signal response can be distinguished from the noise level.

[0015] On the one hand, it is conceivable that the threshold value can be determined according to the absolute value of the signal response. On the other hand, it is conceivable that the threshold value can be determined according to the absolute value of the real part of the signal response and / or according to the absolute value of the imaginary part of the signal response. For example, the threshold value can be determined in such a way that in the signal response (e.g., the absolute value of the signal response having a real part and an imaginary part and which can be regarded as a complex number), multiple values ​​caused by noise are waited for at least 2 ... 5ns before the identified midpoint of the first signal path in time. For example, the threshold value can be selected in such a way that the threshold value is higher than the noise level. Therefore, such a position or point of the signal response can be considered, at which the signal curve also rises toward the midpoint of the first signal path. The absolute value of the signal response and / or the absolute value of the real part of the signal response and / or the absolute value of the imaginary part of the signal response can be regarded as a signal.

[0016] Furthermore, it is conceivable that if the threshold is determined based on the absolute value of the real part of the signal response and based on the absolute value of the imaginary part of the signal response, a correspondingly earlier time can be selected as the relevant position for determining the phase difference. In other words, a correspondingly earlier time can be selected as the relevant position for determining.

[0017] Furthermore, it can be provided that the threshold value is determined according to two threshold values. For example, it is conceivable that the threshold value can be determined as the maximum of the two threshold values. Furthermore, the first threshold value can be determined according to the noise level and a first factor, in particular a first factor greater than 1. Furthermore, the second threshold value can be determined according to a first signal path in the signal response and a second factor, in particular a second factor less than 1. In other words, the threshold value can be defined as a combination of two differently calculated threshold values, for example as the maximum or the larger value of the two threshold values.

[0018] The first threshold value may be a threshold value that ensures that the signal response exceeds the noise and the first signal component of the first signal path becomes effective. A first factor, for example significantly greater than 1, such as 5, may be defined here, by which the noise level is multiplied. For example, the maximum value may be selected from a plurality of absolute values ​​within the noise range to determine the noise level. The first threshold value may then be determined as follows:

[0019] S1=F1*max(abs(CIR_Noise))

[0020] The second threshold value may be a threshold value that can represent a portion of the average value or selected value / peak value of the first signal path of the signal curve. A second factor F2 less than 1 may be defined, such as 0.2, so that the second threshold value may be determined as follows:

[0021] S2=F2*abs(CIR_Pick)

[0022] In order to ensure that the final threshold is both sufficiently above the noise level and occurs as early as possible before the average value or the picked value / peak value of the first signal path of the signal curve, the final threshold may be determined by a combination of two thresholds.

[0023] Advantageously, the signal responses at the two receiving antennas can be synchronized, in particular using a correspondingly earlier time as the relevant position for determining the phase difference. If the scanning of the receiving antennas is not exactly synchronized, the signal responses can preferably be synchronized using an earlier time, whereby, for example, a slight offset along the x-axis can occur so that the correspondingly earlier times exactly overlap in the case of the two receiving antennas.

[0024] Preferably, possible phase shifts can be taken into account when determining the phase position for the first receiving antenna and the phase position for the second receiving antenna, which phase shifts can be caused, for example, by the antenna design. In other words, possible phase shifts can be taken into account when determining the phase position for the first receiving antenna and the second receiving antenna, which phase shifts can be caused, for example, by the antenna design.

[0025] Furthermore, it is conceivable that if the receiving antennas recognize and / or output different first signal paths in the signal response, then preferably the earlier first signal path is used for determining the threshold value. Furthermore, it is conceivable that if the receiving antennas recognize and / or output different first signal paths in the signal response, then the first signal path of the predefined receiving antenna is used for determining the threshold value. In this way, a reliable determination can be achieved despite possible signal differences.

[0026] Furthermore, it can be provided that the signal response is interpolated by means of a filter to form a continuous curve, in particular with a certain proportion (e.g. one tenth) of the sampling step width of the signal response, preferably with the aid of a filter having the property that the positions for determining the phase difference in the signal response remain unchanged. Since the signal response is usually sampled at fixed sampling times, for example at 1 GHz, and therefore raw values ​​are generated in the corresponding signal response in time steps (e.g. every 1 ns), it can be advantageous to interpolate these raw values ​​by means of a filter, for example with one tenth (or a similar proportion) of the actual sampling step width, to form a smooth curve. Preferably, a filter can be used here with the property that the support points remain unchanged in the interpolated signal.

[0027] Furthermore, it can be provided that the position history of the mobile device is taken into account when determining the angle of incidence and / or the direction of arrival. In this way, improved results can be achieved.

[0028] Furthermore, it can be provided that when determining the angle of incidence and / or the direction of arrival, the phase difference is determined a plurality of times over a time window and the result is determined from the determined values ​​(for example as an average value). In this way, a reliable determination can be achieved.

[0029] Advantageously, the signal strength at the position(s) used for determining the phase difference on the first signal path and / or in the signal response may be taken into account to improve the determination of the angle of incidence and / or direction of arrival. Preferably, a signal strength of the signal response closer to the receiving antenna of the mobile device may be taken into account.

[0030] Furthermore, it can be provided that, for determining the angle of incidence and / or the direction of arrival, selected results are taken into account when determining the phase difference, which results are preferably selected by means of a machine learning method and / or which results are in particular from different receiving units. Advantageously, the outputted additional information, such as the signal strength (for example in combination with the calculated phase difference), can be checked by means of a machine learning method in order to determine the best possible result from the existing data. Training can be carried out both during development and in the field. In the field, for example when the vehicle has been sold and is on the road, the angle of incidence and / or the direction of arrival can be determined by means of multilateration - at least always where possible. Furthermore, only data with a high degree of reliability are used.

[0031] Furthermore, it can be provided that when determining the angle of incidence and / or the direction of arrival, a confidence value (English: confidence level, or abbreviated as C) can be output, which can depend on the signal strength and / or the determined angle of incidence and / or the determined direction of arrival, for example. In order to determine the angle of incidence and / or the direction of arrival, the results of different receiving units can preferably be taken into account. In order to determine the angle of incidence and / or the direction of arrival, the results of such receiving units can preferably be taken into account, which have a high, advantageously the highest, confidence value. Preferably, the best value can be selected with the aid of a machine learning method. In addition to the phase difference (or the angle of incidence and / or the direction of arrival resulting therefrom), a relevant descriptive confidence value can also be calculated and output. The confidence value (i.e. the information about the reliability of the result of the determination of the phase difference or the determination of the angle of incidence) is highest when the wavefront is incident vertically (AoA=0°) and decreases towards the boundary area, i.e. when the wavefront is incident from the side (AoA is approximately -90° or 90°). If, for example, it is known that certain angular positions provide less accurate results, the calculation of this value can preferably also be improved by additional measurements on the vehicle. Calibration with the aid of the reliability value can be performed on site, preferably in a self-learning manner, for example whenever multiple UWB receivers are active simultaneously or multiple UWB receivers can measure the distance to the mobile device. The actual position of the mobile device relative to the vehicle can then be determined by multilateration.

[0032] Furthermore, it is advantageously possible to take into account the position of the UWB receiver on the vehicle in order to improve the result of the determination of the phase difference or of the angle of incidence.

[0033] The present invention proposes a computer program product, which comprises instructions, which, when the computer executes the computer program product, cause the computer to perform the method as described above. With the computer program product, the same advantages as described above in conjunction with the method according to the invention can be achieved. Reference is now made to these advantages in full.

[0034] The invention proposes a control unit (ECU) having a computing unit and a storage unit, in which a code is stored, which, when at least partially executed by the computing unit, executes a method that can be run as described above. The same advantages as described above in conjunction with the method according to the invention can be achieved by means of the control unit (ECU). Reference is made here to these advantages in full.

[0035] The invention proposes a receiving unit (100), in particular a UWB receiver, for a vehicle, which has a control unit (ECU) which can be implemented as described above. The same advantages as described above in conjunction with the method according to the invention can be achieved with the receiving unit (100). Reference is made here to these advantages in full. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention is described in detail below with the help of the accompanying drawings. The accompanying drawings are as follows:

[0037] Figure 1 is an exemplary description for performing a method;

[0038] Figure 2 is an exemplary display of locations in the signal response where improved results may be achieved. DETAILED DESCRIPTION

[0039] The present invention proposes a method for determining an angle of incidence (English: "angle of arrival" or abbreviated as AoA) and / or a direction of arrival (English: "direction of arrival" or abbreviated as DoA) of an electromagnetic wave W from a mobile device 200 on a receiving unit 100, in particular a UWB receiver, by means of Figure 1 and 2 To explain the method.

[0040] At least two receiving antennas AE1 and AE2 may be provided in the receiving unit 100 or the UWB receiver.

[0041] Angle of incidence AoA (at Figure 1 The phase difference (also marked as α) can be calculated from the phase difference (English: “phase difference of arrival” or abbreviated as PDoA) at the two receiving antennas AE1 and AE2.

[0042] The present invention recognizes that if the receiving unit 100 or the UWB receiver is mounted close to metal, such as close to a vehicle body, problems may arise in determining the phase difference PDoA or the angle of incidence AoA or the direction of arrival DoA.

[0043] Through the proximity of metal, a signal path may be generated that is only slightly longer than the first signal path (English: "line of sight" or abbreviated as LoS) or the direct line of sight of the receiving unit 100 or the UWB receiver, i.e. the shortest signal path. Such a signal path may influence the determination of the phase difference PDoA for the shortest signal path or the first signal path LoS (i.e. the signal path of interest or importance), which leads to erroneous results when determining the phase difference PDoA and thus adversely affects the determination of the angle of incidence AoA or the direction of arrival DoA.

[0044] The following application example can be imagined. A mobile device 200, such as a smartphone, is to be positioned relative to a vehicle with the aid of a receiving unit 100 or a UWB receiver. It may happen here that only a single UWB receiver receives the signal from the mobile device 200. This may occur, for example, when other UWB receivers are blocked and / or the signal from the mobile device 200 is weak. In this case, the UWB receiver can measure the distance to the mobile device 200. If at least two receiving antennas AE1, AE2 are arranged at a defined distance d (d is less than λ / 2) from each other in the receiver, the phase difference PDoA of the signals on the two receiving antennas AE1, AE2 can be determined. Therefore, the angle of incidence AoA or the direction of arrival DoA of the signal can be determined from the phase difference PDoA. This function can be advantageous for vehicle access systems.

[0045] The phase difference PDoA may also be referred to as phase difference ΔΦ and the angle of incidence AoA may be referred to as angle α.

[0046] like Figure 1 As shown, the observed wavefront W arrives at the second receiving antenna AE2 at time t0 and arrives at the first receiving antenna AE1 at time (t0+Δl / c0), with a path difference of Δl. From this and with the aid of the period duration T or frequency f, it can be obtained that:

[0047] ΔΦ=2πf(Δl / c0)

[0048] The relationship with the angle of incidence AoA is as follows:

[0049] ΔΦ=(2π / λ)d cosα

[0050] If the phase difference ΔΦ or PDoA is known, the angle of incidence AoA can be calculated as follows:

[0051] α=arc cos((ΔΦλ) / (2πd))

[0052] In the known method, the midpoint M or the peak value in the first signal path LoS of the signal is used to determine the phase difference PDoA. As mentioned above, such determination of the phase difference on the first signal path of the signal may lead to erroneous results when determining the angle of incidence AoA or the direction of arrival DoA.

[0053] The present invention now recognizes that UWB pulses are not ideal Dirac impulses t=0, but have a finite pulse width, for example about 2ns. As a result, a signal component is visible in the channel impulse response (English: "channel impulse response" or abbreviated as CIR), which extends over several nanoseconds. When the UWB receiver is installed close to metal, there may now be a strong reflection path, depending on the arrival direction, which is only a few centimeters longer than the first signal path LoS of interest and whose signal components are superimposed on the signal components of the first signal path and are thus distorted. Therefore, in this case, the phase difference is not optimal until it is determined at the midpoint M or peak of the first signal path LoS.

[0054] The proposed method enables an improved determination of the angle of incidence AoA and / or direction of arrival DoA with better accuracy, enabling improved access functionality to the vehicle, increased customer comfort and increased trust in the access system.

[0055] like Figure 2 As shown, according to the present invention, a phase difference PDoA is determined at such a position (or multiple such positions) in the signal response CIR, and the position is also before the corresponding midpoint M of the first signal path LoS in the signal response CIR (here in time).

[0056] In other words, the present invention proposes that the phase difference PDoA in the signal response CIR is not calculated at the midpoint M of the first signal path LoS, but at an earlier (preferably as early as possible) position, at which the signal response CIR exceeds a specific or purposefully set threshold S, for example.

[0057] In this way, the influence of signal components of the slightly longer reflection paths, which can be superimposed on the signal components of the first signal path LoS and thus possibly distorted, can be reduced when determining the phase difference PDoA.

[0058] like Figure 2 As shown, the threshold value S may be determined in such a way that the one or more positions for determining the phase difference PDoA appear as early as possible in the signal response CIR and are already above the noise level Noise.

[0059] like Figure 2For schematic purposes only, it is conceivable that the threshold S can be determined based on the absolute value Abs CIR of the signal response CIR. On the other hand, it is conceivable that the threshold S can be determined based on the absolute value Abs I of the real part I of the signal response CIR and / or the absolute value Abs Q of the imaginary part Q of the signal response CIR.

[0060] For example, the threshold S can be determined such that in the signal response CIR (e.g. the absolute value Abs CIR of the signal response CIR having a real part I and an imaginary part Q and which can be regarded as a complex number) a plurality of values ​​caused by the noise Noise are waited for at least 2 . . 5 ns in time before the identified midpoint M of the first signal path LoS.

[0061] For example, the threshold value S can be selected such that it is above the noise level Noise.Thus, positions or points of the signal response CIR can be considered at which the signal curve still rises toward the midpoint M of the first signal path CIR.

[0062] The absolute value Abs CIR of the signal response CIR, and / or the absolute value AbsI of the real part I of the signal response CIR, and / or the absolute value Abs Q of the imaginary part Q of the signal response CIR may be regarded as a signal (see Figure 2 ).

[0063] It is also conceivable that the threshold value S is determined based on two threshold values ​​S1, S2. For example, it is conceivable that the threshold value S can be determined as the maximum value max(S1, S2) of the two threshold values ​​S1, S2.

[0064] For example, the first threshold value S1 can be determined as a function of the noise level Noise and a first factor F1 , in particular a first factor greater than 1.

[0065] For example, the second threshold value S2 may be determined as a function of the first signal path LoS in the signal response CIR and a second factor F2 , in particular a second factor smaller than 1.

[0066] The first threshold S1 may be a threshold that ensures that the signal response CIR exceeds the noise Noise and the first signal component of the first signal path becomes effective. Here, a first factor F1, for example, significantly greater than 1, such as 5, may be defined, by which the noise level Noise is multiplied. For example, the maximum value may be selected from a plurality of absolute values ​​Abs CIR within the noise range to determine the noise level Noise. The first threshold S1 may then be determined as follows:

[0067] S1=F1*max(abs(CIR_Noise))

[0068] The second threshold value S2 may be a threshold value that can represent a portion of the average value M or the selected value / peak value Abs(CIR_Pick) of the first signal path of the signal curve. A second factor F2 less than 1 may be defined, such as 0.2, so that the second threshold value S2 may be determined as follows:

[0069] S2=F2*abs(CIR_Pick)

[0070] In order to ensure that the final threshold S is sufficiently higher than the noise level Noise and appears as early as possible before the average value M or the picked value / peak value abs(CIR_Pick) of the first signal path of the signal curve, the final threshold S can be determined by a combination of two thresholds S1 and S2.

[0071] When determining the phase position for the first receiving antenna AE1 and the second receiving antenna AE2 , possible phase offsets may be taken into account, which may be caused, for example, by the antenna design.

[0072] Furthermore, it is conceivable that if the receiving antennas AE1 , AE2 recognize and / or output different first signal paths LoS in the signal response CIR, then preferably the earlier first signal path LoS is used to determine the threshold value S. In this way, a reliable determination can be achieved despite possible signal differences.

[0073] Since the signal response CIR is usually sampled at fixed sampling times, for example at 1 GHz, and raw values ​​are therefore generated in the corresponding signal response CIR in time steps (for example every 1 ns), it can be advantageous to interpolate these raw values ​​(for example at one tenth of the actual sampling step width (or a similar ratio)) with the aid of a filter to form a smooth curve. Preferably, a filter can be used here that has the property that the support points remain unchanged in the interpolated signal.

[0074] Advantageously, the location history of the mobile device 200 is taken into account when determining the angle of incidence AoA and / or the direction of arrival DoA.

[0075] Furthermore, when determining the angle of incidence AoA and / or the direction of arrival DoA, the phase difference PDoA can be determined multiple times over a time window and the result can be determined from the determined values ​​(for example as an average value).

[0076] Advantageously, the signal strength at the position(s) used for determining the phase difference PDoA on the first signal path LoS and / or in the signal response CIR may be considered to improve the determination of the angle of incidence AoA and / or the direction of arrival DoA. Preferably, it may be considered that the signal strength of the signal response CIR is greater at the receiving antennas AE1, AE2 closer to the mobile device 200.

[0077] Furthermore, in order to determine the angle of incidence AoA and / or the direction of arrival DoA, selected results are taken into account when determining the phase difference PDoA, which results are preferably selected with the aid of a machine learning method and / or which results, in particular, come from different receiving units 100. Advantageously, outputted additional information, such as the signal strength (for example in combination with the calculated phase difference PDoA), can be checked with the aid of a machine learning method in order to determine the best possible result from the existing data. Training can be carried out both during development and in the field. In the field, for example when the vehicle has been sold and is on the road, the angle of incidence AoA and / or the direction of arrival DoA can be determined with the aid of multilateral positioning - at least always where possible. Furthermore, only data with a high degree of reliability are used.

[0078] Furthermore, when determining the angle of incidence AoA and / or the direction of arrival DoA, a reliability value C (English: “confidence level” or abbreviated as C) may be output, which reliability value may depend, for example, on the signal strength and / or the determined angle of incidence AoA and / or the determined direction of arrival DoA.

[0079] To determine the angle of incidence AoA and / or the direction of arrival DoA, the results of different receiving units 100 can preferably be taken into account.

[0080] For determining the angle of incidence AoA and / or the direction of arrival DoA, the results of the receiving unit 100 which have a high reliability value C, advantageously the highest, can preferably be used.

[0081] The optimal value can preferably be selected with the aid of machine learning methods.

[0082] The reliability value C (i.e., information about the reliability of the result of the determination of the phase difference PDoA or the determination of the angle of incidence AoA) is highest when the wavefront is incident vertically (AoA=0°) and decreases towards the boundary area, i.e., when the wavefront is incident from the side (AoA is approximately -90° or 90°).

[0083] If, for example, it is known that certain angular positions provide less accurate PDoA or AoA results, the calculation of this value can preferably also be improved by taking additional measurements on the vehicle.

[0084] Calibration with the aid of reliability value C can be performed on site, preferably in a self-learning manner. For example, whenever multiple UWB receivers are active simultaneously or multiple UWB receivers can measure the distance to the mobile device. The actual position of mobile device 200 relative to the vehicle can then be determined by multilateration.

[0085] Furthermore, it is advantageously possible to take into account the position of the UWB receiver on the vehicle in order to improve the result of the determination of the phase difference PDoA or of the angle of incidence AoA.

[0086] Furthermore, the invention relates to a corresponding computer program product for carrying out a corresponding method, a corresponding control unit and a corresponding receiving unit 100 , in particular a corresponding UWB receiver.

[0087] The above description of the embodiments describes the invention only within the scope of examples. Of course, the individual features of these embodiments can be freely combined with one another as long as it makes technical sense, without leaving the scope of the invention.

[0088] Reference Symbols List

[0089] 100 Receiving unit, UWB receiver

[0090] 200 Mobile devices

[0091] AE1 Receiving Antenna

[0092] AE2 Receiving Antenna

[0093] W axis

[0094] CIR signal response

[0095] Abs Absolute value

[0096] I Real part

[0097] Q Imaginary part

[0098] LoS first signal path

[0099] AoA, α angle of incidence, angle

[0100] DoA Direction of Arrival

[0101] PDoA, ΔΦ phase difference, phase difference

[0102] t_PDoA Earlier time

[0103] S Threshold

[0104] Noise Noise level, noise

[0105] Δl path difference

[0106] d Distance

[0107] ECU Control Unit

Claims

1. A method for determining an angle of incidence (AoA) and / or a direction of arrival (DoA) of an electromagnetic wave (W) from a mobile device (200) on a receiving unit (100), in particular a UWB receiver, wherein: The receiving unit (100) has at least two receiving antennas (AE1, AE2), wherein a phase difference (PDoA) between signal responses (CIR) at the receiving antennas (AE1, AE2) is determined in order to determine an angle of incidence (AoA) and / or a direction of arrival (DoA), wherein the phase difference (PDoA) is determined at a position in the signal response (CIR) that is also before a corresponding midpoint (M) of a first signal path (LoS) in the signal response (CIR).

2. The method according to claim 1, wherein: The phase difference (PDoA) is determined at those positions in the signal response (CIR) which exceed a certain threshold (S) in the signal response (CIR).

3. The method according to claim 2, wherein: The threshold value (S) is determined such that the position at which the phase difference (PDoA) is determined occurs as early as possible in the signal response (CIR), ie still before the midpoint (M), and is already above the noise level (Noise).

4. The method according to claim 2 or 3, wherein: The threshold (S) is determined according to the absolute value (Abs(CIR)) of the signal response (CIR), and / or determining the threshold value (S) based on an absolute value (Abs(I)) of a real part (I) of the signal response (CIR) and / or based on an absolute value (Abs(Q)) of an imaginary part (Q) of the signal response.

5. The method according to any one of the preceding claims 2 to 4, wherein: If the threshold value (S) is determined based on the absolute value (Abs(I)) of the real part (I) of the signal response (CIR) and based on the absolute value (Abs(Q)) of the imaginary part (Q) of the signal response, a correspondingly earlier time (t_PDoA) is selected as the relevant position for determining the phase difference (PDoA).

6. The method according to any one of the preceding claims 2 to 5, wherein: The threshold (S) is determined based on two thresholds (S1, S2), and / or the threshold value (S) is determined as the maximum value (max(S1, S2)) of the two threshold values ​​(S1, S2), and / or determining a first threshold value (S1) as a function of a noise level (Noise) and a first factor (F1), in particular a first factor greater than 1, And / or determining a second threshold value (S2) based on the first signal path (LoS) and a second factor (F2), in particular a second factor smaller than 1, in the signal response (CIR).

7. A method according to any one of the preceding claims, wherein: When determining the phase position for the first receiving antenna (AE1) and the phase position for the second receiving antenna (AE2), possible phase offsets are taken into account, which can be caused, for example, by the antenna design.

8. A method according to any one of the preceding claims, wherein: If the receiving antennas (AE1, AE2) identify and / or output different first signal paths (LoS) in the signal response (CIR), an earlier first signal path (LoS) or a first signal path (LoS) of a predefined receiving antenna (AE1 or AE2) is preferably used for determining the threshold value (S).

9. A method according to any one of the preceding claims, wherein: The signal response (CIR) is interpolated with the aid of a filter to form a continuous curve, In particular, the interpolation is performed with a certain ratio, such as one tenth, of the sampling step width of the signal response (CIR). Preferably, a filter is used which has the property that the position in the signal response (CIR) for determining the phase difference (PDoA) remains unchanged, and / or taking into account the location history of the mobile device (200) when determining the angle of incidence (AoA) and / or the direction of arrival (DoA), And / or the phase difference (PDoA) is determined multiple times over a time window and a result is determined as a function of the determined values, for example as a mean value.

10. A method according to any one of the preceding claims, wherein: Considering the signal strength at a location on a first signal path (LoS) and / or in a signal response (CIR) for determining a phase difference (PDoA) to improve the determination of an angle of incidence (AoA) and / or a direction of arrival (DoA), and / or considering that the signal strength of a signal response (CIR) at a receiving antenna (AE1, AE2) closer to a mobile device (200) is greater.

11. A method according to any one of the preceding claims, wherein: For determining the angle of incidence (AoA) and / or the direction of arrival (DoA), selected results are taken into account when determining the phase difference (PDoA), which results are preferably selected by means of a machine learning method and / or which results come in particular from different receiving units (100).

12. A method according to any one of the preceding claims, wherein: When determining the angle of incidence (AoA) and / or the direction of arrival (DoA), a reliability value (C) is output, which reliability value is dependent in particular on the signal strength and / or the determined angle of incidence (AoA) and / or the determined direction of arrival (DoA), and / or taking into account the results of different receiving units (100) in order to determine the angle of incidence (AoA) and / or the direction of arrival (DoA), wherein preferably for determining the angle of incidence (AoA) and / or the direction of arrival (DoA), the results of the receiving unit (100) with a high reliability value (C) are taken into account, the high reliability value being preferably selected with the aid of a machine learning method, And / or taking into account the position of the receiving unit (100) on the vehicle when determining the angle of incidence (A) and / or the direction of arrival (DoA).

13. Computer program product comprising instructions which, when executed by a computer, cause the computer to perform the method according to any one of the preceding claims.

14. A control unit (ECU) having a computing unit and a memory unit in which a code is stored which, when at least partially executed by the computing unit, carries out the method according to any one of the preceding claims 1 to 12.

15. A receiving unit (100), in particular a UWB receiver, for a vehicle having a control unit (ECU) according to the preceding claim.

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