Radar sensor device and method of operating the radar sensor device

Abstract

The present invention relates to a radar sensor device (10) comprising at least one radar sensor (RS1) and a control device (SE) connected to the at least one radar sensor (RS1) and configured to control the generation of the transmission signal and the scanning of the received signal of the radar sensor, wherein the transmission signal is a linearly frequency-modulated signal that is periodically repeated, and the center frequency and / or ramp gradient and / or pulse repetition rate of the transmission signal, and / or the number of frequency ramps per measurement cycle and / or the pause between measurement cycles are adjustable, and the control device is configured to detect a pulsed interference occurring in the scanned received signal and calculate the frequency of the transmission causing the interference.

Description

Technical Field

[0001] The present invention relates to a radar sensor device and an operating method of the radar sensor device.

Background Art

[0002] Radar sensors can play an important role in increasing the level of vehicle automation, and the number of radar sensors per vehicle is expected to further increase. In general applications, many vehicles may already have driving assistance functions realized using radar sensors. A radar sensor transmits a modulated electromagnetic wave and determines the distance and relative speed of various reflection points around a traveling vehicle from the received reflection that is delayed and Doppler frequency shifted.

[0003] Currently, the serial sensors of different vehicles use independent modulations, and usually the wavelengths are not adjusted to each other. As a result, the signals of the radar sensors interfere due to the overlap of electromagnetic waves, and the probability of signal quality degradation increases simultaneously.

[0004] Since the number of radar sensors in a vehicle is increasing, in order to reduce the interference of the radar sensors in the vehicle, the radar sensors operate in cooperation. For this purpose, the radar sensors are synchronized on the hardware side.

[0005] M.B.A1abd, B.Nuss, C.Winkler and T.Zwick, "Partial Chirp Modulation Technique for Chirp Sequence based Radar Communications (Partial Chirp Modulation Technique for Radar Communications Based on Chirp Sequences)", 2019 16th European Radar Conference (EuRAD), 2019, pp.173 - 176. describes an application example of a modulation method.

[0006] European Patent Application Publication No. 3572828 describes a system combining radar and communication.

Prior Art Documents

[0007] [Non-Patent Document 1] MBA1abd, B. Nuss, C. Winkler and T. Zwick, "Partial Chirp Modulation Technique for Chirp Sequence based Radar Communications" 2019 16th European Radar Conference (EuRAD), 2019, pp. 173-176. [Patent Documents]

[0008] [Patent Document 1] European Patent Application Publication No. 3572828 [Overview of the project] [Means for solving the problem]

[0009] The present invention provides a radar sensor device according to claim 1, and a method for operating the radar sensor device according to claim 6. A preferred form of improvement is the subject matter of a cited claim. [Effects of the Invention]

[0010] The fundamental idea of ​​this invention is to describe a radar sensor device and a method of operating the radar sensor device that allows for better selection of scanning operations for a radar sensor at specific times and signal waveforms. Here, scanning refers to the reception of a high-frequency signal transmitted from the radar sensor, which is characterized by linear frequency modulation, i.e., a frequency ramp over time. In the receiver, the signal received by the antenna system is mixed down with the transmitted signal into the baseband and scanned by an analog-to-digital converter.

[0011] According to the present invention, a radar sensor device includes at least one radar sensor and a control device connected to the at least one radar sensor and configured to apply a transmit signal to the radar sensor and execute a scanning sequence in the radar sensor, wherein a specific period of the transmit signal and / or receive signal in the radar sensor can be selected in order to apply the scanning sequence.

[0012] According to the present invention, a radar sensor device includes at least one radar sensor and a control device connected to at least one radar sensor and configured to control the generation of a transmit signal and the scanning of a receive signal of the radar sensor, wherein the transmit signal is a linear frequency modulated signal that repeats periodically, the center frequency and / or ramp gradient and / or pulse repetition rate of the transmit signal and / or the number of frequency ramps per measurement cycle and / or pauses between measurement cycles are adjustable, and the control device is configured to detect pulse-like interference occurring in the scanned receive signal and to calculate the frequency of the transmission causing it.

[0013] According to a preferred embodiment of the radar sensor device, the causative transmission relates to and originates from another radar sensor. According to a preferred embodiment of the radar sensor device, the radar sensor device includes a reference control unit and a reference sensor configured to transmit a reference transmit signal, wherein the control unit is connected to the radar sensor and the transmit signal of the radar sensor can be synchronized with the reference transmit signal of the reference sensor with respect to transmission and scanning by the control unit.

[0014] According to a preferred embodiment of the radar sensor device, the transmitted signal includes a triangular signal. According to a preferred embodiment of the radar sensor device, a reference unit including a reference control unit and a reference sensor, and a further sensor unit including a control unit and a radar sensor are located in different vehicles.

[0015] The (specified) scanning sequence can be used to evaluate the received signal from the radar sensor and infer the distance and movement of an object. The scanning and / or transmission points in terms of frequency and time can be advantageously selected, for example, at a specific time and frequency of the signal, for example, in terms of number and duration and / or similar. The frequency change can be a specific type of frequency waveform at the selected scanning point, for example, a section where the frequency of a signal ramp increases (e.g., linearly or non-linearly), or decreases, or both.

[0016] Therefore, the sign of the ramp's inclination (ramp direction) can be changed during scanning, or scanning can be performed when the signal gradient is desired. In other words, scanning can be selected even within the signal interval of a "chirp sequence" measurement cycle. A special advantage of this method is that, because it is simple, it can be used immediately without affecting subsequent signal processing. The desired signal can be set, and the interval to scan can be selected.

[0017] The ramp direction within the measurement cycle can be arbitrarily selected, offering various possibilities for the radar sensor. Thus, triangular wave modulation can be used with nearly constant signal processing, eliminating the need for return in the phase control loop and increasing the ramp repetition rate. Eliminating the return reduces interference and eliminates the need to switch off the transmitting amplifier. Furthermore, coordinating sensors can be synchronized, allowing for wireless adjustment of transmissions to avoid interference. Additionally, communication between radar sensors is enabled by selecting the ramp direction according to an information data stream (e.g., a series of 0 and 1 symbols). This can be used to coordinate communicating radar sensors and exchange information.

[0018] According to a preferred embodiment of the radar sensor device, the radar sensor device includes a reference sensor on which a reference transmit signal is transmitted and / or on which a reference scan signal is used, and a control device that controls the reference transmit signal and the reference scan signal with respect to time, frequency and ramp direction.

[0019] Furthermore, the operation adjustment between multiple radar sensors or the synchronization of the operation or scanning of the radar sensors can be improved. According to a preferred embodiment of the radar sensor device, a predetermined transmission signal includes a triangular signal, and preferably includes a triangular signal that is a function of time of the frequency of the transmission signal.

[0020] The transmission signal can preferably be variable and thus can be adapted / synchronized to a reference signal and / or a reference scanning rate. According to a preferred embodiment of the radar sensor device, the scanning can be performed between a frequency increase signal ramp of the transmission signal and / or the reception signal, and / or between a frequency decrease signal ramp of the transmission signal and / or the reception signal, and / or the gradient of the signal ramp can be selected by the control device.

[0021] According to a preferred embodiment of the radar sensor device, the radar sensor device includes a plurality of radar sensors that can be installed in the same vehicle or particularly different vehicles, and the transmission signals and scanning sequences in these radar sensors can be synchronized with a reference scanning signal and a reference transmission signal by the plurality of radar sensors.

[0022] In addition to synchronization, communication between radar sensors can be performed via an air interface. According to the present invention, a method for operating a radar sensor device includes providing a radar sensor device according to the present invention including at least one radar sensor and a reference sensor, detecting a pulse interference generated in the reception signal of the radar sensor by the transmission of the reference sensor, and calculating the transmission frequency of the transmission of the reference sensor, and driving and controlling the radar sensor by a control device such that the detected frequency of the frequency generated by the reference sensor in the reception signal of the radar sensor becomes constant by appropriate adjustment of modulation parameters, particularly the center frequency, ramp gradient, and transmission time.

[0023] According to a preferred embodiment of the present method, the transmission from the radar sensor is synchronized with the transmission from the reference sensor, and the control device drives and controls the radar sensor in a sequence of ramp slopes suitable for minimizing the duration of the amplitude pulse interference and thus the interference.

[0024] According to a preferred embodiment of the present method, further, the control device drives and controls the radar sensor in a sequence of ramp slopes suitable for generating a series of amplitude pulse interferences for transmitting a notification based on a prescribed codebook in the received signal of the reference sensor.

[0025] According to a preferred embodiment of the present method, further, in connection with driving and controlling the radar sensor by the control device in a sequence of ramp slopes having an appropriate time offset with respect to the transmission from the radar sensor in order to avoid or reduce the interference generated by the reference sensor in the received signal of the radar sensor, the interference of the notification in the radar sensor is minimized.

[0026] According to a preferred embodiment of the present method, further, in connection with driving and controlling the radar sensor by the control device in a sequence of ramp slopes having an appropriate frequency offset with respect to the transmission from the reference sensor in particular in order to avoid or reduce the interference generated by the reference sensor in the received signal of the radar sensor, the interference of the notification in the radar sensor is minimized.

[0027] According to a preferred embodiment of the present method, the reference sensor transmits a notification for adjusting the transmissions of various radar sensors by transmitting an appropriate lamp sequence after synchronization and transmission of notifications from a plurality of radar sensors, and the control device of the radar sensor interprets the notification according to a pre-prescribed codebook.

[0028] According to the present invention, the method for operating a radar sensor device includes the steps of providing the radar sensor device according to the present invention, driving and controlling the radar sensor with a transmitted signal, and executing a scanning sequence on the radar sensor, wherein a specific period of the transmitted signal and / or received signal is selected in order to apply the scanning sequence.

[0029] According to a preferred embodiment of this method, the sign of the ramp gradient of the transmitted signal and / or the received signal and / or scan sequence is selected according to a set value. According to a preferred embodiment of this method, the reference sensor transmits a reference transmission signal that a second (or further) radar sensor uses a control device to synchronize its own transmission signal.

[0030] According to a preferred embodiment of this method, a reference sensor generates a reference transmit signal and / or reference scan signal, which are then synchronized by a second sensor, using its control device, with respect to the transmit signal of the second sensor to the reference transmit signal of the reference sensor for both transmit and scan.

[0031] The proposed method is easy to implement and technically applicable directly to current radar sensors. However, given the current regulations on radar frequency bands, which separate radio positioning services from communications, this method is also considered suitable for future sensors, particularly in newer frequency bands such as above 100 GHz. Expanding the speed evaluation range benefits the sensor itself, and reducing interference benefits all radar sensors used.

[0032] Radar sensor devices can also be characterized by the features and advantages described in relation to the method, and vice versa. Further features and advantages of embodiments of the present invention will become apparent from the following description with reference to the accompanying drawings. [Brief explanation of the drawing]

[0033] The present invention will be described in more detail below with reference to the embodiments shown in the schematic diagrams. [Figure 1] This is a schematic diagram of the frequency-as-time signal waveform for operating the radar sensor device according to the comparative example and the two embodiments of the present invention. [Figure 2] This is a block diagram of a method step for operating a radar sensor device according to a further embodiment of the present invention. [Figure 3] This diagram shows interference signals from perfectly synchronized radar sensors and their deviations.

[0034] In the figures, the same reference numeral indicates the same or functionally identical element. [Modes for carrying out the invention]

[0035] Figure 1 is a schematic diagram of signal waveforms for operating a radar sensor device according to a comparative example and two embodiments of the present invention. In Figure 1, a ramp signal (transmitted or received signal) of frequency f is shown over time t, which corresponds to a conventional chirp signal. Scanning typically occurs only at frequency drop-off bifurcations via scan point di.

[0036] The sawtooth "chirp sequence" modulation scheme shown in Figure 1a can be assumed to be prior art. Figure 1a shows the modulation scheme on an ascending signal frequency ramp in a radar sensor and the indicated scan point di. After two-dimensional scanning in the time and frequency directions, the distance (via time delay) and velocity (via Doppler frequency shift) of the radar target can be determined (for example, by superimposing the transmitted and received signals).

[0037] In contrast, Figures 1b and 1c follow an inventive approach that allows the “chirp sequence” modulation scheme to be used in an adapted form without affecting radar signal processing. Instead, the application of modulation is improved, leading to further applicability, such as synchronization and communication of coordinating radar sensors. In a typical chirp sequence radar, the generated transmit signal (a frequency ramp with frequency dependence f(t)) is simultaneously used as the input signal to the mixer in the receive path (homodyne principle). After the mixer, the receive signal is filtered through an anti-aliasing filter (AAF) with a low-pass filter at cutoff frequency fAAF. The signal is then scanned by an A / D converter.

[0038] According to the homodyne principle, the frequency band sensitive to signal reception is effectively shifted along with f(t). The sign of each individual ramp in the signal in the radar sensor can be changed within the measurement cycle, in other words, the frequency waveform of the radar transmission signal can be selected to follow a specific sequence with positive or negative slopes, and it is also possible to pause between ramps (or multiple ramps).

[0039] To reverse the ramp direction without affecting signal processing, the scanning of the frequency ramp needs to be adapted so that the scan value corresponds to the same instantaneous frequency of the ramp, as shown in Figure 1b; that is, even for ramps with decreasing frequency, the scan points have the same time step width.

[0040] In a system consisting of two radar sensors (a reference sensor, or a first sensor and a second sensor), the second sensor operates in a complementary sequence to the first sensor. That is, the reference sensor uses a signal whose frequency increases over time, while the second sensor uses a signal whose frequency decreases over time.

[0041] Both the first and second sensors detect the scan value in the received signal, which is subject to interference from other sensors. Interference occurs when a sensor receives high-frequency signals transmitted by other sensors. The interference manifests as amplitude pulse interference in the scanned received signal. This pulse interference is mapped to a specific frequency at the receiver (Figure 3).

[0042] In particular, the second sensor detects the scan value that has been interfered with by the signal from the first sensor as amplitude pulse interference. In the "Chirp Sequence" scheme of Figure 1a, the scan value of the interference of the signal from the first sensor in the perfectly synchronized second sensor (which has a sequence complementary to the first sensor with respect to the ramp gradient) is advantageously in the middle of the frequency span swept by the frequency ramp for each chirp at the same frequency. In this case, the start times of the frequency ramps of the first and second sensors are synchronized.

[0043] During the duration of a radar channel, i.e., a ramp (e.g., a sub-section of an ascending or descending ramp), it can be assumed that the signal reflected by an object is constant in time with respect to frequency within the baseband, and only the order of the scan values ​​needs to be reversed on the opposite ramp. This method does not affect subsequent signal processing.

[0044] As shown in Figure 1a, since there is no return to the beginning of the rising ramp (a new scanning sequence starts again with the rising ramp, and the frequency scan value returns to the minimum value of the scan in known methods, but in the method steps according to the present invention, such a return can be omitted), firstly, the repetition rate of the ramp can be increased, thereby significantly increasing the measurable speed. Secondly, this reduces the possibility of interference and eliminates the need to switch off the transmitting amplifier when the ramp returns.

[0045] Furthermore, as shown in Figure 1c, a series of different regions of the signal—ascending, descending, or stationary—can be used, each succeeding the others, and this change in ramp direction can be understood as binary coding (for example, an ascending ramp corresponds to 1 and a descending ramp corresponds to 0; see code 1101 in Figure 1c).

[0046] The meaning assigned to this code can be used to intentionally transmit information. It should be noted that the time for return should be considered based on a constant ramp repetition rate.

[0047] Thus, ramp direction encoding can also be used for data transmission between radar sensors. When synchronization is performed between the first and second sensors, it is possible to identify whether the received interference signal is an ascending or descending ramp based on the temporal position of the pulsed interference.

[0048] Pulsed interference in the received signal is caused by the transmission signal of the first sensor, which has a frequency-dependent fsi(t), crossing the frequency range of the second sensor that detects reception, which has a cutoff frequency fs2(t)±fAAF,2. This signal appears as pulsed interference in the scanned baseband signal.

[0049] The actual frequency of the interference can be calculated from the temporal position of the interfered scan value and fs2(t). Subsequently, decoding is performed, enabling simple interference detection on the receiving end.

[0050] The pulsed interference caused by this communication can be limited to certain scan values ​​in the scan sequence and can be appropriately corrected after decoding using conventional methods by appropriate filtering or by replacing the interfered scan values ​​with estimated values.

[0051] As described above, by assigning meaning to the encoded sequences of ascending and descending ramps used by the first sensor, any information that can be used to improve radar sensor coordination can be transmitted. For example, this could include the ID (identification) of the function performed by the radar sensor, prioritization of frequency bands, and transmission of sensor type identifiers, the center frequency and bandwidth to be used.

[0052] During communication, i.e., during data transmission between radar sensors, the synchronization of the frequency ramps of both sensors can be readjusted (corrected, improved, or adapted) by comparing the timing of the expected interference pulse with the timing of the actual interference pulse. The difference functions as a control variable for the digital control of the signal output of the ramp sequence.

[0053] Figure 2 is a block diagram of the method steps for operating a radar sensor device according to a further embodiment of the present invention. In a method of operating a radar sensor device, the radar sensor device according to the present invention is provided, in S1, the radar sensor is driven and controlled by a transmit signal, S2, a scanning sequence is performed on the radar sensor, and a specific period of the transmit signal and / or receive signal is selected to apply the scanning sequence.

[0054] Figure 3 shows interference signals from perfectly synchronized radar sensors and their deviations. This method can be used for synchronizing coordinated radar sensors. Here, "coordinated" can mean that the radar sensors are connected to each other in some way and / or their operating modes are coordinated with each other. For this purpose, a reference sensor and a fixed bit sequence of transmit and / or scan signals can be predetermined, and the reference sensor transmits and measures in this sequence, which is known to all other sensors. The synchronized radar sensors use inverted codes, such as shown as 0100 in Figure 1c, for example.

[0055] If the measurement cycles are perfectly synchronized, pulsed interference Int can occur in the middle of all ramp or baseband signals, as shown in Figure 3a. The frequency constant line Int indicates that the pulsed interference occurs at the same point (time or frequency associated in the ramp function) for all ramps of the second sensor. This "same point" is advantageously at the center of the ramps of the second signal. This ensures that the time and frequency are perfectly synchronized. The ramps of the first and second sensors are advantageously orthogonal to each other as increments, which corresponds to perfect synchronization. If there is a deviation (such as the ramps being tilted from waveforms that are orthogonal to each other, as shown in Figure 3b), the ramps can be corrected and synchronized.

[0056] If the interference is distributed towards the upper and lower limits (i.e., towards higher and lower frequency values), as shown in Figure 3b, synchronization no longer exists and can be detected by conventional interference detection methods. The length of the pulses deviated from the interference signal can be signified for arbitrary behavior, depending on the error correcting the synchronization (a time shift or time stretch of the signal fS2(t)). The shifted bar of signal Int can represent the frequency position of the pulsed interference that occurred, in this case, it is not synchronized. The width of individual interference pulses can be the degree of the ramp slope of the interference signal. This feature can also be used to classify the desired pulse sequence of the synchronized sensor, and the rising and falling ramp sequences of the first sensor can be estimated. If the deviation of the maximum interference value is detected as a control difference (when bar Int is shifted from the horizontal center), synchronization becomes a simple control task. If the interference occurs only sporadically, the measurement cycles are not yet superimposed, and rough synchronization needs to be restored, for example, by delay.

[0057] For synchronization, the sensor being synchronized switches to its original code, i.e., the code of the second sensor that is optimal for its function, taking into account an additional delay, particularly a predetermined deviation from a specified reference signal, so that the sensors can always transmit a pause to each other without interference. Once synchronization is achieved, the second sensor (e.g., its control unit) can know when the first sensor is not transmitting and intentionally pause, at which point it can select an ascending and descending ramp sequence that is optimal for its measurement task.

[0058] For example, in the case of two sensors, sawtooth modulation can be used for synchronization (1111 and 0000). By changing the ramp direction, deviations can be detected more effectively due to the drift of time-interference pulses (the intersection of signals when superimposed in the time-frequency diagram). Equalization of the ramp clock between the reference sensor and the radar sensor can be achieved by inserting additional pauses in the ramp sequence. Furthermore, different codes may be used for the sensors to be synchronized in order to synchronize multiple sensors.

[0059] By reducing interference signals not originating from the synchronized sensors, the robustness of the described method can be improved. Interfering signals can be associated with individual sensors by identifying them and classifying them appropriately according to their signal strength. For this purpose, it is advantageous to use only interfering signals with sufficiently similar amplitudes.

[0060] Signal filtering can be performed by correlating the interfering pulse train with the expected code (for example, prior knowledge from a so-called codebook that specifies the code used by the communication / cooperative sensor) to filter out only the pulses desired for synchronization.

[0061] According to the homodyne principle, the width of individual interference pulses can be proportional to the degree of the ramp slope of the interference signal. This is because the more the frequency ramp of the first sensor approximates the ramp slope of the first sensor, the wider the interference pulses generated by the second sensor. Advantageously, this feature can be used to classify a desired pulse sequence of synchronized sensors.

[0062] Although the present invention has been described above based on preferred embodiments, the present invention is not limited thereto and can be modified in various ways.

Claims

1. - At least one radar sensor (RS1), - A control device (SE) connected to at least one radar sensor (RS1) and configured to control the generation of the transmission signal and the scanning of the reception signal of the radar sensor, Includes, The transmitted signal is a linear frequency modulated signal that is periodically repeated. The center frequency and / or ramp gradient and / or pulse repetition rate of the transmitted signal and / or the number of frequency ramps per measurement cycle and / or pauses between measurement cycles are adjusted. The control device detects pulse-like interference occurring in the scanned received signal, calculates the transmission frequency causing it, and When the ramp gradient of the transmitted signal rises or falls, and the received signal is scanned, the number and interval of scan points in terms of frequency and time can be selected, thereby obtaining the frequency response at the selected scan points. In a radar sensor device (10) configured as follows, - Step (S2) of detecting pulse interference generated in the received signal of the radar sensor (RS1) by the transmission of the reference sensor (Ref), and calculating the transmission frequency of the transmission of the reference sensor (Ref), - Step (S3) of driving and controlling the radar sensor (RS1) by the control device (SE1) to adjust modulation parameters, including the center frequency, ramp gradient, and transmission time, so that the detection frequency of the frequency generated by the reference sensor (Ref) in the received signal of the radar sensor (RS1) remains constant. A radar sensor device (10) that performs the following.

2. The radar sensor device (10) according to claim 1, wherein the transmission causing the above-mentioned event relates to and originates from another radar sensor.

3. Reference control unit (SE) ｒｅｆ A radar sensor device (10) according to claim 1, comprising a radar sensor (RS1) and a reference sensor (Ref) configured to transmit a reference transmission signal, wherein the control device (SE1) is connected to the radar sensor (RS1), and the transmission signal of the radar sensor (RS1) is synchronized with the reference transmission signal of the reference sensor with respect to transmission and scanning by the control device (SE1).

4. The radar sensor device (10) according to claim 1, wherein the transmitted signal includes a triangular signal.

5. The aforementioned reference control unit (SE ｒｅｆ ) and the reference unit (SE) including the reference sensor (Ref) ｒｅｆ The radar sensor device (10) according to claim 3, wherein a further sensor unit including the control device (SE) and the radar sensor (RS1) is located in a different vehicle.

6. - A step of synchronizing the transmission from the radar sensor (RS1) with the transmission from the reference sensor (Ref), - A step of driving the radar sensor (RS1) with the control device (SE1) using a ramp gradient sequence suitable for minimizing the duration of the amplitude pulse interference and, consequently, the interference, The radar sensor device (10) according to claim 1, further comprising the following steps.

7. - The radar sensor device (10) according to claim 1, wherein the control device (SE1) drives the radar sensor (RS1) in a sequence of ramp gradients suitable for generating a series of amplitude pulse interferences in the received signal of the reference sensor, the series of amplitude pulse interferences further comprising the step of transmitting a notification based on an electronic codebook.

8. - The radar sensor device (10) according to claim 7, further comprising the step of minimizing notification interference in the radar sensor (RS1), in connection with the control device (SE1) driving the radar sensor (RS1) in a sequence of ramp gradients having an appropriate time offset with respect to the transmission from the radar sensor (Ref) in order to avoid or reduce interference generated by the reference sensor (Ref) in the received signal of the radar sensor (RS1).

9. - A radar sensor device (10) according to claim 7, wherein the step of minimizing notification interference in the radar sensor (RS1) is performed in relation to driving the radar sensor (RS1) by the control device (SE1) with a sequence of ramp gradients having an appropriate frequency offset with respect to the transmission from the reference sensor (Ref), in order to avoid or reduce interference generated by the reference sensor (Ref) in the received signal from the radar sensor (RS1).

10. The radar sensor device (10) according to claim 7, wherein the reference sensor transmits a notification to coordinate the transmissions of the various radar sensors by transmitting an appropriate ramp sequence after the synchronization and transmission of notifications from the plurality of radar sensors (RS1, RS2, RS3), and the control device of the radar sensor interprets the notification according to an electronic codebook.

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