Identifying interference in received echo signals from a group of sensors

Abstract

The invention relates to a method for operating a sensor arrangement (12) having a control unit (14) and a number of sensors (16) arranged in at least one group (18, 20), the sensors (16) being connected to a common power supply, in particular via the control unit (14), comprising the steps of emitting a sensor signal using the sensors (16), the sensor (16) in each group (18, 20) emitting its sensor signal in its specific group transmission phase, receiving an echo signal based on a reflection of the sensor signal, transmitting the received echo signal from the sensor (16) to the control unit (14), and identifying interference (38) in the received echo signal from at least one group (18, 20) based on a comparison of at least two of the received echo signals from the corresponding group (18, 20). The invention also relates to a corresponding sensor arrangement (12) for a vehicle (10) for operating according to the above method. The invention also relates to a driving assistance system for a vehicle (10) having a sensor arrangement (12) as described above.

Description

[Technical field]

[0001] The present invention relates to a method for operating a sensor device comprising a control unit and a plurality of sensors arranged in at least one group, the sensors being connected to a common power supply, in particular via the control unit.

[0002] The invention also relates to a method for operating a sensor device comprising a control unit and a plurality of sensors arranged in at least two groups, the sensors being connected to a common power supply, in particular via the control unit.

[0003] The invention also relates to a sensor device for a vehicle, comprising a control unit and a plurality of sensors arranged in at least one group, the sensors being connected to a common power source, in particular via the control unit, the sensor device being designed to operate using the method described above.

[0004] The invention further relates to a sensor arrangement for a vehicle, comprising a control unit and a plurality of sensors arranged in at least two subgroups, the sensors being connected to a common power supply, in particular via the control unit.

[0005] The invention also relates to a driving assistance system for a vehicle, comprising a sensor device as described above. [Background technology]

[0006] Modern vehicles are increasingly equipped with sensors for monitoring the environment around the vehicle. These sensors, hereafter also called ambient sensors, provide environmental information that can be used, for example, by various driver assistance systems belonging to the vehicle. Depending on the type of driver assistance system, the driver assistance systems may assist the driver of the associated vehicle or provide functions for implementing autonomous driving.

[0007] In the sensor unit, the sensors are often connected to a common power supply. For this purpose, for example, the sensors are connected to a control unit via a supply line that not only supplies power to the surrounding sensors, but also receives and evaluates sensor information from the sensors in order to detect objects in the environment that pose a danger to the vehicle and generate a corresponding warning. The sensor information may include echo signals received as reflections of the sensor signals emitted by the sensors. For example, the echo signals include the time of the first echo from an object in the environment detected by the respective sensor. The echo is characterized in that the reception amplitude of the sensor is above a limit value. In addition to the time of the reception echo, the echo signals may include the duration of the reception echo and / or the reception amplitude of the reception echo. The echo signals may also include multiple echoes from objects in the environment detected by the respective sensor. In relation to the reception echoes, the above-mentioned statements apply. For times when no echo is received, for example when the reception amplitude is below a limit value, no signal is generated. In addition, the sensors may generate envelopes that include the echo signals and transmit them to the control unit. The envelope includes the temporal profile of the received amplitude, and therefore also the amplitude values ​​for intervals during which the received amplitude at the respective sensor is below the limit value, i.e., by definition, no echoes are received. For example, the limit value may have a temporal profile because, due to dispersion, reflections from nearby objects are received at higher amplitudes than reflections from other similar objects that are more distant.

[0008] A common supply of the sensors allows a simple wiring arrangement of the sensors to be implemented. In particular, by providing a common supply of the sensors via the control unit, wiring can be implemented according to the data connection from the control unit to the sensors, which is also required. Thus, the supply lines can be laid parallel to the data lines, and therefore preferably simultaneously, or only one wire can be laid, which is used as both a supply line and a data line.

[0009] The sensors mentioned may be, for example, ultrasonic sensors or radar sensors, etc. These sensors emit sensor signals and, based on them, receive echo signals from which objects in the vehicle's environment can be identified as echoes. Thus, ultrasonic sensors emit ultrasonic pulses and receive ultrasonic echoes of the emitted ultrasonic pulses from objects in the vehicle's environment. In modern vehicles, it is common for a first sensor group to be arranged along the front of the vehicle and a second sensor group along the rear of the vehicle. Each group currently comprises 4 to 6 individual sensors. These sensors are therefore arranged in a close spatial relationship and detect adjacent parts of the vehicle's environment. It is also becoming increasingly common to arrange ultrasonic sensors along the long sides of the vehicle, which, for the reasons mentioned above, can also be connected to the control unit as independent groups.

[0010] To emit an ultrasonic pulse, ultrasonic sensors in particular require a large amount of energy, so that a large amount of power needs to be provided to emit ultrasonic pulses substantially simultaneously. Therefore, to reduce the required power, different groups of sensors emit their sensor signals in groups with a time offset relative to other groups. After the emission of the ultrasonic pulse, the ultrasonic sensor receives an echo signal based on the reflection of the emitted sensor signal from an object in the vehicle's environment. In order to be able to detect the reflection of the sensor signal at the object as an echo in the echo signal, an electrical signal amplification of the received echo signal is required, since the amplitude of the received echo signal decreases rapidly with increasing duration after the emission of the ultrasonic pulse.

[0011] Interferences in the supply of the ultrasonic sensors can lead to reception errors of the echo signals. These errors can lead to an inaccurate detection of objects in the vehicle's environment, i.e. erroneous detection of non-existent objects, which can lead to, for example, erroneous activation of the emergency braking system. Interferences can be caused by external influences or by the supply itself, for example in the control unit. In particular, if it is required to provide the control unit with high power levels, as is the case, for example, when emitting sensor signals using the sensors of each group, so-called ripple currents can occur, in which an AC voltage component is superimposed on the DC voltage provided as supply voltage.

[0012] The power supply problem may be exacerbated by current sensors or driving assistance systems, since current sensors emit a sensor signal for a longer period of time compared to older sensors, especially in the form of several individual signal pulses that together form the sensor signal. This means that the sensor has to be supplied with the required power for a longer period of time. In addition, the pulses result in larger AC components in the supply. To avoid interference with the supply, in principle various circuit-based solutions could be used, for example capacitors or ripple filters. However, these involve a great deal of effort and the corresponding costs. Summary of the Invention [Problem to be solved by the invention]

[0013] Based on the above-mentioned prior art, the object of the present invention is therefore to identify a method for operating a sensor device having multiple sensors, as well as a corresponding sensor device, which enables simple and cost-effective detection of an interference-free environment. [Means for solving the problem]

[0014] This object is achieved according to the invention by means of the features of the independent claims. Advantageous configurations of the invention are set forth in the dependent claims.

[0015] Therefore, according to the present invention, a method for operating a sensor device having a control unit and a plurality of sensors arranged in at least one group, the sensors being connected to a common power source, in particular via the control unit, is specified, comprising the steps of emitting sensor signals using the sensors, the sensors of each group emitting their sensor signals in their respective group transmission phase, receiving echo signals based on reflection of the sensor signals, transmitting the received echo signals from the sensors to the control unit, and identifying interference in the received echo signals from at least one group based on a comparison of at least two of the received echo signals from corresponding groups.

[0016] According to the present invention, there is also provided a method for operating a sensor device having a control unit and a plurality of sensors arranged in at least two groups, the sensors being connected to a common power supply, in particular via the control unit, comprising the steps of emitting sensor signals using the sensors, the sensors of each group emitting their sensor signals in their respective group transmission phases, the group transmission phases of at least two groups being offset in time, receiving echo signals based on reflection of the sensor signals, transmitting the received echo signals from the sensors to the control unit, and identifying interference in the received echo signals of each group based on the time offset of the group transmission phases and the duration of the group transmission phase of at least one other group.

[0017] According to the invention, a sensor device for a vehicle is also specified, which comprises a control unit and a plurality of sensors arranged in at least one group, the sensors being connected to a common power source, in particular via the control unit, and the sensor device is designed to operate using the above method.

[0018] According to the invention there is further specified a sensor device for a vehicle, comprising a control unit and a plurality of sensors arranged in at least one group, the sensors being connected to a common power source, in particular via the control unit, the sensor device being designed to operate according to the above method.

[0019] According to the invention, a driving assistance system for a vehicle is also specified, which comprises one of the above-mentioned sensor devices.

[0020] The basic idea of ​​the invention is therefore to be able to identify cases of interference of the received echo signals resulting from disturbances in the common supply and thereby to be able to deal with them appropriately. In particular, if it is required, for example via the control unit, to operate at a high power level, as for example in the case of emitting sensor signals using at least one group of sensors, so-called ripple currents may occur, where an AC voltage component is superimposed on the DC voltage provided as supply voltage. If such interference caused by ripple currents can be reliably identified, such interference in the echo signals can be eliminated or ignored, so that the control unit does not detect objects inaccurately. Thus, interference can be overcome cost-effectively by improved signal processing of the received echo signals, resulting in a reliable detection of objects in the vehicle's environment, in particular avoiding false positives in the detection of objects in the vehicle's environment. As part of the provision of a common supply, for example in the control unit, the avoidance or elimination of such interference by circuit-based solutions such as capacitors or ripple filters can be achieved, which allows a cost-effective dealing with the interference. Also, using the sensors, the sensor signals can be transmitted over a longer period of time compared to previous implementations, especially in the form of several individual signal pulses that together form the respective sensor signal, which means that the sensor requires more power or the same power for a longer period of time without the need to increase the power supply via the control unit. Interference that can be expected to occur over a longer period of time can be identified and overcome, so that the detection of objects in the vehicle's environment can be performed without major limitations. Depending on the method for operating the sensor device, interference can be identified for a single sensor group, i.e. individually, without knowledge of the operation of further sensor groups. Alternatively, interference is identified by the coordinated operation of several sensor groups, as defined by different group transmission phases.

[0021] The interference in the received echo signals of each group can be identified in different ways, which can be based on the emitted sensor signals as well as on the received echo signals. Thus, in both cases, in order to identify or prevent the interference, it is not necessary to directly address the source of the disturbance, i.e. the supply, which involves a great deal of effort in the latter case.

[0022] Thus, interference can be identified on the one hand by comparing several instances of received echo signals in one group. This usually applies to simultaneously obtained echo signals, where a disturbance in a common supply, which concerns a common supply of all sensors in the corresponding group, affects all sensors in the corresponding group by interference effects in the reception of the echo signals. Depending on the design of the sensor device with the arrangement of sensors in several groups, the effect of a supply disturbance in the common supply of some groups can also arise in principle, depending on the operation of the sensors of the different groups and the type of supply. In particular, the emission of a sensor signal using a sensor of another group can interfere with the supply of sensors of another group or other groups, whereby interference appears in the received echo signal of the corresponding group. Interference effects can be identified both in the supply of the sensors due to external influences, for example by external interfering signals that are unpredictable and / or that can occur randomly, and also interference from the operation of the supply of the sensors, for example in the control unit. Interference in the received echo signals of at least one group can be identified in a fundamentally different way, based on a comparison of at least two of the received echo signals from the corresponding groups. Details have already been given above and are also given below. For example, interference may be detected based on coincident echoes in the echo signal and / or echoes having excessive amplitude and / or similar types of echoes in the echo signal.

[0023] On the other hand, the identification of interference can be performed by identifying the corresponding time window of this group transmission phase as interference based on the group transmission phase of at least one other group. In this case, no further investigation or comparison of the received echo signals is necessary and the interference can be identified with little effort. By identifying the interference based on the time offset and duration of the group transmission phase of at least one other group, the echo signals from the sensors of the group that receive the echo signals during the group transmission phase of another group can be identified as interference during this group transmission phase. As a result, the real echoes of objects in the environment of the vehicle cannot always be detected and processed. However, in order to be able to provide a valid echo signal even within this time window, various measures are possible, which are described below. In this case, the interference effect in the corresponding group usually occurs for all the sensors involved, since these sensors receive the echo signals at the same time and have a common power supply. Similarly, the interference effect in the common supply caused by the interference in the reception of the echo signal affects all the sensors in the corresponding group, which are identified together based on the time offset of the group transmission phase and the duration of the group transmission phase. The group transmission phase in this case is controlled by the control unit so that the interference can be easily and directly identified in the control unit. For example, the time offset is relative to the start of the respective group transmission phase of the different groups. The time offset between the individual group transmission phases may for example differ between the different groups. The time offset may be selected such that the group transmission phases of the different groups do not overlap. In this case, the group transmission phases are each paired discontinuous time intervals. The duration of the individual group transmission phases may differ for the different groups. The duration of the group transmission phases of the different groups may in principle also differ in different cycles. The method is preferably repeated for the different groups.This may also result in interference for each of the sensor groups based on activity by the sensors of the other groups, in particular the transmission of sensor signals. The time offset specifies the point in time when interference can start to occur based on the joint supply of multiple sensor groups, and together with the duration of the corresponding group transmission phase, the time interval is defined as the interference.

[0024] Interference in the reception of echo signals is typically associated with disturbances in the internal signal processing, i.e. from the physical coupling of the echo signals to the respective sensors, possibly even to the generation of the envelope of the respective echo signals. Due to the dispersion of the emitted sensor signals and the echo signals based on them, it is often necessary to carry out signal processing, in particular signal amplification, of the physically coupled echo signals in order to reliably detect the reflection of the sensor signals as echo signals and to recognize the echoes at the objects contained therein. In order to detect the echo signals from the reflection of the sensor signals at distant objects, an increasingly high electrical signal amplification, in particular signal gain, of the received echo signals is required, which increases with the duration after the emission of the sensor signal, i.e. with the distance of the object from the respective sensor. Thus, by identifying interferences, the sensors can also reliably detect objects at greater distances from the respective sensor. This means that, for example, inaccurate emergency braking actions by the corresponding driving assistance system can be avoided.

[0025] The sensor device is typically part of a driver assistance system of the vehicle or is connected to the driver assistance system in order to provide this system with environmental information about objects in the vehicle's environment. The driver assistance system can in principle be any driver assistance system having one or more assistance functions. Such driver assistance systems are known for example as driver assistance systems that assist a human driver of the vehicle when driving the vehicle, e.g. as emergency braking systems, adaptive cruise control systems, parking assistance systems, etc. However, such driver assistance systems can also provide functions that are used for example for autonomous or semi-autonomous driving of the vehicle.

[0026] A control unit is essentially any computational unit that receives and processes echo signals from the sensors. In the field of vehicles and driver assistance systems, such control units are known, for example, as ECUs (Electronic Control Units). In principle, other components can also be connected to the control unit. If these additional components are connected to and supplied by a common supply of sensors, this leads to further potential sources of interference due to these further components being supplied via a common supply. The principles described herein can be applied accordingly.

[0027] The sensor arrangement comprises a number of sensors, each sensor being preferably designed similarly for each group. For example, the sensors can be ultrasonic or radar sensors, which emit corresponding ultrasonic or radar signals as sensor signals and receive echo signals of these sensor signals as ultrasonic or radar echoes. In modern vehicles, it is common, for example, for a first sensor group to be arranged along the front of the vehicle and a second sensor group along the rear of the vehicle. For example, each group comprises 4-6 individual sensors. In addition, the sensor groups can also be arranged along a long side of the vehicle. The sensors are connected in parallel to a common supply, for example in the form of a supply line. Alternatively, the sensors of a group can be connected in the manner of a daisy chain, in particular to a control unit.

[0028] For example, the supply line may be laid parallel to one of the data lines and thus laid simultaneously, whereby both lines are wired together. Alternatively, only one line may be laid, which is used as both supply line and data line, i.e. the sensor and the control unit communicate via a common line and the control unit supplies the sensor via a common line. The supply line comprises in the usual manner two potentials, typically a supply voltage and a ground, which are provided via one or more individual electrical cables. Various such bus systems are known, and an integral arrangement of supply lines and data lines is implemented, for example, in DSI3 or USV11.

[0029] A common supply provides electrical energy to all connected sensors. In the case of control unit powering, the power is provided by the control unit. For example, the control unit has an internal or external supply circuit that provides electrical energy to all groups via a supply line. In the vehicle, it is possible to carry out a voltage conversion from the on-board vehicle voltage, typically 12 volts, to the desired supply voltage, in particular a voltage increase (boost).

[0030] The sensor signals are emitted by groups in their respective group transmission phases, in which the sensors typically emit their sensor signals in a close time relationship, in particular simultaneously, and receive echo signals in a similar manner, either simultaneously or in a close time relationship. Since the echo signals are based on the reflection of the sensor signals at objects in the vehicle's environment, the distance to the object can be determined from the time difference between the emission of the sensor signal and the reception of the echo of the sensor signal at the object. The echo signal therefore specifies both the time definition of the received echo and the definition of the distance of the object to which the echo belongs.

[0031] Typically, a repeating cycle is formed in which all the groups of sensors emit their sensor signals, receive echo signals and transmit them to the control unit. Thus, the sensors can repeatedly emit sensor signals and receive echo signals. If the sensor signals are emitted simultaneously or nearly simultaneously within each group, a high cycle repetition rate can be achieved, ensuring a continuous and nearly instantaneous recording of the vehicle environment.

[0032] The received echo signals are transmitted from the sensor to the control unit together, in particular within the respective cycle, and for example a time-delayed transmission of the echo signals from the individual sensors to the control unit can be performed within the cycle. In principle, the received echo signals can be transmitted from the sensor to the control unit in the cycle following the emission of the sensor signal in each case, in order to keep the cycles short. Similarly, an echo signal from a current cycle can be received while an echo signal from the previous cycle is being transmitted from the corresponding sensor to the control unit. In principle, the echo signal from one cycle can also be transmitted to the control unit in the next following cycle onwards.

[0033] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least one group, the sensors of at least one group emit their sensor signals in their respective group transmission phase, the emission of the sensor signals using the sensors comprises a step of emitting at least two different sensor signals from the sensors of the at least one group, the reception of the echo signals based on the reflection of the sensor signals comprises a step of receiving at least two different echo signals based on the reflection of the at least two different sensor signals, and the identification of interference in the received echo signals of the at least one group is based on a comparison of the at least two different received echo signals. The different sensor signals are emitted by essentially identical sensors, but have at least one different characteristic, in particular with regard to the frequency of the sensor signals. For example, if ultrasonic sensors are used, sensor signals having different ultrasonic frequencies can be used. Only one type of sensor signal can be emitted by the sensors of each respective group, or at least some of the sensors of the respective group emit different sensor signals in a regular or random sequence. For example, current ultrasonic sensors can operate at different frequencies in the range of about 45 kHz to 60 kHz. In particular, interference effects from ripple currents often have a non-uniform effect on the reception of the corresponding echo signals. Thus, interference can be identified, for example, from the fact that it occurs only for one frequency of the echo signal. Thus, interference is essentially identified based on different echoes in at least two different echo signals. This is especially true when the same echo is expected from a real object for each of the different sensor signals based on the spatial proximity of the sensors receiving the different echo signals. Even when multiple different echo signals are considered, it is possible to identify the corresponding differences and detect interference. This is also true for radar sensors.

[0034] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least one group, the emission of at least two different sensor signals by means of at least one group of sensors comprises the step of emitting at least two different sensor signals by means of at least one group of different sensors. For example, different sensor signals can be emitted alternately from the ultrasonic sensors of the respective groups according to their arrangement along the supply line. This makes it possible to reliably monitor the environment on the basis of different echo signals, if the echo signals can be assigned to the different sensor signals. Mutual interference of the echo signals by the different sensor signals is reduced.

[0035] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least one group, the reception of at least two different echo signals based on reflection of at least two different sensor signals comprises a step of receiving at least two different echo signals with at least one of the sensors of the at least one group. When different types of echo signals are received at one sensor, different sensor recordings can be made for the corresponding sensor location. This provides a reliable way to determine whether an echo signal is interference or whether the echoes contained therein belong to a real object. The emission of different sensor signals is typically achieved by a plurality of sensors, in particular by adjacent sensors, in particular along a supply line. When different echo signals are received at one sensor, in particular echoes occurring for only one type of echo signal can be identified as interference, since a real object should generate a corresponding echo for each of the different sensor signals for the respective sensor location.

[0036] In an advantageous embodiment of the method for operating a sensor device with a number of sensors arranged in at least one group, interferences in the received echo signals of the group are identified on the basis of a comparison of at least two received echo signals from two different sensors of at least one group, in particular two sensors with different arrangements. Interferences in the common feed of the group affect all sensors in the group in the same way, so that interferences in the feed caused by false echoes are noticeable in all sensors in the group. The false echoes are very similar or even identical in terms of time and amplitude. Thus, interferences can be detected in the received echo signals of all sensors, and in principle, only a partial examination of the received echo signals may be sufficient to detect interferences. Preferably, the different arrangements of the sensors are those related to the first and the last arrangements of the corresponding sensor group, i.e. the most distant sensors are examined to identify interferences, since for these sensors the probability of simultaneous echoes from real objects is particularly low. It is therefore possible to identify interferences particularly reliably.

[0037] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least one group, the method comprises a step of masking the interference identified in the received echo signals of at least one group, in particular in all received echo signals of at least one group. The masking of the interference makes it possible to reliably avoid false positives in the detection of objects in the environment of the vehicle. To mask the interference in the echo signals received from all sensors in the corresponding group, it is sufficient that the interference is identified only in a part of the received echo signals. The masking of the interference has a direct effect on the echo signals transmitted to the control unit synchronously, i.e. in the same cycle. The reception of the echo signals and the transmission of the received echo signals to the control unit can be performed in different cycles.

[0038] In a further advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least one group, the masking of the interference identified in the received echo signals of at least one group comprises a step of masking the identified interference when receiving a further echo signal of the group. The further echo signal is transmitted from the sensor to the control unit at a later time, for example in a subsequent cycle. The further echo signal thus relates to an echo signal received at a later time. In the case of periodic interference signals, the masking can also be applied to signals other than the currently received echo signal, i.e. in future cycles. The expression "when receiving a further echo signal" means that the interference in the currently received echo signal is not initially identified, but the masking is also applied to subsequently received echo signals of the group based on the previously identified interference. The masking is preferably performed in the control unit, the masking can be performed immediately after the reception of the echo signal or at a later time during the processing of the echo signal.

[0039] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least one group, the plurality of sensors of the sensor device are arranged in at least two groups, the sensors of each group emitting their sensor signals in their respective group transmission phase, the group transmission phases of the at least two groups being offset in time, and the identification of interference in the received echo signal of at least one group is based on a comparison of at least two received echo signals from the corresponding group, taking into account the time offset of the group transmission phases of the other groups. For example, the time offset relates to the start of the respective group transmission phases of the different groups. The time offset between the individual group transmission phases may for example be different for the different groups. In principle, the time offset may also be different in different cycles. The time offset may be selected such that the group transmission phases of the different groups do not overlap. In this case, the group transmission phases are each paired discontinuous time intervals. The duration of the individual group transmission phases may be different for the different groups. The duration of the group transmission phases of the different groups may in principle also be different in different cycles. The method is preferably performed repeatedly for the different groups. This may also result in interference for each of the sensor groups based on activity by the sensors of the other groups, in particular on the transmission of sensor signals. Interference in the received echo signals can also be identified for each of the sensor groups. Thus, if the time offset is known, it is possible to specifically search for interference effects in the received echo signals and identify them. The time offset thus indicates the time when interference may occur based on a common supply of multiple sensor groups. Preferably, the time intervals during which these interference effects may occur are defined together with the known duration of the corresponding group transmission phase. To emit a signal pulse, the sensor typically requires a particularly large amount of energy, and the emission of a signal pulse in the group transmission phase of the corresponding group requires a large amount of power to be provided in a short time.This can lead to increased interference in the received echo signals of each group during the group transmission phase of the other group. The sensors receive the echo signals after the signal pulse is emitted, which typically requires less power to be provided, reducing the chance of interference occurring.

[0040] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least one group, the method comprises the step of varying the time offset between the group transmission phases of at least two groups between two cycles and emitting the sensor signals of the corresponding groups. When varying the time offset between the group transmission phases of at least two groups, the time window in which interference effects can occur also shifts. As a result, for example, when masking interference in a received echo signal, one region can be masked and in the subsequent envelope, another region can be masked. Thus, given a suitable change in the time offset, a complete capture of the environment can be achieved based on two received time-offset echo signals. Thus, a permanent masking of a certain region in the received echo signal can be avoided by varying the masking according to the time offset. In particular, in the case of low dynamics in the vehicle's environment, i.e. slow movement of objects relative to the vehicle in the vehicle's environment, it is possible to very reliably and completely capture the environment by the sensor despite the masking, even in the case of periodically occurring interference signals.

[0041] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least one group, the identification of interference in the received echo signals of at least one group based on a comparison of at least two of the received echo signals from the corresponding group comprises a step of identifying echoes in the received echo signals with a corrected time offset over at least two cycles. This means that to identify interference, received echo signals from more than one cycle are examined. Repetition of echoes of an object in the received echo signals that are essentially static with respect to the corresponding group transmission phase can indicate interference. This means that in particular in the case of high dynamics in the vehicle's environment, i.e. rapid movement of objects relative to the vehicle in the vehicle's environment, repeated echoes can be reliably identified as interference signals.

[0042] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least one group, the emission of sensor signals using each group of sensors in a respective group transmission phase comprises emitting sensor signals from each group of sensors in at least two subgroups with a time interval between the emission of the sensor signals of the at least two subgroups, and the identification of interference in the received echo signals of the at least one group based on a comparison of at least two of the received echo signals from the corresponding group comprises identifying echoes in the at least two received echo signals with a time interval. The sensor signals are usually emitted by the sensors of the at least two subgroups with a short time interval so that the corresponding group transmission phase is as short as possible. Preferably, the time interval is of the order of magnitude of the duration of the emission of the sensor signals. For example, the time interval can be several milliseconds, for example 3 milliseconds or more, an exemplary sensor signal having a duration of about 2.5 milliseconds. On the other hand, the use of at least two subgroups can reduce the maximum required power for the corresponding sensor group, thereby reducing the risk of occurrence of ripple currents. On the other hand, if the sensor signals are emitted in at least two subgroups with a time interval, the resulting interference signals show characteristic echoes in the received echo signal, which can be easily and reliably detected in order to identify them as interference. The time interval is, for example, related to the start of the transmission of the sensor signals of the subgroup. The emission of the sensor signals of the sensors of the at least two subgroups can in principle overlap in time. However, it is preferred that there is no overlap in order to avoid power peaks due to overlapping emission of the sensor signals with the sensors of the corresponding group. Preferably, the inner and outer sensors each form a subgroup, i.e. sensors at the beginning and end of the supply line, which are usually also positioned correspondingly on the vehicle.

[0043] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least one group, the identification of interference in the received echo signals of at least one group based on a comparison of at least two of the received echo signals from the corresponding group comprises a step of identifying echoes in at least two received echo signals with a time offset of at least two cycles. By emitting sensor signals in at least two subgroups with a time interval, repeated characteristic echoes of objects in the received echo signals can indicate repeated interference that can be identified particularly reliably. The identification of interference is facilitated by the characteristic echoes in the received echo signals.

[0044] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least one group, the emission of sensor signals from the sensors of each group in at least two subgroups with a time interval between the emission of the sensor signals of at least two subgroups comprises a step of modifying the time interval between two cycles for emission in their respective group transmission phase, emitting the sensor signals of the corresponding group, and the identification of interference in the received echo signals of at least one group based on a comparison of at least two of the received echo signals from the corresponding group comprises a step of identifying echoes in the received echo signals with the modified time interval over at least two cycles. By varying the time interval, the interference signal can be identified particularly reliably over at least two cycles, since the interference also changes with the change in the time interval. On the other hand, a real object does not change the shape of its echo in the received echo signal with a change in the time interval, so that it is possible to identify interference reliably. The interference can therefore be recognized firstly by its shape and secondly by a change corresponding to the change in the time interval.

[0045] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least one group, the reception of echo signals based on reflections of the sensor signals comprises a step of receiving an envelope with the received echo signals, the transmission of the received echo signals from the sensor to the control unit comprises a step of transmitting the envelope with the received echo signals, and the identification of interference in the received echo signals of at least one group is based on a comparison of at least two envelopes with the respective received echo signals of the corresponding group. The received echo signals are thus transmitted from the sensor to the control unit with their envelopes. The envelope curve is generated, for example, starting from the emission of the sensor signal or after a specified time interval. The end of the envelope is brought about from the end of the reception time for receiving reflections of the sensor signal. The envelope curve can be a continuous or discrete envelope with a plurality of individual points that together define the envelope. For the transmission of the envelope with the received echo signals, the above statement regarding the transmission of the received echo signals applies mutatis mutandis.

[0046] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least two groups, the method comprises the steps of varying the time offset between the group transmission phases of the at least two groups between two cycles and emitting the sensor signals of the at least two groups. When varying the time offset between the group transmission phases of the at least two groups, interference effects also occur modified in time. As a result, for example, when masking interference in a received echo signal, one region can be masked and in the subsequent envelope, another region can be masked. Thus, given a suitable change in the time offset, a complete capture of the environment can be achieved based on two received time-offset echo signals. Thus, a permanent masking of a certain region in the received echo signal can be avoided by varying the masking according to the time offset. In particular, in the case of low dynamics in the vehicle's environment, i.e. slow movement of objects relative to the vehicle in the vehicle's environment, it is possible to very reliably and completely capture the environment by the sensor despite the masking, even in the case of periodically occurring interference signals.

[0047] In an advantageous embodiment of the method for operating a sensor device with a plurality of sensors arranged in at least two groups, the identification of interference in the received echo signals of each group based on the time offset of the group transmission phases and the duration of the group transmission phases of the other groups comprises a step of identifying interference in the received echo signals of each group based on a comparison of at least two of the received echo signals of the corresponding group. This means that the time offset and the duration of the group transmission phases specify a time window or time interval during which an interference signal is identified based on a comparison of at least two of the received echo signals of the corresponding group. This allows for a precise identification of the interference signal by first limiting the occurrence of interference by a time window and then identifying the interference in this time window in a targeted manner. The area outside this time window does not have to be checked for interference, which also allows the method to be implemented very efficiently. With regard to the echo signals, reference is made to the above description of the method for operating a sensor device with a plurality of sensors arranged in at least one group.

[0048] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least two groups, the identification of interference in the received echo signal of each group based on a comparison of at least two of the received echo signals from the corresponding group comprises a step of identifying echoes in the received echo signal of each group with a corrected time offset over at least two cycles. This means that, to identify interference, received echo signals from more than one cycle are examined. Repetition of echoes of objects in the received echo signal that are essentially static with respect to the corresponding group transmission phase can indicate interference. This means that, especially in the case of high dynamics in the vehicle's environment, i.e. rapid movement of objects relative to the vehicle in the vehicle's environment, repeated echoes, i.e. essentially static echoes, can be reliably identified as interference signals.

[0049] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least two groups, the method comprises a step of masking the interference identified in the received echo signals of at least two groups, in particular in all received echo signals of the at least two groups. The masking of the interference makes it possible to reliably avoid false positives in the detection of objects in the environment of the vehicle. The masking of the interference directly affects the echo signals transmitted synchronously, i.e. in the same cycle, to the control unit. The reception of the echo signals and the transmission of the received echo signals to the control unit can be performed in different cycles. In addition, the masking of the interference identified in the received echo signals of at least one group can comprise a step of masking the identified interference when receiving a further echo signal of the group. The further echo signal is transmitted from the sensor to the control unit at a later time, for example in a subsequent cycle. The further echo signal is thus related to the echo signal received at a later time. In the case of periodic interference signals, the masking can also be applied to signals other than the currently received echo signal, i.e. in future cycles. The expression "when receiving further echo signals" means that interference in each of the currently received echo signals is not identified initially, but masking is also applied to subsequently received echo signals of the group based on previously identified interference. Masking is preferably performed in the control unit, where masking can take place immediately after reception of the echo signals or at a later time during the processing of the echo signals.

[0050] In an advantageous embodiment of the method for operating a sensor device having a plurality of sensors arranged in at least two groups, the reception of echo signals based on reflections of the sensor signals comprises a step of receiving an envelope with the received echo signals, and the transmission of the received echo signals from the sensor to the control unit comprises a step of transmitting the envelope with the received echo signals. The received echo signals are thus transmitted from the sensor to the control unit as a whole together with their envelope. The envelope curve is generated, for example, starting from the emission of the sensor signal or after a specified time interval. The end of the envelope results from the end of the reception time for receiving reflections of the sensor signal. The envelope curve can be a continuous or discrete envelope with a plurality of individual points that jointly define the envelope. For the transmission of the envelope with the received echo signals the above statement regarding the transmission of the received echo signals applies mutatis mutandis.

[0051] The present invention will be described in more detail below based on preferred embodiments with reference to the accompanying drawings. Each of the illustrated features can represent an aspect of the present invention both individually and in combination. Features of different exemplary embodiments can be transferred from one exemplary embodiment to another exemplary embodiment. [Brief description of the drawings]

[0052] [Figure 1] 1 is a schematic diagram of a vehicle equipped with a driving assistance system having a sensor device according to a first preferred embodiment; [Diagram 2] 2 is a schematic diagram of a part of the sensor arrangement of FIG. 1 with a control unit and a sensor group connected to each other via supply lines; [Diagram 3] FIG. 2 is an exemplary diagram of an envelope curve of an echo signal transmitted from one of the sensors of the sensor device via a supply line to the control unit, without interference; [Figure 4] 4 is an exemplary diagram of an envelope curve of an echo signal transmitted from one of the sensors of the sensor device via a supply line to a control unit with interference; [Diagram 5] 3 is a flowchart of a first embodiment method for operating the first embodiment sensor device. [Figure 6] 10 is a flowchart of a method of a third embodiment for operating the sensor device of the first or second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] FIG. 1 shows a vehicle 10 having a driving assistance system according to a first preferred embodiment.

[0054] The driving assistance system can in principle be any driving assistance system having one or more assistance functions. The driving assistance system can be designed as a driver assistance system that assists a human driver of the vehicle 10 when driving the vehicle 10, e.g. as an emergency braking system, an adaptive cruise control system, a parking assistance system, etc. Alternatively or additionally, the driving assistance system may provide functions that are used for autonomous or semi-autonomous driving of the vehicle 10.

[0055] The driving assistance system comprises a sensor arrangement 12. The sensor arrangement 12 comprises a control unit 14 and a number of sensors 16. The control unit 14 is any computing unit. In the field of vehicles 10 and driving assistance systems, such a control unit 14 is known for example as an ECU (Electronic Control Unit).

[0056] A number of sensors 16 are arranged on the vehicle 10 in two groups 18, 20. In this exemplary embodiment, the sensors 16 are configured as ultrasonic sensors 16. All sensors 16 here are similarly designed. A first group 18 with sensors 16 is arranged along the front of the vehicle 10, and a second group 20 with sensors 16 is arranged along the rear of the vehicle 10. Each of the two groups 18, 20 is shown in FIG. 1 with five individual sensors 16 as an example. The sensors 16 perform monitoring of the environment 22 of the vehicle 10 by detecting objects within the environment 22 of the vehicle 10.

[0057] The sensors 16 of each of the two groups 18, 20 are connected in parallel to a supply line 24 formed in each case by two individual wires 26, 28. Each of the two groups 18, 20 with sensors 16 is connected to the control unit 14 via a separate supply line 24. The sensors 16 of both groups 18, 20 receive a common power supply from the control unit 14 via the corresponding supply line 24.

[0058] The supply line 24 is used here simultaneously as the data line 30, i.e. the sensor 16 and the control unit 14 communicate via the supply line 24. Various such bus systems are known, and an integral arrangement of the supply line 24 and the data line 30 is implemented, for example, in DSI3 or USV11. An extract of the sensor device 12 is shown in detail in FIG. 2 together with the supply line 24 and the data line 30. Alternative embodiments of the supply line 24 with the data line 30 are also possible.

[0059] The control unit 14 is connected to a battery 32 of the vehicle 10 and receives from the battery 32 electrical energy for supplying the sensors 16 of the two groups 18 , 20 via corresponding supply lines 24 .

[0060] 5 for operating the sensor device 12 of the first embodiment is described below. The order of steps specified in the described method can be modified or some of the steps are optional, as will be apparent to those skilled in the art.

[0061] The method begins at step S100 with emitting a sensor signal using the sensor 16. The ultrasonic sensor 16 emits an ultrasonic pulse or sequence of ultrasonic pulses as the sensor signal. The ultrasonic sensors 16 of each group 18, 20 emit their sensor signals simultaneously in a common group transmission phase. In this process, two different sensor signals are emitted by the ultrasonic sensors 16 of each group 18, 20, namely, an ultrasonic signal having a high ultrasonic frequency and an ultrasonic signal having a low ultrasonic frequency in a frequency range for ultrasonic signals of about 45 kHz to 60 kHz.

[0062] The ultrasonic sensors 16 of each group 18 , 20 alternately emit two different sensor signals according to their location along the supply line 24 .

[0063] Step S110 concerns receiving an echo signal based on the reflection of the sensor signal. The echo signal is received based on the reflection of the sensor signal emitted in step S100. Thus, two different echo signals based on the reflection of the two different sensor signals are received by each ultrasonic sensor 16 of the groups 18, 20. Each of the ultrasonic sensors 16 simultaneously receives echo signals for both ultrasonic frequencies of the emitted ultrasonic signal, i.e. each ultrasonic sensor 16 receives on two frequency channels.

[0064] In this case, the ultrasonic sensor 16 receives envelopes 34, 36 that accompany the received echo signal. Examples of corresponding envelopes 34, 36 are shown in Figs.

[0065] Reflections of the sensor signal occur off objects in the environment 22 of the vehicle 10 so that the control unit 14 can determine the distance to the object from the time difference between the emission of the sensor signal and the receipt of the echo signal.

[0066] Step S120 concerns the transmission of envelopes 34, 36 with the received echo signals from the sensor 16 to the control unit 14. Each envelope 34, 36 in this exemplary embodiment comprises, by way of example, a complete period from the emission of the sensor signal to the end of the reception time for receiving the reflection of the sensor signal. The envelopes 34, 36 can be continuous or discrete envelopes 34, 36 with a number of individual points that together define the envelopes 34, 36. The envelopes 34, 36 are transmitted together with the echo signals received from the sensor 16 to the control unit 14, the transmission of the envelopes 34, 36 from the individual sensors 16 being time shifted. In addition, the envelopes 34, 36 are transmitted from the sensor 16 to the control unit 14 in each case in a cycle following the emission of the sensor signal.

[0067] Step S130 relates to identifying interference 38 in the envelopes 34,36 of the received echo signals of each group 18,20 based on a comparison of the envelopes 34,36 of the received echo signals from the corresponding groups 18,20.

[0068] First, interference 38 is identified in the envelopes 34, 36 of the received echo signals of the groups 18, 20 based on a comparison of the envelopes 34, 36 of the multiple sensors 16 of the groups 18, 20 for the same frequency channel in each case. As can be seen from Figure 3, the illustrated envelope 34 does not have interference 38. The envelope 34 of Figure 3 includes multiple echoes 40 of objects in the environment 22 of the vehicle 10.

[0069] In contrast, the envelope 36 in Fig. 4 shows, in addition to the echo 40 also shown in Fig. 3, an interference signal 38 appearing in a similar manner in the envelopes 34, 36 of all sensors 16 for the same frequency channel, which means that the interference 38 in the examined envelopes 34, 36 is similar or identical in terms of time or distance and amplitude for the corresponding frequency channel. Thus, if the interference 38 is visible for the same frequency channel for all sensors 16, the interference 38 is thus detected.

[0070] In addition, interference 38 is identified by comparing the two respective envelopes 34, 36 for each of the ultrasonic sensors 16 based on the two different echo signals, i.e. the envelopes 34, 36 of the two receive frequency channels are compared with each other for each of the sensors 16. Interference 38 may for example be visible in only one of the frequency channels depending on the type of interference 38, i.e. the envelope 34, 36 of the frequency channel is free of detectable interference 38 as shown in Figure 3 and the envelope 34, 36 of the other frequency channel shows detectable interference 38 as shown in Figure 4. Interference 38 is identified by the fact that one frequency channel shows interference 38 and the other frequency channel does not show interference.

[0071] Step S140 involves masking the identified interference 38 in all envelopes 34, 36 of the received echo signals of each of the groups 18, 20. As a result, the interference 38 is masked in the envelopes 34, 36 so that no false positive detection of an object occurs within the environment 22 of the vehicle 10. Depending on the type of interference 38, the masking may affect the envelopes 34, 36 of only one frequency channel or both frequency channels.

[0072] In this exemplary embodiment, the method is performed repeatedly in cycles, with a cycle for the sensor 16 comprising steps S100-S120. The iterative method in its general form also comprises steps S130 and S140.

[0073] The following text describes a second embodiment based on the sensor device 12 and method of the first embodiment. The differences between the two embodiments are therefore explained. Features of the second embodiment that are not described in detail correspond, in case of doubt, to the features of the first embodiment.

[0074] The method of the second embodiment is carried out using the sensor device 12 of the second embodiment, which has the same structure as the sensor device 12 of the first embodiment.

[0075] In contrast to the method of the first embodiment, step S100 comprises emitting sensor signals using the sensors 16, the sensors 16 of each group 18, 20 emitting their sensor signals in their respective group transmission phases, the group transmission phases of the two groups 18, 20 being offset in time. The time offset is selected such that the group transmission phases of the different groups 18, 20 do not overlap. In this case, the group transmission phases are of discontinuous time intervals.

[0076] In contrast to the method of the first embodiment, step S130 comprises the identification of interferences 38 in the envelopes 34, 36 of the received echo signals of the respective groups 18, 20, taking into account the time offset of the group transmission phases. Based on the known time offset and the duration of the corresponding group transmission phase, which is also known, a time interval is obtained in which an interference signal 38, i.e. an interference signal caused by the emission of the echo signal of the respective other group 18, 20, may occur in the supply. The identification of interferences 38 in the envelopes 34, 36 of the received echo signals of the groups 18, 20 is therefore performed precisely for these time ranges. The result is a time interval in which these interference signals 38 may occur. In this time interval, the control unit 14 specifically searches for interference signals 38 based on the supply in the envelopes 34, 36 during the transmission of the sensor signals and easily identifies them.

[0077] Also in this exemplary embodiment, the method is repeatedly performed in cycles, each cycle for the sensor 16 comprising steps S100 to S120. The cycles of the two groups 18, 20 are offset with respect to each other by a time offset.

[0078] The following text describes the method according to the third embodiment shown in Fig. 6 for operating the sensor device 12 of the first embodiment. The order of the steps specified in the described method can be partially modified or some of the steps are optional, as will be clear to the skilled person. In principle, the method can also be performed in the same way using the sensor device 12 of the second embodiment.

[0079] The method of the third embodiment corresponds in part to the method of the first embodiment. Therefore, the differences between the two embodiments will be described. Features of the third embodiment that are not described in detail correspond, in case of doubt, to the features of the first embodiment.

[0080] The method begins at step S200 with emitting a sensor signal using the sensor 16. Step S200 essentially corresponds to step S100 of the method of the first embodiment.

[0081] Step S210 concerns receiving an echo signal based on reflection of the sensor signal. Step S210 corresponds to step S110 of the method of the first embodiment.

[0082] Step S220 concerns the transmission of the envelopes 34, 36 with the received echo signals from the sensor 16 to the control unit 14. Step S220 corresponds to step S120 of the method of the first embodiment.

[0083] Step S230 relates to identifying interference 38 in the received envelope 34, 36 of each group 18, 20 based on the time offset of the group transmission phases and the duration of the group transmission phase of at least one other group 18, 20. The group transmission phase of the first group 18 is identified as interference in the envelope 34, 36 of the sensors 16 of the second group 20 and the group transmission phase of the second group 20 is identified as interference in the envelope 34, 36 of the sensors 16 of the first group 18. Interference is identified for all sensors 16 of the corresponding group 18, 20.

[0084] Step S240 involves masking the identified interference 38 in all envelopes 34, 36 of the received echo signals of each of the groups 18, 20. Step S240 corresponds to step S140 of the method of the first embodiment.

[0085] Step S250 relates to correcting the time offset between the group transmission phases of the two groups 18,20 between the two cycles for emitting the sensor signals of the two groups 18,20.

[0086] The method of the third embodiment is now repeatedly performed in cycles, a cycle for the sensor 16 comprising steps S200 to S220. The iterative method in its general form further comprises steps S230 to S250. [Explanation of symbols]

[0087] 10 Vehicles 12 Sensor device 14 Control unit 16 Sensors, Ultrasonic Sensors 18 First Group 20 Second Group 22 Environment 24 Supply Line 26 Wire 28 Wire 30 Data Lines 32 Battery 34 Interference-free envelope, channel 1 36 Envelope with interference, channel 2 38 Interference 40 Echo

Claims

1. A method for operating a sensor device (12) having a control unit (14) and a plurality of sensors (16) arranged in at least one group (18, 20), the sensors (16) being connected to a common power source via the control unit (14), using said sensors (16) to emit sensor signals, said sensors (16) of each group (18, 20) emitting their sensor signals in their respective group transmission phase; receiving an echo signal based on a reflection of the sensor signal; transmitting received echo signals from said sensor (16) to said control unit (14); identifying interference (38) in the received echo signals from at least one of the groups (18, 20) based on a comparison of at least two of the received echo signals from corresponding groups (18, 20); Equipped with The method, wherein the interference (38) is due to interference effects from ripple currents.

2. Emitting sensor signals using the sensors (16), in which the sensors (16) of the at least one group (18, 20) emit their sensor signals in their respective group transmission phases, includes emitting at least two different sensor signals using the sensors (16) of the at least one group (18, 20); Receiving echo signals based on reflections of the sensor signals includes receiving at least two different echo signals based on reflections of the at least two different sensor signals; and identifying interference (38) in the received echo signals from the at least one group (18, 20) based on a comparison of at least two different received echo signals.

2. The method according to claim 1 .

3. Emitting at least two different sensor signals using the sensors (16) of the at least one group (18, 20) includes emitting the at least two different sensor signals using different sensors (16) of the at least one group (18, 20).

3. The method according to claim 2 .

4. Receiving at least two different echo signals based on reflection of the at least two different sensor signals includes receiving the at least two different echo signals using at least one of the sensors (16) of the at least one group (18, 20).

4. The method according to claim 2 or 3.

5. the identification of interference (38) in the received echo signals of a group (18, 20) is based on a comparison of at least two received echo signals from two different sensors (16) of the at least one group (18, 20); 5. The method according to claim 1, wherein the

6. The method includes masking identified interference (38) in the received echo signals of the at least one group (18, 20).

6. The method according to claim 1 , characterized in that

7. the plurality of sensors (16) of the sensor device (12) are arranged in at least two groups (18, 20), the sensors (16) of each group (18, 20) emitting their sensor signals in their respective group transmission phases, the group transmission phases of the at least two groups (18, 20) being offset in time; the identification of interference (38) in the received echo signals of at least one of the groups (18, 20) is based on a comparison of at least two of the received echo signals from the corresponding group (18, 20) taking into account a time offset of the group transmission phase of the other group (18, 20); 7. The method according to claim 1, wherein the

8. The method includes the step of modifying a time offset between the group transmission phases of the at least two groups (18, 20) between two cycles for emitting the sensor signals of the corresponding groups (18, 20). The method of claim 7.

9. and identifying interference (38) in the received echo signals of at least one of the groups (18, 20) based on a comparison of at least two of the received echo signals from the corresponding groups (18, 20) includes identifying echoes in the received echo signals with the corrected time offset over at least two cycles. The method according to claim 8.

10. Emitting a sensor signal using the sensor (16) of each group (18, 20) in a group transmission phase includes emitting the sensor signal from the sensor (16) of each group (18, 20) in at least two subgroups with a time interval between emission of the sensor signals of the at least two subgroups; Identifying interference (38) in the received echo signals of at least one of the groups (18, 20) based on a comparison of at least two of the received echo signals from the corresponding groups (18, 20) includes identifying echoes in at least two of the received echo signals with the time interval.

10. The method according to any one of claims 1 to 9, characterized in that

11. and identifying interference (38) in the received echo signals of at least one of the groups (18, 20) based on a comparison of at least two of the received echo signals from the corresponding groups (18, 20) includes identifying echoes in at least two of the received echo signals with the time interval spanning at least two cycles. The method of claim 10.

12. The emission of the sensor signals from the sensors (16) of each group (18, 20) in the at least two subgroups with a time interval between the emission of the sensor signals of the at least two subgroups includes a step of modifying the time interval between two cycles for emitting the sensor signals of the corresponding group (18, 20); Identifying interference (38) in the received echo signals of at least one of the groups (18, 20) based on a comparison of at least two of the received echo signals from the corresponding groups (18, 20) includes identifying echoes in the received echo signals with the modified time interval spanning at least two cycles. The method of claim 11.

13. Receiving an echo signal based on a reflection of the sensor signal includes receiving an envelope (34, 36) accompanying the received echo signal; Transmitting the received echo signal from the sensor (16) to the control unit (14) includes transmitting the envelope (34, 36) with the received echo signal; the identification of interference (38) in the received echo signals from at least one group (18, 20) is based on a comparison of at least two envelopes (34, 36) in each case with the echo signals received from the corresponding group (18, 20), 13. The method according to any one of claims 1 to 12, characterized in that

14. A sensor device (12) for a vehicle (10), comprising: A control unit (14); a plurality of sensors (16) arranged in at least one group (18, 20); having The sensors (16) are connected to a common power source via the control unit (14); The sensor device (12) is designed to operate according to the method according to any one of claims 1 to 13. A sensor device (12) for a vehicle (10).

15. A driving assistance system for a vehicle (10), comprising a sensor device (12) according to claim 14.

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