identifying interference in received echo signals from a set of sensors

Abstract

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

Description

Technical Field

[0001] The present invention relates to a method for operating a sensor device having a control unit and a plurality of sensors arranged in at least one group, wherein the sensors are connected to a common power source, particularly via the control unit.

[0002] The present invention also relates to a method for operating a sensor device having a control unit and a plurality of sensors arranged in at least two groups, wherein the sensors are connected to a common power source, specifically via the control unit.

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

[0004] The present invention also relates to a sensor device for a vehicle having a control unit and a plurality of sensors arranged in at least two subgroups, wherein the sensors are connected to a common power source via the control unit.

[0005] The present invention also relates to a driving assistance system for a vehicle having the above-described sensor device. Background Technology

[0006] Modern vehicles are increasingly equipped with sensors to monitor their surroundings. These sensors (hereinafter also referred to as environmental sensors) provide environmental information that can be used by various driver assistance systems (ADAS) of the vehicle. Depending on the type of ADAS, it can assist the driver or provide functions to enable autonomous driving.

[0007] In a sensor unit, sensors are typically connected to a common power source. For this purpose, the sensors are connected to the control unit via a power line that not only powers the environmental sensors but also receives and evaluates sensor information from them to detect objects in the environment that pose a hazard to the vehicle and generate appropriate warnings. Sensor information may include echo signals received as reflections of sensor signals emitted by the sensors. For example, the echo signal contains the time of the first echo detected by the corresponding sensor from an object in the environment. The echo is characterized by the sensor's received amplitude being above a threshold value. In addition to the time of echo reception, the echo signal may contain the duration of the received echo and / or the received amplitude of the received echo. The echo signal may also contain multiple echoes detected by the corresponding sensor from objects in the environment. The statements given above regarding echo reception apply. During periods when no echo is received, for example, if the received amplitude is below a threshold value, no signal is generated. Furthermore, the sensors may generate envelopes containing echo signals and transmit them to the control unit. The envelope contains the time profile of the received amplitude and therefore also contains the amplitude values ​​of the intervals during which the received amplitude of the corresponding sensor is below a threshold value, i.e., when no echo is received by definition. Limits can have a time profile because, for example, due to dispersion, reflections from nearby objects are received at a greater extent than reflections from objects that are more distant but otherwise similar.

[0008] By utilizing a common power supply for the sensors, a simple wiring layout for the sensors can be achieved. In particular, by providing a common power supply to the sensors via the control unit, wiring can be implemented based on the data connection from the control unit to the sensors, which is also necessary. Therefore, the power line can be laid parallel to the data line, and is therefore preferably laid simultaneously, or only a single conductor can be laid that serves as both a power line and a data line.

[0009] The sensors mentioned can be, for example, ultrasonic sensors, radar sensors, or other sensors. These sensors emit sensor signals and receive echo signals based on these signals, thereby identifying objects in the vehicle environment as echoes. Therefore, ultrasonic sensors emit ultrasonic pulses and receive the ultrasonic echoes of the emitted ultrasonic pulses from objects in the vehicle environment. In modern vehicles, typically the first set of sensors is arranged along the front of the vehicle, and the second set along the rear. Each set currently includes four to six individual sensors. Thus, these sensors are arranged in a narrow spatial relationship and detect continuous portions of the vehicle environment. Arranging ultrasonic sensors along the long side of the vehicle is also becoming increasingly common, and for the reasons mentioned above, these sensors can also be connected to the control unit as a separate group.

[0010] To emit ultrasonic pulses, ultrasonic sensors require exceptionally high energy; therefore, the near-simultaneous emission of ultrasonic pulses necessitates a significant amount of electrical power. To reduce the required power, different groups of sensors emit their sensor signals within their group with a time offset relative to other groups. After emitting the ultrasonic pulse, the ultrasonic sensor receives the echo signal based on the sensor signal reflected from objects in the vehicle environment. To detect the reflection of the sensor signal at the object as an echo in the echo signal, the received echo signal needs to be electrically amplified because the amplitude of the received echo signal decreases sharply as the duration after ultrasonic pulse emission increases.

[0011] Errors in the reception of echo signals can occur due to interference in the power supply of ultrasonic sensors. These errors can lead to incorrect detection of objects in the vehicle environment, i.e., false detection of non-existent objects, which, for example, can cause the emergency braking system to be erroneously activated. Interference can be caused by external influences or the power supply itself, for example, within the control unit. In particular, if the control unit needs to provide a high power level, such as when using each group of sensors to transmit sensor signals, so-called ripple current may occur, where the DC voltage supplied as the power supply voltage is superimposed with the AC voltage component.

[0012] Current sensors or driver assistance systems exacerbate power supply issues because, compared to older sensors, current sensors emit sensor signals over a longer period, specifically as multiple individual signal pulses that combine to form the sensor signal. This means the sensor must receive the required power over a longer time period. Furthermore, the pulses result in a larger AC component in the power supply. To avoid interference with the power supply, various circuit-based solutions, such as capacitors or ripple filters, can theoretically be used. However, these all come with significant effort and corresponding costs. Summary of the Invention

[0013] Therefore, based on the above-mentioned prior art, the object of the present invention is to provide a method for operating a sensor device having multiple sensors and a corresponding sensor device, which allows for simple, cost-effective, and interference-free detection of the environment.

[0014] According to the invention, this objective is achieved by the features of the independent claim. Advantageous configurations of the invention are specified in the dependent claims.

[0015] 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, wherein the sensors are connected to a common power supply via the control unit, the method comprising the steps of: transmitting sensor signals using the sensors, wherein the sensors of each group transmit their sensor signals during their respective group transmission phase; receiving echo signals based on reflections 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 received echo signals from corresponding groups.

[0016] 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 two groups, wherein the sensors are connected to a common power supply, particularly via the control unit, the method comprising the steps of: transmitting sensor signals using the sensors, wherein the sensors of each group transmit their sensor signals during their respective group transmission phases, and the group transmission phases of at least two groups are time-shifted; receiving echo signals based on reflections 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 shift of the group transmission phases and the duration of the group transmission phases of at least one other group.

[0017] According to the present invention, a sensor device for a vehicle is also provided, having a control unit and a plurality of sensors arranged in at least one group, wherein the sensors are connected to a common power source via the control unit, and the sensor device is designed to operate using the method described above.

[0018] According to the present invention, a sensor device for a vehicle is also provided, having a control unit and a plurality of sensors arranged in at least one group, wherein the sensors are connected to a common power supply via the control unit, and the sensor device is designed to operate according to the method described above.

[0019] According to the present invention, a driving assistance system for a vehicle is also provided, which has one of the aforementioned sensor devices.

[0020] Therefore, the basic idea of ​​this invention is to identify interference in the received echo signals caused by faults in the common power supply, and thus be able to handle them appropriately. In particular, if the power supply via the control unit needs to operate at a high power level, for example, when transmitting sensor signals using at least one set of sensors, so-called ripple currents may occur, where the DC voltage supplied as the power supply voltage is superimposed with the AC voltage component. If such interference caused by ripple currents can be reliably identified, this interference in the echo signal can be eliminated or ignored, preventing the control unit from falsely detecting objects. Therefore, interference can be cost-effectively overcome by improved signal processing of the received echo signals, thereby achieving reliable detection of objects in the vehicle environment, and in particular avoiding false alarms in object detection in the vehicle environment. This interference can be avoided or eliminated through circuit-based solutions, such as capacitors or ripple filters, as part of the common power supply, for example in the control unit, which makes it possible to handle the interference cost-effectively. Furthermore, using sensors allows sensor signals to be transmitted over longer periods compared to previous implementations, particularly in the form of multiple individual signal pulses that together form the corresponding sensor signal. This means that the sensors will require more power, or they may require the same power over longer periods, without needing to increase the power supply via the control unit. Interference that may occur over longer periods can be identified and overcome, allowing for the detection of objects in the vehicle environment without significant limitations. Depending on the method of operating the sensor device, interference can be identified individually for a single set of sensors, i.e., without knowing the operation of other sets of sensors. Alternatively, interference can be identified through the coordinated operation of multiple sets of sensors, as defined by the different transmission phases of each set.

[0021] Interference in the received echo signals of each group can be identified in different ways, based on both the transmitted sensor signal and the received echo signal. Therefore, in both cases, it is not necessary to directly address the source of the fault, i.e., the power supply, in order to identify or prevent interference, as the latter involves a great deal of effort.

[0022] Therefore, interference can be identified by comparing multiple examples of received echo signals within a group. This is generally applicable to echo signals acquired simultaneously, where a fault in the common power supply of all sensors in a corresponding group affects all sensors in that group due to interference effects in the echo signal reception. Depending on the design of a sensor device with sensors arranged in multiple groups, the impact of power supply faults in the common power supply of multiple groups may also occur, depending on the operation and power supply type of different groups of sensors. In particular, the transmission of sensor signals using other groups of sensors may interfere with the power supply of another group or other groups of sensors, causing interference to appear in the received echo signals of the corresponding group. Interference effects in sensor power supplies can be identified due to external influences, such as unpredictable and / or potentially random external interference signals, and due to interference from sensor power supply operation, such as in the control unit. Based on a comparison of at least two received echo signals from a corresponding group, interference in the received echo signals of at least one group can be identified in fundamentally different ways. Details have been described above, and are also given below. For example, interference can be detected based on simultaneous echoes in the echo signal and / or echoes with excessive amplitude and / or echoes of similar type in the echo signal.

[0023] On the other hand, interference identification can be performed by identifying the corresponding time window of the 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 required, and interference can be identified effortlessly. Identifying interference based on the time offset and duration of the group transmission phase of at least one other group can cause echo signals from sensors in that group to be identified as interference during that group's group transmission phase, while that group receives echo signals during the group transmission phase of another group. As a result, the true echoes of objects in the vehicle environment cannot always be detected and processed. However, various measures described below are possible to provide effective echo signals even within that time window. In this case, interference effects in the corresponding group typically occur on all included sensors because these sensors receive echo signals simultaneously and share a common power supply. Similarly, interference effects in the common power supply caused by interference in echo signal reception affect all sensors in the corresponding group, which are identified together based on the time offset and duration of the group transmission phase. In this case, the group transmission phase is controlled by the control unit, allowing interference to be easily identified directly in the control unit. For example, the time offset relates to the start of the corresponding group transmission phase of different groups. The time offsets between the transmission phases of different groups can be different, for example, between different groups. The time offset can be chosen so that the transmission phases of different groups do not overlap. In this case, each transmission phase of a group is a pair of non-overlapping time intervals. The duration of each transmission phase of a group can be different for different groups. The duration of the transmission phases of different groups can also, in principle, be different in different cycles. Preferably, this method is repeated for different groups. This may also be based on the activity of sensors in other groups, particularly the transmission of sensor signals, causing interference to each group of sensors. The time offset specifies the point at which joint supply interference based on multiple groups of sensors may begin to occur, and together with the duration of the corresponding transmission phase of a group, the time interval is defined as the interference.

[0024] Interference in echo signal reception is typically related to faults in internal signal processing, specifically the physical coupling from the echo signal to the corresponding sensor, potentially extending to the generation of the echo signal's envelope. Due to the dispersion of the transmitted sensor signals and the echo signals based on them, signal processing, particularly signal amplification, is usually required for the physically coupled echo signals to reliably detect reflections of the sensor signals as echoes and identify echoes from objects contained within them. To detect echoes reflected from sensor signals at distant objects, increasingly higher electrical signal amplification of the received echo signals is required, particularly the signal gain, which increases with the duration of the sensor signal transmission, i.e., with the distance between the object and the corresponding sensor. By identifying interference, the sensor can thus reliably detect objects at greater distances from the corresponding sensor. For example, this means that incorrect emergency braking operations in corresponding driver assistance systems can be avoided.

[0025] Sensor devices are typically part of, or connected to, a vehicle's driver assistance system to provide the system with environmental information related to objects in the vehicle's environment. A driver assistance system can, in principle, be any system with one or more assistance functions. Such systems are known, for example, to assist the driver while driving the vehicle, such as emergency braking systems, adaptive cruise control systems, parking assistance systems, etc. However, such systems can also provide functions, for example, for autonomous or semi-autonomous driving of the vehicle.

[0026] The control unit is an inherently arbitrary computing unit that receives and processes echo signals from sensors. In the field of vehicles and driver assistance systems, such a control unit is, for example, called an ECU (Electronic Control Unit). In principle, other components can also be connected to the control unit. If these additional components are connected to and powered by the sensors' common power supply, this will introduce more potential sources of interference, since these additional components are powered by the common power supply. The principles described here can be applied accordingly.

[0027] The sensor device comprises multiple sensors, each preferably designed in the same manner for each group. For example, the sensors may be ultrasonic or radar sensors, emitting corresponding ultrasonic or radar signals as sensor signals and receiving the echo signals of these sensor signals as ultrasonic or radar echoes. In modern vehicles, typically the first group of sensors is arranged, for example, along the front of the vehicle, and the second group along the rear. For example, each group includes four to six individual sensors. Alternatively, sensor groups may be arranged along the long side of the vehicle. The sensors are connected in parallel to a common power source, for example, via power lines. Alternatively, a group of sensors may be daisy-chained, particularly to a control unit.

[0028] For example, power lines can be laid parallel to one of the data lines, allowing them to be laid simultaneously, with both lines running together. Alternatively, a single line can be laid that serves as both a power and data line, where the sensor and control unit communicate via a common line, and the control unit powers the sensor via the common line. Power lines typically consist of two potentials, usually the power supply voltage and ground potential, provided through one or more separate cables. Various bus systems are also known that integrate power and data lines, such as DSI3 or USV11.

[0029] A common power supply provides power to all connected sensors. When powered by a control unit, the power is provided by the control unit. For example, the control unit has internal or external power supply circuitry to provide power to all groups via power lines. In a vehicle, voltage conversion can be performed from the typically 12-volt onboard vehicle voltage to the desired power supply voltage, specifically voltage boosting (step-up).

[0030] During the corresponding group transmission phase, sensor signals are transmitted for each group. In this phase, these sensors typically transmit their signals in close timing, particularly simultaneously, so as to similarly receive echo signals simultaneously or in close timing. The echo signals are based on the reflection of sensor signals at objects in the vehicle environment, allowing the distance to the object to be determined from the time difference between the transmission of the sensor signal and the reception of the echo at the object. Therefore, the echo signals define the time definition of the received echo and the distance to the object to which the echo belongs.

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

[0032] The received echo signals are transmitted from the sensors to the control unit, specifically within a corresponding loop, where, for example, delayed transmission of the echo signals from each sensor to the control unit can occur within the loop. In principle, in each case, the received echo signals can be transmitted from the sensors to the control unit in the loop following the transmission of the sensor signal, in order to keep the loop short. Similarly, the echo signal of the current loop can be received, while the echo signal of the previous loop is transmitted from the corresponding sensor to the control unit. In principle, the echo signal from one loop can also be transmitted to the control unit in the next loop or thereafter.

[0033] In an advantageous embodiment of the method for operating a sensor device having multiple sensors arranged in at least one group, sensor signals are transmitted using the sensors, wherein the sensors of at least one group transmit their sensor signals during their respective group transmission phases, including transmitting at least two different sensor signals from the sensors of at least one group, receiving echo signals based on the reflection of the sensor signals, including receiving at least two different echo signals based on the reflection of the at least two different sensor signals, and identifying interference in the received echo signals of at least one group based on the comparison of the at least two different received echo signals. The different sensor signals are emitted by substantially the same sensors but have at least one different characteristic, particularly with respect to the frequency of the sensor signals. For example, if ultrasonic sensors are used, sensor signals with different ultrasonic frequencies can be used. Each corresponding group of sensors can only transmit one type of sensor signal, or at least some sensors in the corresponding group transmit different sensor signals in a regular or random order. For example, current ultrasonic sensors can operate at different frequencies in the range of about 45 kHz to 60 kHz. In particular, the interference effect of ripple current typically has a non-uniform effect on the reception of the corresponding echo signals. Therefore, interference can be identified, for example, based on the fact that the interference only appears at one frequency of the echo signal. Thus, interference is identified substantially based on the differences in the echoes of at least two different echo signals. This is especially true if, based on the spatial proximity of sensors receiving different echo signals, the echo from a real object is expected to be the same for each different sensor signal. Even when considering multiple different echo signals, the corresponding differences can be identified to detect interference. The same applies to radar sensors.

[0034] In an advantageous embodiment of the method for operating a sensor device having multiple sensors arranged in at least one group, transmitting at least two different sensor signals with at least one group of sensors includes transmitting at least two different sensor signals with different sensors in at least one group. For example, different sensor signals can be alternately transmitted from ultrasonic sensors in corresponding groups according to their arrangement along power lines. If echo signals can be assigned to different sensor signals, this allows for reliable monitoring of the environment based on different echo signals. Mutual interference of echo signals due to different sensor signals is reduced.

[0035] In an advantageous embodiment of a method for operating a sensor apparatus having multiple sensors arranged in at least one group, the reception of at least two different echo signals based on the reflection of at least two different sensor signals includes receiving at least two different echo signals with at least one sensor from at least one group. When different types of echo signals are received with a single sensor, different sensor records can be made for the positions of the corresponding sensors. This provides a reliable method for determining whether an echo signal is interference or whether the echo contained therein belongs to a real object. The transmission of different sensor signals is typically achieved through multiple sensors, particularly through adjacent sensors, especially along power lines. When different echo signals are received with a single sensor, echoes appearing only for one type of echo signal can be identified as interference, because for the position of the corresponding sensor, a real object should produce a corresponding echo for each different sensor signal.

[0036] In an advantageous embodiment of the method for operating a sensor device having multiple sensors arranged in at least one group, interference in the received echo signals of the group is identified based on a comparison of at least two received echo signals from two different sensors in the at least one group, particularly from two sensors with different arrangements. Interference in the common power supply of the group affects all sensors in the group in the same way, so interference in the power supply caused by spurious echoes is apparent in all sensors in the group. Spurious echoes are very similar or even identical in time and amplitude. Therefore, interference can be detected in the received echo signals of all sensors, where, in principle, only a partial examination of the received echo signals is sufficient to detect interference. Preferably, the different arrangements of the sensors involve arrangements at the beginning and end of the respective groups of sensors, i.e., examining those sensors furthest apart to identify interference, because with these sensors, the probability of simultaneous echoes from real objects is particularly low. Therefore, interference can be identified particularly reliably.

[0037] In an advantageous embodiment of a method for operating a sensor device having multiple sensors arranged in at least one group, the method includes shielding against interference identified in the received echo signals of at least one group, particularly interference identified in all received echo signals of at least one group. Interference shielding ensures that false positives in object detection within the vehicle environment can be reliably avoided. It is sufficient to identify interference only in a portion of the received echo signals to shield against interference in echo signals received from all sensors in the corresponding group. Interference shielding directly affects the echo signals synchronously (i.e., in the same cycle) transmitted to the control unit. The reception of echo signals and the transmission of the received echo signals to the control unit can be performed in different cycles.

[0038] In another advantageous embodiment of the method for operating a sensor device having multiple sensors arranged in at least one group, shielding against interference identified in the received echo signals of at least one group includes shielding against the identified interference when additional echo signals of that group are received. At a later time, such as in a subsequent cycle, additional echo signals are transmitted from the sensors to the control unit. Therefore, the additional echo signals are associated with the later received echo signals. In the case of periodic interference signals, shielding can also be applied to signals other than the currently received echo signals, i.e., applied to another cycle. The statement "when additional echo signals are received" means that interference in the currently received echo signals was not initially identified, but shielding is also applied to subsequently received echo signals of that group based on previously identified interference. Shielding is preferably performed in the control unit, wherein shielding can occur immediately upon receiving an echo signal or at a later time during echo signal processing.

[0039] In an advantageous embodiment of the method for operating a sensor device having multiple sensors arranged in at least one group, the multiple sensors of the sensor device are arranged in at least two groups, wherein the sensors of each group transmit their sensor signals in their respective group transmission phase, and the group transmission phases of the at least two groups are time-shifted, and the identification of interference in the received echo signals 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 shifts of the group transmission phases of the other groups. For example, the time shift relates to the start of the corresponding group transmission phase of different groups. The time shifts between the various group transmission phases can be different, for example, for different groups. In principle, the time shifts can also be different in different cycles. The time shifts can be selected such that the group transmission phases of different groups do not overlap. In this case, each group transmission phase is a pair of non-overlapping time intervals. The duration of each group transmission phase can be different for different groups. The duration of the group transmission phases of different groups can also, in principle, be different in different cycles. The method is preferably repeated for different groups. This may also be based on the activity of the sensors in other groups, particularly the transmission of sensor signals, which may cause interference to each group of sensors. Interference in the received echo signals can also be identified for each group of sensors. If the time offset is known, it becomes possible to specifically search for interference effects in the received echo signals in order to identify them. Therefore, the time offset indicates the time during which interference may occur based on the common power supply of multiple groups of sensors. Preferably, the time interval at which these interference effects may occur is defined together with the known duration of the corresponding group's transmission phase. To transmit signal pulses, sensors typically require particularly high energy, where transmitting signal pulses during the group transmission phase of a corresponding group requires providing a large amount of electrical power in a short period. This can lead to increased interference in the received echo signals of the corresponding groups during the group transmission phases of other groups. After transmitting the signal pulse, the sensor receives the echo signal, which typically requires less electrical power and reduces the likelihood of interference.

[0040] In an advantageous embodiment of a method for operating a sensor device having multiple sensors arranged in at least one group, the method includes changing the time offset between the group transmission phases of at least two groups between two cycles to transmit sensor signals for the corresponding group. Changing the time offset between the group transmission phases of at least two groups causes the time window in which interference effects may occur to also shift. As a result, for example, when shielding interference in the received echo signal, one area can be shielded, while in the subsequent envelope, another area can be shielded. Therefore, given an appropriate change in the time offset, the environment can be completely captured based on the received echo signals with two time offsets. Thus, by changing the shielding with the time offset, permanent shielding of certain areas in the received echo signal can be avoided. Particularly in low-dynamic situations in vehicular environments, i.e., when only slow movement of objects relative to the vehicle exists in the vehicular environment, the environment can be captured very reliably and completely using sensors, regardless of shielding, even in the case of periodically occurring interference signals.

[0041] In an advantageous embodiment of the method for operating a sensor device having multiple sensors arranged in at least one group, identifying interference in the received echo signals of at least one group based on a comparison of at least two received echo signals from corresponding groups includes identifying echoes in the received echo signals with a modified time offset within at least two cycles. This means that echo signals received from two or more cycles are examined to identify interference. Repeating echoes of objects in the received echo signals (which are substantially static relative to the corresponding group's transmission phase) can indicate interference. This means that, particularly in high-dynamic situations in a vehicle environment, i.e., when objects in a vehicle environment are moving rapidly relative to the vehicle, recurring echoes can be reliably identified as interference signals.

[0042] In an advantageous embodiment of a method for operating a sensor device having multiple sensors arranged in at least one group, transmitting sensor signals using sensors from each group during their respective group transmission phase includes transmitting sensor signals from sensors in each of the at least two subgroups at time intervals between the transmission of sensor signals from at least two subgroups, and identifying interference in the received echo signals of at least one group based on a comparison of at least two received echo signals from the corresponding group includes identifying echoes in the at least two received echo signals at the time interval. Sensor signals are typically transmitted by sensors from at least two subgroups at short time intervals, such that the corresponding group transmission phase is as short as possible. Preferably, the time interval is on the order of the sensor signal transmission duration. For example, the time interval can be a few milliseconds, such as three milliseconds or longer, with exemplary sensor signals having a duration of about 2.5 milliseconds. On the one hand, using at least two subgroups can reduce the maximum power required by the corresponding group of sensors, thereby reducing the risk of ripple current occurrence. On the other hand, transmitting sensor signals from at least two subgroups at time intervals causes the resulting interference signals to exhibit characteristic echoes in the received echo signals, which can be easily and reliably detected for identification as interference. The time interval, for example, relates to the start of sensor signal transmission for the subgroup. The transmission of sensor signals from at least two subgroups of sensors can, in principle, overlap in time. However, it is preferable that there is no overlap to avoid power spikes caused by overlapping transmissions of sensor signals from corresponding groups of sensors. Preferably, internal and external sensors each form a subgroup, i.e., sensors at the beginning and end of the power line, which are typically also located on the vehicle accordingly.

[0043] In an advantageous embodiment of the method for operating a sensor device having multiple sensors arranged in at least one group, identifying interference in the received echo signals of at least one group based on a comparison of at least two received echo signals from corresponding groups includes identifying echoes in the at least two received echo signals with a time offset within at least two cycles. By transmitting sensor signals in at least two subgroups at time intervals, repetitive characteristic echoes of objects in the received echo signals can indicate reproducible interference that can be identified particularly reliably. Characteristic echoes in the received echo signals aid in identifying interference.

[0044] In an advantageous embodiment of the method for operating a sensor device having multiple sensors arranged in at least one group, transmitting sensor signals from sensors in each of the at least two subgroups at time intervals between the transmission of sensor signals from at least two subgroups includes modifying the time interval between two cycles for transmission in their respective group transmission phases, which include transmitting sensor signals from corresponding groups. Identifying interference in the received echo signals of at least one group based on a comparison of at least two received echo signals from corresponding groups includes identifying echoes in the received echo signals within at least two cycles at the modified time interval. By changing the time interval, interference signals can be identified particularly reliably within at least two cycles because the interference also changes with the time interval. On the other hand, when the time interval changes, a real object will not change its echo shape in the received echo signal, thus allowing reliable identification of interference. Therefore, interference can be identified first by its shape and secondly by the change corresponding to the change in the time interval.

[0045] In an advantageous embodiment of the method for operating a sensor device having multiple sensors arranged in at least one group, receiving echo signals based on reflections of sensor signals includes receiving an envelope of the received echo signals; transmission of the received echo signals from the sensor to the control unit includes transmitting the envelope of the received echo signals; and identification of interference in the received echo signals of at least one group is based on comparison of at least two envelopes with corresponding received echo signals of the corresponding group. Thus, the received echo signals, along with their envelopes, are transmitted from the sensor to the control unit. For example, an envelope curve is generated from the start of the transmission of the sensor signal or after a specified time interval. The end of the envelope is generated from the end of the reception time for receiving the reflections of the sensor signal. The envelope curve can be a continuous or discrete envelope with multiple individual points that together define the envelope. The above statements regarding the transmission of the received echo signals, with necessary modifications, apply to the transmission of the envelope containing the received echo signals.

[0046] In an advantageous embodiment of a method for operating a sensor device having multiple sensors arranged in at least two groups, the method includes changing the time offset between the group transmission phases of at least two groups between two cycles to transmit at least two groups of sensor signals. Changing the time offset between the group transmission phases of at least two groups causes interference effects to also appear in a temporally modified manner. As a result, for example, when shielding interference in the received echo signal, one area can be shielded, while in a subsequent envelope, another area can be shielded. Therefore, given an appropriate change in the time offset, the environment can be completely captured based on the received echo signals with two time offsets. Thus, by changing the shielding with the time offset, permanent shielding of certain areas in the received echo signal can be avoided. Particularly in low-dynamic situations in vehicular environments, i.e., when only slow movement of objects relative to the vehicle exists in the vehicular environment, the environment can be captured very reliably and completely using sensors, regardless of shielding, even in the case of periodically occurring interference signals.

[0047] In an advantageous embodiment of the method for operating a sensor device having multiple sensors arranged in at least two groups, identifying interference in the received echo signals of each group based on the time offset of the group transmission phase and the duration of the group transmission phase of other groups includes identifying interference in the received echo signals of each group based on a comparison of at least two received echo signals of the corresponding group. This means that the time offset and duration of the group transmission phase specify a time window or time interval, in which interference signals are identified based on a comparison of at least two received echo signals of the corresponding group. This allows for precise identification of interference signals by first limiting the occurrence of interference through the time window and then identifying the interference in a targeted manner within that time window. It is not necessary to examine interference in areas outside the time window, which also allows the method to be performed very efficiently. Regarding echo signals, refer above to the description of the method for operating a sensor device having multiple sensors arranged in at least one group.

[0048] In an advantageous embodiment of the method for operating a sensor device having multiple sensors arranged in at least two groups, identifying interference in the received echo signals of each group based on a comparison of at least two received echo signals from corresponding groups includes identifying echoes in the received echo signals of each group within at least two cycles with a modified time offset. This means that echo signals received from two or more cycles are examined to identify interference. Recurring echoes of objects in the received echo signals (which are substantially static relative to the transmission phase of the corresponding group) can indicate interference. This means that, particularly in high-dynamic situations in a vehicle environment, i.e., where objects in a vehicle environment are moving rapidly relative to the vehicle, recurring echoes, i.e., substantially static echoes, can be reliably identified as interference signals.

[0049] In an advantageous embodiment of a method for operating a sensor device having multiple sensors arranged in at least two groups, the method includes shielding against interference identified in the received echo signals of at least two groups, particularly interference identified in all received echo signals of at least two groups. Interference shielding ensures that false positives in object detection within the vehicle environment can be reliably avoided. Interference shielding directly affects the echo signals synchronously (i.e., in the same cycle) transmitted to the control unit. The reception of echo signals and the transmission of the received echo signals to the control unit can occur in different cycles. Furthermore, shielding against interference identified in the received echo signals of at least one group can include shielding against the identified interference when another echo signal from that group is received. At a later time, for example in a subsequent cycle, another echo signal is transmitted from the sensor to the control unit. Therefore, the additional echo signal is related to the later received echo signal. In the case of periodic interference signals, shielding can also be applied to signals other than the currently received echo signal, i.e., applied to another cycle. The statement "when another echo signal is received" means that interference in each currently received echo signal was not initially identified, but shielding is also applied to subsequent received echo signals of that group based on previously identified interference. Shielding is preferably performed in the control unit, wherein shielding can occur immediately upon receiving an echo signal or at a later time during echo signal processing.

[0050] In an advantageous embodiment of the method for operating a sensor device having multiple sensors arranged in at least two groups, receiving an echo signal based on the reflection of a sensor signal includes receiving an envelope containing the received echo signal, and the transmission of the received echo signal from the sensor to the control unit includes transmitting the envelope containing the received echo signal. Thus, the received echo signal, along with its envelope, is transmitted from the sensor to the control unit. For example, an envelope curve is generated at the start of the transmission of the sensor signal or after a specified time interval. The end of the envelope is generated at the end of the reception time for receiving the reflection of the sensor signal. The envelope curve can be a continuous or discrete envelope having multiple individual points that together define the envelope. The above statements regarding the transmission of the received echo signal, with necessary modifications, apply to the transmission of the envelope containing the received echo signal.

[0051] The invention will now be explained in more detail with reference to the accompanying drawings based on preferred embodiments. Each feature shown may individually or in combination represent an aspect of the invention. Features of different exemplary embodiments may be transferred from one exemplary embodiment to another. Attached Figure Description

[0052] In the attached diagram:

[0053] Figure 1A schematic diagram of a vehicle with a driving assistance system is shown, the driving assistance system having a sensor device according to a first preferred embodiment.

[0054] Figure 2 It shows Figure 1 This is a schematic diagram of a portion of a sensor device, which includes a control unit and a set of sensors interconnected via power lines.

[0055] Figure 3 An exemplary representation of the envelope curve of an echo signal is shown, which is transmitted from one of the sensors of the sensor device to the control unit via a power line without interference.

[0056] Figure 4 An exemplary representation of the envelope curve of an echo signal is shown, which is transmitted via a power line from one of the sensors of a sensor device to the control unit, and has interference.

[0057] Figure 5 A flowchart illustrating a method for operating a sensor device according to a first embodiment is shown, and...

[0058] Figure 6 A flowchart is shown of a method for operating a sensor device of the first or second embodiment. Detailed Implementation

[0059] Figure 1 A vehicle 10 having a driving assistance system according to a first preferred embodiment is shown.

[0060] A driving assistance system can, in principle, be any driving assistance system with one or more assistance functions. A driving assistance system can be designed to assist a human driver of vehicle 10 in driving vehicle 10, such as an emergency braking system, adaptive cruise control system, parking assistance system, etc. Alternatively or additionally, the driving assistance system can provide functions for autonomous or semi-autonomous driving of vehicle 10.

[0061] The driving assistance system includes a sensor device 12. The sensor device 12 includes a control unit 14 and multiple sensors 16. The control unit 14 is any arbitrary computing unit. In the field of vehicles 10 and driving assistance systems, such a control unit 14 is, for example, referred to as an ECU (electronic control unit).

[0062] Multiple sensors 16 are arranged in two groups 18, 20 on the vehicle 10. In this exemplary embodiment, the sensors 16 are configured as ultrasonic sensors 16. All the sensors 16 are designed in the same manner. The first group 18 with sensors 16 is arranged along the front of the vehicle 10, and the second group 20 with sensors 16 is arranged along the rear of the vehicle 10. As an example, each of the two groups 18, 20 is arranged in... Figure 1 The image shows five separate sensors 16. The sensors 16 monitor the environment 22 of the vehicle 10 by detecting objects in the environment 22 of the vehicle 10.

[0063] Each of the two groups 18 and 20 has its sensor 16 connected in parallel to a power line 24, which is formed by two separate wires 26 and 28, respectively. Each of the two groups 18 and 20 with sensor 16 is connected to the control unit 14 via a separate power line 24. The sensors 16 of the two groups 18 and 20 receive a common power supply from the control unit 14 via their respective power lines 24.

[0064] Power line 24 is also used here as data line 30, i.e., sensor 16 and control unit 14 communicate via power line 24. Various bus systems are known in which the power line 24 and data line 30 are integrated, such as DSI3 or USV11. Figure 2 A portion of the sensor device 12 is shown in detail, including a power line 24 and a data line 30. Alternative embodiments of the power line 24 with the data line 30 are also possible.

[0065] The control unit 14 is connected to the battery 32 of the vehicle 10. The control unit 14 receives electrical energy from the battery 32 and uses it to supply power to the two sets of sensors 16 18 and 20 via the corresponding power lines 24.

[0066] The following explanation Figure 5 The method shown is for operating the sensor device 12 of the first embodiment. It will be apparent to those skilled in the art that the order of the steps specified in the described method may be partially modified, or some steps may be optional.

[0067] The method begins with step S100, which involves transmitting a sensor signal using sensor 16. The ultrasonic sensor 16 transmits ultrasonic pulses or sequences of ultrasonic pulses as sensor signals. The ultrasonic sensors 16 of each group 18, 20 simultaneously transmit their sensor signals during the common group transmission phase. During this process, two different sensor signals are transmitted by the ultrasonic sensors 16 of each group 18, 20: an ultrasonic signal with a high ultrasonic frequency and an ultrasonic signal with a low ultrasonic frequency within the frequency range of approximately 45 kHz to 60 kHz.

[0068] The ultrasonic sensors 16 of corresponding groups 18 and 20 alternately emit two different sensor signals according to their arrangement along the power line 24.

[0069] Step S110 involves receiving the 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. Therefore, two different echo signals based on the reflection of two different sensor signals are received by the ultrasonic sensors 16 of each group 18, 20. Each ultrasonic sensor 16 simultaneously receives echo signals of two ultrasonic frequencies of the emitted ultrasonic signal, that is, each ultrasonic sensor 16 receives on two frequency channels.

[0070] In this case, the ultrasonic sensor 16 receives envelopes 34 and 36 containing the received echo signals. Examples of envelopes 34 and 36 are shown in... Figure 3 and 4 As shown in the image.

[0071] The reflection of the sensor signal occurs at an object in the environment 22 of the vehicle 10, so that the distance to the object can be determined in the control unit 14 based on the time difference between the transmission of the sensor signal and the reception of the echo signal.

[0072] Step S120 involves transmitting envelopes 34, 36 containing the received echo signals from sensor 16 to control unit 14. In this exemplary embodiment, each envelope 34, 36 includes, for example, a complete time period from the transmission of the sensor signal to the end of the reception time for receiving the reflected sensor signal. Envelopes 34, 36 may be continuous or discrete envelopes 34, 36 having multiple individual points that together define envelopes 34, 36. Envelopes 34, 36 are transmitted to control unit 14 together with the echo signals received from sensor 16, wherein the transmission of envelopes 34, 36 from each sensor 16 is time-shifted. Furthermore, envelopes 34, 36 are transmitted from sensor 16 to control unit 14 in cycles following the transmission of the sensor signal.

[0073] Step S130 involves identifying interference 38 in the envelopes 34 and 36 of the received echo signals from each group 18 and 20 based on a comparison of the envelopes 34 and 36 of the received echo signals from the corresponding groups 18 and 20.

[0074] First, based on a comparison of the envelopes 34 and 36 of the multiple sensors 16 in groups 18 and 20 for the same frequency channel, interference 38 is identified in the envelopes 34 and 36 of the received echo signals from groups 18 and 20. Figure 3 It can be seen that the envelope 34 shown here does not interfere with 38. Figure 3 The envelope 34 contains multiple echoes 40 of objects in the environment 22 of the vehicle 10.

[0075] In comparison, except Figure 3 The echo 40 is also shown in the middle. Figure 4 Envelope 36 also shows interference signal 38, which appears in a similar manner in the envelopes 34, 36 of all sensors 16 in the same frequency channel. This means that the interference 38 in the examined envelopes 34, 36 is similar or even the same in terms of time or distance and amplitude in the corresponding frequency channel. Therefore, if interference 38 is visible to the same frequency channel of all sensors 16, then interference 38 is detected in the same way.

[0076] Furthermore, based on two different echo signals, interference 38 is identified by comparing the corresponding two envelopes 34, 36 of each ultrasonic sensor 16; that is, for each sensor 16, the envelopes 34, 36 of the two received frequency channels are compared with each other. For example, depending on the type of interference 38, interference 38 may be visible only in one frequency channel, i.e., as... Figure 3 As shown, the envelopes 34 and 36 of a frequency channel have no detectable interference 38, while... Figure 4 As shown, the envelopes 34 and 36 of another frequency channel indicate detectable interference 38. Interference 38 is identified by the fact that interference 38 is indicated by one frequency channel while interference 38 is not indicated by the other frequency channel.

[0077] Step S140 includes shielding the identified interference 38 in all envelopes 34, 36 of the received echo signals of each group 18, 20. As a result, the interference 38 is shielded in the envelopes 34, 36, preventing false positive detections of objects in the environment 22 of the vehicle 10. Depending on the type of interference 38, the shielding may affect the envelopes 34, 36 of only one frequency channel or both frequency channels.

[0078] In this exemplary embodiment, the method is repeatedly executed in a loop, wherein the loop of sensor 16 includes steps S100 to S120. The general form of the repeating method also includes steps S130 and S140.

[0079] A second embodiment of the sensor device 12 and method based on the first embodiment is described below. Therefore, the differences between the two embodiments are described. In case of doubt, features not described in detail in the second embodiment correspond to features in the first embodiment.

[0080] The method of the second embodiment is performed using the sensor device 12 of the second embodiment, wherein the sensor device 12 of the second embodiment has the same structure as the sensor device 12 of the first embodiment.

[0081] Contrary to the method of the first embodiment, step S100 includes transmitting sensor signals using sensor 16, wherein the sensor 16 of each group 18, 20 transmits its sensor signal during its respective group transmission phase, and the group transmission phases of the two groups 18, 20 are time-shifted. The time shift is selected such that the group transmission phases of different groups 18, 20 do not overlap. In this case, the group transmission phases are disjoint time intervals.

[0082] Compared to the method of the first embodiment, step S130 includes identifying interference 38 in the envelopes 34 and 36 of the received echo signals of the corresponding groups 18 and 20, taking into account the time offset of the group transmission phase. Based on the known time offset and the also known duration of the corresponding group transmission phase, a time interval is obtained where the interference signal 38 may occur in the power supply, i.e., interference caused by the emission of the echo signal from the corresponding other group 18 and 20. Therefore, the identification of interference 38 in the envelopes 34 and 36 of the received echo signals of groups 18 and 20 is performed precisely within these time ranges. The result is the time interval in which these interference signals 38 may occur. Within this time interval, the control unit 14 specifically searches for interference signals 38 based on the power supply in the envelopes 34 and 36 during sensor signal transmission to easily identify them.

[0083] Also in this exemplary embodiment, the method is repeated cyclically, wherein the cycle of sensor 16 includes steps S100 to S120. The cycles of the two sets 18 and 20 are offset relative to each other by the time offset.

[0084] The following describes a third embodiment. Figure 6 The method described is for operating the sensor device 12 of the first embodiment. It will be apparent to those skilled in the art that the order of the steps specified in the described method may be partially modified, or some steps may be optional. In principle, this method can also be performed in the same manner using the sensor device 12 of the second embodiment.

[0085] The method portion of the third embodiment corresponds to the method of the first embodiment. Therefore, the differences between the two embodiments are described. Features of the third embodiment, not described in detail, correspond to features of the first embodiment in case of doubt.

[0086] The method begins with step S200, which includes transmitting a sensor signal using sensor 16. Step S200 substantially corresponds to step S100 of the method in the first embodiment.

[0087] Step S210 involves receiving the echo signal based on the reflection of the sensor signal. Step S210 corresponds to step S110 of the method of the first embodiment.

[0088] Step S220 involves transmitting the envelopes 34 and 36 containing 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.

[0089] Step S230 involves identifying interference 38 in the received envelopes 34, 36 of each group 18, 20 based on the time offset and 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 envelopes 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 envelopes 34, 36 of the sensors 16 of the first group 18. Interference is identified for all sensors 16 of corresponding groups 18, 20.

[0090] Step S240 includes shielding the identified interference 38 from all envelopes 34, 36 of the received echo signals of each group 18, 20. Step S240 corresponds to step S140 of the method of the first embodiment.

[0091] Step S250 involves modifying the time offset between the group transmission phases of the two groups 18 and 20 between two cycles used to transmit sensor signals for the two groups 18 and 20.

[0092] The method of the third embodiment is repeated cyclically here, wherein the cycle of sensor 16 includes steps S200 to S220. The general form of the repetition method also includes steps S230 to S250.

[0093] List of reference numerals

[0094] 10 vehicles

[0095] 12 Sensor Devices

[0096] 14 Control Unit

[0097] 16. Sensors, Ultrasonic Sensors

[0098] 18 Group 1

[0099] 20 Group 2

[0100] 22 Environment

[0101] 24 Power cord

[0102] 26 wires

[0103] 28 wires

[0104] 30 Data Cable

[0105] 32 batteries

[0106] 34. Interference-free envelope, channel 1

[0107] 36 Interference-prone envelope, channel 2

[0108] 38 Interference

[0109] 40 echoes

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, wherein the sensors (16) are connected to a common power source, specifically via the control unit (14), the method comprising the steps of: Sensors (16) transmit sensor signals, wherein each group of sensors (16) transmits its sensor signal during its respective group transmission phase. Based on the reflection and reception of echo signals from sensor signals, The received echo signal from sensor (16) is transmitted to control unit (14), and Based on the comparison of at least two received echo signals from corresponding groups, interference (38) in the received echo signals from at least one group is identified, said interference (38) being caused by the interference effect of ripple current.

2. The method as described in claim 1, characterized in that, Using the sensors (16) to transmit sensor signals, wherein the at least one group of sensors (16) transmits their sensor signals during their respective group transmission phases, including using at least one group of sensors (16) to transmit at least two different sensor signals. The reflection reception of echo signals based on the sensor signals includes the reflection reception of at least two different echo signals based on at least two different sensor signals, and Interference (38) in received echo signals from at least one group is identified based on a comparison of at least two different received echo signals.

3. The method as described in claim 2, characterized in that, Using at least one group of sensors (16) to transmit at least two different sensor signals includes using at least one group of different sensors (16) to transmit at least two different sensor signals.

4. The method as described in claim 2 or 3, characterized in that, Receiving at least two different echo signals based on the reflection of at least two different sensor signals includes receiving at least two different echo signals using at least one sensor (16) from at least one group of the above.

5. The method according to any one of claims 1 to 3, characterized in that, Interference (38) in the received echo signals of a group is identified based on a comparison of at least two received echo signals from two different sensors (16) of the at least one group.

6. The method according to any one of claims 1 to 3, characterized in that, The method includes shielding the identified interference (38) from the received echo signals of the at least one group.

7. The method according to any one of claims 1 to 3, characterized in that, The sensor device (12) comprises a plurality of sensors (16) arranged in at least two groups, wherein the sensors (16) of each group transmit their sensor signals during their respective group transmission phase, and the group transmission phases of the at least two groups are time-shifted. Interference in the received echo signals of at least one group is identified (38) 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 phase of other groups.

8. The method as described in claim 7, wherein, The method includes modifying the time offset between group transmission phases of at least two groups between two cycles used to transmit sensor signals of the corresponding group.

9. The method as described in claim 8, wherein, Identifying interference in the received echo signals of at least one group based on comparison of at least two received echo signals from the corresponding group (38) includes identifying echoes in the received echo signals with a modified time offset within at least two cycles.

10. The method according to any one of claims 1 to 3, characterized in that, The transmission of sensor signals by the sensors (16) of each group during their respective group transmission phase includes transmitting sensor signals from the sensors (16) of each group in at least two subgroups at time intervals between the transmission of sensor signals of at least two subgroups, and Identifying interference in the received echo signals of at least one group based on a comparison of at least two received echo signals from the corresponding group (38) includes identifying echoes in at least two received echo signals at the time interval.

11. The method as described in claim 10, wherein, Identifying interference in the received echo signals of at least one group based on a comparison of at least two received echo signals from the corresponding group (38) includes identifying the echoes of at least two received echo signals at the time interval within at least two cycles.

12. The method as described in claim 11, wherein, Transmitting sensor signals from the sensor (16) of each of the at least two subgroups at a time interval between the transmission of sensor signals of the at least two subgroups includes changing the time interval between two cycles used to transmit the sensor signals of the corresponding group, and Identifying interference in the received echo signals of at least one group based on comparison of at least two received echo signals from the corresponding group (38) includes identifying echoes in the received echo signals at modified time intervals within at least two cycles.

13. The method according to any one of claims 1 to 3, characterized in that, Receiving echo signals based on sensor signal reflection includes receiving the envelope (34, 36) of the received echo signal. Transmitting the received echo signal from the sensor (16) to the control unit (14) includes transmitting the envelope (34, 36) of the received echo signal, and Interference (38) in received echo signals from at least one group is identified based on a comparison of at least two envelopes (34, 36) with echo signals received from the corresponding group.

14. The method as described in claim 5, characterized in that, Interference (38) in a set of received echo signals is identified based on a comparison of at least two received echo signals from two sensors (16) with different arrangements.

15. The method as described in claim 6, characterized in that, The method includes shielding the identified interference in all received echo signals of at least one group (38).

16. A sensor device (12) for a vehicle (10), comprising: Control unit (14), and Multiple sensors (16) arranged in at least one group, wherein, The sensor (16) is specifically connected to a common power source via the control unit (14). Its features are, The sensor device (12) is designed to operate as described in any one of claims 1 to 15.

17. A driving assistance system for a vehicle (10) having a sensor device (12) as described in claim 16.

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