Method for determining position using an ultrasonic sensor system, device for determining position, and computer program product

Abstract

The invention relates to a method for determining position using an ultrasonic sensor system (10) comprising at least one ultrasonic sensor (12a, 12b, 12c, 12d), the method comprising the steps of: - generating a control signal (S10) for emitting an ultrasonic signal (18) at a time (ts); - receiving at least one reflection signal (24) (S12) within a time window at a time (te) and ascertaining a position (S14) of an object (22) off which the ultrasonic signal (18) was reflected, the position being ascertained on the basis of the propagation time of the ultrasonic signal (18); and - carrying out a measurement adaptation, the measurement adaptation comprising shortening the time window for receiving reflection signals (24) (S16a) or the measurement adaptation comprising discarding the data received by the at least one ultrasonic sensor (12a, 12b, 12c, 12d) after the time defined by the threshold value time or by the time (te) until the end of the time window.

Description

[0001] Method for determining position using an ultrasonic sensor system, device for determining position and computer program product

[0002] Description

[0003] The invention relates to a method for determining position using an ultrasonic sensor system, in particular for use in a vehicle, a device for determining position and a corresponding computer program product.

[0004] Motor vehicles are increasingly being equipped with ultrasonic sensors, typically integrated into the bodywork, designed to assist the driver in the timely detection of obstacles in the vehicle's path, particularly in areas poorly visible to the driver, as well as in estimating the distance of obstacles. The functionality of such an ultrasonic sensor is based on the transmission of ultrasonic signals and the detection of echoes of the transmitted ultrasonic signals emanating from obstacles that may be within the sensor's detection range. The ultrasonic pulses generated for this purpose can have a temporally constant frequency. Approaches with temporally variable frequencies ("chirps") and multiple separate transmission and reception channels (e.g., through frequency division multiplexing) are also known.

[0005] Ultrasonic sensors are used today in a wide variety of applications, ranging from parking aids to assistance systems for blind spots ("dead-spot detection"). In the field of autonomous driving in urban environments ("urban driving"), ultrasonic sensors have so far been used only rarely. The reason for this is, on the one hand, the desire for higher-performance systems, especially in partially or fully automated driving, but also the limitation of the range in combination with the sampling rate of the ultrasonic sensors, which is limited by the speed of sound.

[0006] The speed of sound largely determines the range and sampling rate of an ultrasonic sensor. Ranges of up to 10 m are now conceivable with ultrasonic sensors in the automotive sector. Due to the speed of sound, such a measurement with an ultrasonic sensor takes just 60 ms under normal conditions. This would ideally result in 16 measurements per second. If multiple sensors are used in a system and multiple measurement steps are required for full system coverage, the measurement rate for the complete system typically drops to 5-8 updates per second. Each ultrasonic sensor generates data with each measurement that must be processed. However, for the vehicle, only the nearest object that could disrupt a driving maneuver is relevant. Objects behind it therefore generally play a minor role at best. The data generated by the ultrasonic sensors therefore contains unnecessary information.

[0007] The invention is based on the object of proposing an optimized method for determining position that increases the efficiency of position determination. The objects underlying the invention are achieved by the features of the independent patent claims. Embodiments are specified in the dependent patent claims.

[0008] To solve this problem, a method for determining position using an ultrasonic sensor system is provided. The ultrasonic sensor system comprises at least one ultrasonic sensor. The method comprises the following steps:

[0009] - Generating a control signal for emitting an ultrasonic signal at a time t s ;

[0010] - in response to generating the control signal, receiving within a time window at least one reflection signal from the at least one ultrasonic sensor within the time window at a time t eand determining a position of an object at which the ultrasonic signal was reflected, the position being based on the propagation time of the ultrasonic signal between the transmission of the ultrasonic signal at time t s and receiving the at least one reflection signal at time t e is determined; and

[0011] - If the time t e receiving the at least one reflection signal less than a predetermined threshold time after the time t s is, performing a measurement adjustment at a time that is based on the threshold time cidor the time t ebased, wherein o the measurement adjustment comprises either shortening the time window for receiving reflection signals and repeating the steps of generating the control signal for transmitting a further ultrasonic signal and receiving a further reflection signal for a further position determination or o the measurement adjustment comprises discarding the signals received by the at least one ultrasonic sensor after the time determined by the threshold value or the time t e defined point in time until the end of the time window.

[0012] In a first step, the ultrasonic sensor system generates a control signal for transmitting an ultrasonic signal at a time t sThe signal can be generated, in particular, by a control unit or other suitable control unit of the ultrasonic sensor system. An ultrasonic transmitting device is preferably used to generate the ultrasonic signal. This can be, for example, a dynamic and electrostatic loudspeaker, a piezo loudspeaker, or generally an ultrasonic transducer. Furthermore, the ultrasonic transmitting device can be embodied as part of the ultrasonic sensor system or as an external device. The ultrasonic transmitting device can be communicatively connected to the ultrasonic sensor system, for example, via a plug-and-play connection or in another way, in order to receive the generated control signal for transmitting the ultrasonic signal.

[0013] From the transmission of the ultrasonic signal at time t sThe at least one ultrasonic sensor of the ultrasonic sensor system is configured to receive a reflection signal. The at least one ultrasonic sensor therefore opens at least one channel through which it listens for ultrasonic signals in its surroundings.

[0014] In principle, a reflection signal is also an ultrasonic signal. For the purposes of this invention, transmitted signals are referred to as ultrasonic signals, whereas received signals are referred to as reflection signals.

[0015] If the time t e receiving the at least one reflection signal less than a predetermined threshold time after the time t s is, a measurement adjustment is carried out. The measurement adjustment is carried out at a time that is based on the threshold time or the time t eThis can be the threshold time or the echo time itself, or the threshold time or echo time plus a buffer period of a few milliseconds (e.g., 1 ms - 5 ms).

[0016] The measurement adjustment can involve one of two measures for an ultrasonic sensor and / or a receiving channel.

[0017] A first option for adjusting the measurement is to shorten the time window for receiving reflected signals and then generate a control signal to transmit another ultrasonic signal. This adjustment can reduce the time required for the position measurement (e.g., position or distance determination), which in turn corresponds to a higher sampling rate. The ultrasonic sensor system does not wait for potentially irrelevant objects further away to be detected during each measurement cycle. Instead, the measurement is restarted upon detection of the object after the threshold time has been reached.

[0018] The higher sampling rate can increase the precision of position determination. Any measurement tolerances of the individual ultrasonic sensors can be reduced by performing a larger number of measurements. This is particularly important for short distances. The higher sampling rate also enables faster response times. If a vehicle uses autonomous or semi-autonomous driving functions, the higher sampling rate allows it to react more quickly to avoid potential hazards or handle critical situations. This also increases the vehicle's safety. The same applies to other machines or tools that use autonomous or automated processes that use ultrasound to determine distances or positions.

[0019] The second possibility of measurement adjustment is to adjust the measurement by the at least one ultrasonic sensor after receiving the reflection signal and after reaching the threshold time or after the time t e to discard the acquired data. This should also be understood as meaning that this happens immediately after the threshold time or after the echo time t e itself or after reaching the threshold time or the echo time plus a buffer period of a few milliseconds (e.g. 1ms - 5ms).

[0020] The received reflection signal indicates that an object is within a certain proximity to at least one ultrasonic sensor. Additional reflection signals, which would only be attributable to more distant objects, can be ignored. They do not need to be transmitted to an evaluation or control unit, which reduces both the bandwidth required for transmitting the measured values ​​and the computing resources required for evaluating the measured values.

[0021] To activate the measurement adjustment, the ultrasonic sensor system can be equipped with its own control unit, which is configured to monitor the at least one ultrasonic sensor to determine whether a reflection signal is being received. In one embodiment, the control unit for detecting the information as to whether a reflection signal has been detected can be different from a control unit that, for example, determines the distance of the object to be detected from the travel time and / or determines whether the measurement adjustment needs to be performed. The control unit can preferably be an integrated circuit, a control unit, or a dedicated computing unit with a processor.

[0022] In one embodiment, the ultrasonic sensor system comprises multiple channels, wherein the measurement adjustment occurs only when a presence of the object has been validated by reflection signals on at least two of the channels.

[0023] Every sensor captures false data with a certain degree of probability. Ultrasonic sensors (or the systems used for them) are no different. An ultrasonic sensor (or system) can essentially make two errors. The first error is the false detection of a reflection signal that does not exist (false positive). The second error is the failure to detect a reflection signal that should have been detected (false negative).

[0024] Using different channels for receiving reflection signals can counteract the false negative detection of a reflection signal, as at least a second receiving channel must validate the reflection signal received by the first receiving channel. The probability of a false positive reflection signal is significantly higher than the probability of a false negative signal. This is because there are many sources of interference that can be mistakenly identified as a reflection signal. Therefore, more false reflection signals tend to be detected than true reflection signals are missed. Validating a reflection signal by at least one additional receiving channel can therefore reduce the overall error rate of the ultrasonic sensor system.

[0025] In one embodiment, the ultrasonic sensor system comprises a plurality of the ultrasonic sensors and each of the ultrasonic sensors has at least one of the channels, wherein the generation of the control signal for emitting an ultrasonic signal and the corresponding reception of a reflection signal is performed for a plurality of the ultrasonic sensors, wherein the measurement adjustment is performed only when a presence of the object has been validated by reflection signals using at least two of the ultrasonic sensors.

[0026] It is possible for an ultrasonic sensor to monitor its environment for signals on more than one channel. Therefore, interference may occur on multiple channels, resulting in false detection even if validation of a reflection signal is provided on at least two channels in the same ultrasonic sensor. Validating the reflection signal with a second ultrasonic sensor therefore advantageously reduces the probability of false detections due to interference on multiple channels simultaneously.

[0027] In one embodiment, the steps of generating the control signal for transmitting the further ultrasonic signal and receiving the further reflection signal for the further position determination are carried out immediately after the end of the shortened time window.

[0028] Once the measurement adjustment has been made by shortening the time window, the position determination (or, analogously, the position determination of the object) can be performed. This implicitly means that the unit performing the position determination must receive a signal to do so, otherwise it will wait until the end of the original time window. In this embodiment, the unit for determining the position is therefore activated from the measurement data in order to actually determine the position, e.g., object distance or object position, earlier.

[0029] The buffer time after receiving the reflected signal can serve to ensure that the received signal has been completely received. This could be essential for subsequent analysis for accurate location determination and signal validation. In one embodiment, the threshold time is less than 40%, preferably less than 30% or 20%, of the duration of the unabbreviated time window.

[0030] The more the time window is shortened by the threshold time, the higher the sampling rate of the ultrasonic sensor system can be. On the other hand, the time window should not be chosen too short to allow validation by receiving multiple, consecutive reflection signals from the same object at constant time intervals. These signals can be derived from ultrasonic signals that may have been transmitted by different ultrasonic transmitters. These later signals can be used to validate the first reflection signal. The above values ​​therefore represent good compromises for establishing predefined thresholds.

[0031] On the other hand, the threshold time should not be chosen too long. The measurement adjustment should be performed when the resulting effect is sufficiently effective. An example can illustrate this. The ultrasonic sensor system registers a reflection signal a few moments before the detection time window would close anyway. Performing a measurement adjustment at this time could result in the bandwidth saved by not transmitting the discarded measured values ​​or the advantage of the higher sampling rate by shortening the time window being too small to justify the computational effort of the measurement adjustment. In the worst case, the measurement adjustment could even require more computational effort than processing the collected data.For this reason, choosing a threshold time point less than 40%, preferably less than 30% or 20%, of the duration of the unabbreviated time window might be advantageous. Conversely, the threshold time point should be greater than 10% of the duration of the unabbreviated time window.

[0032] In one embodiment, the generation of the control signal, the reception of the reflection signal and the measurement adjustment take place in one measurement cycle and the measurement cycle is carried out cyclically, wherein the method further comprises a comparison of the position of the object which was determined for reflection signals in successive measurement cycles, wherein the measurement adjustment is reversed if the comparison results in a deviation of the position from one another that is greater than a predetermined deviation value or a reflection signal is no longer received, for example in a subsequent measurement cycle.

[0033] The monitoring of the environment is based in particular on the fundamental assumption of plausibility. A detected object can only move in the environment at a limited speed. If the object approaches at least one ultrasonic sensor, the travel times of the reflection signals shorten over time. The time window for receiving reflection signals also shortens. If the object moves away again, the travel times also become longer again. The comparison of the travel times of reflection signals puts them in a temporal context with one another. Movement of the object can be deduced from the change over time. If no more reflection signals are received, it is possible that the object has moved out of the field of view of the ultrasonic sensor, for example, sideways. Another possibility is that the object has moved away and the reflection signal is included in the measurement data that was discarded up to that point.In any case, even more distant objects can be reliably detected due to the reset of the time window and thus the reversal of the measurement adjustment.

[0034] In one embodiment, the ultrasonic sensor system comprises a control unit, wherein the control unit performs the generation of the control signal, receives the reflection signal and performs the measurement adjustment.

[0035] A control unit in the ultrasonic sensor system advantageously allows the method to be implemented using a plug-and-play system. The host system, such as a vehicle, does not require complex adjustments to the method, for example, by separately procuring and configuring a suitable control unit. It is sufficient to use the ultrasonic sensor system as such to implement the method.

[0036] In one embodiment, the control unit is integrated into the at least one ultrasonic sensor or is part of a central control unit for a plurality of ultrasonic sensors.

[0037] Control units integrated directly into the ultrasonic sensor(s) allow the decision as to whether or not to perform a measurement adjustment to be made directly within the sensor, without the need to transfer data from one subsystem to another. This can, for example, reduce the bandwidth required for the communication connection. In particular, no signals for measurement adjustment need to be transmitted to the ultrasonic sensors, so this direction of communication can be eliminated. In a particularly preferred embodiment, each of the ultrasonic sensors comprises its own control unit that performs the measurements. Furthermore, the control units are preferably independently capable of reversing the measurement adjustments.

[0038] Central coordination of measurement adjustments by a central control unit advantageously allows validation of reflection signals from multiple ultrasonic sensors to be performed centrally. Once a reflection signal has been validated, the central control unit can generate a measurement adjustment signal and send it to all ultrasonic sensors.

[0039] Furthermore, a central control unit offers the advantage that fewer control units are required overall, thereby reducing the costs of the ultrasonic sensor system. In a further aspect, the invention relates to a computer program product, in particular a computer-readable storage medium, wherein the computer program product comprises computer-executable code, wherein the code is executable by at least one processor of a computer device to cause the computer device to perform the method as described above.

[0040] In a further aspect, the invention relates to a device for determining position using an ultrasonic sensor system comprising at least one ultrasonic sensor, the device comprising:

[0041] - Means for generating a control signal for emitting an ultrasonic signal at a time t s ;

[0042] - means for receiving, in response to the generation of the control signal, within a time window, at least one reflection signal from the at least one ultrasonic sensor within the time window at a time t e and determining a position of an object at which the ultrasonic signal was reflected, the position being based on the propagation time of the ultrasonic signal between the transmission of the ultrasonic signal at time t s and receiving the at least one reflection signal at time t e is determined; and

[0043] - Means for performing a measurement adjustment at a predetermined threshold time or the time t e based time, provided that the time t e receiving the at least one reflection signal less than the threshold time after the time t s wherein the measurement adjustment comprises either shortening the time window for receiving further reflection signals and repeating the steps of generating the control signal for transmitting a further ultrasonic signal and receiving a further reflection signal for a further position determination or wherein the measurement adjustment comprises discarding the signals received by the at least one ultrasonic sensor after the time determined by the threshold value or the time t e defined point in time until the end of the time window.

[0044] Those skilled in the art will understand that aspects of the present invention may be embodied as a device, method, or computer program or computer program product. Accordingly, aspects of the present invention may take the form of a purely hardware embodiment, a purely software embodiment (including firmware, in-memory software, microcode, etc.), or an embodiment combining software and hardware aspects, all of which may be generally referred to herein as a "circuit," "module," "unit," or "system." Furthermore, aspects of the present invention may take the form of a computer program product carried by one or more computer-readable media in the form of computer-executable code. A computer program also includes computer-executable code. "Computer-executable code" may also be referred to as "computer program instructions."

[0045] Any combination of one or more computer-readable media may be used. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A "computer-readable storage medium," as used herein, includes a tangible storage medium capable of storing instructions executable by a processor of a computing device. The computer-readable storage medium may be referred to as a computer-readable non-transitory storage medium. The computer-readable storage medium may also be referred to as a tangible computer-readable medium. In some embodiments, a computer-readable storage medium may also be capable of storing data that allows it to be accessed by the processor of a computing device.Examples of computer-readable storage media include, but are not limited to: a floppy disk, a magnetic hard disk, a solid-state hard disk, flash memory, a USB flash drive, random access memory (RAM), read-only memory (ROM), an optical disk, a magneto-optical disk, and the processor's register file. Examples of optical disks include compact disks (CDs) and digital versatile disks (DVDs), for example, CD-ROM, CD-RW, CD-R, DVD-ROM, DVD-RW, or DVD-R disks. The term computer-readable storage medium also refers to various types of recording media suitable for being retrieved by the computing device over a network or communications link. For example, data may be retrieved via a modem, over the Internet, or over a local area network.Computer-executable code embodied on a computer-readable medium may be transmitted over any suitable medium, including, but not limited to, wireless, wired, fiber optic, RF, etc., or any suitable combination of the foregoing media.

[0046] A computer-readable signal medium may include a propagated data signal containing the computer-readable program code, for example, in a baseband signal or as part of a carrier signal (carrier wave). Such a propagated signal may be in any form, including, but not limited to, an electromagnetic form, an optical form, or any suitable combination thereof. A computer-readable signal medium may be any computer-readable medium other than a computer-readable storage medium that can transmit, disseminate, or transport a program for use by or in connection with an instruction-executing system, device, or apparatus.

[0047] "Computer memory" or "memory" is an example of a computer-readable storage medium. Computer memory is any memory directly accessible by a processor.

[0048] "Computer storage" or "data storage" are further examples of a computer-readable storage medium. Computer storage is any non-transitory computer-readable storage medium. In some embodiments, computer memory may also be computer data storage, or vice versa.

[0049] A "processor," as used herein, includes an electronic component capable of executing a program- or machine-executable instruction or computer-executable code. Reference to the computing device including a "processor" should be interpreted to potentially include more than one processor or processing cores. The processor may, for example, be a multi-core processor. A processor may also refer to a collection of processors within a single computer system or distributed across multiple computer systems. The term computing device and the term computer should also be interpreted to possibly refer to a collection or network of computing devices or computers, each including one or more processors.The computer-executable code may be executed by multiple processors, which may be distributed within the same computing device or even across multiple computers.

[0050] Computer-executable code may comprise machine-executable instructions or a program that causes a processor to perform an aspect of the present invention. Computer-executable code for performing operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object-oriented programming language such as Java, Smalltalk, C++, or the like, and conventional procedural programming languages ​​such as the "C" programming language or similar programming languages, and translated into machine-executable instructions. In some cases, the computer-executable code may be in the form of a high-level programming language or in a pre-translated form and used in conjunction with an interpreter that generates the machine-executable instructions.

[0051] The computer-executable code may run entirely on a user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on the remote computer or server. In the latter case, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, over the Internet using an Internet service provider).

[0052] The computer program instructions can be executed on one or more processors. In the case of multiple processors, these can be distributed across several different entities (e.g., clients, servers). Each processor could execute a portion of the instructions intended for the respective entity. Therefore, when referring to a system or method that encompasses multiple entities, the computer program instructions are understood to be adapted to be executed by a processor assigned to or associated with the respective entity.

[0053] Aspects of the present invention are described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It is noted that each block or portions of the blocks of the flowchart illustrations, and / or block diagrams may be implemented by computer program instructions, optionally in the form of computer-executable code. It is further noted that combinations of blocks may be combined in different flowchart illustrations, and / or block diagrams if they are not mutually exclusive.These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing device to produce a device such that the instructions, executed via the processor of the computer or other programmable data processing device, produce means for performing the functions / steps defined in the block or blocks of the flowcharts and / or block diagrams.

[0054] These computer program instructions may also be stored on a computer-readable medium that can direct a computer or other programmable data processing apparatus or other apparatus to function in a particular manner such that the instructions stored on the computer-readable medium produce a manufactured article, including instructions that implement the function / step specified in the block or blocks of the flowcharts and / or block diagrams.

[0055] The computer program instructions may also be stored on a computer, other programmable data processing apparatus, or other devices to cause execution of a series of process steps on the computer, other programmable data processing apparatus, or other devices to produce a computer-executed process, such that the instructions executing on the computer or other programmable devices produce methods for implementing the functions / steps defined in the block or blocks of flowcharts and / or block diagrams.

[0056] Further advantages and features will become apparent from the following description in conjunction with the accompanying drawings, in which: Figure 1 schematically illustrates the sequence of the method for determining the position according to one embodiment,

[0057] Figure 2 schematically shows an embodiment of an ultrasonic sensor system, and

[0058] Figure 3 shows the exemplary and schematic course of a reflection signal received by an ultrasonic sensor.

[0059] The method begins in step S10 by generating a signal for transmitting an ultrasonic signal. The signal is generated by a control unit that is communicatively connected to an ultrasonic transmitting device. The ultrasonic transmitting device can, for example, be a correspondingly modulated ultrasonic sensor or a piezo element explicitly provided for this purpose. The ultrasonic signal is then transmitted by the ultrasonic transmitting device at a time t s sent out.

[0060] After being transmitted, the ultrasonic signal travels through the room at the speed of sound until it encounters an obstacle and is reflected there as a reflection signal. During this time, the ultrasonic sensor system waits for a reflection signal to be received by at least one ultrasonic sensor. For this purpose, a time window is opened by the ultrasonic sensor system listening for reflection signals with one or more ultrasonic sensors on one or more channels. In step S12, the reflection signal is finally received at a time t e received.

[0061] In step S14, the transit time of the reflection signal, i.e. t e - t sThe position, e.g., the distance to the object from which the reflection signal was reflected, is determined. The determined position or distance can be used for a variety of applications. These include, for example, parking assistance for autonomous or semi-autonomous driving functions of a vehicle or the control of robot arms in a production facility.

[0062] Upon detection of the reflection signal in step S12, a measurement adjustment is carried out at a predetermined threshold time or the time t e based time, provided that the time t e receiving the at least one reflection signal less than the threshold time after the time t s The measurement adjustment may comprise one of two possible measures, which are illustrated in Figure 1 as step S16a and step S16b.

[0063] In step S16a, the time window for detecting a reflection signal is shortened, i.e., in particular, the detection of (further) reflection signals is aborted, whereupon the method immediately returns to step S10, in which a new signal is generated to transmit another ultrasonic signal. This speeds up the method, allowing multiple position determinations to be performed in the same time. This, in turn, increases the sampling rate with which the surroundings can be searched for objects. Higher sampling rates allow, among other things, a higher (temporal) resolution of the objects, which allows not only the position of an object but also its speed to be determined very precisely. This is particularly important for predicting the object's movements.

[0064] With alternative step S16b, the data generated by one or more ultrasonic sensors are stored after the time defined by the threshold value or after the time defined by the time t e This data is ignored at a defined point in time. This data is neither used for position determination nor in any other way, so it no longer plays a role in the process. Ignoring this data conserves the bandwidth of the data transmission within the ultrasonic sensor system, especially from the respective ultrasonic sensor to a control unit. Since less data needs to be transmitted, fewer computing steps are required to execute the process, thus reducing the energy consumption for position determination.

[0065] In one embodiment, the two possibilities can also be carried out in parallel if the ultrasonic sensor system uses at least two ultrasonic sensors to receive reflection signals by applying step S16a for sensor 1 and step S16b for sensor 2.

[0066] Independently of this, the ultrasonic sensor system can, for example, be further configured to perform the position determination only after the reflection signal has been validated on a second channel and / or with a second ultrasonic sensor. This can be illustrated by a concrete example.

[0067] A reflection signal is received on a first channel. The data generated after receiving the reflection signal in the first channel is ignored according to step S16b. This data is no longer required. However, a second channel can still be open until a reflection signal is received there as well. If a reflection signal is then received on the second channel and the reflection signal is thus validated, the time windows for receiving reflection signals on both channels can be closed. The position determination can be performed, and the method can begin again with step S10, the generation of a signal for transmitting an ultrasonic signal.

[0068] In the described embodiment, two measurement adjustments are therefore performed, with each channel and / or each ultrasonic sensor undergoing its own measurement adjustment. In further embodiments, the ultrasonic sensor system can use multiple channels and / or ultrasonic sensors combined into groups. These groups can then also undergo joint measurement adjustments.

[0069] Figure 2 schematically shows an exemplary configuration of an ultrasonic sensor system 10.

[0070] The illustrated ultrasonic sensor system 10 comprises four ultrasonic sensors 12a, 12b, 12c and 12d, which are configured to detect ultrasound and transmit it as electrical signals in analog or digital form to a control unit 14.

[0071] The control unit 14 comprises several modules for processing the data. A first module 16 is configured to generate a signal for transmitting an ultrasonic signal 18. The ultrasonic signal 18 can be generated, for example, by an ultrasonic transmitting device 20, in particular a piezo element.

[0072] If the ultrasonic signal 18 encounters an object 22 in the vicinity of the ultrasonic sensor system, it is reflected as a reflection signal 24. The reflection signal 24 can then be captured and detected by the ultrasonic sensors 12a, 12b, 12c, and 12d with a certain propagation time. A second module 26 of the control unit 14 is configured to determine the distance to the object 22, or generally its position or orientation relative to the respective ultrasonic sensor, from the propagation times of the reflection signals 24 or from the difference between the times of transmission of the ultrasonic signal 18 and reception of the reflection signal 24.

[0073] In the illustrated embodiment, the ultrasonic sensors 12b and 12c are positioned closer to the object 22 than the ultrasonic sensors 12a and 12d. The difference in distance results in a difference in the propagation time of the reflection signals 24. Depending on where the object 22 is positioned in space, not only the distance to the object but also the direction to the object can be determined from the different propagation times. By considering the distance and direction over time, predictions can be made about the future behavior of the object 22. This can be useful, for example, in traffic monitoring when the ultrasonic sensor system 10 is installed in a vehicle and the proposed method is used for environmental monitoring. The predictions can use autonomous or semi-autonomous driving functions for vehicle control or driver assistance.

[0074] The control unit 14 further includes a third module 28, which the control unit can use to make measurement adjustments for the ultrasonic sensors 12a, 12b, 12c, and 12d. The module 28 is configured to inform the ultrasonic sensors 12a, 12b, 12c, and 12d that the additional data can be ignored for the remainder of a defined time window. Additionally or alternatively, the module 28 can be configured to send a signal to the module 16, causing the module 16 to again send a signal to transmit an ultrasonic signal 18 to the ultrasonic transmitting device 20.

[0075] The control unit 14 can further comprise a fourth module 30 configured to control the remaining modules. The module 30 can, for example, start or end the position determination method, depending on the task of the ultrasonic sensor system. In a vehicle, for example, it is not necessary in all scenarios to continuously measure the distance to rear objects. The method can be limited to reversing the vehicle. The module 30 can therefore be a communication interface with another system not shown here.

[0076] Figure 3 shows, by way of example, the profile of the amplitude A of an exemplary signal received by an ultrasonic sensor when used for position measurement. In a first time range 32, an ultrasonic signal is transmitted by an ultrasonic transmitting device at a time t sThe signal not only propagates outside the ultrasonic sensor system, but can also be detected by the ultrasonic sensor due to internal system vibrations. Time range 32 can therefore be ignored for data evaluation, as indicated by hatching.

[0077] Also shown is a time range 34 which, at a threshold time after the time t s begins and ends with the end of the measuring cycle.

[0078] At a time t e The ultrasonic sensor receives a signal that has been reflected by an object in the vicinity of the ultrasonic sensor system. The amplitude of the reflected signal is lower than the originally emitted signal. To validate the signal as a reflection signal, the ultrasonic sensor system used here is configured to receive at least one further echo of the ultrasonic signal.

[0079] If the ultrasonic sensor system is configured to transmit more than one ultrasonic signal, in particular by means of at least two ultrasonic transmitting devices, several reflection signals are also received. These additional reflection signals are shown in Figure 3 at times t' e or t" e The reflection signal at time t' e can be used, for example, to validate the first reflection signal. The third reflection signal at time t" e is then not required, so that the data of the ultrasonic sensor after time t' e , possibly plus a buffer time, can be discarded.

[0080] Since the time t e or t' e of receiving the reflection signal less than the predetermined threshold time after the time t s, i.e., before range 34, a measurement adjustment is now carried out at a time based on the threshold time. In the example shown, the time of the measurement adjustment corresponds to the threshold time. Not shown here is the variant where the time is based on time t e of the echo, e.g. t' e However, the logic remains the same for the following explanations.

[0081] In one example of measurement adjustment, measurement data obtained after the threshold time point is discarded for the remaining process, e.g., signal evaluation. The measurement cycle begins again from the beginning after the expiration of the time period 34. In an alternative example of measurement adjustment, the ultrasonic sensor system can be configured to generate a new ultrasonic signal immediately at the threshold time point, i.e., to end the measurement cycle at the beginning of the time period designated by reference numeral 34 and then immediately begin a new measurement cycle.

[0082] List of reference symbols

[0083] 10 Ultrasonic sensor system

[0084] 12a Ultrasonic sensor

[0085] 12b Ultrasonic sensor

[0086] 12c ultrasonic sensor

[0087] 12d ultrasonic sensor

[0088] 14 Control unit

[0089] 16 Module

[0090] 18 Ultrasonic signal

[0091] 20 Ultrasound transmitting device

[0092] 22 objects

[0093] 24 reflection signal

[0094] 26 Module

[0095] 28 Module

[0096] 30 Module

[0097] 32 time range

[0098] 34 Time range

[0099] S10 Step

[0100] S12 Step

[0101] S14 Step

[0102] S16a Step

[0103] S16b Step

Claims

Patent claims 1. A method for determining position using an ultrasonic sensor system (10) comprising at least one ultrasonic sensor (12a, 12b, 12c, 12d), the method comprising the steps of: - generating a control signal (S10) for emitting an ultrasonic signal (18) at a time t s ; - In response to generating the control signal (S10), receiving within a time window at least one reflection signal (24) (S12) from the at least one ultrasonic sensor (12a, 12b, 12c, 12d) within the time window at a time t e and determining a position (S14) of an object (22) at which the ultrasonic signal (18) was reflected, wherein the position is determined based on the propagation time of the ultrasonic signal (18) between the transmission of the ultrasonic signal (18) at the time t s and receiving the at least one reflection signal (24) at time t e is determined; and - If the time t e receiving the at least one reflection signal (24) less than a predetermined threshold time after the time t s is, performing a measurement adjustment at a time point based on the threshold value or the time t e based time, wherein the measurement adaptation comprises either shortening the time window for receiving further reflection signals (24) (S16a) and repeating the steps of generating the control signal (S10) for transmitting a further ultrasonic signal (18) and receiving a further reflection signal (24) (S12) for a further position determination (S14) or wherein the measurement adaptation comprises discarding the signals received by the at least one ultrasonic sensor (12a, 12b, 12c, 12d) after the time determined by the threshold value or the time t e defined point in time until the end of the time window (S16b).

2. Method according to one of the preceding claims, wherein the ultrasonic sensor system (10) comprises a plurality of channels, wherein the measurement adjustment is only carried out if a presence of the object (22) with the position has been validated by reflection signals (24) on at least two of the channels.

3. The method according to claim 3, wherein the ultrasonic sensor system (10) comprises a plurality of the ultrasonic sensors (12a, 12b, 12c, 12d) and each of the ultrasonic sensors (12a, 12b, 12c, 12d) has at least one of the channels, wherein the generation of the control signal (S10) for transmitting an ultrasonic signal (18) and the corresponding reception of a reflection signal (24) (S12) for a plurality of the ultrasonic sensors (12a, 12b, 12c, 12d) is carried out, wherein the measurement adjustment only takes place when a presence of the object (22) with the position has been validated by reflection signals (12a, 12b, 12c, 12d) using at least two of the ultrasonic sensors (12a, 12b, 12c, 12d).

4. Method according to one of the preceding claims, wherein the steps of generating the control signal (S10) for transmitting the further ultrasonic signal (18) and receiving the further reflection signal (24) (S12) for the further position determination are carried out immediately after the end of the shortened time window.

5. Method according to one of the preceding claims, wherein the measurement adjustment takes place at a predetermined time which is greater than the propagation time of the reflection signal (24), and / or wherein the measurement adjustment takes place at a time which corresponds to the propagation time of the reflection signal (24) plus a predetermined buffer time.

6. Method according to one of the preceding claims, wherein the threshold time is less than 40%, preferably less than 30% or 20% of the duration of the unabridged time window.

7. Method according to one of the preceding claims, wherein the generation of the control signal (S10), the reception of the reflection signal (S12) and the measurement adjustment take place in one measuring cycle and the measuring cycle is carried out cyclically, the method further comprising a comparison of the positions which were determined for reflection signals (24) in successive measuring cycles, the measurement adjustment being reversed if the comparison results in a deviation of the position greater than a predetermined deviation value or a reflection signal (24) is no longer received.

8. The method according to any one of the preceding claims, wherein the ultrasonic sensor system (10) comprises a control unit (14), wherein the control unit (14) carries out the generation of the control signal (S10), receives the reflection signal (24) and carries out the measurement adjustment.

9. The method according to claim 10, wherein the control unit (14) is integrated into the at least one ultrasonic sensor (12a, 12b, 12c, 12d) or is part of a central control unit for a plurality of the ultrasonic sensors (12a, 12b, 12c, 12d).

10. Computer program product, in particular a computer-readable storage medium, wherein the computer program product comprises computer-executable code, wherein the code is executable by at least one processor of a computer device, to cause the computer device to perform the method according to any one of the preceding claims.

11. Device for determining position using an ultrasonic sensor system (10) comprising at least one ultrasonic sensor (12a, 12b, 12c, 12d), the device comprising: - means for generating a control signal (S10) for emitting an ultrasonic signal (18) at a time t s ; - means for receiving (S12), in response to the generation of the control signal, within a time window at least one reflection signal (24) from the at least one ultrasonic sensor (12a, 12b, 12c, 12d) within the time window at a time t e and determining a position (S14) of an object (22) at which the ultrasonic signal (18) was reflected, the position being determined based on the propagation time of the ultrasonic signal (18) between the transmission of the ultrasonic signal (18) at the time t s and receiving the at least one reflection signal (24) (S12) at time t e is determined; and - Means for performing a measurement adjustment at a predetermined threshold time or the time t e based time, provided that the time t e receiving the at least one reflection signal less than the threshold time after the time t swherein the measurement adjustment comprises either shortening the time window for receiving further reflection signals and repeating the steps of generating the control signal for transmitting a further ultrasonic signal and receiving a further reflection signal for a further position determination or wherein the measurement adjustment comprises discarding the signals received by the at least one ultrasonic sensor after the time determined by the threshold value or the time t e defined point in time until the end of the time window.

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