WO2022171585A2

WO2022171585A2 - Parking assistance system and building

Info

Publication number: WO2022171585A2
Application number: PCT/EP2022/052929
Authority: WO
Inventors: Sylvio Salomon
Original assignee: Valeo Schalter Und Sensoren Gmbh
Priority date: 2021-02-10
Filing date: 2022-02-08
Publication date: 2022-08-18
Also published as: DE102021103071A1; WO2022171585A3

Abstract

The invention relates to a parking assistance system (100). The parking assistance system comprises: at least one stationary ultrasonic sensor assembly (1, 101-106), wherein the ultrasonic sensor assembly (1, 101-106) comprises an ultrasonic sensor (2) having a housing (4), an ultrasonic diaphragm (5) mechanically decoupled from the housing (4), an ultrasonic transducer element (7) for oscillation excitation and oscillation detection of the ultrasonic diaphragm (5), and a cover portion (3) situated in front of the ultrasonic diaphragm (5) and made of an acoustic metamaterial; and a control device (110) coupled to the ultrasonic sensor assembly (1, 101-106), which control device is designed to activate the ultrasonic sensor assembly (1, 101-106) in order to transmit and/or receive an ultrasonic signal (25).

Description

PARK ASSISTANCE SYSTEM AND BUILDING

The present invention relates to a parking assistance system and a building with such a parking assistance system.

Parking assistance systems are known which are intended for stationary use, for example in or on a building. Such parking assistance systems can support a provider of parking spaces and/or users of the parking spaces provided in various ways. For example, an occupancy of a parking garage can be determined by means of a corresponding system and thus efficient operation of the parking garage can be improved. The occupancy information can also be used to direct a motorist to a free parking space.

Autonomous or semi-autonomous vehicles can be supplied with additional data that is recorded and processed by the stationary parking assistance system, so that orientation of the vehicles can be improved and autonomous driving functions can be provided more safely and at the same time more quickly.

Further applications are possible in the area of automatic valet parking. Here, a stationary parking assistance system can take over the control of a remote-controlled vehicle. The stationary parking assistance system records and monitors the driving maneuvers carried out by the vehicle using the stationary sensors. This is attractive because in this case the vehicle does not have to have its own sensor system, but only needs to be remotely controllable.

Ultrasonic sensors are used for parking assistance systems, whether mobile or stationary, known. A short blind time of the ultrasonic sensor to the outside of the ultrasonic signal, a low background noise and a high signal-to-noise ratio are desirable. In other words, high amplitudes of the measured return Echo signal and low structural vibrations of the housing and possibly other compo elements desired.

DE 102017209823 A1 teaches an ultrasonic sensor whose vibration membrane is designed as an acoustic metamaterial that exhibits resonant behavior within a frequency band of the membrane.

US 2017059697 A1 teaches an arrangement in which an ultrasonic sensor is arranged concealed behind an inside of a molded part and is intended to detect objects on the outside of the molded part. A prestressing structure presses the ultrasonic sensor against the inside of the molded part, with a coupling element being arranged between the ultrasonic sensor and the inner surface. In an area outside of the coupling element, a damping material is attached to the inside of the molded part.

DE 10 2016 200 813 A1 discloses a method for determining a vehicle position of a vehicle, in which an ultrasonic beacon is provided. An ultrasonic sensor in a vehicle emits a coded ultrasonic signal that includes a transmission code. The coded ultrasonic signal is received by the ultrasonic beacon. If the transmission code is recognized by the ultrasonic beacon, a position signal is emitted by the ultrasonic beacon. The position signal is received by the vehicle's ultrasonic sensor and the vehicle's position relative to the position of the ultrasonic beacon is determined using a time elapsed between transmission of the encoded ultrasonic signal and receipt of the position signal.

Against this background, the object of the present invention is to provide an improved parking assistance system.

The inventors of the present application have developed the idea that using a broadband metamaterial for non-resonant impedance matching, as described in GD Aguanno et. al. "Broadband metamaterial for nonresonant matching of acoustic waves", Sci. Rep. 2, 340: D0l:10.1038/srep003401 (2012), accessed 21.10.2020 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3314304/7toohpmcentrez, for medical diagnostic purposes and other micromechanical systems is described, could also offer advantages in the field of ultrasonic measurement of a motor vehicle environment or interior, and through further considerations and experiments finally arrived at the solution described below.

According to a first aspect, a parking assistance system is proposed with at least one stationary ultrasonic sensor arrangement and with a control device. The ultrasonic sensor arrangement comprises an ultrasonic sensor with a housing, an ultrasonic membrane mechanically decoupled from the housing and a sound transducer element for exciting and detecting vibrations of the ultrasonic membrane, and a diaphragm section made of an acoustic metamaterial arranged in front of the ultrasonic membrane. The control device is coupled to the ultrasonic sensor arrangement and is set up to actuate the ultrasonic sensor arrangement to transmit and/or to receive an ultrasonic signal.

This parking assistance system has the advantage that it can be made simpler than conventional parking assistance systems with ultrasonic sensors due to the use of the ultrasonic sensor arrangement configured as described, which has a particularly high signal-to-noise ratio. In particular, fewer ultrasonic sensor arrangements can be required for a given area, or the electronics for controlling and/or reading out the ultrasonic sensor arrangement, for example the control device, can be made less complex since the requirements for signal processing are lower. The inventors have experimentally determined the surprising effect that the acoustic metamaterial arranged in front of the ultrasonic membrane not only does not reduce the amplitude of the measured signal, which corresponds to the reflected ultrasonic wave, compared to an ultrasonic sensor arranged uncovered, but significantly increases it. Thus, the signal-to-noise ratio can be significantly improved. The parking assistance system can also be referred to as a stationary parking assistance system. The parking assistance system is integrated in a building, for example. The fact that the ultrasonic sensor arrangement is arranged “stationarily” means in particular that it is arranged on a fixed structure, for example a structural structure anchored to the ground.

The control device can be implemented in terms of hardware and/or software. In the case of a hardware implementation, the control device can be designed as a computer or as a microprocessor, for example. In the case of a software implementation, the control device can be designed as a computer program product, as a function, as a routine, as an algorithm, as part of a program code or as an executable object. Furthermore, the control device can also be designed as part of a higher-level system, such as a building control system and/or a monitoring system.

The ultrasonic sensor arrangement described also has the advantage that the panel section can cover the ultrasonic sensor optically and mechanically and thus protect it from being looked at and from the effects of impacts and the like, for example.

In particular, the screen section is arranged in front of the ultrasonic membrane in such a way that it covers the ultrasonic membrane. “Covered” is to be understood as meaning that ultrasonic waves emitted by the ultrasonic membrane into a spatial area to be measured and ultrasonic waves reflected from there back to the ultrasonic membrane pass through the aperture section in each case. “Uncovered” means that ultrasonic waves can be emitted unhindered into the spatial area to be measured and reflected back from it, ie there is only air between the ultrasonic membrane and the object to be measured in the spatial area to be measured. The ultrasonic membrane can be acoustically decoupled from the housing of the ultrasonic sensor, for example by means of a decoupling ring made of an acoustically soft material such as silicone. The ultrasonic membrane can be inserted into an opening in the housing, with the decoupling ring being arranged between the ultrasonic membrane and the housing inner edge of the opening.

The sound transducer element can be a sound transducer element on a mechanical-inductive, mechanical-capacitive, mechanical-resistive, magnetostrictive or electrostrictive basis. The sound transducer element can be a piezo element, for example. The sound transducer element can be glued to the ultrasonic membrane within the housing, welded to the water or connected to the ultrasonic membrane in some other way. The sound transducer element can be connected to an external electrical contact of the ultrasonic sensor via a loose decoupling wire.

The screen section can be a section of a larger molded part, such as a wall paneling or cover, which forms the screen section only in an area that is arranged in front of the ultrasonic membrane of the ultrasonic sensor. However, the panel portion may also comprise a substantially entire area of a standalone panel or the like that is purpose-specifically provided to conceal the ultrasonic membrane from the latter.

An acoustic metamaterial is to be understood in particular as a material which is given advantageous acoustic properties by structuring processing, which the unprocessed or unstructured material does not have.

The acoustic meta-material can in particular be a meta-material which, according to the publication by D'Aquanno et al. the principles described, to which express reference is made. The fact that the control device is set up to activate the ultrasonic sensor arrangement to emit an ultrasonic signal is understood to mean in particular that the control device emits an electrical signal with a predetermined frequency to the ultrasonic sensor arrangement or applies the electrical signal to it, causing the sound transducer element to oscillate and thus the ultrasonic membrane is stimulated to emit the ultrasonic signal. The frequency with which the ultrasonic signal is generated can be variable and adjustable.

The fact that the control device is set up to activate the ultrasonic sensor arrangement to receive an ultrasonic signal is understood to mean in particular that the control device is set up to detect an electrical signal that can be picked up by a vibration of the sound transducer element thereon. When receiving the ultrasonic signal, a signal path is reversed: the ultrasonic membrane is set in motion by an incoming ultrasonic wave, which is transmitted to the baffle element and can be detected there as an electrical signal with the corresponding frequency.

According to one embodiment of the parking assistance system, the acoustic meta-material is a broadband acoustic meta-material through which ultrasonic waves can be tunneled non-resonantly at least in an angle of incidence range.

“Broadband” means in particular that the acoustic metamaterial is uniformly well permeable not only for ultrasonic waves with a specific frequency, but also for ultrasonic waves in a broad frequency band of, for example, 40 to 60 kHz, preferably 16 to 100 kHz.

By "non-resonantly tunnelable" is meant, in particular, that an ultrasonic wave incident on the acoustic metamaterial "feels" an equal acoustic impedance in the medium, such as air, from which it arrives, and in the acoustic metamaterial, such that regardless of the Frequency of the ultrasonic wave and independent of the thickness of the acoustic metamaterial, essentially no reflections occur either at the entry surface or at the exit surface.

“Non-resonant” is to be understood in particular as meaning that no resonant pressure antinodes form within the metamaterial when tunneling through the acoustic metamaterial. Such a non-resonant tunnelability corresponds to the broadband nature of the acoustic metamaterial.

The non-resonant tunneling capability is preferably present at least in an ultrasonic wave angle of incidence range that includes a substantially perpendicular direction of incidence onto a surface of the diaphragm section made of the acoustic metamaterial. In practical terms, angular ranges between 0° and 30° to 85° against the surface normal can be achieved.

In other words, an acoustic impedance on one side of the acoustic metamaterial baffle section can be matched to an acoustic impedance of the air in the space to be measured, and an acoustic impedance on another side of the baffle section can also be matched to the acoustic impedance of air or both be matched to the acoustic impedance of the ultrasonic membrane of the ultrasonic sensor arranged on the other side.

According to a further embodiment of the parking assistance system, the acoustic metal is formed from a reverberant base material in which a grid of several ren passage openings is formed.

"Resonant" is to be understood in particular as meaning a base material which, in the unprocessed state, has a high acoustic resistance and which, in the unprocessed state, reflects when sound waves impinge on it. Examples of a rigid base material include a metal sheet, a plastic plate, a composite material plate, a fiber board, a wooden board, and the like. The plurality of through openings can in particular be openings with a round cross section, which extend from one side of the screen section to the opposite side of the screen section.

Compared to other possible configurations of an acoustic metamaterial, a configuration with a lattice made up of a plurality of round through-openings is characterized by particularly favorable transmission properties.

According to a further embodiment of the parking assistance system, a diameter of a respective passage opening is smaller than a wavelength of the ultrasonic waves to be emitted and received by the ultrasonic membrane.

The frequency of the ultrasonic waves to be transmitted and received, i. H. the natural frequency of the ultrasonic membrane is, for example, between 16 and 100 kHz, preferably between 40 and 60 kHz and particularly preferably 50 kHz. Accordingly, at a temperature of 20° C., the wavelength of the ultrasonic waves to be sent and received by the ultrasonic membrane is between 21 and 3 mm, preferably between 9 and 6 and particularly preferably 7 mm. Different temperatures result in different wavelengths. The diameter of the respective openings is very particularly preferably chosen to be a value which is smaller by a factor of 2 or more, preferably an integer, than the corresponding wavelength to be expected at 20° C., for example 1 mm.

According to a further embodiment of the parking assistance system, a distance between two adjacent openings in the grid is larger than the diameter of the openings and smaller than the wavelength of the ultrasonic waves to be emitted and received by the ultrasonic membrane.

For example, the hole spacing can be chosen between 2 and 4 mm and particularly preferably 2.5 mm. The inventors were able to increase the received signal amplitude with an acoustic metamaterial designed in this way, which included a plate-shaped panel section made of steel, aluminum or plastic with a perforated grid with a hole spacing of 2.5 mm and a hole diameter of 1 mm, and a corresponding Improvement of the signal-to-noise ratio, depending on the distance between the ultrasonic membrane and the diaphragm section - by a factor of 1.5 to 10 compared to an uncovered arrangement of the ultrasonic sensor.

According to a further embodiment of the parking assistance system, the proposed ultrasonic sensor arrangement further comprises a molded part, to which the ultrasonic sensor is attached in such a way that the ultrasonic membrane faces the molded part, and the molded part comprises the diaphragm section made of the acoustic metamaterial in a section in front of the ultrasonic membrane.

The molded part can in particular be formed from the base material from which the acoustic metamaterial is also formed, for example from sheet metal or plastic. In particular, the molded part can be formed in one piece with the panel section. The panel section can be formed subsequently in the molded part, for example by perforating the molded part.

The molded part can be a trim part that creates an aesthetic visual appearance, to which the ultrasonic sensor is additionally attached according to the proposal, and to which a diaphragm section made of an acoustic metamaterial is formed by structuring in an area in front of the ultrasonic membrane of the ultrasonic sensor. In this way, the sensor can be hidden behind the molded part and still measure the spatial area on the other side of the molded part with a high echo signal amplitude.

Alternatively, the molding may be dedicated for attaching the ultrasonic sensor thereto and forming the aperture portion. For example, the ultrasonic sensor, which could be used unobscured in a conventional manner, can be provided with an aperture which need only be slightly larger than the ultrasonic sensor and the purpose of which is to take advantage of the acoustic metamaterial aperture portion for the ultrasonic sensor array.

According to one embodiment of the parking assistance system, the ultrasonic sensor is attached to the molded part in that an outer wall of the housing of the ultrasonic sensor is connected to a bracket and the bracket is attached to the molded part in an area outside the panel section, with the surface of the ultrasonic membrane being parallel to the Molding is arranged behind the panel portion of the molding.

In this way, the housing can advantageously be stably attached to the molded part, whereas the sensor membrane mechanically decoupled from the housing is not attached to the molded part or mechanically decoupled from the molded part.

According to a further embodiment of the parking assistance system, the ultrasonic membrane lies against the panel section.

In particular, the ultrasonic membrane can bear against the diaphragm section without contact pressure and/or without being fixed to the diaphragm section.

In particular, the acoustic impedance of the side of the acoustic metamaterial facing the ultrasound membrane can be matched to the acoustic impedance of the ultrasound membrane.

In the present embodiment, the noted effect of drastically increasing the echo signal amplitude can be advantageously obtained. In addition, damping elements, such as bores or damping material, can be provided on the molded part outside of the panel section. In this way, the development of structure-borne noise in the molded part can also be counteracted.

According to a further embodiment of the parking assistance system, the ultrasonic membrane and the diaphragm section are mechanically decoupled from one another.

For example, an air gap is formed between the ultrasonic membrane and the diaphragm section. The air gap is a possible means of mechanically decoupling the ultrasonic membrane from the panel section or the molded part. Since the ultrasonic membrane is also mechanically decoupled from the housing of the ultrasonic sensor, there is therefore no mechanical or acoustic coupling between the ultrasonic membrane and the molded part to which the housing of the ultrasonic sensor is attached. Accordingly, the structural vibration is hardly excited to the molding. Accordingly, damping elements on the molded part, such as attached damping material, bores provided for damping and the like are advantageously unnecessary.

Due to the good transmission properties of the proposed acoustic Metama material, it is not necessary to mechanically couple the ultrasonic membrane to the aperture section. The air gap can preferably be made thin, particularly preferably thinner than 1 mm, and particularly preferably 0.1 mm thin or even thinner. In this case, the advantageous effect of amplifying the echo signal amplitude can be achieved particularly well by the acoustic metamaterial.

According to a further embodiment of the parking assistance system, a protective device is provided which is arranged in a fixed position together with the ultrasonic sensor arrangement and which is set up to shield the ultrasonic sensor arrangement from external influences. This embodiment has the advantage that the ultrasonic sensor arrangement is protected from external influences, in particular weather influences such as rain, radiation or dust. This is advantageous in particular for the proper functioning of the acoustic metamaterial, since the advantageous properties of the acoustic metamaterial can be lost if, for example, dirt clogs the acoustic metamaterial. The protective device is designed in such a way that ultrasonic signals are not impaired by it, at least in a predetermined solid angle range.

The protective device can enclose the ultrasonic sensor arrangement at least in sections. For example, the protective device is designed as a housing, with this being designed in such a way that sound propagation from the ultrasonic sensor in the spatial area to be measured or to the ultrasonic sensor from the spatial area to be measured is essentially unaffected. For example, the molded part in which the acoustic metamaterial is formed can also form the protective device. As an alternative or in addition, the protective device can comprise a separate component or element which is arranged in a stationary manner at a distance from the ultrasonic sensor arrangement.

According to a further specific embodiment of the parking assistance system, the control device is also set up to determine an object in the vicinity of the ultrasonic sensor arrangement on the basis of an ultrasonic signal received from the ultrasonic sensor arrangement.

The ultrasonic signal received by the ultrasonic sensor arrangement can be a reflection signal, ie it can be an ultrasonic signal originally sent by the ultrasonic sensor arrangement and reflected on the object. The received ultrasonic signal can also be a reflected ultrasonic signal that was originally not emitted by the ultrasonic sensor arrangement itself, but by another ultrasonic sensor arrangement of the parking assistance system. In addition, it can be an ultrasonic signal emitted by a vehicle, more precisely by an ultrasonic sensor arrangement arranged on a vehicle. The object is, for example, a vehicle, a cyclist or a pedestrian.

The object can be determined, for example, on the basis of a transit time and/or an amplitude and/or a signal characteristic of a received reflection signal.

In embodiments it can be provided that an object classification is carried out depending on the received ultrasonic signal. In the case of a reflection signal, its signal characteristics depend, for example, on a shape and/or a material of the reflecting surface, which can be used for a corresponding classification.

According to a further embodiment of the parking assistance system, the control device is also set up to determine a movement state of the determined object based on a Doppler frequency shift of the received ultrasonic reflection signal and/or based on at least two ultrasonic signals received at different times.

The state of movement includes in particular the information as to whether the object is moving towards or away from the ultrasonic sensor arrangement. When the object moves towards the ultrasonic sensor array, the frequency of the reflected ultrasonic signal will be greater than that of the ultrasonic signal originally emitted. If the object moves away from the ultrasonic sensor arrangement, then the frequency of the reflected ultrasonic signal will be lower than that of the originally transmitted ultrasonic signal. If the propagation time of the reflected ultrasonic signal changes between two ultrasonic signals emitted at different points in time, the state of motion of the object can also be inferred from here.

According to a further embodiment of the parking assistance system, the parking assistance system comprises a plurality of ultrasonic sensor arrangements which are stationarily arranged in a predetermined spatial arrangement, the control device for determining a position and/or an orientation and/or a shape of an object arranged in the vicinity of the ultrasonic sensor arrangements depending on at least two ultrasonic signals received from different ultrasonic sensor arrangements of the plurality and the predetermined spatial arrangement of the ultrasonic sensor arrangements.

The control device is advantageously set up to activate all ultrasonic sensor arrangements of the parking assistance system.

The predetermined spatial arrangement of the multiple ultrasonic sensor arrays includes, for example, information about a respective distance and a direction between two ultrasonic sensor arrays. One can also say that the predetermined spatial arrangement is given by respective coordinates of the ultrasonic sensor arrays. The coordinates preferably include two or three position coordinates and, in addition, several directional coordinates. The directional coordinates are used to specify the spatial area into which a respective ultrasonic sensor arrangement sends an ultrasonic signal and the spatial area from which the respective ultrasonic sensor arrangement receives an ultrasonic signal. The directional coordinates can be given, for example, in the form of spherical coordinates, which can also include area details, for example in the form of intervals.

A position, an alignment and/or a shape of the object can be determined from the at least two received ultrasonic signals by means of multilateration. The more signals are received, the more precisely the determination can be made.

The multiple ultrasonic sensor arrays are controlled by the control device in particular in such a way that they do not all emit an ultrasonic signal at the same time, but rather only a subgroup of the multiple ultrasonic sensor arrays at a given point in time. The subgroups are selected in such a way that under normal circumstances it is not to be expected that a specific subgroup will Summarized ultrasonic sensor arrays received a reflection signal due to the spatial arrangement of another ultrasonic sensor array of the subgroup. For example, ultrasonic sensor arrays that emit in different spatial angles and/or between which a wall or the like is arranged can form a subgroup. In other words, those ultrasonic sensor arrangements that are not contained in the subgroup emitting ultrasonic signals at a specific point in time are spatially arranged in such a way that it can be expected that they will receive a reflection signal of the emitted ultrasonic signals. An information density relating to the object can thus be increased, which enables the position, orientation and/or shape to be determined even more precisely.

Alternatively or additionally, it can be provided that some or all ultrasonic sensor arrangements are assigned a specific frequency with which they emit the ultrasonic signal. On the basis of the frequency of a received ultrasonic signal, conclusions can then be drawn about the ultrasonic sensor arrangement that originally transmitted the ultrasonic signal.

In embodiments of the parking assistance system, the control device is also set up to determine a trajectory of the object on the basis of the position and/or orientation of the object determined at different points in time.

The trajectory can also be referred to as a movement profile. By means of the trajectory, the object can be tracked within a building, for example. This means that it can be determined when the object leaves a first area and enters a second area. In particular, seamless tracking, that is to say there are no "blind areas" in which there is no ultrasonic sensor arrangement, can have advantages for the function of the parking assistance system. For example, this can be used for intelligent traffic flow control. In embodiments of the parking assistance system, the control device is also set up to actuate the ultrasonic sensor arrangement to emit a coded ultrasonic signal that includes coded information, and is set up to determine coded information contained in a received ultrasonic signal.

In this embodiment, the ultrasonic sensor arrangement can be used for communication with other ultrasonic sensor arrangements, in particular for data transmission. Because of the advantageously high signal-to-noise ratio of the ultrasonic sensor arrangement designed as proposed, the communication can be carried out more stably and less susceptible to interference than with conventional ultrasonic sensors.

The information is encoded in particular by means of a modulation method, which means that the encoded ultrasonic signal is a correspondingly modulated ultrasonic signal. In games are frequency modulation, amplitude modulation or pulse code modulation.

According to a further embodiment of the parking assistance system, the parking assistance system is also set up to receive an ultrasonic signal emitted by an ultrasonic sensor arrangement of a vehicle, and the control device is set up to, in response to the received ultrasonic signal, cause the ultrasonic sensor arrangement to emit a to drive another ultrasonic signal with predetermined properties depending on the received ultrasonic signal.

The predetermined properties of the ultrasound signal to be transmitted include a transmission time to be determined relative to a reception time of the received ultrasound signal. This means that the ultrasonic signal is transmitted after a predetermined period of time has elapsed after the ultrasonic signal was received. The ultrasonic signal with predetermined properties can also be an encoded ultrasonic signal that includes encoded information. The information includes, for example, a position of the ultrasonic sensor arrangement, for example in the form of GPS coordinates. The information is coded in particular by means of a modulation method, i.e. that the coded ultrasonic signal is a correspondingly modulated ultrasonic signal. Examples are frequency modulation, amplitude modulation or pulse code modulation.

In this embodiment, the vehicle can advantageously be assisted in localization. Due to the advantageous properties of the ultrasonic sensor arrangement designed as proposed, which enables a greater range when receiving and transmitting the ultrasonic signal, this can be done with a greater distance between the vehicle and the ultrasonic sensor arrangement than is possible with conventional ultrasonic sensors. It should be noted that the ultrasonic sensor arrangement of the vehicle can comprise a conventional ultrasonic sensor arrangement and/or an ultrasonic sensor arrangement designed as proposed.

According to a second aspect, a building, in particular a parking garage, is proposed. The building includes at least one parking area for a vehicle. The building includes a parking assistance system according to the first aspect.

The building may include a single garage, a parking garage, an underground parking lot, an open parking area such as a parking lot, or the like. The building includes structural structures, such as walls, pillars, walls or the like, which are firmly connected to the ground.

The parking assistance system is preferably arranged in an integrated manner in the building, for example necessary power and signal lines run in a concealed manner, in particular they are laid in a manner similar to flush-mounting. The parking assistance system can also be attached to the building later, for example as part of a modernization.

If the parking assistance system comprises a plurality of ultrasonic sensor arrangements, these are arranged in particular in a distributed manner in or on the building attached to different building structures and set up to measure different areas of space.

Further possible implementations of the invention also include combinations of features or embodiments described above or below with regard to the exemplary embodiments that are not explicitly mentioned. The person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

Further advantageous refinements and aspects of the invention are the subject matter of the subclaims and of the exemplary embodiments of the invention described below.

The invention is explained in more detail below on the basis of preferred embodiments with reference to the enclosed figures.

1 shows a schematic view of a parking assistance system according to a first exemplary embodiment;

2 shows a schematic sectional view of an ultrasonic sensor arrangement according to a second exemplary embodiment;

3 shows a schematic sectional view of an ultrasonic sensor arrangement according to a third exemplary embodiment;

4 shows a schematic top view of a molded part with a screen section made of an acoustic metamaterial according to exemplary embodiments;

5 shows a plot of a measured echo signal with an uncovered ultrasonic sensor;

FIG. 6 shows a plot of a measured echo signal with the ultrasonic sensor from FIG. 5 when covered by the diaphragm section of the molded part from FIG. 4; 7 shows a plot of an angle-dependent transmission directional characteristic of an ultrasonic sensor covered with a metamaterial and of an uncovered ultrasonic sensor;

8 shows a schematic view of a parking assistance system according to a fourth exemplary embodiment; 9 shows a schematic view of a parking assistance system according to a fifth exemplary embodiment;

10 shows a schematic view of a parking assistance system according to a sixth exemplary embodiment; and

FIG. 11 shows a schematic view of a parking assistance system according to a seventh exemplary embodiment.

Elements that are the same or have the same function have been provided with the same reference symbols in the figures, unless otherwise stated.

1 shows a schematic view of a parking assistance system 100 according to a first exemplary embodiment. In this example, the parking assistance system 100 is integrated in a building 300, which is embodied here as a multi-storey car park. 1 is thus also an example of a building 300 with a parking assistance system 100. The parking assistance system 100 here comprises two ultrasonic sensor arrangements 1, each of which is connected to a control device 110. The control device 100 is set up to control the ultrasonic sensor arrangements 1 . In this example, the two ultrasonic sensor arrangements 1 serve the purpose of monitoring the occupancy of parking spaces in the multi-storey car park 300 . For this purpose, the ultrasonic sensor arrays 1 are arranged on the ceiling above the respective parking space. Each ultrasonic sensor array 1 is set up to measure an area in the environment 200 below the respective ultrasonic sensor array 1 . For this purpose, the respective ultrasonic sensor arrangement 1 is controlled by the control device 110 to emit an ultrasonic signal 25 into the area to be measured. The ultrasonic signal 25 can be reflected from objects 210 or from the floor of the parking garage, and a reflection signal 26 can be received.

If an object 210, for example a motor vehicle, is located in one of the parking spaces, then a signal propagation time of the reflection signal 26 is shorter, from which it can be concluded that the motor vehicle is present. Since the ultrasonic sensor arrangements 1 are designed as described below with reference to one of FIGS. 2-4, this results in a favorable signal-to-noise ratio. Therefore, for example, the control device 110 can have a comparatively simple structure, since the signal processing for detecting the motor vehicle does not have to be as complex as would be the case with a conventional ultrasonic sensor.

FIG. 2 shows a schematic sectional view of an ultrasonic sensor arrangement according to a second exemplary embodiment. The ultrasonic sensor arrangement 1 comprises an ultrasonic sensor 2 and an aperture section 3.

The ultrasonic sensor 1 has a housing 4 which is made of a reverberant plastic. An ultrasonic membrane 5 is fitted into a decoupling ring 6 made of an acoustically soft material such as silicone. A sound transducer element 7, such as a piezoelectric element, is glued to an inner surface of the ultrasonic membrane 5. The assembly consisting of the piezo element 7, the ultrasonic membrane 5 and the decoupling ring 6 is fitted into an opening in the housing 4.

The piezoelectric element 7 is connected to a first metallic contact pin 9 via a decoupling wire 8 . The decoupling wire 8 may be of excess length and thus not under tension. A second metallic contact pin 10 is led out of the housing 4 to the outside. A circuit board 11 is placed on the metal contact pins 9,10. Electronic components 12 for electrically controlling the piezo element 7 are mounted on the circuit board 11 .

The control device 110 (see Fig. 1 or 8-11) of the parking assistance system 100 (see Fig. 1 or 8-11) can thus be connected to the electronic components 12 of the ultrasonic sensor 2 via a line (not shown here) and the contact pin 10 and through Transmission of electrical signals to the ultrasonic sensor 2 can cause the components 12 to control the piezoelectric element 7 and to excite the ultrasonic membrane 5 to oscillate and accordingly emit an ultrasonic signal 25 (see FIG. 1, 10 or 11). Likewise, the control device 110 of the parking assistance system 100 electrical signals Signals received by the ultrasonic sensor 2, which are indicative of a vibration of the ultrasonic membrane 5 detected by the piezo element 7, and in this way a received reflection signal 26 (see FIG. 1 or 11) measure.

It should be noted that the assembly of ultrasonic membrane 5 and piezo element 7 is fitted into the opening of the housing 4 by means of the decoupling ring 6 and is electrically contacted by means of the decoupling wire 8 . In this way, the ultrasonic membrane 5 is completely mechanically decoupled from the housing 4.

The diaphragm section 3 is arranged in front of the ultrasonic membrane 5 of the ultrasonic sensor 2 and is made of an acoustic metamaterial, in particular a broadband one, which is described in detail with reference to FIGS.

In particular, the aperture section 3 is provided separately from the ultrasonic sensor 2 . Specifically, the bezel portion 3 is provided without a coupling member for coupling the ultrasonic sensor 2 to the bezel portion 3 . A thin air gap 15 (see FIG. 3) can be formed between the ultrasonic membrane 5 and the panel section 3 in order to mechanically decouple the ultrasonic membrane 5 from the panel section 3 and other parts (not shown) connected to the panel section 3 (molded parts, brackets and the like) to effect. It is also possible for the ultrasonic membrane 5 to rest against the panel section 3 without contact pressure.

The acoustic metamaterial of the panel section 3 arranged in this way can advantageously significantly improve the signal-to-noise ratio of the measurement signal supplied by the ultrasonic sensor 2 .

FIG. 3 shows a schematic sectional view of an ultrasonic sensor arrangement according to a third exemplary embodiment. The ultrasonic sensor 2 and the panel section 3 of the ultrasonic sensor arrangement 1 of the third exemplary embodiment can, for example, Be ultrasonic sensor 2 and the aperture portion 3 of the second embodiment and will not be described again.

In the third exemplary embodiment, the diaphragm section 3 is a section which is formed in one piece with a molded part 13 and is made of the same reverberant base material as the molded part 13 . This means that the panel section 3 of the third exemplary embodiment is a section of the molded part 13 .

The molded part 13 can be, for example, a wall panel or a decorative panel or the like. The molded part 13 can be made of sheet metal, wood, a composite material, plastic, glass, stone or the like. Since the molded part 13 is formed from a reverberant base material, structure-borne noise and/or body vibrations can occur in the molded part 13 .

In the diaphragm section 3 of the molded part 13, the base material of the molded part 13 is formed into an acoustic metamaterial by structuring processing.

Flalters 14 are attached to an outside of the housing 4 . The flaps 14 are in turn attached to the molded part 13 . Specifically, the flares 14 are fixed to the molding 13 in an area outside the panel portion 3 . The ultrasonic sensor 2 is held by the flaps 14 in such a way that the ultrasonic membrane 5 of the ultrasonic sensor 2 is arranged parallel to the molded part 13 behind the aperture section 3 of the molded part 13 . In this case, an air gap 15 that is approximately 0.1 mm thin, for example, is preferably formed between the acoustic metamaterial of the diaphragm section 3 and the ultrasonic membrane 5 of the ultrasonic sensor 2 .

Although thus the molded part 13, the Flalterungen 14 and the housing 4 of the ultrasonic sensor 2, which are each formed from reverberant materials, mechanically coupled mitei nander. However, as was explained with reference to the first exemplary embodiment, the ultrasonic membrane 5 is mechanically separated from the housing 4 of the ultrasonic sensor 2 decoupled. Furthermore, the ultrasonic membrane 2 is also mechanically decoupled from the molded part 13 by the air gap 15 . Since the panel section 3 made of the acoustic metamaterial for ultrasonic waves can also be tunneled through non-resonantly, the influence of structural vibrations of the structure made of molded part 13, flaring 14 and housing 4 on the quality of the measurement signal supplied by the ultrasonic sensor arrangement 1 is greatly reduced.

According to a modification of the third exemplary embodiment, the ultrasonic membrane 5 bears against the diaphragm section 3 or against the acoustic metamaterial 3 (not shown). That is, according to the modification, no air gap 15 is provided. The acoustic impedance of the acoustic metamaterial of the panel section 3 can be matched to the acoustic impedance of the ultrasonic membrane 5 on the side facing the ultrasonic sensor 2 .

According to this modification, no acoustic decoupling, or less good acoustic decoupling, may be achieved between the ultrasonic membrane 5 and the molded part 13 . However, the effect of an amplification of the amplitudes of the measured echo signals brought about by the acoustic metamaterial 3 can be even stronger without the air gap 15 due to better impedance matching. As a result, the signal-to-noise ratio can be improved even further.

According to the modification, damping elements such as damping materials, damping bores or the like can be provided on the shaped part 13 for better acoustic decoupling of the shaped part 13 in an area outside the panel section 3 . Alternatively, it is also possible to mathematically remove coupled-in structural vibrations from the measurement signal of the ultrasonic sensor 2 .

FIG. 4 shows a schematic plan view of a molded part 13 with an aperture section 3. The molded part 13 is made of a reverberant base material. Various prototypes for the molded part 13 were produced from the basic materials aluminum with a thickness of 1 mm, plastic with a thickness of 3 mm and steel with a thickness of 0.9 mm. The prototypes each had an area of 10×10 cm ² . An acoustic metamaterial was formed in the screen section 3 of the molded part 13 by perforating the base material of the molded part 13 in the screen section 3 in a special way. Here, a regular lattice of twenty-one round through-openings 24 was formed. The round through holes 24 each have a diameter of 1 mm. The grid has a hole spacing (distance between each two adjacent openings 24) of 2.5 mm. The diameter of the through-openings 24 and the hole spacing are each significantly smaller than the wavelength of the ultrasonic waves emitted by an ultrasonic sensor 2 (see FIG. 2 or 3), which is typically around 7 mm at room temperature. At the same time, the hole spacing was larger than the opening diameter.

The perforated panel section 3 of the prototype 13 was arranged in front of an ultrasonic membrane 5 (see FIG. 2 or 3) of an ultrasonic sensor 2 and thus in each case an ultrasonic sensor arrangement 1 (see FIG. 1-3, 8 or 11) with a concealed ultrasonic sensor 2 was formed. The ultrasonic membrane 5 was arranged parallel to the panel section 3, with an air gap 15 (see FIG. 3) of 0.1 mm remaining between the panel section 3 and the ultrasonic membrane 5.

All of the named prototypes of the molded part 13 showed the advantageous effects described here. There is thus a high degree of design freedom with regard to the material and thickness of the molded part 13, behind which the ultrasonic sensor 2 can be arranged without the described advantages being lost.

5 - 7, measurement results for a concealed ultrasonic sensor arrangement 1, which is formed from an ultrasonic sensor 2 and the prototype molded part 13 made of 0.9 mm thick steel with the perforated grid comprising twenty-one through openings 24 as described above, are shown below with reference to FIGS compared, which were achieved with the same ultrasonic sensor 2 under the same test conditions, but without the diaphragm section 3 with the acoustic metamaterial. Fig. 5 shows a plot of a measured reflection signal 26, which can also be referred to as an echo signal, with an uncovered ultrasonic sensor, and Fig. 6 shows a plot of a measured reflection signal 26 with the covered ultrasonic sensor arrangement 1. Along the horizontal axis in Fig. 5 and 6 scans of the measurement signal supplied by the respective ultrasonic sensor 1 are plotted; the horizontal axis in FIGS. 5 and 6 can also be interpreted as a time axis. The voltage amplitude of the measurement signal is plotted in volts on the vertical axis in FIGS. 5 and 6 .

In a time range from 0 to 2000, structural vibrations 27 of the ultrasonic sensor 2 are measured, which inevitably occur when emitting an ultrasonic signal despite the mechanical decoupling of the ultrasonic membrane 5's.

After a time of about 8700 samples, the reflection signal 26 is detected. The figures clearly show that the amplitude of the reflection signal 26 in FIG. 6 of the ultrasonic sensor arrangement 1 covered with the acoustic metamaterial is increased by a factor of approximately 10 compared to the amplitude of the reflection signal 26 in FIG. 5 of the uncovered ultrasonic sensor 2 is, with otherwise identical test conditions. Accordingly, the signal-to-noise ratio is improved by a factor of approximately 10.

For this reason, evaluation electronics for analyzing the received ultrasonic signal can be constructed with simpler components that have a lower sensitivity for the same detection threshold value, which is why the evaluation electronics can be designed more simply overall. Alternatively, a higher detection range can be achieved with the same evaluation electronics.

Fig. 7 shows a plot of an angle-dependent transmission directional characteristic of an uncovered ultrasonic sensor 2 and the covered ultrasonic sensor arrangement 1 (see Fig. 1 - 3, 8 or 11) in the same measuring arrangement that is also used for the in Fig. 5 and Fig. 6 shown measurements was used. An angle is plotted in degrees relative to the surface normal of the molding 13 along the horizontal axis in FIG. 7, and a sound pressure level of the transmission signal is plotted in dB along the vertical axis in FIG.

The dashed curve 28 shows the transmission characteristic of the uncovered ultrasonic sensor 2, and the solid curve 29 shows the transmission characteristic of the covered ultrasonic sensor arrangement 1.

As can be seen in FIG. 7, the concealed ultrasonic sensor arrangement 1 with the broadband acoustic metamaterial proves to be advantageous in the entire relevant angle range of approximately −85° to 85°. The sound pressure level is consistently significantly higher than with the uncovered ultrasonic sensor 2.

This shows that the structure of an aperture section 3 described with reference to FIG. 4 leads to the formation of an acoustic metamaterial that can be tunnelled through in a non-resonant manner by both outgoing and incoming ultrasonic waves in a wide angular range.

FIG. 8 shows a schematic view of a parking assistance system 100 according to a fourth exemplary embodiment. The parking assistance system 100 comprises an ultrasonic sensor arrangement 1 arranged on a wall of a building 300, which is designed as described with reference to FIGS. The parking assistance system 100 also includes a protective device 16 arranged above the ultrasonic sensor arrangement 1. The protective device 16 is designed as a roof for the ultrasonic sensor arrangement 1 and provides a protected area 17 . The ultrasonic sensor arrangement 1 is therefore protected from rain 18 by the roof 16 . FIG. 9 shows a schematic view of a parking assistance system 100 according to a fifth exemplary embodiment. In this example, parking assistance system 100 comprises six ultrasonic sensor arrangements 101-106, which are each designed as described with reference to FIGS. 1-4 and achieve the corresponding advantageous effects, and a control device 110, which is set up to activate ultrasonic sensor arrangements 101-106 . The ultrasonic sensor arrangements 101-106 are arranged, for example, on a wall of a building 300, for example a multi-storey car park. The spatial arrangement of the ultrasonic sensor arrangements 101 - 106 is predetermined, which means that, for example, the distances between the ultrasonic sensor arrangements 101 - 106 are known. A lane on which a vehicle 210 is currently located and is moving at a specific speed V runs in the area in front of the wall. The vehicle is initially at a first position A.

In this position A, vehicle 210 is detected by ultrasonic sensor arrangements 101 , 102 and 104 , for example. The ultrasonic sensor arrangement 102 detects, for example, a reflection of the ultrasonic signal 25 emitted by the ultrasonic sensor arrangement 101 (see FIG. 10). The position of vehicle 210 can be inferred by considering the ultrasonic signals received by ultrasonic sensor arrangements 101 , 102 and 104 together. This is done, for example, by means of multilateration. Sensor fusion methods can also be used to evaluate the signals received from the plurality of ultrasonic sensor arrays 101-106.

As the vehicle 210 moves, it moves out of the area directly in front of the ultrasonic sensor assembly 101 and into the area directly in front of the ultrasonic sensor assembly 102 . Assuming a constant speed V of vehicle 210, the speed V of vehicle 210 can be determined from the time it takes vehicle 210 to move from the area in front of first ultrasonic sensor arrangement 101 to the area in front of second ultrasonic sensor arrangement 102 . Alternatively, the speed V can also be determined on the basis of a frequency shift in the reflection signal 25 received by the ultrasonic sensor arrangement 104 . white Afterwards, the length of the vehicle 210 can be inferred from the length of time that the vehicle 210 occupies the area directly in front of the first ultrasonic sensor arrangement 101 and the speed V.

The trajectory TR of the vehicle 210 can also be determined by using a plurality of ultrasonic sensor arrangements 101-106 as shown in FIG. In this example, the vehicle travels from position A along trajectory TR to position B, successively traveling through a respective detection range of the various ultrasonic sensor arrays 101-106. On the basis of the sensor signals detected in the process, control device 110 is set up to determine the state of motion, the trajectory TR, a shape and/or an alignment of vehicle 210 .

FIG. 10 shows a schematic view of a parking assistance system 100 according to a sixth exemplary embodiment. In this example, parking assistance system 100 includes four ultrasonic sensor arrangements 101-104, which are each designed as described with reference to FIGS. 1-4 and achieve the corresponding advantageous effects, and a control device 110, which is set up to activate ultrasonic sensor arrangements 101-104. The ultrasonic sensor arrangements 101-104 are arranged, for example, on a wall of a building 300, for example a garage. The spatial arrangement of the ultrasonic sensor arrays 101-104 is predetermined. This is illustrated in this exemplary embodiment by the coordinate system comprising an x and a y axis. The first ultrasonic sensor arrangement 101 has the coordinates (x1, y1). The second ultrasonic sensor arrangement 102 has the coordinates (x2, y1). The third ultrasonic sensor arrangement 103 has the coordinates (x3, y2). The fourth ultrasonic sensor arrangement 104 has the coordinates (x3, y3).

An object 210, for example a motor vehicle, is located in the environment 200 of the ultrasonic sensor arrangements 101-104. In this example, several signal paths of ultrasonic signals 25 sent out are shown. In order to determine the position, orientation and/or shape of motor vehicle 210 as precisely as possible using the plurality of ultrasonic sensors rarrangements 101 - 104 to be determined, the control device 110 is set up to activate the ultrasonic sensor arrangements 101 - 104 one after the other in accordance with a predetermined sequence in order to emit a respective ultrasonic signal 25 . The sequence specifies, for example, that only a specific subgroup of all ultrasonic sensor arrangements 101-104 are activated at a given point in time. In this example, the first and third ultrasonic sensor arrays 101, 103 form a first group and the second and fourth ultrasonic sensor arrays 102, 104 form a second group.

The reason for this is that the second ultrasonic sensor arrangement 102 receives a reflection signal 25 of the ultrasonic signal 25 emitted by the first ultrasonic sensor arrangement 101 depending on the position, shape and/or alignment of the motor vehicle 210 . The same applies in reverse. The same also applies to the third and fourth ultrasonic sensor arrangement 103, 104. Due to the alternating activation, an advantageous signal that is received in each case can be unambiguously assigned to the transmitting ultrasonic sensor arrangement. Additional information that is helpful for multilateration is thus recorded.

In this example, the points P1-P4 of the motor vehicle 210 can be determined, for example. The shape, the orientation and the position of the motor vehicle 210 are thus already determined with the exception of a few degrees of freedom. In a next measurement interval (not shown), the second and fourth ultrasonic sensor arrays 102, 104 each emit an ultra-sound signal 25, with the first and third ultrasonic sensor arrays 101, 103 only listening passively. After the second measurement interval, the shape, orientation, and position of motor vehicle 210 may be further restricted.

FIG. 11 shows a schematic view of a parking assistance system 100 according to a seventh exemplary embodiment. In this example, parking assistance system 100 includes an ultrasonic sensor arrangement 1, which is designed as described with reference to FIGS. The ultrasonic sensor Order 1 is arranged, for example, on a wall of a building 300, for example a garage.

In the surroundings 200 of the ultrasonic sensor arrangement 1 there is an object 210 which in this example is a car with its own ultrasonic sensor arrangement 211 . The ultrasonic sensor arrangement 211 of the car emits an ultrasonic signal 212, for example. The ultrasonic sensor arrangement 1 of the parking assistance system 100 receives the ultrasonic signal 212. The control device 110 determines that the received ultrasonic signal 212 is that of the car 210. In response to this, the control device 110 causes the ultrasonic sensor arrangement 1 to emit its own ultrasonic signal 25 after a predetermined time interval after the receipt of the ultrasonic signal 212, which can be detected by the ultrasonic sensor arrangement 211 of the vehicle. For example, the car 210 can determine a distance from the ultrasonic sensor arrangement 1 of the parking assistance system 100 on the basis of the predetermined time interval and the transit time of the ultrasonic signal 25 .

The ultrasonic signal 25 preferably includes coded information, such as a position of the ultrasonic sensor arrangement 1. The coded information can be transmitted by the ultrasonic signal 25 using a modulation method, for example. The car 210 can orientate itself using the correspondingly transmitted information.

Although the present invention has been described using exemplary embodiments, it can be modified in many ways. REFERENCE LIST

1 ultrasonic sensor assembly

2 ultrasonic sensor

3 aperture section

4 housing

5 ultrasonic membrane

6 decoupling ring

7 sound transducer element, piezo element

8 decoupling wire

9 contact pin

10 contact pin

11 circuit board

12 electronic components

13 molding

14 mounts

15 air gap

16 protection device

17 protected area

18 rain

24 through holes

25 ultrasonic signal

26 reflection signal

27 structural vibrations

28 Transmission directional characteristics of an uncovered ultrasonic sensor

29 Transmission directional characteristic of the concealed ultrasonic sensor arrangement

100 parking assistance system

101 ultrasonic sensor array

102 ultrasonic sensor array

103 ultrasonic sensor array 104 ultrasonic sensor array

105 ultrasonic sensor array

106 ultrasonic sensor arrangement 110 control device 200 environment

210 object 211 ultrasonic sensor array 212 ultrasonic signal 300 building

A location

B position

P1 position

P2 position P3 position P4 position V movement x coordinate axis x1 coordinate x2 coordinate x3 coordinate y coordinate axis yi coordinate y2 coordinate y3 coordinate

Claims

PATENT CLAIMS

1. Parking assistance system (100), comprising: at least one stationary ultrasonic sensor arrangement (1, 101 - 106), where the ultrasonic sensor arrangement (1, 101 - 106) has an ultrasonic sensor (2) with a housing (4), one of the housing (4) mechanically decoupled ultrasonic membrane (5), a sound transducer element (7) for exciting and detecting vibrations in the ultrasonic membrane (5) and a panel section (3) made of an acoustic metamaterial arranged in front of the ultrasonic membrane (5), and one with the ultrasonic sensor arrangement (1, 101 - 106) coupled control device (110), which is set up to control the ultrasonic sensor arrangement (1, 101 - 106) to emit and/or receive an ultrasonic signal (25).

2. Parking assistance system according to claim 1, wherein the acoustic meta-material of the ultrasonic sensor arrangement (1, 101-106) is a broadband acoustic meta-material through which ultrasonic waves can be tunneled non-resonantly at least in an angle of incidence range.

3. Parking assistance system according to one of the preceding claims, wherein the acoustic meta-material of the ultrasonic sensor arrangement (1, 101-106) is formed from a reverberant base material in which a grid of a plurality of through-openings (24) is formed.

4. Parking assistance system according to claim 3, wherein a diameter of a respective through-opening (24) is smaller than a wavelength of the wavelength of the ultrasonic membrane (5) to be emitted and received by ultrasonic waves.

5. Parking assistance system according to claim 4, wherein a distance between two adjacent through-openings (24) of the grating is greater than the diameter of the through-openings (24) and smaller than the wavelength of the ultrasonic membrane (5) to be emitted and received.

6. Parking assistance system according to one of claims 1 to 5, wherein the ultrasonic sensor arrangement (1, 101 - 106) further comprises: a molded part (13) to which the ultrasonic sensor (2) is attached in such a way that the ultrasonic membrane (5) the molded part (13) faces, and the molded part (13) in a section in front of the ultrasonic membrane (5) comprises the aperture section (13) made of the acoustic metamaterial.

7. Parking assistance system according to claim 6, wherein the ultrasonic sensor (2) of the ultrasonic sensor arrangement (1, 101 - 106) is attached to the molded part (13) in that an outer wall of the housing (4) of the ultrasonic sensor (2) is provided with a holder ( 14) and the holder (14) is attached to the molded part (13) in a region outside the panel section (3), with a surface of the ultrasonic membrane (5) parallel to the molded part (13) behind the panel section (3) of the molded part (13) is arranged.

8. Parking assistance system according to one of claims 1 to 7, wherein the ultrasonic membrane (5) of the ultrasonic sensor arrangement (1, 101 - 106) rests on the panel section (3).

9. Parking assistance system according to one of claims 1 to 8, wherein the ultrasonic membrane (5) of the ultrasonic sensor arrangement (1, 101-106) and the aperture section (3) are mechanically decoupled from one another.

10. Parking assistance system according to one of claims 1 to 9, a protective device (16) being provided which is stationarily arranged together with the ultrasonic sensor arrangement (1, 101 - 106) and which is set up to shield the ultrasonic sensor arrangement (1, 101 - 106) from external influences (18).

11. Parking assistance system according to one of claims 1 to 10, wherein the control device (110) is further set up to detect an object (210 ) in the area (200) of the ultrasonic sensor arrangement (1, 101 - 106) to determine.

12. Parking assistance system according to claim 11, wherein the control device (110) is further set up to based on a Doppler frequency shift of the received ultrasonic signal (25, 26) and / or based on at least two ultrasonic signals received at different times ( 25, 26) to determine a state of motion of the determined object (210).

13. Parking assistance system according to one of claims 1 to 12, wherein the parking assistance system (100) comprises a plurality of ultrasonic sensor arrangements (1, 101 - 106) which are stationary angeord net in a predetermined spatial arrangement, the control device (110) for determining a Position and/or an alignment and/or a shape of an object (210) arranged in the vicinity (200) of the ultrasonic sensor arrangements (1, 101 - 106) depending on at least two of different ultrasonic sensor arrangements (1, 101 - 106) of the Multiple received ultrasonic signals (25, 26) and the predetermined spatial arrangement of the ultrasonic sensor arrays (1, 101 - 106) is set up.

14. Parking assistance system according to one of claims 1 to 13, wherein the parking assistance system (100) is further set up to receive an ultrasonic signal (212) emitted by an ultrasonic sensor arrangement (211) of a vehicle (210), and wherein the control device ( 110) is set up to respond to the received ultrasonic signal (212) to control the ultrasonic sensor arrangement (1, 101 - 106) for emitting a further ultrasonic signal (25) with predetermined properties depending on the received ultrasonic signal (212).

15. Building (300), in particular parking garage, with at least one parking space for a

Motor vehicle and having a parking assistance system (100) according to one of Claims 1 to 14.