DE102022004032A1 - Locating method, locating device and application of a locating method for locating a sound source directed at a vehicle - Google Patents

Abstract

The invention relates to a locating method for locating at least one sound source (2) directed at a vehicle (1) by means of a sensor device (10) arranged on the vehicle (1), comprising a reference sensor (10r) and at least one relative to the reference sensor (10r). a sound pressure sensor (10x, 10y, 10z) offset by an offset (Δx, Δy, Δz). An acoustic model (120) is determined by acoustic simulation. Sound emitted by the sound source (2) is received by the sound pressure sensors (10r, 10x, 10y, 10z) and converted into a sound signal (s _r (t), s _x (t), s _y (t), s _z (t )) converted. For each of the sound pressure sensors (10x, 10y, 10z) offset from the reference sensor (10r), the sound signals (s _r (t), s _x (t), s _y (t), s _z (t)) and/or or their _Fourier transforms each have _a transit time difference ( _Δt (10x, 10y, 10z). Using the acoustic model (120), at least one sound corridor (g, g _' , g _' ') and/or a position (p) of the sound source (2) is assigned to the at least one transit time difference (Δt x _, Δt y, Δt z) relative to assigned to the vehicle (1).
The invention further relates to the application of such a locating method and a locating device which is set up to carry out such a locating method.

Description

The invention relates to a locating method according to the preamble of claim 1, the application of such a locating method and a locating device according to the preamble of claim 8.

Non-lethal acoustic weapons impose energy and power on a target via acoustic waves, usually emitted in the low-frequency infrasound frequency range. In addition to the auditory effect, such sound attacks can limit the ability to act due to disorientation and general confusion. Vehicles do not offer effective protection against such attacks. Evasive and countermeasures are made more difficult because acoustic perception means that a subjective location of a low-frequency sound source is not possible or is only possible very imprecisely. Therefore, in order to defend against attack scenarios in which acoustic weapons are directed against a vehicle, there is a need for a method and a device for locating these weapons.

The patent specification DE 11 2017 007 495 B4 describes an object detection device that includes a receiving unit, a disturbance assessment unit and an object detection unit. The receiving unit is set up to receive signals detected with a receiving device provided in a mobile body. The signals include a reflected wave that is generated by reflecting an acoustic signal emitted by the mobile body on an object.

The disruption assessment unit is set up to detect a disruption attack. A jamming attack is recognized by whether a degree of fluctuation of an envelope of the signals received by the receiving unit is less than or equal to a reference value.

The object detection unit is set up to detect an object in the surroundings of the mobile body in the event that the interference assessment unit judges that there is no interference attack.

The invention is based on the object of specifying an improved locating method for locating a sound source directed at a vehicle. This object is achieved according to the invention using a locating method with the features of claim 1.

The invention is also based on the object of specifying an application for an improved locating method for locating a sound source directed at a vehicle. This object is achieved according to the invention with an application having the features of claim 8.

The invention is also based on the object of specifying an improved locating device for locating a directed sound source. This object is achieved according to the invention with a locating device with the features of claim 9.

Advantageous embodiments of the invention are the subject of the subclaims.

In a first aspect of the invention, in a locating method for locating at least one sound source directed at a vehicle by means of a sensor device arranged on the vehicle, which comprises a sound pressure sensor designed as a reference sensor and at least one further sound pressure sensor, each offset by an offset relative to the reference sensor, according to the invention in In a first step, an acoustic model is determined through acoustic simulation.

The acoustic model assigns at least one sound corridor and/or a position to at least one transit time difference at which a potential sound source that triggers this transit time difference can be located. A transit time difference is assigned to an offset sound pressure sensor and detects the difference in the transit time of an acoustic wave from a position in the environment of the vehicle to the assigned offset sound pressure sensor, compared with the transit time of an acoustic wave from the same position to the sound pressure sensor designed as a reference sensor. Here and in the following, a sound corridor is understood to mean the set of all positions that cannot be distinguished based on the transit time differences. In other words: when a sound source moves within such a sound corridor, the transit time differences recorded by the offset sound pressure sensors remain unchanged.

In a further step, sound that is emitted by a sound source in the vicinity of the vehicle is received by each of the sound pressure sensors, i.e. both by the reference sensor and by the sound pressure sensors arranged offset from it, and converted into a sound signal.

Based on these sound signals, a transit time difference is determined for at least one of the offset sound pressure sensors, which represents the difference between the transit time of the sound and the sound source to the respective offset sound pressure sensor, compared with the transit time of the sound from the sound source to the reference sensor.

The transit time difference can be determined by direct comparison of the respective sound signals in the time domain, for example by determining a cross-correlation signal that detects the delay-dependent cross-correlation between the sound signal of the offset sound pressure sensor and the reference sensor and determining the delay at which the cross-correlation signal reaches a maximum.

A cross-correlation signal can also be determined indirectly using the Fourier transform of the respective sound signals and subsequent transformation back into the time domain.

Alternatively, the transit time difference can also be determined by comparing the phase position of components of the Fourier transform of the sound signals in which the energy density is maximum and/or exceeds a threshold value.

At least one sound corridor and/or a position of the sound source relative to the vehicle is assigned to the at least one transit time difference formed in this way based on the acoustic model.

An advantage of the method according to the invention is that attacks from sound sources that cannot be localized subjectively or only unreliably and inaccurately due to their intensity and/or their frequency characteristics, in particular attacks from low-frequency sound sources emitting in the infrasound frequency range, can be located. Location is also understood to mean a significant restriction on the variety of possible locations from which such an attack could have occurred, without the precise determination of a single location of the attack being absolutely necessary.

This allows vehicle occupants to be warned of such an attack and take countermeasures.

In one embodiment of the locating method, standardized transit time differences are determined and used instead of absolute (that is, stated in physical time units) transit time differences. A standardized transit time difference is determined by relating an absolute transit time difference for the respective offset sound pressure sensor to the propagation time with which an acoustic wave propagates along the respective offset from the offset sound pressure sensor to the reference sensor.

Standardized transit time differences range from -1 to +1. A standardized transit time difference of -1 is determined when a sound signal moves towards the sound pressure sensor along the line drawn from the reference sensor to the offset sound pressure sensor. A standardized transit time difference of +1 is determined when a sound signal moves towards the reference sensor along the line drawn from the reference sensor to the offset sound pressure sensor. If the sound signal propagates obliquely to the line that is spanned by the reference sensor to the offset sound pressure sensor, a standardized transit time difference of greater than -1 and less than +1 is determined. If the sound signal propagates perpendicular to this line, a standardized transit time difference of zero is determined.

By using normalized transit time differences, the acoustic model can be simplified and generalized because it is independent of the physical dimensions of the sound pressure sensor arrangement.

In one embodiment of the locating method, a first and a second sound corridor for the sound source are determined based on a transit time difference or on the basis of a standardized transit time difference. An advantage of this embodiment is that, in addition to the reference sensor, only one additional offset sound pressure sensor is required. As a result, the method can be simplified and implemented with a sensor device that is particularly simple and inexpensive.

In one embodiment of the locating method, a sound corridor for the sound source is determined based on two transit time differences or on the basis of two standardized transit time differences, each of which is assigned to one of at least two sound pressure sensors offset in different directions relative to the reference sensor. An advantage of this embodiment is that in addition to the reference sensor, only two additional offset sound pressure sensors are required. As a result, the method can be simplified and implemented with a sensor device that is particularly simple and inexpensive. Another advantage is that with the sound corridor determined in this way, the direction from which a sound attack occurs is clearly determined. This allows more precise countermeasures to be taken.

In one embodiment of the locating method, three transit time differences or three standardized transit time differences are used, each of which is one of at least three relative to the reference sensor in different directions offset sound pressure sensors are assigned, a position for the sound source is determined. An advantage of this embodiment is that the position of the sound source in the three-dimensional space of the vehicle environment is clearly determined. This allows precise countermeasures to be taken.

In one embodiment of the location method, the acoustic model is at least partially formed by a multilayer artificial neural network that includes an input layer, an output layer and at least one hidden layer arranged therebetween. The artificial neural network is trained using a supervised learning method, with sound signals and/or parameters derived therefrom being presented in the input layer and parameters of the position and/or the at least one sound corridor, which is assigned to the acoustically simulated sound source, being presented in the output layer are.

A parameter-free acoustic model can be created using an artificial neural network. This is particularly advantageous if a mathematical model for sound propagation in the vehicle environment is not known or is very complex.

In one embodiment, further acoustically effective parameters of a vehicle environment can be presented in the input layer, for example air temperature, air pressure and/or air humidity. This improves the accuracy of the acoustic model and thus also the accuracy of locating a sound source.

In one embodiment, the acoustic model is at least partially designed as a lookup table, with each row of the lookup table assigning a position and/or at least one sound corridor of the sound source to a tuple with at least one transit time difference and/or at least one standardized transit time difference.

A lookup table enables a particularly simple and quick assignment of positions or sound corridors to transit time differences that were determined based on the sound signals. Furthermore, a lookup table enables a parameter-free acoustic model and is advantageous if a mathematical model for sound propagation in the vehicle environment is not known or is very complex.

In one embodiment, transit time differences that are not recorded in a lookup table can be assigned to similar transit time differences, positions and/or sound corridors recorded in the lookup table by interpolation. This limits the effort and storage space required to create a lookup table and ensures a sufficiently high level of accuracy when locating.

In a second aspect, the invention relates to the application of a location method according to the first aspect of the invention. During the application, the sound power recorded by the sound pressure sensors is determined. If this sound power exceeds a warning threshold, the at least one sound corridor and/or the position of a potential attacker is determined using the location method according to the first aspect of the invention. A warning is issued via the vehicle's visual display means. The advantages of the application correspond to the advantages of the location method in that an accurate and improved response to a sound attack is enabled.

In one embodiment, an escape route is determined that bypasses the at least one sound corridor and/or the position of the potential attacker. This means that a sonic attack and any further attacks that may be planned afterwards can be avoided quickly and safely.

In a third aspect, the invention relates to a locating device for locating a directed sound source, comprising a sensor device and a computing and signal processing unit. The sensor device comprises a sound pressure sensor designed as a reference sensor and at least one further sound pressure sensor, each offset from the reference sensor. The computing and signal processing unit is set up to carry out a location method according to the first aspect of the invention. For example, the computing and signal processing unit can be designed as a microcontroller and/or as a digital signal processor. The advantages of the locating device correspond to the advantages of the locating method according to the first aspect of the invention.

• - ein erster versetzter Schalldrucksensor gegenüber dem Referenzsensor um einen Versatz entlang einer x-Richtung versetzt angeordnet,
• - ein zweiter versetzter Schalldrucksensor gegenüber dem Referenzsensor um einen Versatz entlang einer y-Richtung versetzt angeordnet, wobei die y-Richtung senkrecht gegenüber der x-Richtung angeordnet ist und
• - ein dritter versetzter Schalldrucksensor gegenüber dem Referenzsensor um einen Versatz entlang einer z-Richtung versetzt angeordnet, wobei die z-Richtung senkrecht gegenüber der x-Richtung und senkrecht gegenüber der y-Richtung angeordnet ist.

In one embodiment, a locating device is

• - a first offset sound pressure sensor arranged offset from the reference sensor by an offset along an x-direction,
• - A second offset sound pressure sensor is arranged offset from the reference sensor by an offset along a y-direction net, where the y-direction is arranged perpendicular to the x-direction and
• - A third offset sound pressure sensor is arranged offset from the reference sensor by an offset along a z-direction, the z-direction being arranged perpendicular to the x-direction and perpendicular to the y-direction.

The computing and signal processing unit is set up to determine at least one sound corridor and/or a position of a sound source based on the transit time differences assigned to the first, the second and the third offset sound pressure sensor.

One advantage of this embodiment is, on the one hand, that with the proposed three offset sound pressure sensors and the reference sensor, it is possible to clearly determine the position of the sound source in the three-dimensional space of the vehicle environment. On the other hand, there is an advantage in that a particularly precise and reliable location of the sound source is possible due to the mutually perpendicular spacing of the offset sound pressure sensors relative to the reference sensor.

Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

• 1 schematisch ein von einer Schallkanone angegriffenes Fahrzeug,
• 2 schematisch von Schalldrucksensoren erfasste Schallsignale,
• 3 schematisch die Bestimmung eines Laufzeitunterschieds mittels eines aus zwei Schallsignalen berechneten Kreuzkorrelationssignals,
• 4 schematisch ein Verfahren zur Bestimmung eines akustischen Modells,
• 5 schematisch ein künstliches Neuronales Netz zur Bestimmung der Position einer Schallquelle,
• 6 schematisch ein Verfahren zur Bestimmung von Laufzeitunterschieden zwischen von verschiedenen Schalldrucksensoren erfassten Schallsignalen sowie
• 7 bis 9 schematisch Verzögerungs-Diagramme zur Darstellung normierter Laufzeitverzögerungen in Abhängigkeit vom Abstand einer Schallquelle von einem Fahrzeug.

Show:

• 1 schematically a vehicle attacked by a sound cannon,
• 2 schematic sound signals recorded by sound pressure sensors,
• 3 schematically the determination of a transit time difference using a cross-correlation signal calculated from two sound signals,
• 4 schematically a method for determining an acoustic model,
• 5 schematically an artificial neural network for determining the position of a sound source,
• 6 schematically a method for determining transit time differences between sound signals detected by different sound pressure sensors and
• 7 until 9 Schematic delay diagrams to show standardized transit time delays depending on the distance of a sound source from a vehicle.

Corresponding parts are provided with the same reference numbers in all figures.

1 shows schematically a vehicle 1 and a sound source 2 in its surroundings. In one in 1 In the attack scenario shown, the sound source 2 represents an attacker 2 who tries to impose energy on the vehicle 1 and its occupants via acoustic waves by directed emission of sound energy, preferably in the low-frequency infrasound frequency range. This sound energy primarily affects auditory perception, but also the associated sense of balance, leading to disorientation, general confusion and, accordingly, limited ability to act.

Long Range Acoustic Devices (LRAD) are known from the prior art, which emit a sound pressure level of approximately 150 decibels at a radiation solid angle of approximately 15 degrees to 30 degrees in the frequency range from approximately 2000 Hertz to 3100 Hertz.

The use of such devices as non-lethal weapons is known. By way of example, an attacker 2 can be designed as an LRAD, also referred to below as a sound cannon 2. The sound cannon 2 emits an acoustic sound pressure field which propagates in a sound funnel 3 along a sound propagation direction 20 towards the vehicle 1. The range of a sound cannon 2 can be several kilometers.

In particular, the vehicle interior does not offer sufficient protection against low-frequency excitation in the infrasound frequency range and therefore represents an attack vector that is interesting for kidnapping scenarios. The aim of the invention is to preserve the ability of vehicle occupants to act in the event of such an attack and to restore it as quickly as possible by detecting such attacks and located as precisely as possible.

A sensor device 10, shown only schematically, is arranged on the vehicle 1 and comprises four sound pressure sensors 10r, 10x, 10y and 10z. Starting from a reference sensor 10r, an offset sound pressure sensor 10x, 10y, 10z is arranged along an x-direction x, along a y-direction y or along a z-direction z at an offset Δx, Δy, Δz. In the present case, the x-direction x, the y-direction y and the z-direction z are selected perpendicular to one another. However, it is sufficient if the directions x, y, z are chosen to be linearly independent.

In the in 1 In the situation shown, the sound pressure sensor 10y, which is offset in the y direction y from the reference sensor 10r, is closest to the sound cannon 2 and has a distance dy from it that the sound has to pass through. The ones in x- In contrast, sound pressure sensors 10x, 10z offset in the x direction and z in the z direction have larger distances dx, dy. The reference sensor 10r is located furthest from the emission point of the sound cannon 2 at a distance dr. Sound emitted by the sound cannon 2 hits the sound pressure sensors 10r, 10x, 10y, 10z with different time delays, corresponding to the different distances dr, dx, dy, dz.

Of course, the distance conditions can change in the event of a different attack situation or due to a movement of the vehicle 1 compared to the one in 1 change the situation presented. In any case, however, a position p of the sound cannon 2 can be determined relative to the coordinate system spanned by the linearly independent directions x, y, z.

The invention is based on the knowledge that the sound propagation direction 20 and the position p of the sound cannon 2 can be determined from the delay or advance of the sound pressure compared to the sound pressure detected by the reference sensor 10r with a known arrangement geometry of the sound pressure sensors 10x, 10y, 10z.

2 shows schematically the sound signals s _r (t), s _x (t), s _y (t), s _z (t) detected by the sound pressure sensors 10r to 10z, assuming that the sound cannon 2 emits a sound burst 4. The sound burst 4 is determined by a narrow-band energy distribution, that is: around a main or center frequency, energy is emitted in a frequency band that is narrow compared to the main frequency, for example only one tenth of the main frequency wide.

The sound burst 4 arrives at the reference sensor 10r at a time t _r . Since the other sound pressure sensors 10x, 10y, 10z according to in 1 If the situation outlined is closer to the sound cannon 2 than the reference sensor 10r, the sound burst 4 arrives there at earlier times t _x , t _y , t _z . In other _{words : The} sound signals _s each offset by a transit time difference Δt _x , Δt _y , Δt _z .

oder alternativ für zeitdiskrete Schallsignale s_r(n), s_y(n) mit $$r_{x,y}\left(l\right)={\displaystyle \sum _{n=-\infty }^{\infty }{s}_r\left(n\right)\cdot s_y\left(n\mp l\right)}$$

bestimmt werden kann. _{Such a transit time difference Δt _} ) is determined on another sound pressure sensor 10x, 10y, 10z. 3 shows, by way of example and schematically, a cross-correlation signal r _r,y (τ) between the sound signal s _r (t) at the reference sensor 10r and the sound signal s _y (t) at the sound pressure sensor 10y offset in the y direction y by the offset Δy, whereby the of the delay τ dependent cross-correlation signal r _r,y (τ) for time-continuous sound signals s _r (t), _sy (t). $$r_{r,y}\left(\tau \right)={\displaystyle {\int }_{-\infty }^{\infty }{s}_r\left(t\right)\cdot s_y\left(t\mp \tau \right)}dt$$

or alternatively for discrete-time sound signals s _r (n), s _y (n) with $$r_{x,y}\left(l\right)={\displaystyle \sum _{n=-\infty }^{\infty }{s}_r\left(n\right)\cdot s_y\left(n\mp l\right)}$$

can be determined.

The transit time difference Δt _y is determined as the delay τ at which the cross-correlation signal r _r,y (τ) is maximum. This transit time difference Δt _y is caused by the difference between the longer distance dr of the reference sensor 10r and the shorter distance dy of the sound pressure sensor 10y from the sound cannon 2, which is in the right part of 3 is shown again schematically.

vorteilhaft, wie er nachfolgend in den 7 bis 9 näher dargestellt ist: $$\begin{array}{ccc}\mathrm{\Delta }{t}_x^{\prime }=\frac{\mathrm{\Delta }{t}_x}{\mathrm{\Delta }x\cdot c_{Luft}},& \mathrm{\Delta }{t}_y^{\prime }=\frac{\mathrm{\Delta }{t}_y}{\mathrm{\Delta }y\cdot c_{Luft}},& \mathrm{\Delta }{t}_z^{\prime }=\frac{\mathrm{\Delta }{t}_z}{\mathrm{\Delta }z\cdot c_{Luft}}\end{array}$$

wobei c_Luft die Schallgeschwindigkeit in Luft bezeichnet. Ein Vorteil der Verwendung normierter Laufzeitunterschiede $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_z^{\prime }$

besteht darin, dass diese wegen |Δt_x,y,z | ≤ Δy · c_Luft unabhängig von der physikalischen Anordnung auf den Bereich $-1\le \mathrm{\Delta }{t}_{x,y,z}^{\prime }\le$

+1 beschränkt sind und dadurch insbesondere für Verfahren der nichtparametrischen Modellierung leichter einsetzbar sind.The transit time difference Δt _x,y,z of a sound signal s _x (t), s _y (t), s _z (t) detected at the sound pressure sensor 10x, 10y, 10z compared to the sound signal s _r (t), which is detected by the reference sensor 10r , is limited by the sound propagation time (in air) along the respective offset Δ _x , Δ _y , Δ _z . Therefore, the specification of a standardized transit time difference is necessary $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

advantageous, as explained below in the 7 to 9 is shown in more detail: $$\begin{array}{ccc}\mathrm{\Delta }{t}_x^{\prime }=\frac{\mathrm{\Delta }{t}_x}{\mathrm{\Delta }x\cdot c_{Luft}},& \mathrm{\Delta }{t}_y^{\prime }=\frac{\mathrm{\Delta }{t}_y}{\mathrm{\Delta }y\cdot c_{Luft}},& \mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }=\frac{\mathrm{\Delta }{t}_{\mathrm{e.g}}}{\mathrm{\Delta }\mathrm{e.g}\cdot c_{Luft}}\end{array}$$

where c _air denotes the speed of sound in air. An advantage of using standardized delay differences $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

is that this is due to |Δt _x,y,z | ≤ Δy · c _air regardless of the physical arrangement on the area $-1\le \mathrm{\Delta }{t}_{x,y,\mathrm{e.g}}^{\prime }\le$

+1 are limited and are therefore easier to use, especially for non-parametric modeling methods.

4 schematically shows a flowchart for a method for determining an acoustic model 120 for locating a sound attack. In a step 100, vehicle data and positions for sound pressure sensors 10r to 10z are determined. In particular, the x-direction x, the y-direction y, the z-direction z and the direction-related offsets Δ _x , Δ _y , Δ _z are determined for the arrangement of the sound pressure sensors 10x, 10y, 10z relative to the reference sensor 10r. Furthermore, it will prove to be advantageous to set the directions x, y, z to one parent, in 1 Vehicle coordinate system not shown in detail.

zugeordnet werden.In a subsequent step 101, an acoustic simulation is carried out based on these parameters. A simulated sound source 2 can be moved to different positions p in the surroundings of the vehicle 1 and/or aligned with different sound propagation directions 20. For each of these positions p and sound propagation directions 20, a transit time difference Δt _x , Δt _y , Δt _z can be determined for each of the sound pressure sensors 10x to 10z based on the reference sensor 10r by calculating the acoustic wave propagation. For example, the environment of the vehicle 1 can be divided into discrete, preferably equally sized and equidistantly arranged voxels and each voxel can have a triple of transit time differences Δt _x , Δt _y , Δt _z and/or standardized transit time differences $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

be assigned.

darstellbar ist, wobei die Werte $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_z^{\prime }$

die anhand der erfassten Schallsignale s_r(t), s_x(t), s_y(t), s_z(t) ermittelten Laufzeitunterschiede bezeichnen und wobei der Funktionswert von $F\left(\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_z^{\prime }\right)$

eine Position p der zugeordneten Schallquelle 2 angibt, beispielsweise als x, y und z Koordinaten entlang der x-, y- beziehungsweise z-Richtung x, y, z. Zusätzlich kann die Funktion $F\left(\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_z^{\prime }\right)$

auch weitere Parameter erfassen, die die Ausbreitung von akustischen Wellen beeinflussen, beispielsweise die Temperatur und/oder die Feuchtigkeit der Luft.In a subsequent step 110, an acoustic model 120 is generated. Based on an assignment rule determined by the acoustic simulation for mapping location coordinates along the directions x, y, z, which are given, for example, as discrete voxels, to transit time differences Δt _x , Δt _y , Δt _z, a model approximation can be determined. For example, in a step 111 a model approximation can be determined by a regression analysis, which is used as a function $F\left(\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }\right)$

can be represented, where the values $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

denote the transit time differences determined based on the recorded sound signals s _r (t), s _x (t), s _y (t), s _z (t) and where the function value of $F\left(\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }\right)$

indicates a position p of the associated sound source 2, for example as x, y and z coordinates along the x, y and z directions x, y, z. In addition, the function can $F\left(\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }\right)$

also record other parameters that influence the propagation of acoustic waves, for example the temperature and/or humidity of the air.

Using such a function, a compact mathematical representation can be developed that only has a small number of parameters and can therefore be implemented in a memory-efficient manner.

gegebenen Stützstellen jeweils eine Position p einer Schallquelle 2 zu, die derartige Laufzeitunterschiede $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_z^{\prime }$

bewirkt. Naturgemäß können nicht alle physikalisch möglichen Laufzeitunterschiede $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_z^{\prime }$

erfasst werden, jedoch kann bei ausreichend enger Erfassung mit guter Genauigkeit zwischen den in der Lookup - Tabelle erfassten Stützstellen interpoliert werden.Alternatively or additionally, a lookup table can be developed in a step 112, which tabulates an inverse function to the assignment rule determined from the acoustic simulation. Such a lookup table organizes in a tabular form a tuple of standardized runtime differences $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

Given support points each assign a position p of a sound source 2, which has such transit time differences $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

effects. Naturally, not all physically possible transit time differences can occur $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

can be captured, however, if the capture is sufficiently narrow, it is possible to interpolate with good accuracy between the support points captured in the lookup table.

The advantage of using a lookup table is that even very complex mathematical relationships for the inverse function can be easily recorded and optional interpolation can be calculated by looking up the lookup table.

The determination of a lookup table can also be combined with the determination of a model approximation through regression analysis, for example by creating a mathematically easy to formulate model for a certain range of transit time differences Δt _x , Δt _y , Δt _z and for another range of transit time differences Δt _x , Δt _y , Δt _z a mathematically complex model is bypassed by forming a lookup table.

Alternatively or in addition to steps 111 and 112, an artificial neural network 115 can be trained in a step 113, which is in 5 is shown schematically.

The artificial neural network 115 includes an input layer 116 with at least four input neurons, each of which is fed with a sound signal s _r (t), s _x (t), _sy (t), s _z (t). The input layer 116 may include additional input neurons that are fed with parameters that influence acoustic propagation, for example an ambient temperature, an air pressure and/or a humidity.

Furthermore, the artificial neural network 115 includes an output layer 117, the output neurons of which encode the position p of a sound source 2. For example, three output neurons can be provided, each of which encodes a coordinate value related to a direction x, y, z.

The artificial neural network 115 can be adapted to the acoustic simulation via a method of supervised learning in such a way that for certain parameters and signals that result from the acoustic simulation are fed into the input layer 116 and correspond to a predetermined position p of an acoustic source , exactly this predetermined position p is output again at the output layer 117.

An artificial neural network 115 trained in this way can therefore be used directly as an acoustic model 120 can be used to locate a sound source 2.

eingespeist werden. Dabei ist das Training des künstlichen Neuronalen Netzes 115 an die übergeordnete Verarbeitungskette anzupassen, indem zum Training die gemäß dieser Verarbeitungskette einzuspeisenden Eingangswerte verwendet werden.However, it is also possible to use an artificial neural network 115 as an element of a higher-level processing chain. For example, instead of the four sound signals s _r (t), s _x (t), s _y (t), s _z (t) in the input layer 116, the sound signals s _r (t), s _x (t), s _y (t), s _z (t) determined transit time differences Δt _x , Δt _y , Δt _z (or, preferably, the corresponding standardized transit time differences $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

be fed in. The training of the artificial neural network 115 must be adapted to the higher-level processing chain by using the input values to be fed in according to this processing chain for training.

The acoustic model 120 determined in this way thus allows the assignment of a position p of a sound source 2 to transit time differences Δt _x , Δt _y , Δt _z , which consist of sound signals s _r (t), s _x (t), _sy ( _t ), s _z ( _t ) were determined, which were detected by the sound pressure sensors 10r to 10z.

6 shows schematically a flowchart for a method for determining the position p of a sound source 2 relative to the sensor device 10 with the reference sensor 10r and the further sound pressure sensors 10x, 10y, 10z. The method includes steps 200 to 203, which are carried out in parallel for the sound pressure sensors 10x, 10y, 10z along a signal processing path SPx, SPy, SPz.

In step 200, the sound pressure detected by the respective sound pressure sensor 10x, 10y, 10z is detected as a sound signal s _r (t), s _x (t), s _y (t), s _z (t). The sound signal s _r (t), s _x (t), _sy (t), s _z (t) is preferably sampled as a digital signal. In the subsequent step 201, the respective transit time difference Δt _x , Δt _y , Δt _z is determined compared to the sound signal s _r (t) detected at the reference sensor 10r. For this purpose, various process variants, which are summarized in step 210, can be used alternatively or additionally.

For example, as shown by 3 has already been explained as an example for the sound pressure signal _sy (t), in a step 211 a cross-correlation signal _{r r,x} (τ), r _r,y (τ), r _r,z (τ) is calculated and in a subsequent step 212 whose maximum value is sought. The value of the delay τ at which the cross-correlation signal r _r,x (τ), r _r,y (τ), r _r,z (τ) reaches a maximum indicates the respective transit time difference Δt _x , Δt _y , Δt _z . If the sound source 2 (in the case of an attack, for example a sound cannon 2) is closer to the sound pressure sensor 10x, 10y, 10z than to the reference sensor 10r, the respectively assigned transit time difference Δt _x , Δt _y , Δt _z is positive, that is: a high cross-correlation becomes achieved by delaying the sound signal s _x (t), _sy (t), s _z (t). If, on the other hand, the sound source 2 (in the event of an attack, for example a sound cannon 2) is closer to the reference sensor 10r than to the sound pressure sensor 10x, 10y, 10z, the respectively assigned transit time difference Δt _x , Δt _y , Δt _z is negative, that is: a high cross-correlation is achieved by delaying the sound signal s _r (t).

As an alternative to such a determination in the time domain, a transit time difference Δt _x , Δt _y , Δt _z can also be determined in the frequency domain. For this purpose, the Fourier transform of the respective sound signal s _x (t), s _y (t), s _z (t) can be determined in a step 213. For narrow-band sound bursts 4, the Fourier transform has a main or peak frequency with a maximum power density. In a subsequent step 214, the phase shift of this main frequency, that is: the difference in the phase at the main frequency in the Fourier transform of the respective sound signal s _x (t), s _y (t), s _z (t) compared to the phase at the main frequency in the Fourier transform of the sound signal s _r (t) of the reference sensor 10r. From this phase shift, the respective transit time difference Δt _x , Δt _y , Δt _z is calculated, taking the main frequency into account.

In one embodiment, only a frequency at which the power density of the Fourier transform reaches or exceeds a threshold value is determined as a main frequency.

This method, implemented by steps 213 and 214, can be implemented in a particularly computationally efficient manner. It is particularly advantageous to implement the Fourier transformation as a fast Fourier transformation (FFT, Fast Fourier Transform) for digital, that is: time and value discretized sound signals s _r (t), s _x (t), s _y (t), s _z (t ).

As an alternative to steps 213 and 214 _, the transit time differences Δt _x , Δt _y , Δt _z can also be determined by determining the cross-correlation by multiplying the Fourier transform of the sound signals s _r (t), _s , s _z (t) and subsequent inverse transformation into the time domain is determined. This method variant can also be used if a sound burst 4 does not have a sufficiently narrow band, so that a main frequency in the Fourier transform cannot be delimited sufficiently reliably. Compared to determining the cross-correlation in the time domain by using steps 211 and 212, this method variant can enable reduced computing effort, particularly for very long sound signals s _r (t), s _x (t), s _y (t), s _z (t).

überführt, wie dies bereits anhand von 3 erklärt wurde. Entlang eines jeden Signalverarbeitungspfades SPx, SPy, SPz wird abschließend im Schritt 203 jeweils ein normierter Laufzeitunterschied $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_z^{\prime }\in \left[-\mathrm{1,1}\right]$

bereitgestellt.A transit time difference Δt _x , Δt _y , Δt _z determined as a result of step 212 or step 214 or by cross-correlation in the frequency range is then determined in step 202 by reference to the maximum possible sound latency along the respective offset Δ _x , Δ _y , Δ _z a standardized transit time difference $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

transferred, as already done using 3 was explained. Finally, in step 203, a standardized transit time difference is created along each signal processing path SPx, SPy, SPz $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }\in \left[-1.1\right]$

provided.

ein akustisches Modell 120 angewendet, das anhand der 4 und 5 bereits erklärt worden ist.In the subsequent step 204, a tuple of standardized transit time differences formed in this way is used $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

an acoustic model 120 is applied, which is based on the 4 and 5 has already been explained.

optional unter Berücksichtigung weiterer Parameter wie Lufttemperatur, Luftdruck und/oder Luftfeuchtigkeit, im nachfolgenden Schritt 205 eine Position p der Schallquelle 2 relativ zur Sensorvorrichtung 10 zugeordnet. Mit einer nachfolgend noch genauer erklärten Ausführungsform können dabei mögliche Mehrdeutigkeiten durch eine Plausibilisierung aufgelöst werden.By using the acoustic model 120, the standardized transit time differences are achieved $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime },$

optionally taking into account further parameters such as air temperature, air pressure and / or humidity, in the subsequent step 205 a position p of the sound source 2 is assigned relative to the sensor device 10. With an embodiment explained in more detail below, possible ambiguities can be resolved through a plausibility check.

In a subsequent step 206, reactions of the vehicle 1 are triggered. In an advantageous method variant, the triggering and/or type of such a reaction will depend on the detected sound amplitude. _For example, _{if the transit} time _{differences Δt} (t), s _z (t) are integrated in a predetermined bandwidth range around the determined main frequency and a reaction is only triggered when the integrated power density exceeds a threshold value.

A reaction can be triggered, for example, by warning vehicle occupants by activating visual displays in the vehicle 1, for example through a head-up display, a navigation system, interior lighting and/or ambient lighting. If the vehicle 1 is designed as an at least partially autonomous vehicle 1, at least one possible trajectory for an escape corridor can additionally be created and navigation along such a trajectory can be initiated.

In addition, other vehicles, for example those that drive in a convoy with the attacked vehicle 1, can be informed of a threat using vehicle-to-vehicle (V2V) data exchange or vehicle-to-everything (V2X) data exchange. In particular, an automated emergency call can also be made.

Additionally or alternatively, if an active sound attack is detected, a counter sound system can be activated in the vehicle interior, which is aimed at compensating for the acoustic waves emitted by the detected sound source 2. It is also possible to localize and compensate for disturbing sound events that do not have any intention to attack by adapting threshold values for the sound power to such events.

The following is based on the 7 to 9 Methods are explained in more detail with which ambiguities in the localization of a sound source 2 can be resolved.

darstellt, die ein um den Versatz Δx in x-Richtung x gegenüber dem Referenzsensor 10r versetzter Schalldrucksensor 10x erfährt, der von einer Schallquelle 2 beschallt wird. Hierbei ist entlang der horizontalen Achse des x-Verzögerungs-Diagramms 300 der Abstand dx der Schallquelle 2 in x-Richtung x und entlang der vertikalen Achse des x-Verzögerungs-Diagramms 300 der Abstand dy der Schallquelle 2 aufgetragen. Im Mittelpunkt des x-Verzögerungs-Diagramms 300 sind beide Abstände dx, dy Null. Vom Mittelpunkt ausgehend sind nach links beziehungsweise nach oben positive Werte der Abstände dx, dy aufgetragen, in der entgegengesetzten Richtung sind negative Werte der Abstände dx, dy aufgetragen. 7 schematically shows an x-delay diagram 300, which shows the standardized propagation delay $\mathrm{\Delta }{t}_x^{\prime }$

represents, which is experienced by a sound pressure sensor 10x offset by the offset Δx in the x direction x relative to the reference sensor 10r, which is irradiated by a sound source 2. Here, the distance dx of the sound source 2 in the x direction x is plotted along the horizontal axis of the x-delay diagram 300 and the distance dy of the sound source 2 is plotted along the vertical axis of the x-delay diagram 300. At the center of the x-delay diagram 300, both distances dx, dy are zero. Starting from the center point, positive values of the distances dx, dy are plotted to the left or upwards, and negative values of the distances dx, dy are plotted in the opposite direction.

durch einen Grauwert kodiert zu, wobei ein weißer Grauwert einer normierten Laufzeitverzögerung $\mathrm{\Delta }{t}_x^{\prime }$

von 1, ein mittelgrauer Grauwert einer normierten Laufzeitverzögerung $\mathrm{\Delta }{t}_x^{\prime }$

von 0 und ein schwarzer Grauwert einer normierten Laufzeitverzögerung $\mathrm{\Delta }{t}_x^{\prime }$

von -1 entspricht.Thus, each point corresponds to the in 7 shown x-delay diagram 300 a point in the plane spanned by the x-direction x and the y-direction y, the center of the x-delay diagram 300 corresponding to the location of the reference sensor 10r. The x-delay diagram 300 assigns a standardized propagation delay to each of these points according to the value scale plotted to the right of the x-delay diagram 300 $\mathrm{\Delta }{t}_x^{\prime }$

coded by a gray value, where a white gray value corresponds to a standardized propagation delay $\mathrm{\Delta }{t}_x^{\prime }$

of 1, a medium gray gray value of a standardized propagation delay $\mathrm{\Delta }{t}_x^{\prime }$

of 0 and a black gray value of a standardized propagation delay $\mathrm{\Delta }{t}_x^{\prime }$

of -1 corresponds.

zugeordnet, negativen Abständen dx entsprechend negative Werte. Je weiter die Schallquelle 2 von der durch die x-Richtung x gebildeten Achse entfernt ist, desto stärker nähert sich die normierte Laufzeitverzögerung $\mathrm{\Delta }{t}_x^{\prime }$

dem Wert Null an, unabhängig von der Richtung der Entfernung von dieser Achse (das heißt: unabhängig vom Vorzeichen des Abstandes dy).Positive distances dx in the x direction x are positive values of the standardized propagation delay $\mathrm{\Delta }{t}_x^{\prime }$

assigned, negative distances dx corresponding to negative values. The further away the sound source 2 is from the axis formed by the x-direction x, the closer the standardized transit time delay approaches $\mathrm{\Delta }{t}_x^{\prime }$

the value zero, regardless of the direction of the distance from this axis (that is: regardless of the sign of the distance dy).

zu. Zur beispielhaften Illustration sind vorliegend eine erste und eine zweite Gerade g, g' eingezeichnet. Jede Gerade g, g' im x-Verzögerungs-Diagramm 300 oder in einem der nachfolgend noch erklärten weiteren Verzögerungs-Diagramme 301, 302 entspricht in der physikalischen Welt einer Menge von Orten mit bestimmten, durch die Punkte der jeweiligen Geraden g, g' teilweise (das heißt: in zwei Dimensionen) festgelegten Koordinaten. Eine solche Menge von physikalischen Orten wird hier und im Folgenden auch als Schallkorridor g, g' bezeichnet.Accordingly, the x-delay diagram 300 is mirror-symmetrical with respect to the horizontal line along the value dy=0 and anti-symmetrical with respect to the vertical line along the value dx=0. Furthermore, the x-delay diagram 300 is ambiguous, that is: it has the same values of the normalized propagation delay for a plurality of tuples of distances (dx, dy). $\mathrm{\Delta }{t}_x^{\prime }$

to. For exemplary illustration, a first and a second straight line g, g' are shown here. Each straight line g, g' in the x-delay diagram 300 or in one of the further delay diagrams 301, 302 explained below corresponds in the physical world to a set of locations with certain points partially defined by the points of the respective straight line g, g' (that is: in two dimensions). Such a set of physical locations is also referred to here and below as a sound corridor g, g'.

A sound source 2 generates the same standardized transit time delay at any position p whose assigned distances dx, dy from the reference sensor 10r lie on one of these straight lines g, g ' $\mathrm{\Delta }{t}_x^{\prime }$

7 clarifies that based on measurements of the reference sensor 10r and only a single further sound pressure sensor (in the present case the sound pressure sensor 10x), the position p of the sound source 2 cannot be clearly determined, but is limited to only two possible sound corridors g, g 'corresponding to the straight lines g, g' leaves.

gemäß der rechts angeordneten Werteskala in gleicher Weise wie das x-Verzögerungs-Diagramm 300. Die Bedeutung der vertikalen und der horizontalen Achse des y-Verzögerungs-Diagramm 301 ist unverändert gegenüber dem x-Verzögerungs-Diagramm 300. Die vertikale Linie entlang des Wertes dx=0 bildet im y-Verzögerungs-Diagramm 301 die Symmetrieachse für die Spiegelsymmetrie. Entsprechend bildet die horizontale Linie entlang des Wertes dy=0 hier die Symmetrieachse für die Antisymmetrie. 8th shows the x-delay diagram 300 7 and underneath there is also a y-delay diagram 301. The gray value of the y-delay diagram 301 encodes the standardized transit time difference $\mathrm{\Delta }{t}_y^{\prime }$

according to the value scale on the right in the same way as the x-delay diagram 300. The meaning of the vertical and horizontal axes of the y-delay diagram 301 is unchanged compared to the x-delay diagram 300. The vertical line along the value dx =0 forms the symmetry axis for the mirror symmetry in the y-delay diagram 301. Accordingly, the horizontal line along the value dy=0 forms the symmetry axis for the antisymmetry.

By considering the y-delay diagram 301 in addition to the x-delay diagram 300, the ambiguity in determining a position p can be limited, but not resolved. For illustration, straight lines g, g', g'' are drawn in the delay diagrams 300, 301, each of which begins at the coordinate origin of the diagram (that is: at the location dx=0, dy=0).

Ferner bewirken sämtliche Orte entlang der Geraden g für die Schallausbreitung in y-Richtung y einen gleichen normierten Laufzeitunterschied $\mathrm{\Delta }{t}_y^{\prime },$

der sich jedoch von dem normierten Laufzeitunterschied $\mathrm{\Delta }{t}_x^{\prime }$

in x-Richtung x unterscheiden kann.The first straight line g runs through a position p at which a sound source 2 is located. All locations along the straight line g cause the same standardized transit time difference for the sound propagation in the x direction x $\mathrm{\Delta }{t}_x^{\prime }.$

Furthermore, all locations along the straight line g cause the same standardized transit time difference for the sound propagation in the y-direction y $\mathrm{\Delta }{t}_y^{\prime },$

which, however, differs from the standardized transit time difference $\mathrm{\Delta }{t}_x^{\prime }$

can distinguish x in the x direction.

Mirrored on the horizontal line along the value dy=0, the second straight line g' runs symmetrically to the first straight line g in the x-delay diagram 300. Mirrored on the vertical line along the value dx=0, the third straight line g'' runs symmetrically to the first straight line g in the y-delay diagram 301.

für die Schallausbreitung entweder in x-Richtung x oder in y-Richtung y nicht von der Position p (oder einem beliebigen anderen Ort entlang der ersten Gerade g) unterscheidbar.Conditioned by the based on 7 Already explained symmetry relationships of the delay diagrams 300, 301 are also all locations (that is: all tuples of distances dx, dy) along the second and third straight lines g ', g'' based on only a single standardized transit time difference $\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime }$

for sound propagation either in the x-direction x or in the y-direction y cannot be distinguished from the position p (or any other location along the first straight line g).

in x-Richtung x wie die Position p einen dieser Position p gegenüber anderen normierten Laufzeitunterschied $\mathrm{\Delta }{t}_y^{\prime }$

in y-Richtung y auf. Analog weisen die Orte entlang der dritten Geraden g'' mit gleichem normierten Laufzeitunterschied $\mathrm{\Delta }{t}_y^{\prime }$

in y-Richtung y wie die Position p einen anderen normierten Laufzeitunterschied $\mathrm{\Delta }{t}_x^{\prime }$

in x-Richtung x auf. Somit können sowohl die zweite Gerade g' als auch die dritte Gerade g'' als mögliche Orte einer Schallquelle 2 ausgeschlossen werden.However, the locations along the second straight line g' have the same normalized transit time difference $\mathrm{\Delta }{t}_x^{\prime }$

in the x direction x like the position p one of this position p compared to other normalized transit time difference $\mathrm{\Delta }{t}_y^{\prime }$

in the y direction y. Analogously, the locations along the third line g'' point with the same normalized transit time difference $\mathrm{\Delta }{t}_y^{\prime }$

in the y-direction y like the position p a different standardized transit time difference $\mathrm{\Delta }{t}_x^{\prime }$

in the x direction x. Thus, both the second straight line g 'and the third straight line g'' can be excluded as possible locations of a sound source 2.

However, even in their entirety, the delay diagrams 300, 301 do not enable clear positioning, but rather limit the possible location of a sound source 2 only to a single location corresponding to the first straight line g Sound corridor g. In other words: With the two sound pressure sensors 10x, 10y offset in the x direction x and in the y direction y relative to the reference sensor 10r, the direction, but not the distance, from which a sound attack occurs can be clearly determined. However, by cleverly arranging the sound pressure sensors 10r, 10x, 10y, 10z, it is possible to mathematically exclude, based on this ambiguity, locations of a sound attack that are possible but physically implausible or not very plausible, for example under the vehicle 1 or locations located under the earth's surface.

9 shows the x-delay diagram 300 at the top left, which is based on the 7 and 8th has already been explained. Top right shows 9 the y-delay diagram 301, which is based on the 8th has already been explained.

kodiert, den der in z-Richtung z versetzte Schalldrucksensor 10z gegenüber dem Referenzsensor 10r erfährt. Die Kodierung der Grauwerte sowie die Bedeutung der vertikalen und der horizontalen Achse ist gegenüber dem bereits erläuterten x-Verzögerungs-Diagramm 300 und gegenüber dem bereits erläuterten y-Verzögerungs-Diagramm 301 unverändert.Bottom left shows 9 a z-delay diagram 302, in which the gray value represents the standardized transit time difference $\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

coded, which the sound pressure sensor 10z, which is offset in the z-direction z, experiences compared to the reference sensor 10r. The coding of the gray values and the meaning of the vertical and horizontal axes are unchanged compared to the x-delay diagram 300 already explained and compared to the y-delay diagram 301 already explained.

entlang der Linie dy=0 in einem z-Verzögerungs-Profil 303 dargestellt, das unten rechts in 9 gezeigt ist.The gray value distribution of the z-delay diagram 302 is point-symmetrical to the coordinate origin (that is: to the location dx=0, dy=0). For better clarity, the curve of the standardized transit time difference is shown $\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

along the line dy=0 in a z-delay profile 303, which is shown at the bottom right in 9 is shown.

weil die Wegdifferenz zwischen der Schallausbreitung zum Referenzsensor 10r und der Schallausbreitung zum Schalldrucksensor 10z in dieser Lage maximal ist. Mit zunehmender Entfernung der Schallquelle 2 von der Achse der z-Richtung z nähert sich der normierte Laufzeitunterschied $\mathrm{\Delta }{t}_z^{\prime }$

dem Wert 0, weil die Wegdifferenz zwischen der Schallausbreitung zum Referenzsensor 10r und der Schallausbreitung zum Schalldrucksensor 10z dabei abnimmt.A sound source 2, which radiates in the z-direction z, that is: directly above the reference sensor 10r, causes a maximum magnitude, negative normalized transit time difference in the present example $\mathrm{\Delta }{t}_{\mathrm{e.g},}^{\prime }$

because the path difference between the sound propagation to the reference sensor 10r and the sound propagation to the sound pressure sensor 10z is maximum in this position. As the distance of the sound source 2 from the axis of the z direction z increases, the standardized transit time difference approaches $\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

the value 0 because the path difference between the sound propagation to the reference sensor 10r and the sound propagation to the sound pressure sensor 10z decreases.

und $\mathrm{\Delta }{t}_y^{\prime }$

bewirkt wie an der Position p. Wie jedoch aus dem z-Verzögerungs-Diagramm 302 und noch deutlicher aus dem z-Verzögerungs-Profil 303 ersichtlich wird, unterscheiden sich alle auf der ersten Geraden g liegenden Orte hinsichtlich des normierten Laufzeitunterschieds $\mathrm{\Delta }{t}_z^{\prime }$

für die Schallausbreitung in z-Richtung z. Daher kann unter Berücksichtigung dieses normierten Laufzeitunterschieds $\mathrm{\Delta }{t}_z^{\prime }$

für die Schallausbreitung in z-Richtung z nicht nur die Richtung (das heißt: ein der ersten Geraden g entsprechender Schallkorridor g), sondern auch die Entfernung und somit die Position p einer Schallquelle 2 eindeutig bestimmt werden.In the delay diagrams 300, 301, 302 of 9 the position p of an assumed sound source 2 and the first straight line g were drawn again, which includes all locations where this sound source 2 has the same standardized transit time differences $\mathrm{\Delta }{t}_x^{\prime }$

and $\mathrm{\Delta }{t}_y^{\prime }$

effects as at position p. However, as can be seen from the z-delay diagram 302 and even more clearly from the z-delay profile 303, all locations lying on the first straight line g differ in terms of the normalized transit time difference $\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

for sound propagation in the z direction. Therefore, taking this normalized transit time difference into account $\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }$

For the sound propagation in the z direction z, not only the direction (that is: a sound corridor g corresponding to the first straight line g), but also the distance and thus the position p of a sound source 2 can be clearly determined.

Reference symbol list

1

vehicle

2

Sonic cannon, sound source, attacker

3

bell

4

Sonic Burst

10

Sensor device

10r

Reference sensor, sound pressure sensor

10x, 10y, 10z

Sound pressure sensor

20

Direction of sound propagation

100, 101

Step

110 to 113

Step

115

artificial neural network

116

Input layer

117

Output layer

120

acoustic model

200 to 206

Step

210 to 214

Step

300

x-delay diagram

301

y-delay diagram

302

z-delay diagram

303

y-delay profile

dr, dx, dy, dz

Distance

g, g', g''

first to third straight, sound corridor

p

position

rr,y (τ)

Cross-correlation signal

SPx, SPy, AFZ

Signal processing path

sr(t),sx(t), sy(t), sz(t)

sound signal

tr, tx, ty, tz

time

x, y, z

x direction, y direction, z direction; Direction

Δtx, Δty, Δtz

Difference in transit time

Δtx, Δty, Δtz

standardized transit time difference

Δx, Δy, Δz

offset

τ

delay

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 112017007495 B4 [0003]

Claims (10)

Locating method for locating at least one sound source (2) directed at a vehicle (1) by means of a sensor device (10) arranged on the vehicle (1), comprising a reference sensor (10r) and at least one relative to the reference sensor (10r) by an offset (Δx , Δy, Δz) offset sound pressure sensor (10x, 10y, 10z), characterized in that - an acoustic model (120) is determined by acoustic simulation, which corresponds to the at least one transit time difference (Δt _x , Δt _y , Δt _z ), which the simulated sound propagation from a position (p) in the surroundings of the vehicle (1) to the at least one offset sound pressure sensor (10x, 10y, 10z), compared with the simulated sound propagation from the position (p) to the reference sensor (10r). , assigns at least one sound corridor (g, g', g'') and/or a position (p) relative to the vehicle (1), - sound emitted by the sound source (2) from the sound pressure sensors (10r, 10x, 10y, 10z) is received and converted into a sound signal (s _r (t), s _x (t), s _y (t), s _z (t)), - for at least one of the sound pressure sensors (10r) offset relative to the reference sensor (10r). 10x, 10y, 10z) by comparing the sound signals (s _r (t), s _x (t), s _y (t), s _z (t)) and/or their Fourier transforms, a transit time difference (Δt _x , Δt _y , Δt _z ) is determined as the difference between the transit time of the sound from the sound source (2) to the reference sensor (10r) and the transit time of the sound from the sound source (2) to the respective sound pressure sensor (10x, 10y, 10z) and - based on the acoustic model (120) which has at least one transit time difference (Δt _x , Δt _y , Δt _z ) at least one sound corridor (g, g', g'') and/or a position (p) of the sound source (2) relative to the vehicle ( 1) is assigned. location procedure Claim 1 , characterized in that the at least one transit time difference (Δt _x , Δt _y , Δt _z ) assigned to an offset sound pressure sensor (10x, 10y, 10z) is based on the propagation time of the sound along the respective offset (Δx, Δy, Δz) compared to the Reference sensor (10r) is obtained and from this a standardized transit time difference is obtained $\left(\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }\right)$

is determined. Locating method according _to one of the preceding claims, characterized in that a first and a second sound corridor (g, g') of the sound source (2) are determined based on a transit time difference (Δt _x , Δt y, Δt _z ). Locating method according to one of the preceding claims, characterized in that based on two transit time differences (Δt _x , Δt _y , Δt _z ), each of which is assigned to one of at least two sound pressure sensors (10x, 10y) offset in different directions (x, y), a sound corridor (g) of the sound source (2) is determined. Locating method according to one of the preceding claims, characterized in that based on three transit time differences (Δt _x , Δt _y , Δt _z ), each of at least three sound pressure sensors (10x, 10y, 10z) offset in different directions (x, y, z). ) are assigned, the position (p) of the sound source (2) is determined. Locating method according to one of the preceding claims, characterized in that the acoustic model (120) is at least partially designed as a multi-layer artificial neural network (115) with an input layer (116), an output layer (117) and at least one hidden layer arranged between them and with a supervised learning method is trained, wherein - in the input layer (116) sound signals (s _r (t), s _x (t), s _y (t), s _z (t)) and / or parameters derived therefrom and optionally acoustically effective Parameters of a vehicle environment are presented and - in the output layer (117) parameters of the position (p) assigned to the values of the input layer (116) and / or of the at least one assigned sound corridor (g, g ', g'') of the sound source ( 2) be presented. Locating method according to one of the preceding claims, characterized in that the acoustic model (120) is at least partially designed as a lookup table, with each row of the lookup table being a tuple with at least one transit time difference (Δt _x , Δt _y , Δt _z ). and/or at least one standardized transit time difference $\left(\mathrm{\Delta }{t}_x^{\prime },\mathrm{\Delta }{t}_y^{\prime },\mathrm{\Delta }{t}_{\mathrm{e.g}}^{\prime }\right)$

one position (p) and/or at least one sound corridor (g, g', g'') is assigned to the sound source (2). Application of a locating method according to one of the preceding claims, characterized in that - the sound power detected by the sound pressure sensors (10r, 10x, 10y, 10z) is determined and, if it exceeds a warning threshold, - the at least one sound corridor (g, g ', g'') and/or the position (p) of a potential attacker (2) is determined and - a warning is issued via visual display means of the vehicle (1) and/or at least one escape route is issued using a navigation means of the vehicle (1). is determined by bypassing the at least one sound corridor (g, g', g'') and/or the position (p) of the potential attacker (2). Locating device for locating at least one directed sound source (2), comprising a sensor device (10) and a computing and signal processing unit, characterized in that - the sensor device (10) has a sound pressure sensor (10r) designed as a reference sensor (10r) and at least one further, in each comprises an offset (Δx, Δy, Δz) along different directions (x, y, z) relative to the reference sensor (10r) offset sound pressure sensor (10x, 10y, 10z) and - the computing and signal processing unit for carrying out a locating method according to one of Claims 1 until 7 is set up. locating device Claim 9 , characterized in that - a first offset sound pressure sensor (10x) is arranged offset from the reference sensor (10r) by an offset (Δx) along an x-direction (x), - a second offset sound pressure sensor (10y) from the reference sensor (10r ) is arranged offset by an offset (Δy) along a y-direction (y), the y-direction (y) being arranged perpendicular to the x-direction (x) and - a third offset sound pressure sensor (10z) relative to the reference sensor (10r) is arranged offset by an offset (Δz) along a z-direction (z), the z-direction (z) being arranged perpendicular to the x-direction (x) and perpendicular to the y-direction (y). and wherein - the computing and signal processing unit for determining at least one sound corridor (g, g', g'') and/or a position (p) of a sound source (2) based on the sound pressure sensor (10x.) offset from the first, the second and the third , 10y, 10z) assigned transit time differences (Δt _x , Δt _y , Δt _z ).

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