CN111308475A - Method and apparatus for sensing the surroundings of a vehicle and a vehicle having the same - Google Patents

Abstract

The invention relates to a method for sensing a vehicle surroundings, the method comprising the steps of receiving at least one acoustic signal (36, 46) from the vehicle surroundings (30) by means of at least one vehicle-bound acoustic sensor (14). ); the received signal is evaluated and at least one characteristic of the surrounding environment (30) is determined based on this analysis; characterized in that at least one vehicle-bound acoustic sensor (14) is arranged in the underbody of the vehicle (10) ( 12) such that the received acoustic signal (16) is at least partially reflected by the roadway surface (20) from an area of the surrounding environment (30) of the vehicle (10) to the vehicle-bound acoustic sensor (14), In this case, the surroundings ( 30 ) of the vehicle ( 10 ) include, in particular, the roadway in the vicinity of the vehicle body and/or the area below the vehicle ( 10 ). The invention also relates to a device and a vehicle having the device.

Description

Method and apparatus for sensing the surroundings of a vehicle and a vehicle having the same

technical field

The present invention relates to a method for sensing the surroundings of a vehicle by receiving at least one acoustic signal reflected from the surroundings of the vehicle by means of at least one acoustic sensor and/or by means of an additional receiver bound to the vehicle and for all the acoustic signals reflected from the surroundings of the vehicle. The received echo signals are evaluated and at least one property of the surrounding environment is determined based on the evaluation. The invention also relates to a device configured for carrying out the method of the invention. Furthermore, the invention relates to a vehicle having such a device.

Background technique

Today, a large number of sensors are required for autonomous driving, among which are lidar sensors, camera sensors, radar sensors and ultrasonic sensors. Ultrasonic sensors are usually visibly mounted on the bumper of the vehicle.

It is known from DE 10 2014 221 990 A1 to sense the surroundings of the vehicle by means of a vehicle-based surroundings sensor device, measure the geometry of the collision-relevant structures of the road surface in the surroundings, and compare the The geometry of the crash-related structure is compared to the current configuration of the vehicle, and if the comparison results in an expected collision between the structure and the vehicle's rim and/or the vehicle's underside and/or the vehicle's spoiler, output Signal. In this case, the surroundings sensor device is preferably arranged on the vehicle housing, ie in the region of the vehicle bumper, and can be designed as an ultrasonic sensor.

SUMMARY OF THE INVENTION

For autonomous driving, environmental recognition should be improved by sensors that are as inexpensive as possible. In addition, the safety of special situations, such as the start of autonomous driving, should be better ensured.

According to a first aspect of the present invention, a method for sensing a surrounding environment of a vehicle is proposed, the method comprising the following steps:

- receiving at least one acoustic signal from the surroundings of the vehicle by means of at least one vehicle-bound acoustic sensor and optionally by means of an additional vehicle-bound receiver,

- analyzing and evaluating the received signal and determining at least one characteristic of the surrounding environment based on the analyzing and evaluating,

Thereby, according to the invention, at least one vehicle-bound acoustic sensor is arranged in the underbody area of the vehicle in such a way that the received acoustic signal is at least partially reflected by the road surface from the area of the vehicle surroundings to the vehicle-bound acoustic sensor sensor.

Preferably, before the step of receiving at least one acoustic signal from the vehicle surroundings, the acoustic signal is transmitted by means of at least one vehicle-bound acoustic sensor, wherein the transmitting acoustic sensor is arranged in the underbody area of the vehicle such that the transmitted acoustic signal is transmitted The acoustic signal is at least partially reflected by the road surface into the region of the vehicle surroundings, wherein the received signal comprises an echo signal of the transmitted signal. In particular, the transmitting acoustic sensor can also be used to receive acoustic signals from the surroundings of the vehicle. In other words, the sensor unit can function as both a transmitter and a receiver.

In this context, the surroundings of the vehicle refer in particular to the roadway in the vicinity of the body or the outer contour of the vehicle. The surroundings of the vehicle can also include the area adjoining the vicinity and/or the area below the vehicle, for example the area in front of the tires (the so-called tire track to be driven) in the direction of travel. The properties of the surrounding environment can be, for example, information on whether obstacles are present in the surrounding environment, and what type these obstacles are and/or how far apart these obstacles are from the host vehicle and relative to the vehicle. Where the vehicle is located. Alternatively or additionally, the properties of the surrounding environment can also include the current state of the road surface, such as roughness and/or friction value and/or wetness and/or snow and/or ice.

Therefore, the acoustic sensor, which can be designed in particular as an ultrasonic sensor, is fastened to the underbody of the vehicle and oriented such that its sound cone or its receiving area is directed onto the roadway such that the received And if necessary the transmitted sound is at least partially reflected by the road surface. Therefore, the acoustic signal can travel largely unhindered from the body region of the vehicle into the surroundings of the vehicle and from the surroundings to the sensor. In particular, the acoustic sensor does not point vertically downwards, but has an azimuth or inclination angle, due to which the transmitted acoustic signal is reflected by the road surface into the surroundings of the vehicle. If the acoustic signal hits an object there, for example, an echo signal is generated, which is reflected back to the sensor substantially on the same path.

Preferably, the analytical evaluation of the received acoustic signal comprises the determination of at least one characteristic of the road surface. Particularly preferably, the properties of the road surface are determined by determining the noise level of the received signal. The characteristics of the road surface, in particular the roughness and/or the humidity of the road surface and/or other characteristics of the road surface can be determined from the noise level.

It is also particularly advantageous if the acoustic sensor is arranged such that its sound cone is at least partially aligned with the track of the tire to be driven over. Thereby, roadway conditions can be sensed particularly effectively (eg wetness, ice and snow through tire noise and scattered ground echoes). Furthermore, it is possible to sense whether obstacles (eg small animals, stones, human toes) are present in the tire track to be driven. In addition, different roadway coverings (eg cement, closed-cell or open-cell asphalt) can be sensed, wherein the influence of road shoulders, railway tracks or roadway markings can be reduced. Furthermore, roadway conditions (eg wet, icy, snowy, polluted, etc.) which are decisive for the frictional contact with the tire can be distinguished and identified.

In a preferred embodiment of the invention, the evaluation of the received echo signals includes the determination of the signal transit time, wherein in particular objects in the surroundings of the vehicle are identified. The advantage here is that when the sound cone is partially directed directly at the object to be recognized, this results in a particularly large range of action of the sensor, since the sound can both directly reach the sensor itself and all objects by reflection from the road surface. the object, wherein the reflections from the object also return to the sensor both directly and indirectly via roadway reflections. Therefore, the identification can preferably be achieved by evaluating the first echo signal of the first signal component of the transmitted acoustic signal and evaluating the second echo signal of the second signal component of the transmitted acoustic signal Object, wherein the first signal component is reflected on the road surface before it hits the object, wherein the second signal component directly hits the object.

It is also advantageous to use, in addition to the acoustic sensors in the vehicle body, higher-positioned sensors, for example in the bumper of the vehicle or on one side, for example in the door sills or in the doors, in order to thereby pass the scattered crosses of the road surface. Echo senses objects and road conditions. This has the advantage that not only the direct reflection properties of the roadway, but also the indirect reflection properties can be measured, and further information about the state of the road can be obtained from the proportional relationship of the two parts and thus more precise and reliable Determine the road state. Furthermore, due to the different sound propagation paths, the sound reflected at the road surface can have positive or negative superposition (interference) with the directly transmitted sound. By additionally evaluating these so-called cross echoes, there is a greater opportunity to benefit from the positive interference effect of the acoustic waves, ie positive superposition, which favors a larger range.

Further preferably, the reflected acoustic echo signal can be received by at least one first receiver and the first transit time can be determined, and the reflected acoustic signal can be received by at least one second receiver and the second transit time can be determined. The first receiver may be the transmitting sensor itself, and the second receiver may be an additional acoustic sensor arranged at another location on the vehicle. The relative position of the reflecting object with respect to the transmitter and/or the receiver can be determined by evaluating the first and second transit times. For example, the first receiver is arranged as part of the acoustic sensor in the underbody area of the vehicle, and the second receiver is arranged on the outer surface of the vehicle, in particular on the side of the vehicle.

According to a second aspect of the present invention, an apparatus for sensing the surroundings of a vehicle is proposed, wherein the apparatus is configured to carry out a method as configured as described above. The device includes:

- at least one vehicle-bound acoustic sensor, in particular an ultrasonic sensor, which is designed for transmitting acoustic signals, in particular ultrasonic signals, and for receiving acoustic signals, in particular ultrasonic signals;

- a control unit configured to actuate the acoustic sensor;

- a computing unit, which is designed to analyze and evaluate the received acoustic echo signals and to determine at least one property of the surrounding environment based on the evaluation.

According to the invention, the at least one acoustic sensor can be arranged in the underbody area of the vehicle in such a way that the transmitted acoustic signal is at least partially reflected by the road surface into the area of the vehicle surroundings.

According to another aspect of the present invention, a vehicle with such a device is proposed.

Particularly advantageous is the position of the acoustic sensor in the underbody of the vehicle in which the sensor does not protrude beyond the underbody cover. As a result, ground clearance is preserved and the sensor is not scratched by obstacles in the roadway. According to the invention, the sensor surface, ie the surface of the sensor which radiates the acoustic signal and receives the reflected acoustic signal (usually the diaphragm), is not mounted flat in the horizontal plane of the vehicle floor, but relative to the road surface The oblique arrangement is such that the corresponding sound cone is at least partially reflected by the road surface into the region of the vehicle surroundings.

Preferably, a horn is also arranged around the sensor surface or the membrane surface, which horn directs the received echo signals to the sensor surface. The horn can, for example, be shaped like an animal horn. For space reasons, the horn-like element can be rolled or folded around itself. Therefore, the sound is coupled by means of the exponential line through the sound channel between the sensor and the surroundings, which increases continuously in cross-section. Here, it is preferable to match the wave impedance of the sensor to the acoustic characteristic impedance of the surrounding air. As a result, a higher range of coverage can be achieved during echo localization and thus during object sensing, and a more accurate distinction of road states can also be achieved.

Acoustic sensors typically used in automobiles have a diaphragm as sensor surface, which is used both for generating and receiving acoustic signals. To generate the acoustic signal, the diaphragm is excited by the transducer element to vibrate, thereby generating the acoustic signal. In order to receive acoustic signals, the diaphragm vibrations caused by the incident sound are sensed by means of transducer elements. After generating the acoustic signal, the diaphragm must first return to a resting state before the incoming acoustic signal can be received by means of the diaphragm. The time period from the end of the excitation of the diaphragm until the stationary state is reached is called the vibration damping time (Ausschwingzeit). Due to the vibration decay time of the diaphragm, objects that are particularly close to the acoustic sensor cannot be detected or can be detected only with low reliability. First, however, it should be possible to reliably detect, for example, the presence of objects in the tire tracks to be driven or very close to the vehicle before autonomous driving begins, so that they can be prevented from being run over. Thus, for example, a person leaning on the vehicle before the start of the journey is detected, so that the person can thus be prevented from being run over. For this reason, it is advantageous to move the acoustic sensor in the horizontal plane as far away from the vehicle contour as possible in the direction of the center axis, so that the distance between the sensor or the sensor surface or the membrane and the object to be detected is greater than that for the object. The identified minimum distance, which is derived in a known manner from the vibration damping time of the sensor after sending the acoustic signal. The minimum distance depends on the structure of the sensor as well as on the transmission frequency and transmission mode and can be, for example, 12 cm to 19 cm in conventional ultrasonic sensors. The acoustic sensor is preferably arranged on the underbody of the vehicle in such a way that the sensor surface or the membrane of the sensor has a defined minimum distance from the outer contour of the vehicle or the track of the tires to be driven, wherein the minimum distance is determined by the acoustic sensor. The vibration damping time is determined.

Preferably, the acoustic sensor is arranged in a recess in the underbody cover and/or on a reinforcing element on the underbody of the vehicle. Advantageously, therefore, existing grooves and surface portions in the underbody fenders, whose normal vectors point approximately in the desired direction of propagation, can be selected as sensor locations. Here, too, the offset for forming the optional horn is easier to implement than on surfaces oriented parallel to the roadway, as a result of which additional large grooves for the horn must be implemented. Advantageously, a mounting location is chosen that is less affected by large temperature fluctuations as occurs in the vicinity of the engine and exhaust system. Thereby, a better fatigue resistance of the sensor can be achieved.

Preferably, a plurality of acoustic sensors are arranged on the underbody of the vehicle, wherein at least one first sensor is arranged in the vehicle front region on the underbody of the vehicle, and at least one second sensor is arranged at the vehicle underbody of the vehicle in the rear area. At least one third sensor is arranged on the underbody of the vehicle in the region of the first side of the vehicle, and at least one fourth sensor is arranged in the region of the second side of the vehicle on the underbody of the vehicle. With this arrangement, it is obtained that the surroundings of the vehicle are largely completely covered by the acoustic sensor.

The following advantages are obtained in particular by the present invention:

- The sensor is not visible from common positions when viewing the vehicle and thus does not limit the design of the vehicle.

- The functional capability of the method or the device of the invention is independent of the vehicle design, thereby reducing costs when applying the system to different vehicle variants.

- The vehicle manufacturer gains degrees of freedom in the configuration of the visible vehicle shell in that the acoustic sensor can be transferred from the visible bumper region into the invisible underbody region.

-Acoustic sensors are better protected from parking scratches and vandalism.

- By using additional acoustic sensors mounted higher on the vehicle, the range of action can be increased overall, since the signal component reflected on the road surface is increased and, in particular, with the aid of the higher sensor compared to the mounting height The chance of positive interference occurring increases in the case of combined analytical evaluations performed by low acoustic sensors.

- The opening angle of the acoustic sensor is greater in the vicinity, since the sound component scattered at the surface of the roadway increases with lower heights.

- Blindness detection (that is to say identifying whether individual sensors are defective or contaminated) is more robust, as ground and vehicle components return clearer echoes and multiple echoes that can be considered for comparative measurements.

- A loudspeaker that intensifies the sound can be used, whereby in general a higher sensitivity of the acoustic sensor and additionally a stronger focus and thus a significantly higher range can be achieved.

- A particularly effective and reliable object recognition can be achieved in the immediate vicinity of the road surface which is reflecting, since these objects can be detected both by direct echoes and by indirect echoes reflected via the road surface.

- Together with sensors not installed in the underbody, the height position of objects can also be calculated by triangulation. It is thus possible to better distinguish between obstacles that can be passed and obstacles that cannot be passed.

- Higher sensing robustness against so-called pseudo-objects caused by special roadway structures such as manhole covers. For acoustic sensors that are not mounted on the vehicle floor, the remote manhole cover often appears as an object and thus erroneously appears as an obstacle.

- It is also possible to detect objects that are in close proximity to the vehicle or that are in contact with the vehicle.

Description of drawings

Figure 1 schematically shows a vehicle according to a first embodiment of the invention in a front view.

Figure 2 schematically shows a vehicle according to a second embodiment of the invention in a front view.

Figure 3 schematically shows a vehicle according to a third embodiment of the invention in a front view.

Figure 4 schematically shows a vehicle according to a fourth embodiment of the invention in a front view.

FIG. 5 schematically shows a bottom view of a vehicle according to a fifth embodiment of the present invention.

FIG. 6 schematically shows a typical underbody of a motor vehicle with mounting positions for the acoustic sensor according to the invention.

Embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the following description of the embodiments of the present invention, the same elements are denoted by the same reference numerals, wherein the repeated description of these elements is omitted if necessary. The drawings show only schematically the subject-matter of the invention.

Detailed ways

FIG. 1 shows the vehicle 10 in a front view. The vehicle has an acoustic sensor 14 in the form of an ultrasonic sensor, which is arranged on the underbody 12 of the vehicle 10 . The vehicle-bound acoustic sensor 14 is fastened to the underbody 12 of the vehicle 10 in such a way that it does not protrude beyond the outer contour 18 of the vehicle 10 . The acoustic sensor 14 is inclined relative to the floor plane 22 of the vehicle 10 in such a way that the acoustic signal 16 emitted by the sensor 14 is at least partially reflected by the road surface 20 into the surroundings 30 of the vehicle. Ultrasonic sensors typically send sound into a roughly cone-shaped area. In this illustration, the transmitted signal 16 is shown schematically by lines 16a and 16b bounding the sound cone. Due to the reflection of the transmitted signal 16 on the road surface 20, the sound cone expands, resulting in an increase in the measuring range. Echo signals can be received from the entire sound cone. The echo signal is returned to the sensor 14 in such a way that the echo signal is reflected again on the road surface 20 if necessary. The system shown thus detects, for example, objects in the surroundings 30 of the vehicle 10 and/or determines the current roadway state by evaluating the echo signals generated by the roadway 20 . For this purpose, a control unit 40 is provided, which is designed to actuate the acoustic sensor 14 , and a computing unit 50 is provided, which is designed to analyze and evaluate the received acoustic echo signals and to determine at least the surrounding environment 30 based on the evaluation. a feature.

FIG. 2 shows the vehicle 10 in a front view. The vehicle has an acoustic sensor 14 in the form of an ultrasonic sensor, which is arranged on the underbody 12 of the vehicle 10 . In contrast to the exemplary embodiment according to FIG. 1 , in this exemplary embodiment, the installation site and installation angle or also the angle of inclination of the sensor 14 is selected such that the acoustic signal 16 sent by the sensor 14 is partly reflected by the road surface 20 to the surface of the vehicle. into the surroundings 30 and partly directly into the surroundings 30 of the vehicle 10 . For this purpose, in the exemplary embodiment according to FIG. 1 a smaller installation angle and an installation location closer to the outer contour 18 of the vehicle are selected. Here, the installation angle or the inclination angle of the sensor 14 refers to the angle between the vehicle floor plane 22 and the main radiation direction of the acoustic sensor 14 . Objects 80 are present in surroundings 30 of vehicle 10 . The object 80 can be identified by evaluating the first echo signal of the first signal component 16 c of the transmitted acoustic signal, wherein the first signal component 16 c was before it hit the object 80 . Reflections occur on the road surface 20 . Furthermore, the second echo signal of the second signal component 16d of the transmitted acoustic signal 16 is evaluated, wherein the second signal component 16d directly hits the object 80 . With this arrangement, the signal can be enhanced by positive superposition and still sense distant objects or weak reflections, especially if the ambient noise generated by the tires is strong, for example when the road is wet and speeds are high the echo of the object.

FIG. 3 shows the vehicle 10 in a front view. The vehicle has an acoustic sensor 14 in the form of an ultrasonic sensor, which is arranged on the underbody 12 of the vehicle 10 , in particular in the same manner as shown in FIG. 1 . Additionally, in this embodiment, the vehicle 10 also has a second acoustic sensor 44 on the side 25 of the vehicle 10 . The acoustic sensor 14 is inclined relative to the floor plane 22 of the vehicle 10 in such a way that the acoustic signal 16 emitted by the sensor 14 is at least partially reflected by the road surface 20 into the vehicle's surroundings 30 . For example, in the region 26 of the road surface, the echo signals 46 generated by the road surface return to the first acoustic sensor 14 and can be evaluated by means of the computing unit 50 . Additionally, the second echo signal 46 is reflected to the second acoustic sensor 44 by the sound arriving on the road surface 20 . The second echo signal 46 can also be evaluated by means of the computing unit 50 . Through the combined analytical evaluation, accurate information about the current state of the roadway surface 20 in the area 26 can be obtained.

Objects 80 are also present in the surroundings 30 of the vehicle 10 . The object 80 can be identified by receiving the first echo signal 36 ′ of the transmitted acoustic signal 16 by the acoustic sensor 14 and then evaluating this echo signal by the computing unit 50 , wherein the echo signal 36 ' is reflected by the road surface 20 before it hits the sensor 14 . The computing unit can, for example, determine the transit time of the signal. Furthermore, the second echo signal 46' of the transmitted acoustic signal 16 is received by the receiver 44 and is also evaluated by the computing unit 50, wherein the two echo signals 36' and 46' can also be evaluated in combination. In particular, with this arrangement, not only the distance to the object 80 in the surroundings 30 of the vehicle 10 can be determined, but also the height and/or the relative position of the object 80 relative to the acoustic sensors 14 and 44 .

FIG. 4 shows the vehicle 10 in a front view. The vehicle has an acoustic sensor 14 in the form of an ultrasonic sensor, which is arranged on the underbody 12 of the vehicle 10 . In contrast to the exemplary embodiment according to FIG. 1 , in this exemplary embodiment the installation site of the sensor 14 is shifted in the direction of the vehicle center axis 11 . This results in the advantage that objects very close to the vehicle 10 can also be detected reliably, since the distance from the acoustic sensor 14 is always sufficiently large that the echoes of such objects after the vibration damping period of the sensor diaphragm of the acoustic sensor 14 are long enough The signal hits the sensor 14 .

In the embodiment of the invention shown in FIG. 5 , a plurality of acoustic sensors 14 a , 14 b , 14 c , 14 d , which can be configured as ultrasonic sensors, for example, are arranged on the underbody of the vehicle. Here, on the underbody 12 of the vehicle 10 five sensors 14 a are arranged in the front region of the vehicle 10 . The five sensors 14 a are oriented at different angles with respect to the vehicle longitudinal axis 13 and thus cover the area in front of the vehicle 10 in a planar manner with their measuring ranges. In a similar manner, on the underbody 12 of the vehicle 10 , further five ultrasonic sensors 14 b are also arranged in the rear region of the vehicle 10 . These sensors 14b are also oriented at different angles with respect to the vehicle longitudinal axis 13 and thus cover the area behind the vehicle 10 in a planar manner with their measuring ranges. On the underbody 12 of the vehicle 10 three further sensors 14 c are arranged in a first side region of the vehicle 10 . The three sensors 14c are oriented at different angles with respect to the vehicle transverse axis 17 and thus cover the area on the right side of the vehicle with their measuring ranges in a planar manner. On the underbody 12 of the vehicle 10 three further sensors 14 d are arranged in the second side region of the vehicle 10 . The three sensors 14d are likewise oriented at different angles with respect to the transverse vehicle axis 17 and thus cover the area on the left side of the vehicle 10 in a planar manner with their measuring ranges.

Vehicle components, such as wheels 15 , which are located within the sound cone region of one of the sensors, generate continuous echo signals and, in part, multiple echoes. Since these components are known, they can be hidden when detecting objects, but they can be used for blindness detection in order to detect, for example, adverse effects on the sensor range due to contamination and, if necessary, also compensate for the adverse effects.

The underbody 12 of a typical motor vehicle 10 is shown in FIG. 6 . The underbody 12 has, in a known manner, an underbody cover 64 and respective different covering elements 65 and has reinforcing elements 66 , sound damping elements 69 and flow shaping elements 68 . These elements may in turn have or form recesses 62 suitable for accommodating the acoustic sensor 14 in order to construct the device of the invention.

Claims (16)

1. A method for sensing a surrounding environment (30) of a vehicle (10), the method comprising the steps of:

-receiving at least one acoustic signal (36,46) from the surroundings (30) of the vehicle by means of at least one acoustic sensor (14) that is tethered to the vehicle,

-analytically evaluating the received signals and determining at least one characteristic of the surroundings (30) from the analytical evaluation,

characterized in that the at least one vehicle-bound acoustic sensor (14) is arranged in the region of the underbody (12) of the vehicle (10) in such a way that the received acoustic signals (36,46) are reflected at least partially by a roadway surface (20) from a region of the surroundings (30) of the vehicle (10) to the vehicle-bound acoustic sensor (14), wherein the surroundings (30) of the vehicle (10) comprise in particular a roadway in the vicinity around the body of the vehicle and/or comprise a region below the vehicle (10).

2. Method according to claim 1, characterized in that, prior to the step of receiving the at least one acoustic signal (36,46) from the surroundings (30) of the vehicle, an acoustic signal (16) is transmitted by means of at least one vehicle-bound acoustic sensor (14), wherein the transmitting acoustic sensor (14) is arranged in the region of the underbody (12) of the vehicle (10) in such a way that the transmitted acoustic signal (16) is reflected at least partially by the roadway surface (20) into the region of the surroundings (30) of the vehicle (10), wherein the received signal (36,36 ', 46, 46') comprises an echo signal of the transmitted signal (16).

3. The method according to claim 1 or 2, characterized in that the analytical evaluation of the received signals (16) comprises determining at least one characteristic of the roadway surface (20).

4. Method according to claim 3, characterized in that the property of the traffic lane surface (20) is determined by ascertaining a noise level of the received signal (16), wherein a property of the traffic lane surface (20), in particular a roughness and/or a humidity of the traffic lane surface (20), is determined from the noise level.

5. Method according to one of claims 2 to 4, characterized in that the evaluation of the received signals comprises a determination of the signal transit time of at least one echo signal of the transmitted acoustic signals (16), wherein in particular objects (80) in the surroundings (30) of the vehicle (10) are identified.

6. Method according to claim 5, characterized in that an object (80) is identified by evaluating the superposition of a first echo signal of a first signal component (16c) of the transmitted acoustic signal (16) and a second echo signal of a second signal component (16d) of the transmitted acoustic signal (16), wherein the first signal component (16c) is reflected on the roadway surface (20) before it strikes the object (80), wherein the second signal component (16d) directly strikes the object (80).

7. The method according to claim 5 or 6, characterized in that the first echo signal (36') is received by at least one first receiver and the first transit time is determined, and a second echo signal (46') is received by at least one second receiver (44) and a second transit time is determined, wherein the relative position of the reflecting object (80) with respect to the transmitting sensor (14) and/or with respect to the receiver (14,44) is determined by evaluating the first and second times of flight, wherein the first receiver is arranged as part of an acoustic sensor (14) in the region of the underbody (12) of the vehicle (10), and the second receiver (44) is arranged on an outer surface (25) of the vehicle (10), in particular on a side of the vehicle (10).

8. Method according to one of claims 1 to 7, wherein a first acoustic signal is received by at least one first receiver from a region (26) of the traffic lane surface (20) and a second acoustic signal is received by at least one second receiver (44) from the region (26) of the traffic lane surface (20), wherein the first receiver is arranged as part of an acoustic sensor (14) in the region of the underbody (12) of the vehicle (10) and the second receiver (44) is arranged on an outer surface (25) of the vehicle (10), in particular on a side of the vehicle (10).

9. An apparatus for sensing the surroundings (30) of a vehicle (10), wherein the apparatus is configured for performing the method according to one of claims 1 to 8, the apparatus comprising:

-at least one acoustic sensor (14) that is vehicle-bound and is designed for receiving acoustic signals, in particular ultrasonic signals;

-a control unit (40) configured for manipulating the acoustic sensor (14) restrained by the vehicle;

a computing unit (50) configured for the analytical evaluation of the received acoustic signals and for the determination of at least one characteristic of the surroundings (30) from the analytical evaluation;

characterized in that the at least one acoustic sensor (14) which is bounded by the vehicle can be arranged in the region of the underbody (12) of the vehicle (10) in such a way that the received acoustic signals (16) are reflected at least partially from the region of the surroundings (30) of the vehicle by the roadway surface (20) to the acoustic sensor (14), wherein the surroundings (30) of the vehicle (10) comprise in particular a roadway in the vicinity of the body surroundings and/or a region below the vehicle (10).

10. The device according to claim 9, characterized in that the acoustic sensor (14) is configured as an ultrasonic sensor.

11. The device according to claim 9 or 10, wherein the acoustic sensor (14) has a sensor surface, in particular a diaphragm, wherein a funnel is arranged around the sensor surface, which funnel is designed to guide sound to the sensor surface and is in particular shaped in such a way that the wave impedance of the sensor is matched to the sound characteristic impedance of the surrounding air and the received signal is thus intensified.

12. Vehicle (10) having a device according to one of claims 9 to 11.

13. Vehicle according to claim 12, characterized in that at least one acoustic sensor (14) is arranged on the underbody (12) of the vehicle (10) in such a way that the diaphragm of the sensor (14) has a defined minimum distance to the outer contour (18) of the vehicle (10), wherein the minimum distance is determined by the vibration damping time of the diaphragm of the acoustic sensor (14).

14. Vehicle according to claim 12 or 13, characterized in that the minimum spacing relative to an outer contour (18) of the vehicle (10) is 12-19 cm.

15. Vehicle according to one of claims 12 to 14, characterized in that the acoustic sensor (14) is arranged in a cutout (62) of a floor covering (64) and/or on a stiffening element (66) on the floor (12) of the vehicle (10).

16. Vehicle according to one of claims 12 to 15, characterized in that a plurality of acoustic sensors (14a,14b,14c,14d) are arranged on the floor (12) of the vehicle (10), wherein at least one first sensor (14a) is arranged on the floor (12) of the vehicle (10) in a front region of the vehicle (10), at least one second sensor (14b) is arranged on the floor (12) of the vehicle (10) in a rear region of the vehicle (10), at least one third sensor (14c) is arranged on the floor (12) of the vehicle (10) in a first lateral region of the vehicle (10), and at least one fourth sensor (14d) is arranged on the floor (12) of the vehicle (10) in a second lateral region of the vehicle (10).

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