GB2500290A

GB2500290A - Ultrasonic detector for vehicle

Info

Publication number: GB2500290A
Application number: GB1300386.8A
Authority: GB
Inventors: Matthias Karl; Peter Preissler
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2012-01-10
Filing date: 2013-01-09
Publication date: 2013-09-18
Anticipated expiration: 2033-01-09
Also published as: GB2500290B; FR2985816B1; DE102012200230A1; FR2985816A1; GB201300386D0

Abstract

An ultrasonic pulse sonar (sodar) is sensitive to climatic (environmental) influences such as air temperature, pressure, humidity, wind strength and direction, temperature changes, etc.. The detector produces a model of the climatic situation in the surroundings of the vehicle from the changes in the received acoustic signal. These variables are taken into account when detecting target range and velocity using a characteristic time curve and/or used for further vehicle functions (braking, acceleration, steering, maximum speed, steering, communication, active roll stabilization). The model of the climatic situation may be produced from propagation time differences of signals that have different propagation directions on otherwise identical propagation paths. Direct (non-reflected) signals may be used. Multiple sensors having different orientations may be used.

Description

Description ^

Title

5

Method and device for detecting the surroundings of a vehicle

Prior art

10

For acoustic detection of the surroundings of vehicles, systems are normally used at present that transmit and receive signals in the ultrasonic range. Systems that measure using pulses are preferably used. With these, 15 acoustic pulses at a frequency of approx. 50 kHz are typically emitted by an electroacoustic transducer at time intervals of 10 ms to 300 ms. The pulses are reflected at objects in the vicinity of the vehicle and received by transmitting or non-transmitting transducers. The distance '20 of the object can be determined from the pulse propagation times. Such a system is described, for example, in WO 2011009786 A1. Gusty wind and momentary temperature differences have a disruptive effect on such measurements * and can falsify the measuring results.

25

DE 33 41 .022 A1 describes a collision warning apparatus for motor vehicles, in which electroacoustic transducers transmitting in the ultrasonic range are used. Wind disruption is not taken into account here. It is described 30 that measuring errors can. be caused by wind in the ultrasonic measurement, as the sound waves are influenced by the wind.

2

DE 10 2009 027 842 describes the simultaneous use of the acoustic signals both for vehicle-vehicle communication and for detecting the vehicle positions relative to one another and the transmission of these vehicle-vehicle movement 5 relationships. Furthermore, further methods for the communication of vehicles with one another are known, for example by the use of radio waves.

DE 10 2005 013 589 describes a method for verifying the 10 function of an ultrasonic -sensor, in which at least one other ultrasonic sensor emits an ultrasonic signal and functioning of the first sensor is established if the amplitude of the signal transmitted by the first sensor without a reflection at an external obstacle exceeds a 15 preset, variable limit.

Disclosure of the invention

The object of the•invention is to specify a device and a 20 method for detecting the surroundings of a vehicle, wherein the influence of the climatic situation in the vicinity of the vehicle is detected and taken into account. Climatic situation in this case is understood to mean climatic properties of the surroundings of the vehicle, in 25 particular the stationary parameters, i.e. parameters that are unchanged over several measurements, and/or momentarily varying parameters of the current wind situation and/or the ambient temperature, in particular of the temperature differences occurring and/or of the air humidity and/or of 30 the air pressure. In particular, the climatic situation can also include changes in the propagation attributes of acoustic signals. In order to determine the influence of

3

the climatic situation, the current climatic situation in the area around the vehicle is determined from the structure of signal changes, which occur in the acoustic detection of the vehicle surroundings and are caused by 5 climatic influences such as wind, for example, and/or by temperature differences. Using this information, a model is produced of the momentary climatic situation, in particular the wind situation momentarily prevailing and/or the temperature differences, which model is taken into 10 account in the acoustic detection of the vehicle surroundings. Measuring errors that are caused by the climate, in particular by the wind and/or by temperature differences, can be compensated for by means of the model. The model can be used optionally to adapt further vehicle 15 functions and/or the driving dynamics to the current climatic situation, in particular to the wind situation, in order to counteract a hazard if applicable. In particular, braking, acceleration, controlling the maximum speed and/or steering of the vehicle can be considered in this case.

20

The invention is based on the"idea, when detecting the surroundings of a vehicle by means of acoustic signals, of detecting changes undergone by a modulated acoustic signal in particular as a result of climatic influences and of 25 producing a model of the momentary climatic situation in the surroundings of the vehicle from the changes in the signal. Variables such as the wind strength, for example, and/or components of the wind direction and/or the occurrence of changes in the propagation attributes of the 30 acoustic signal can be deduced from the model, wherein the changes in the propagation attributes occur as a result of climatic differences, in particular temperature

4

differences. These variables are taken into account in detecting the surroundings of the vehicle and/or used optionally for further vehicle functions. In particular, the model of the momentary climatic situation is produced 5 from propagation time differences of signals, which have different propagation directions on otherwise identical propagation paths. Alternatively or in addition, the model of the momentary climatic situation can be produced or completed on the basis of differences in the signal 10 strength of several signals that differ from one another and/or changes in the signal strength of one signal.

The invention provides a device for detecting the surroundings of a vehicle. This comprises at least one 15 transmitting device, which is formed in particular as an ultrasonic transmitter. The transmitting device is set up to emit a time-modulated acoustic signal. The device also comprises at least one receiving device, which is set up to receive an acoustic signal transmitted by the transmitting 20 device and reflected by one or more objects in the vicinity of-the vehicle. Furthermore, an evaluation apparatus is provided, which is set up to determine information with regard to distance and/or relative speed of the objects in a known manner from the signal received. According to the 25 invention, the evaluation apparatus is also set up to determine the momentary climatic situation in the vicinity of the vehicle.

The climatic situation is preferably determined by 30 recognising characteristic changes in a time curve of a test signal received by the receiving device. The .test signal can be generated by the transmitting device, for

5

example. The momentary wind direction and/or one or more components of the wind direction, and/or wind speed and/or ambient temperature and/or ambient temperature changes are calculated from the test-signal received.

5

In a particularly preferred execution of the invention, it is provided that at least two receiving devices are present on the vehicle.' The evaluation apparatus is set up to determine the momentary climatic situation from the 10 difference's between the test signals received by the receiving devices. To do this, methods such as cross-correlation can be used, for example, which permit differences in the received signals caused by wind and/or ambient temperature differences to be distinguished from 15 other influences, such as reflexivity differences of the objects to be detected or of mostly stationary air humidity of different strength, for example. .

It is especially preferable if at least two groups of one 20 transmitting device and one receiving device respectively are provided, wherein the groups each have different spatial orientations. Due to such an arrangement the accuracy and resolution of the determination of the momentary climatic situation in the vicinity of the vehicle 25 are improved.

The transmitting devices and/or the receiving devices preferably have electronic signal filters, the filter properties of which are adaptable as a function of the 30 momentary climatic situation. Due to the in particular automatic adaptation of the filters, the measuring accuracy of several consecutive measuring cycles can be increased. -

6

The invention also provides a method for the detection of the surroundings of a vehicle with the following steps:

- transmission of an in particular time-modulated acoustic signal, in particular an ultrasonic signal,

5 - receiving of the acoustic signal•• transmitted and reflected by one or more objects in the vicinity of the vehicle,- or transmitted on a direct path, by one or more receivers,

- determination of environmental variables of the vehicle, 10 in particular distance and/or relative speed and/or spatial dimensions of the objects, by evaluation of the signal received.

The following steps are also provided according to the ■invention:

15 - receiving of at least one time-modulated acoustic signal, in particular a test signal,

- production of a model of the momentary climatic situation in the vicinity of the vehicle, in that characteristic changes in the time curve of the signal received and/or

20 characteristic deviations in the direction of movement of the vehicle determined by means of the signal are recognised.

In a preferred execution of the method, the model of the 25 momentary climatic situation is determined from the propagation time differences between two or more test signals emitted in different, in particular opposed, directions and reflected at a stationary object. Alternatively or in addition, the momentary climatic 30 situation is, determined from the time behaviour of the signal strength of a received test signal, for example an

7

echo pulse, and/or by comparison of the time behaviour of two or more consecutive received test signals.

In another preferred execution of the method, the model of 5 the momentary climatic situation is determined from the propagation time differences in the direct transmission of test signals between at least two spatially separated devices, which are suitable for transmitting and receiving acoustic signals. These devices can all be provided on the 10 vehicle. Alternatively, one or more transmitting devices can also be mounted in particular fixedly in the vicinity of the vehicle.

The advantage of such an arrangement consists in the fact 15 that the distance between transmitting and receiving device is known, so that from changes in the signal, in particular shifts in the propagation time and/or in the period duration and/or in phase displacements and/or in the signal strength, in particular in the signal strength in 20 stationary scenes, i.e. in scenes in which the transmitting device,, the receiving device and if applicable the reflecting object located in the transmission path do not move relative to one' another or move according to known ■rules, model-relevant variables such as wind strength, for 25 example, and/or wind direction and/or air temperature can be deduced without further parameters, such as the relative speed or shape of an unknown object in the vicinity of the vehicle, having to be taken into account. ' A simplification of the production of the model of the momentary climatic 30 situation in the vicinity of the vehicle results therefrom.

8

The model of the momentary climatic situation is preferably produced and/or optimised by the evaluation of a momentary . echo curve and/or a momentary■echo period deviation of the test signal. Momentary echo curve is understood here as 5 the time curve of the amplitude of the received signal, in particular test signal. Via the time offset of the momentary echo curve compared with an expected displacement, which results from the distance between transmitting device and receiving device, a component of 10 the wind direction in the direction of the signal propagation can be deduced. If deviations in the amplitude curve also occur for the received signal with regard to the shape of the signal, turbulence due to the influence of the wind and turbulent wind flow can be deduced. Time 15 variations in the signal strength in static scenes, i.e. in scenes in which the- transmitting device, the receiving device and if applicable the reflecting object located in the transmission path do not move relative to one'another, are often the consequence of temperature variations. In 20 addition or alternatively, the momentary echo period deviation can be evaluated. The momentary echo period deviation is understood as the deviation of the period of the received signal from the period of the transmitted, modulated signal.

25

In a preferred execution of the invention, acoustic environmental signals are received at the same time in at least two spatially separated positions of the vehicle. The model of the momentary climatic situation in the 30 vicinity of the vehicle is "optimised advantageously by comparison of the received environmental signals. Due to the environmental signals, additional information from the

vehicle•surroundings is used to improve.the model of the momentary climatic situation. Interference is also recognised as such and can be ignored in the evaluation.

5. A correction in the determination of surrounding variables of the vehicle preferably.takes place by means of the model of the momentary climatic situation., in particular with regard to the distance and/or the relative speed and/or the spatial dimensions of objects. Errors in the detection of 10 the vehicle surroundings that are caused by wind and/or temperature variations and/or other climatic attributes can thus be compensated for in an advantageous manner. Furthermore, setting variables for detection of the surroundings, such as detection thresholds, for example, 15 can be adapted accordingly to the respective climatic situation.

In a preferred execution of the invention, acoustic signals are evaluated that propagate close to the vehicle surface. 20 These include the signals that are transmitted on a direct path between transmitter and receiver, wherein transmitter and receiver are mounted on the vehicle. Due to the proximity to the vehicle surface, influencing of the acoustic signals results. The signal strength of those 25 signals that move in the wind direction is thus increased and of those that move opposite to the wind direction it is decreased. Moreover, temperature differences between the air and the vehicle surface lead to temperature layering close to the surface. This in turn influences the 30 propagation of -the acoustic signals, in particular the signal strength. By evaluating the signal strength, its time curve or other characteristic features of the signal

10

received, it is possible to deduce temperature differences between the air and the vehicle surface. Such temperature differences indicate changes in the intensity of the solar radiation and changes in the air temperature as well as 5 certain driving situations such as entering/exiting tunnels or (underground) car parks. Carrying out combination with further data available in the vehicle, such as the vehicle speed, its time curve and/or the air temperature is especially advantageous for the purpose of evaluation.

10

Functions of the vehicle, in particular the driving dynamics, can preferably be adapted by inclusion of the momentary climatic situation. In addition, the driver can be warned by an acoustic or visual warning signal in the 15 event of hazards caused by the climatic situation, for example a strong side wind.

The vehicle functions that can be adapted as a function of the climatic situation include for example control of the 20 brakes and/or acceleration.

Steering of the vehicle, in particular•the steering angle, can preferably be adjusted as a function of the momentary climatic situation. To do this, a driving angle offset can 25 be determined as a function of the momentary wind situation, for example, or an already set driving angle, offset can be corrected. Likewise the steering ratio can be changed as a function of the momentary climatic situation, due to which effects of steering angles can be 30- influenced.

11

Alternatively or in addition, an active roll stabilisation is preferably realised that uses the information of the momentary climatic situation, in particular the wind situation. Furthermore, the possible maximum speed of the 5 vehicle can alternatively or in addition be adapted to the momentary wind situation, especially in very gusty wind. Communication can preferably also exist with another vehicle, via which information about the momentary climatic .situation is transmitted.

10

Alternatively or in addition, temperature differences established between the air and the vehicle surface are preferably used to regulate the air conditioning/heating of the vehicle interior. Furthermore, in the event of 15 temperature changes in the range around freezing point, a warning can be emitted to the driver. It is likewise conceivable that the very swiftly available information due to the evaluation of the acoustic signals is used to adapt the filter settings of other temperature measuring devices 20 of the vehicle. If entering/exiting a tunnel or a garage is recognised,'for example, adaptations to systems of driving dynamics, for example control adjustments to ABS/ASR can also be undertaken as a function of the air temperature.

25

Further features and advantages of the invention result from the description of the drawings and from the subclaims.

30 Brief description of the drawings

12

Figures 1 a) and b) show schematically the influence of the wind on the signal transmission from a transmitter to a receiver by reflection at an object.

•5 Figure 2 a) shows the echo curve of the.amplitude of the received signal without wind.

Figure 2 b) shows the echo curve of the amplitude of the 'received signal in a stationary side wind.

10

Figure 2 c) shows the echo curve of the amplitude of the . received signal in turbulence.

Figure 3 a) shows the echo curve of the momentary period 15 duration of the received signal without wind.

Figure 3 b) shows the echo curve of the momentary period duration of the received signal with a varying side wind.

20 Embodiments of the invention

The invention is to be described with reference to the propagation time measurement of acoustic - signals measuring in pulse mode. The signals here do not necessarily have 25 frequencies in the ultrasonic range, but can also lie in the audible frequency range, for example, or in the infrasonic range.

Equivalently the method can also be executed with signals 30 which were produced by means of other known modulation methods.- Examples of such modulation methods are e.g.

pulse patterns, chirp or m-ary multicarrier signals such as

13

e.g. frequency hopping, especially in the special forms FSK (frequency shift keying) or PSK (phase shift keying).

If a reflective object O is located at a distance d in the 5 case of systems that measure in pulse mode for the acoustic detection of the vehicle surroundings, as shown schematically in figure 1 a), then an echo of the signal ■ from transmitter S to receiver E at a sound velocity c needs an echo propagation time x,

r=2.^

10 c

As shown in figure 1 b, to clarify the influence of the wind, an emitted acoustic signal is divided in an exemplary way into a component 11 and a component 12, wherein the 15 component 12 represents the portion of the signal that propagates in the wind direction. Component 12 of the emitted acoustic signal is moved in addition to sound velocity c by wind at a speed- vw, while the component 11 propagates exclusively at the sound velocity c. The 20 following applies accordingly:

14

T, = 2- —

t2=2-

c + v.

w

Ar =r2 -t, = 2

c l+2k

^«i

At « 2 ■ — • vw c where Xi designates the echo propagation time of the component 11 and X2 the echo propagation time of component 12.

5

With an exemplary object distance d of approx. 6 m and a sound velocity c of 340 m/s, a propagation time change of Ax « 104 ]js results at a wind speed vw of 1 m/s. At a typical carrier frequency of the acoustic signal of fc = 48 kHz, 10 this propagation time change Axis equivalent to roughly 5 signal periods. Even in fine weather, wind gusts of 5 to 10 m/s can occur, which can correspond to a propagation time change Ax of up to 1 ms.

15 Moreover, the influence of the wind on the air temperature . cannot always be disregarded. The following relationship is known to apply to the temperature dependence of the sound velocity c:

15

C(T)=331,5-

s I

273,15K s IK

A temperature difference AT thus likewis.e causes a propagation time change Ax, according to

A

T, = 2 ■

At-I,

V

1 +

A71

-1

Ar « -

■H?)

-d-AT c(T) T 20,063mls-4¥

d AT

At an exemplary object distance d of 6m and an air temperature T of 20°C, a temperature change AT of 1 K leads 10 to a propagation time change Ax of approx. 60 i_ts, which already corresponds to roughly 3 signal periods at a typical carrier frequency of fc = 48 kHz. If it is taken into account that a signal loss can already occur due to destructive superimposition at a propagation time 15 difference Ax of half a signal period, then at a propagation time difference Ax of roughly 3 signal periods, manifold changes in'the signal strength are to be expected.

16

This effect is utilised according to the invention to obtain information about the current climatic situation and produce a model therefrom, which can be used to correct the effects caused by climatic variations, in particular by 5 wind and/or temperature differences.

Figure 1 a) clarifies the cross-influence of side wind in the example of a signal that is emitted by a transmitter S, reflected at an object 0 and detected by a receiver E. The 10 cross-influence due to stationary side wind in direction vwi from the left is shown by the dashed arrow, the cross-influence due to stationary side wind in direction vw2 from the right is shown by the continuous arrow.

15 In the evaluation of the received signal, the influence of the side wind makes itself noticeable, as shown in figures 2 and 3. Figure 2 shows the curve of the amplitude of the signal that is detected by the receiver. This signal is also described as an echo curve of the amplitude. Figure 3 20 shows the deviation of the period duration of the received echo signal from the period duration of the transmitted signal. This deviation is also described as momentary period duration deviation.- "Valid" in this context means that the momentary period duration deviation is determined 25 during a measuring period during which the amplitude of the echo signal is sufficiently great, thus lies for example above a certain threshold value A0. The influence of disturbances due to noise and ambient noise on the measurement is thus reduced. The illustration in figure 3 30 .is chosen so that a contraction of the period duration produces a positive momentary period duration deviation and

17

an extension of the period duration produces a negative momentary period duration deviation.

In figures 2 a) and 3 a) the situation without wind is 5 shown. The echo is received by the receiver E at a time To, which corresponds to the expected propagation time of the signal at a defined distance d of the object 0. As shown in figure 2 a) , the echo curve of the amplitude 200 has a maximum at time x0. No change in the period duration is 10 established. As shown in figure 3 a), the momentary period duration deviation 300 is close to zero.

In figure 2 b) the situation with a stationary side wind is shown. The dashed curve 210 corresponds to the measured 15 echo signal with a stationary side wind in direction vwi from the transmitter S to the receiver E. The continuous curve 220 corresponds to the measured echo signal with a stationary side wind in direction vw2 from the receiver to the transmitter S.

20

The echo signals 210 and 220 are received by the receiver E at times xwi and xw2. If the wind has a stationary component vwi in the propagation direction of the signal, this leads to a contraction in the propagation time. If the wind has 25 a stationary component vw2 opposite to the propagation direction of the signal, this leads to an extension of the propagation time. The direction and strength of the side wind can thus be calculated from the differences Xo-x„i and Xq—Xw2 .

30

18

If there is a turbulent wind flow, turbulence of the signal occurs. The shape of the echo curve of the amplitude 230 .is changed thereby, as shown by way of example in figure 2 c). The degree of turbulence of the wind flow can thus 5 be. deduced from the deviation of the shape of the echo curve of the amplitude 230 compared to the shape of the emitted signal.

As shown in figure 3b, variable side wind leads to a change 10 in the momentary period duration deviation. Side wind with a variable component in propagation direction from .transmitter to receiver at a wind speed vwi leads to a contraction in the period duration of the modulated acoustic signal and thus to a positive momentary period 15 duration deviation 310. .Side wind with a variable component opposite to the propagation direction from transmitter to receiver at a wind speed vw2 leads to an extension of the period duration of the modulated acoustic signal and thus to a negative momentary period duration 20 deviation 320. From the amount and the direction (positive or.negative) of the deviation, the direction and strength of the momentary side wind can thus likewise be deduced.

If transmission of a signal from E to S also takes place in 25 the arrangement according to figure 1, the transverse portion of the wind flow can be determined even without precise knowledge of the air temperature T and thus of the sound velocity c. By means of the known distance dSE the temperature-dependent portion of the sound velocity c can 30 be concluded in this way and the-external temperature T can . be deduced thus by precise evaluation of the propagation

19

time differences of the direct transmission of the signal-between E and S.

Figure 1 c) shows the general situation with two sensors A .5 and.B, which act respectively as transmitter or receiver. In a stationary wind situation, the external temperature T can be determined from the mean value of the propagation time of a signal from a point A to a point B and the propagation time from point B to point A, each along the 10 known distance dAB- The speed of the stationary wind can be deduced from the difference of the two propagation times. Moreover, further climate features can be deduced. For example, conclusions can also be drawn as to the air humidity from the stationary changes in the signal strength 15 in the propagation along the known distance dAB, as the average signal attenuation is dependent on the moisture content of the air. In unchanged propagation conditions, constructive or destructive superimpositions of the sound signals, which have propagated for example along different 20 paths in different wind and/or temperature situations, can be deduced from the momentary variations in signal strength.

If an object 0 is located before the sensor pair A, B and 25 reflects a sound signal emitted by one sensor to the other sensor respectively, on the path of.the same length AOB or . BOA respectively, the wind speed prevailing perpendicular to the propagation route dflB can also be deduced from the propagation time differences along the different paths.

30

If only the propagation time on a given route, e.g. from A to B, is known, then the cause with reference to a

20

propagation time change in a transmitted signal cannot yet be established unambiguously, as a temperature change and a change in wind speed can bring about the same propagation time change. Only by comparison with the propagation times 5 in the opposite direction, e.g. from B to A, and on the assumption of stationary wind and temperature conditions can the directed variable "wind" be separated from the scalar variable "ambient temperature".

10 This method of separation is applicable on the assumption that the wind speed and/or temperature does not change between the transmission from A to B and the transmission from B to A (stationary climatic situation). Rapidly changing climatic variables, in particular in the case of 15 changes for which there is no deterministic description model, can be detected if the propagation times are recorded simultaneously on both transmission paths A to B and B to A. This can be realised, for example, by emitting a signal shape F1 from A to B and by the simultaneous 20 emission of a signal shape F2 different from Fl, separable for example by filtering, from B to A. The differences in both transmission directions can thus be detected at the same time.

25 Figure 4 shows a motor vehicle 1, which is equipped with a device according to the invention. The side wind acting on the motor vehicle 1 is indicated symbolically by an arrow 2. The device has two acoustic sensors, for example ultrasonic sensors, arranged on the left-hand side and two 30- arranged on the right-hand side of the motor vehicle 1, 3a and 3b and 3c and 3d respectively, wherein one of the sensors on the left side and on the right side respectively

21

is arranged in the front area of the motor vehicle, preferably in the area of the front fender, and one of the sensors on the left side and on the right side respectively is arranged in the rear area of the motor vehicle 1, 5 preferably in the area of the rear fender. Such sensors are often originally assigned to a driver assistance system, for example a parking assistance system, and serve to measure the distance to an obstacle located in the vicinity of the motor vehicle. To this end, further 10 sensors 4 are arranged in the front area and the rear area ' of the motor vehicle 1. On many vehicle models, sensors are also used to monitor the dead angle, and these can be used to determine the momentary climatic situation according to the invention. Here the sensors 3a, 3b, 3c, 15 3d, 4 can be used respectively as transmitters and as receivers for the arrangement shown in figure 1. For example, the sensor 3a can emit a modulated acoustic signal. The signal is"reflected at an object 8 and received again by the sensor 3a. Alternatively or in 20 addition, the signal can also be received by another of the sensors 3b, 3c, 3d, 4 arranged on the vehicle.

The sensors 3a to 3d and 4 are connected via signal lines 5, which can be executed for example as a CAN bus or also 25 as a point-to-point connection, to an evaluation apparatus 6 for evaluating the sensor signals.

By evaluating and comparing the transmitted and received signals through the evaluation apparatus 6, a model of the 30 momentary climatic situation in the vicinity of the vehicle 1 is produced. The evaluation apparatus 6 forwards the information about the momentary climatic situation to a

22

control unit 7, which controls functions of the vehicle, such as braking, acceleration, steering, the maximum speed, the steering angle, communication with another vehicle and/or active roll stabilisation according to the climatic 5 situation. Furthermore, a correction can take place in the evaluation apparatus 6 of the distance measuring values, which were measured in the context of detecting the surroundings of the vehicle by the sensors 3a, 3b, 3c, 3d, 4, wherein the momentary climatic situation is taken into 10 account.

Stationary wind flows run around the vehicle 1 according to known laws. Depending on the vehicle contour and strength of the wind flow, these are turbulent or laminar flows. 15 Due to the fact that several sensors 3a, 3b, 3c, 3d and 4 are arranged in different orientations around the vehicle, the momentary stationary wind situation in the vicinity of the vehicle can be determined alternatively or in addition by evaluating the propagation time differences in a direct 20 transmission of a test signal between the sensors 3a, 3b, 3c, 3d and 4, without a reflection taking place at an obj ect.

In addition, it can be provided that acoustic environmental 25 signals are received simultaneously in at least two spatially separated positions of the vehicle, for example by the sensors 3a, 3b, 3c, 3d or 4. The model of the momentary climatic situation in the vicinity of the vehicle can be improved still further by comparing the 30 environmental signals.

23

The device according to the invention is shown in figure 4 with two sensors on the left side and two sensors on the right side respectively. Even with only one sensor arranged respectively on the left side and the right side, however, determination of the momentary climatic situation according to the invention is possible. Likewise, more than two sensors can naturally also be arranged on both sides of the vehicle.

Claims

Device for detecting the surroundings of a vehicle (1) comprising at least one transmitting device (S, A, B), in particular an ultrasonic transmitter (3a, 3b, 3c, 3d, 4), which is set up to transmit a modulated, acoustic signal,

at least one receiving device (E, A, B), which is set up to receive an acoustic signal transmitted by the transmitting device (S, A, B) and reflected by one or more objects (0) in the vicinity of the vehicle (1) or transmitted directly between transmitter (A, B) and receiver (B, A), an evaluation apparatus (6), which is set up to determine information with regard to distance (d) and/or relative speed between the vehicle (1) and one or more objects (0, 8) from the signal ■ received,.

characterised in that

- the evaluation apparatus (6) is set up furthermore to determine the momentary climatic situation, in particular the wind situation • and/or the ambient temperature and/or the air humidity, in the vicinity of the vehicle (1).

Device according to claim 1, characterised in that

- the evaluation apparatus (6) is set up furthermore to determine .temperature differences between the ambient temperature and the surface of the vehicle (1).

Device according to one of claims 1 or 2,

characterised in that the evaluation apparatus (6) determines the climatic situation, in particular the wind situation and/or the ambient temperature and/or temperature differences between surroundings and vehicle surface, in that characteristic changes in a time curve (200, 210, 220, 230, 300, 310, 320) of a test signal received by the receiving device (E) are recognised and from these the momentary wind direction and/or one or more components of the wind direction, and/or wind speed and/or the ambient temperature and/or temperature differences are calculated.

Device according to claim 3, characterised in that at least two receiving devices (3a, 3b, 3c, 3d) are provided, and the evaluation apparatus (6) is set up to determine the momentary climatic situation, in particular the wind situation and/or the ambient temperature and/or the air humidity, from the differences in the respective test signals received by the receiving devices (3a, 3b, 3c, 3d).

Device according to claim 4, characterised in that at least two groups each comprising a transmitting device and a receiving device (3a, 3b, 3c, 3d, 4) are provided, wherein the groups have different spatial orientations.

Device according to one of claims 1 to 5,

characterised in that the transmitting device and/or' the receiving device (3a, 3b, 3c, 3d, 4) have electronic signal filters, the filter properties of

26

which are adaptable- as a function of the momentary climatic situation.

Method for detecting the surroundings of a vehicle (1)' with the following steps: •

- transmission of an in particular time-modulated acoustic signal, in particular of an ultrasonic signal,

- receiving by one or more receivers of the acoustic signal transmitted and reflected by one or more objects in the vicinity of the vehicle or transmitted on a direct path,

- determination of environmental variables of the vehicle (1), in particular distance and/or relative speed and/or spatial dimensions of the objects (8, 0) by evaluation of "the signal received,

characterised in that furthermore the following steps are provided:

- receiving of at least one time-modulated acoustic signal,

- production of a model of the momentary climatic situation, in particular of the momentary wind situation and/or ambient temperature in the vicinity of the vehicle (lj, in that characteristic changes in the time curve (200, 210, 220, 230, 300, 310, 320) of the received test signal and/or characteristic deviations in the direction of movement of the vehicle (!) determined by means of the test signal are detected.

Method according to claim 7, characterised in that the model of the momentary climatic situation, in

27

particular of the momentary stationary wind situation and/or ambient temperature, is determined from the propagation time differences between two test signals emitted in opposed directions and reflected at a 5 stationary object (0).

9. Method according to claim 7, characterised in that the model of the momentary climatic situation, in-particular of the momentary wind situation and/or

10 ambient temperature, is determined from the propagation time differences in the direct transmission of test signals between at least two spatially separated devices (3a, 3b, 3c, 3d, 4), which are suitable for transmitting and receiving acoustic

15 signals.

10. Method according to one of claims 7 to 9,

characterised in that the model of the momentary stationary climatic situation, in particular of the

20 momentary stationary wind situation and/or ambient temperature and/or air humidity, is determined by evaluation of momentary echo curve (200, 210, 220, 230) and/or momentary echo period deviation (300, 310, 320) of the test signal.

25

11. Method according to one of claims 7 to 10, characterised in that acoustic environmental signals are received simultaneously in at least two spatially separated positions of the vehicle (1), wherein by

30 comparison of the environmental signals the model of the momentary climatic situation, in particular of the momentary wind situation and/or ambient temperature

28

and/or air humidity, is optimised in the vicinity of the vehicle.

12. Method according to one of claims 7 to 11,

5 characterised in that by means of the model of the momentary stationary climatic situation, in particular of the momentary wind situation and/or ambient temperature and/or air humidity, a correction of the measurement of environmental variables of the vehicle 10 (1), in particular distance and/or relative speed and/or spatial dimensions, of objects, is made.

13. Method according to one of claims 7 to 11, characterised in that the model of the momentary

15 climatic situation, in particular of the momentary solar radiation as well as the momentary change in ambient temperature, is determined from the signal strength in the transmission of test signals close to the vehicle surface, in particular in the direct 20 transmission between at least two spatially separated devices (3a, 3b, 3c, 3d, 4), which are suitable for transmitting and receiving acoustic signals.

14. Method according to one of claims 7 to 13,

25 characterised in that functions of the vehicle (1), in particular the driving dynamics, are adapted by inclusion of the momentary climatic ^situation, in particular of the momentary wind situation and/or ambient temperature and/or air humidity and/or 30 temperature changes.

29

15. Method according to claim 14, characterised in that the adaptable functions of the vehicle include braking and/or acceleration and/or steering and/or the maximum speed and/or the steering angle and/or communication

5 with another vehicle and/or active roll stabilisation.

16. Method-according to claim 14 or 15, characterised in that the adaptable functions of the vehicle (1)

include the air conditioning as well as temperature

10 measurement by means of sensors installed in the vehicle by inclusion of the momentary temperature differences between ambient temperature and vehicle surface.

15 17. Method according to claim 16, characterised in that in the event of temperature changes, a warning is output if applicable to the driver.

18. Method according to one of claims 14 to 17,

20 characterised in that on the basis of a temperature change detected by means of acoustic signals, the filter settings of other temperature measuring devices of the vehicle and/or of driving 'dynamics systems of the vehicle are adapted.

25

19. A device for detecting the surroundings of a vehicle substantially as herein described with reference to the accompanying drawings.

30 20.

A method for detecting the surroundings of a vehicle substantially as herein described with reference to the accompanying drawings.