EP2956340A1

EP2956340A1 - Method and beam sensor module for determining the condition of the road ahead in a vehicle

Info

Publication number: EP2956340A1
Application number: EP14703382.3A
Authority: EP
Inventors: Sighard SCHRÄBLER; Bernd Hartmann; Marc Menzel; Hans Magnusson
Original assignee: Conti Temic Microelectronic GmbH; Continental Teves AG and Co OHG
Current assignee: Conti Temic Microelectronic GmbH; Continental Teves AG and Co OHG
Priority date: 2013-02-12
Filing date: 2014-02-10
Publication date: 2015-12-23
Also published as: US20150375753A1; KR20150119136A; WO2014124895A1; DE102013002333A1; CN104995070A; JP2016507750A

Abstract

The invention relates to a method for determining the condition of the road ahead in a vehicle, according to which method the road surface (113) is illuminated with sensor beams (106, 106'), said sensor beams (106, 106 ') being reflected and absorbed in accordance with the condition of the road surface (113) and the condition of the road being determined on the basis of the reflected sensor beams (115). The method is characterised in that the road surface (113) in front of the vehicle in the direction of travel is illuminated. The invention also relates to a corresponding beam sensor module.

Description

Method and radiation sensor module for predictive road condition determination in a vehicle

The invention relates to a method for predictive road condition determination in a vehicle according to the preamble of claim 1 and to a beam sensor module for predictive road condition determination in a vehicle according to the preamble of claim 7.

In the prior art is already a variety of different sensor systems for the automotive sector

Area survey known. By means of these sensor systems for example it is possible to detect other vehicles, Straßenbeschilde ^¬ conclusions or trace limits. Camera sensors, lidar sensors, laser sensors or radar sensors are often used as sensors. The thus detected

Environment information can be used for safety-related interventions, such as autonomous braking or steering interventions. Furthermore, vehicle sensors are known, which primarily determine a vehicle state, but also allow conclusions about environmental conditions, such as inclination sensors.

In this context, DE 10 2007 062 203 A1 discloses a method for determining a coefficient of friction between a

Automotive tire and the surface of a road during acceleration of the motor vehicle. In this case, a first coefficient of friction parameter is determined using a model, wherein a functional relationship between the first friction coefficient parameter and a drive-dependent determined slip of the motor vehicle tire is predetermined. Furthermore, a second Reibwertparameter is determined from the quotient between a longitudinal force and a contact force of the motor vehicle tire and Finally, the coefficient of friction by means of a recursive Schätzal ^¬ rithm of the first and second coefficient of friction parameter determined. The slip is determined from the rotational wheel ^¬ speeds, the longitudinal force of a certain engine torque and the contact force of a longitudinal acceleration and a lateral acceleration. The rotational wheel speeds in turn are usually by means of a

ABS sensor technology determined. In DE 10 2009 008 959 a vehicle system for navigation and / or driver assistance is disclosed. The vehicle system provides the driver via a so-called virtual horizon environmental information in which also by means of a sensor detected environmental information, which allow conclusions about the road condition, incorporated. For this purpose, for example, in a braking operation by means of an electronic brake system, a low coefficient of friction can be detected. Wetness can be detected by a rain sensor or by operating the windscreen wipers. A potential icing of the road may e.g. from the combination of temperatures near freezing and passing a bridge.

DE 10 2012 203 187 AI describes a method for the prediction and adaptation of Bewegungsstra sectors of a motor vehicle to support the driver in his driving task and / or to prevent a collision or reduction of consequences of an accident. In this case, braking and / or steering interventions are provided, which are made in dependence on a calculated Bewegungsstra ektorie in the brake and / or steering system. In order to ensure that the wheel forces resulting from the movement trajectories through combined braking and / or steering interventions are always below the maximum available friction coefficient, this is determined by means of optical roadway sensors, such as laser and / or camera sensors. Also described a determination of the maximum available coefficient of friction by means of vehicle dynamics control systems, driving stability control systems, slip control systems and the inclusion of information from rain, temperature or tire sensors as well as information received by means of car-to-X communication.

From DE 10 2011 015 527 AI sensor for determining a condition of a road surface for a motor vehicle is known. The condition may be a condition such as wet, dry, icy, snowy or a combination thereof. The sensor comprises a light source unit which emits light in at least two mutually different wavelengths and at least two detectors for detecting the reflected light of the light source unit. Depending on the condition of the road surface, the different ones

Wavelengths are reflected differently strong, a conclusion can be drawn from the reflected light on the condition of the road surface. The described sensor is suitable for detecting the condition of a road surface which is illuminated substantially perpendicularly at a distance of 10 cm to 100 cm.

A disadvantage of the methods and devices known from the prior art, however, is that a road condition in many cases is not directly determinable, but only from other parameters, such as. Temperature and humidity, is derived. If the road condition is to be detected directly in accordance with the prior art, this is essentially only possible immediately when driving over the road section to be examined. Especially when using optical

Road condition detection sensors are mounted on the underside of the vehicle according to the prior art and directed at the road surface below the vehicle. However, this limits vehicle dynamics control systems in their effectiveness because they do not have directly measured and forward-looking information about road conditions.

The invention is therefore based on the object to propose a method which allows a predictive determination of a road condition.

This object is achieved by the method for predictive road condition determination in a vehicle according to claim 1.

The invention relates to a method for predictive road state determination in a vehicle, in which a road surface illuminated by sensor beams, wherein the sensor beams are reflected and absorbed in accordance with a road condition of the road ^¬ ßenoberfläche and wherein the road state determination is based on the reflected sensor beams. The method is characterized by the fact that the road surface in the direction of travel is illuminated in front of the vehicle.

In the sense of the invention, the term road condition means different states of the road surface with regard to their coefficient of friction, in particular the states "wet", "dry", "ice-covered" and "snow-covered" are ^different , whereby combinations of the road conditions mentioned are also possible. For example, a puddle of water may cover a layer of ice, so that a combination of the road conditions "wet" and "ice-covered" would exist and be recognized accordingly.

According to the road condition is therefore not only un ^¬ determined indirectly under the vehicle, but with foresight front of the vehicle. This results in the advantage that the particular road condition eg a driving stability control system can be provided early. The Fahrsta ^¬ bilitätsregelsystem can thus be prepared in time and situation-specific before the onset of a critical situation on this. Taking into account the current speed of the vehicle and the set range of the sensor beams, it is also possible to determine the point in time until the respective illuminated road surface is passed over, so that a setting of a largely optimally adjusted setting is

Driving stability control system to all recognized road conditions is possible.

Likewise, a warning to the driver can be given in advance, in order to avoid this, e.g. It should be pointed out that soon it will run over an ice-covered road surface and accordingly should avoid violent steering movements or braking or acceleration processes.

It is preferably provided that a lighting of the road surface and a detection of the reflected sensor beams takes place synchronized-pulsed. On the one hand, a mean emitted radiation power can thus be reduced, which contributes to increasing the service life of the utilized radiation element. In addition, the risk of causing eye damage to people or animals looking into the sensor beams is reduced. At the same time, the energy of an individual

Light pulses are significantly greater than a given in continuous operation over the same period amount of energy, whereby the signal to noise ratio of the information in the reflected sensor beams greatly improved in the road condition determination. In particular, for the improvement of the signal-to-noise ratio, it is important that the detection takes place synchronized with the illumination. In addition, it is preferred that the sensor beams comprise different wavelengths, in particular laser beams with intensity maxima at at least two different wavelengths. This simplifies the determination and, in particular, the differentiation of different road conditions. When using laser beams with intensity maxima at at least two different wavelengths, these advantages are further enhanced by the comparatively high light intensity of the laser beams in a comparatively narrow wavelength band.

In particular, it is preferred that the Straßenzustandsbe ^¬ humor is effected based on intensities of the different wavelengths in the reflected radiation sensor. Since the different road conditions of the road surface have un ^¬ different optical properties and accordingly ^¬ absorbent for certain wavelengths and other reflective, can be concluded from the reflected sensor beams on the particular road conditions of the illuminated road surface. An example of this is the wavelength of 1550 nm, which is relatively strongly absorbed by ice.

Furthermore, it is particularly preferred that the different wavelengths in the reflected sensor beams (115) are assigned to the road condition by means of stochastic assignment methods, in particular by means of a support vector method and / or a k-means algorithm. This results in a ver ^¬ tively reliable detection of different road conditions than with rigidly predetermined limit values for the detection is possible. Above all, it has been found that this is with regard to the detection of combinations of simultaneously existing road conditions, such as a layer of snow, which is located above a layer of water, significant improvements in the reliability of detection. The recognition of such a combination of road conditions is of particular importance in that an ice layer lying under the snow layer represents a significantly greater risk for the driving stability of the vehicle than it emanates from the snow layer above. The person skilled in the art is familiar with various suitable stochastic assignment methods which, taking into account properties of the reflected sensor beams such as variances, standard deviations and mean values, permit assignment to the particular road condition. In particular, those skilled in the art know the so-called support vector methods, which represent the information in the reflected sensor beams in a multi-dimensional space and whose spatial distribution is a reliable determination of the

Road conditions allowed. These support vector methods are also known as "support vector methods." In general, they allow the efficient finding of global minima without being disturbed by local minima, which is achieved in particular by exploiting a multidimensional vector space The k-means algorithms, which assign elements from a set of similar objects to a given number of different groups, are also known to the person skilled in the art, and the k-means algorithms are therefore often referred to as so-called Furthermore, it is preferably provided that the different road conditions are first learned by means of a learning process, which also improves the reliability in the recognition of the different road conditions

Road conditions. In addition, it is provided that a specific road condition is continued on at least one driving stability control system and / or vehicle dynamics control system, in particular an anti-lock braking system and / or an Electronic Stability Program and / or chassis control system, wherein the at least one driving stability control system and / or

Vehicle dynamics control system by means of the specific road condition performs a locally synchronous adjusted control. The control of such a driving stability control system or vehicle dynamics control system therefore improves since, as already described, it already knows in advance the expected coefficient of friction of the road surface and can adopt a corresponding presetting as starting point for a subsequent control. Under locally synchronously adjusted control is understood according to the invention that, taking into account the vehicle speed of the time of crossing the respective point of the road surface whose road condition has been determined, is determined and thus the corresponding default can be made synchronously with the passing of this point.

The invention further relates to a radiation sensor module for predictive road state determination in a vehicle which tektorelement at least two radiating elements, at least one disassembly, an analysis module and a sensor housing, said at least two radiating elements illuminate a road ^¬ ßenoberfläche with sensor beams, wherein the sensor beam of a in accordance with Road condition of the road ^¬ surface reflected and absorbed, wherein the at least one detector element detects the reflected sensor beams and wherein the analysis module makes the road condition determination based on the detected by the at least one detector element reflected sensor beams. The radiation sensor module is characterized by the fact that the sensor housing is transmission is formed on an inner side of a vehicle windshield.

The sensor housing comprises the radiating elements, the detector element and optionally the analysis module, wherein the Analy ^¬ semodul can also be arranged outside the sensor housing. The sensor housing is preferably open to one side. Only by attaching the Sensoreinhausung on the windshield, the open side is closed by the vehicle windshield.

Preferably, the radiation sensor module is mounted on the inside of the vehicle windshield at the level of the rear mirror. In this position, it limits the driver's forward vision is not and has good Beleuchtungsbe ^¬ conditions for lying ahead of the vehicle road surface. Another advantage of this mounting position is that the open side of the sensor housing, through which the sensor beams are emitted and detected, is regularly cleaned by the wiper or wiper of the vehicle. This ensures that the radiation sensor module is not affected in its operation by impurities in the beam path of the sensor beams. By contrast, this is not the case with the prior art optical sensors usually mounted under the vehicle.

Since the radiation sensor module illuminates the road surface in the direction of travel in front of the vehicle as a result of its attachment, this also results in the advantages already mentioned in this connection.

It is preferred that the beam elements are semiconductor lasers of different wavelengths in the wavelength range from 900 nm to 1700 nm, in particular with intensity maxima in the case of Wavelengths 980 nm and / or 1310 nm and / or 1550 nm. These wavelengths are all in the so-called infrared spectral range and are therefore not visible to the human eye, but still pose a threat, since they can nevertheless damage z the human eye z. Thus, irritation of other road users are avoided. The wavelengths mentioned also offer the advantage that they can be produced by means of semiconductor lasers, with gallium-arsenide-based semiconductor lasers and indium-phosphite-based semiconductor lasers in particular being suitable for this purpose. Germanium-based semiconductor lasers are also suitable. Semiconducting ^¬ terlaser are relatively inexpensive and very compact components with high radiation power. If only a single detector element is used for detecting the reflected sensor beams, it is preferably provided to operate the beam elements offset in time, so that only one beam element is in operation and accordingly only one wavelength is emitted or reflected. The analysis module knows the respective operating ^{times of} the individual radiation elements. Thus, the different wavelengths can be evaluated chronologically. Furthermore, it is preferred that a radiation power of the at least two radiation elements does not exceed 1 mW, wherein the radiation power is determined in particular on an outer side of the windscreen. This ensures that damage to human and animal eyes due to the radiation power is avoided. In addition, by determining the radiant power on the outside of the windshield and setting it to 1 mW, no harmlessly usable radiant power is transmitted

Rear reflection effects through the windscreen unused calmly. Since reduced radiation power is accompanied by a reduction of the possible sensor range, the radiant power is preferably determined on the outside of the windshield and set to 1 mW. It is thus the maximum possible radiation power, which is harmless to the human eye, used. Typically, 40% to 60% of the radiant power is reflected by the windshield directly back into the beam sensor module. In particular, it is preferred that the radiation power is emitted pulsed. Since the emitted an average radiation ^¬ performance is paramount to damage to the human or animal eye, the beam elements have a much higher energy can therefore during the "on-phase" shortly be issued than would be possible in continuous operation in the same period, In addition, with regard to the reliability of the determination of a road condition, a significant improvement can be achieved since the signal to noise ratio of the information in the reflected sensor beams at the

Road condition determination increased. This in turn increases the range of the radiation sensor module, within which a reliable determination of the road condition is possible. It is advantageous that the detector element one of the

Windshield determined in the radiation sensor module back reflected portion of the radiation power and the radiation sensor module based on the back-reflected portion of the radiation ^¬ performance on the outside of the vehicle windshield controls. This has the advantage that always the maximum possible, yet harmless to the human eye Strah ^¬ lung power is the road condition determination. Thus, for example, aging effects of

Radiation elements are compensated. In particular, it is advantageous that the beam elements are switched off ^¬ if no back-reflections are detected. In this case it must be assumed that the vehicle windshield to lens ensor module is no longer in front of the radiation, for example due to a driving ^¬ convincing to accident or repair in a workshop. To avoid eye injuries, the radiating elements are switched off in this situation.

It is also advantageous that the radiation sensor module for each radiating element comprises a separate detector element corresponds to its respective sensitivity maximum of the wavelength of the Intensi ^¬ tätsmaximums of the respective beam element. Thus, a simultaneous analysis of the reflected sensor beams can take place, which can therefore also be emitted simultaneously. A temporally offset driving of the beam elements and a synchronization of the detector element are thus not necessary. In addition, in this case, detector elements can be used which have their respective maximum sensitivity of the wavelength at the wavelength of the intensity maximum of the respective beam ^¬ elements, which allows a comparatively more reliable Be ^¬ mood of the road condition and a higher range of the beam ^{sensor module} . However, since the detector element is a comparatively expensive part of the ray sensor ^¬ module, a single detector element may also be used which has a sufficiently wide sensitivity analyzes tätsbereich to detect the different wavelengths of the different radiating elements. In the latter case, the use of wavelength-dependent correction factors may be useful.

It is expediently provided that the detector element is a photodiode, in particular an inductive element. um-gallium arsenide-based photodiode or a germanium-based photodiode. Photodiodes generate an electrical current that is dependent on the wavelength of the light and the intensity of the light impinging on it. Thus, photodiodes are very well suited as detector elements in the context of the invention. The generated current is a measure of the reflected or absorbed sensor beams. When using a Ger manium-based photodiode as a detector element, this is preferably cooled, for example by means of a Peltier element.

Expediently, it is provided that the radiation sensor module further comprises a blocking filter for visible light, which screens the detector element. This reduces Störein ^¬ rivers and prevents false positives. Thus, the reach can be wide, within which a reliable determination of the road ^¬ ßenzustands is possible to be enlarged.

It is preferably provided that the radiation sensor module further comprises at least one converging lens, which focuses the reflected sensor beams on the at least one detector element. Thus, the intensity of the reflected sensor beams guided on the detector is increased. This also leads to a more reliable determination of the road condition and an increase in the effective sensor range of the radiation sensor module. It should be noted that suitable materials must be chosen for the at least one condenser lens which does not absorb the infrared sensor beams.

It is expediently provided that the radiation sensor module comprises a connection to a vehicle bus and, in particular, carries on information about a detected road condition to at least one further vehicle system. Thus, the information about the detected road condition can be made available to another vehicle system, eg a driving stability control system. Since this is already provided ahead with information about the immediately following road conditions, it may also vo ^¬ out looking determine the expected between the road surface and tire coefficient of friction and to adapt to this. Thus, the driving stability control simplifies and there is an increase in driving stability and driving safety compared to systems that can only determine the coefficient of friction immediately when driving over the respective road surface and can not anticipate this set.

Advantageously, it is provided that the at least two radiation ^elements deliver no radiation power in a vehicle ^standstill . Especially when the vehicle is at a standstill, there is a risk that a person, eg a pedestrian, looks directly into the radiation elements from a short distance and thus is exposed to an increased risk of eye damage. This danger can thus be avoided. In addition, it is preferred that the radiation sensor module a

Process according to at least one of claims 1 to 5 executes. This results in the advantages already described.

Further preferred embodiments will become apparent from the subclaims and the following description of an embodiment with reference to figures.

1 shows schematically a radiation sensor module according to the invention during a road condition determination,

2 shows a flow chart with a possible sequence of the method according to the invention and Fig. 3 absorption capabilities of water and ice at three different wavelengths. 1 shows radiation sensor module 101 with housing 103, which is designed in such a way that radiation sensor module 101 can be arranged on the inside of vehicle windshield 102 at the level of the rear mirror base. Windshield 102 closes the open front of enclosure 103. For the sake of clarity, radiation sensor module 101 is shown in cross-section in FIG. 1, so that the walls of enclosure 103 closing the side surfaces are not shown and reveal the interior of enclosure 103. Radiation sensor module 101 further comprises detector element 104, which is designed, for example, as indium gallium arsenide photodiode,

Barrier filter 105 to reduce the incidence of daylight interference on detector element 104, converging lens 111 which focuses reflected sensor beams 106, 106 ^y and all sensor beams (not shown) between sensor beams 106 and 106 'to produce higher light intensity on detector element 104 Analysis module 107 for analyzing the reflected sensor beams and for determining the road condition and three trained as semiconductor lasers with the wavelengths 980 nm, 1310 nm and 1550 nm beam elements 108, 108 ^y and 108 ^yy . In front of each of semiconductor lasers 980 nm, 1310 nm and 1550 nm, further collimator lenses 109, 109 ^y and 109 ^yy are arranged, which form the light generated and emitted by semiconductor lasers 108, 108 ^y and 108 ^yy , ie sensor beams 115, into a largely parallel beam bundle up. Beam members 108, 108 'and 108 ^yy are separated by separation diaphragm 119 of detector ^¬ element 104 to prevent stray radiation from beam elements 108, 108' and 108 ^yy on detector element 104 passes, and so the reliability or accuracy of the

Road condition is affected. Also from Beam sensor module 101 includes is board 110, which has the necessary for the electrical connection of detector element 104, analysis module 107 and beam elements 108, 108 'and 108''interconnects. In order to ensure flexible alignment of the beam elements 108, 108 ^y and 108 ^{/ y} , in contrast to the detector element 104 they are not rigidly coupled to the circuit board 110 but by means of flexible wire connections 112, 112 'and 112 "when mounting the radiation sensor module 101 to vehicle windshield 102 such that road surface 113 at point 114 7m in front of the windshield - and thus in the direction of travel in front of the vehicle - is illuminated by means of sensor beams 115. By way of example, the angle of incidence of sensor beams 115 on road surface 113 at point 114 is 12 °. The different wavelengths (980 nm, 1310 nm and 1550 nm), which are generated by beam elements 108, 108 'and 108''and meet as sensor beams 115 at point 114, there are partially diffuse reflected and partially absorbed according to this embodiment. At point 114 is ice layer 115, which is covered by water layer 116. Since water absorbs wavelengths of 1310 nm comparatively strongly, this wavelength is only weakly reflected at the surface of water layer 116. Accordingly, detector element 104 only weakly detects the wavelength at 1310 nm in reflected sensor beams 106 and 106 '. The remaining wavelengths at 980 nm and 1310 nm permeate water layer 116 relatively well and run into ice 115. ice 115 in turn acts relatively strongly sublingually ^¬ Bierend to the wavelength at 1550 nm, so that detector element 104, the wavelength of 13550 nm only weakly in reflected Sensor beams 106 and 106 'can detect. The wavelength at 980 nm, however, also penetrates ice 116 comparatively well and is finally reflectors ^¬ advantage of lying under ice road surface 116 113th Since detector element 104 thus comparatively strongly detects the wavelength at 980 nm, the wavelengths at 1310 nm and 1550 nm, however, only a relatively weak, Ana ^¬ lysis module 107 determines the road condition at point 114 that it is covered with ice and water layer 115 116th Due to the low coefficient of friction of ice layer 115, which is also not visible to a driver, as it is hidden under water layer 116, starts from point 114, a danger to the vehicle. About connections 117 to the vehicle CAN bus information on road conditions and the associated low friction values of a driving stability system be continued, which can already determine the appropriate control values ahead ^¬ looking thus and it must determine when crossing point 114 not only. Furthermore, the radiation sensor module 101 has connection 118 to a driving source energy supply

Energy supply.

FIG. 2 shows a flow chart with a possible sequence of the method according to the invention for predictive road condition determination in a vehicle. In method step 21, the road surface is illuminated with sensor beams, wherein the sensor beams are emitted pulsed and do not exceed an average radiation power of 1 mW. In the following step 22, a first part of the sensor beams incident on the road surface is absorbed by the road surface, in step 23, a second part of the sensor beams incident on the road surface is reflected from the road surface. The reflected sensor ^beams are finally detected in step 24 by means of a detector element and in step 25 the road condition in front of the vehicle is determined by means of an analysis module based on intensities of the different wavelengths in the reflected sensor beams. The determination is carried out by means of a so-called support vector method. Fig. 3 shows the absorption capabilities of water and ice for three different wavelengths of electromagnetic radiation. The absorption capacity is plotted on the Y axis, and the wavelengths 980 nm, 1310 nm and 1550 nm are shown on the X axis. The display of the absorption ^¬ skills is not to scale. As can be seen, the wavelength at 980 nm as a whole is weakest absorbed, with water absorption being somewhat greater than the absorbency of ice 32. The wavelength at 1310 nm absorbs the wavelength of both water 33 and ice 34 more than that wavelength at 980 nm. in addition, the absorption capacity of water 33 at 1310 nm significantly stronger than that of ice 34. again, stronger absorption capacity of water 35 and ice 36 at the wavelength at 1550 nm. in contrast to the mentioned prior ^¬ wavelengths, the wavelength but more strongly absorbed by ice 35 at 1550 nm than by water 36.

Claims

claims

1. A method for predictive road state determination in a vehicle in which a road surface (113) with sensor beams (106, 106 ') is illuminated, said Sen ^¬ sorstrahlen (106, 106') in accordance with a road condition of the road surface (113) reflects and absorbs and wherein the road condition determination is based on the reflected sensor beams (115),

characterized in that the road surface (113) in

Direction of travel is illuminated in front of the vehicle.

2. The method according to claim 1,

characterized in that a lighting of the road surface (113) and a detection of the reflected sensor beams (115) takes place synchronized-pulsed.

3. The method according to at least one of claims 1 and 2, characterized in that the sensor beams (106, 106 ') comprise different wavelengths, in particular La ^¬ serstrahlen (106, 106') with intensity maxima at least two different wavelengths.

4. The method according to claim 3,

characterized in that the road condition determination is based on intensities of the different wavelengths in the reflected sensor beams (115).

5. The method according to claim 4,

characterized in that the different wavelengths in the reflected sensor beams (115) by means of stochastic assignment method, in particular by means of a Stützvektorverfahrens and / or a

k-Means algorithm to be assigned to the road condition.

6. The method according to at least one of claims 1 to 5, characterized in that a certain road condition at least one driving stability control system and / or vehicle dynamics control system is continued, in particular to an ant iblockiersystem and / or electronic stability program and / or chassis control system, wherein the at least one driving stability control system and / or vehicle dynamics control system by means of the determined road condition performs a locally synchronous control adapted.

7. ray sensor module (101) for predictive road state determination in a vehicle, comprising at least two radiating elements (108, 108 ^y, 108 ^yy), at least a de ^¬ tektorelement (104), an analysis module (107) and a

Sensor housing (103), wherein the at least two beam ^¬ elements (108, 108 ^y , 108 ^yy ) illuminate a road surface (113) with sensor beams (106, 106 ^y ), wherein the sensor beams (106, 106 ') in accordance with a road condition of the Street surface (113) are reflected and absorbed, wherein the at least one detector element (104) detects the re ^¬ inflected sensor beams (115) and

wherein the analysis module (107) carries out the road condition determination on the basis of the reflected sensor beams (115) detected by the at least one detector element (104), characterized in that the sensor housing (103) is designed to be mounted on an inner side of a vehicle windshield (102).

8. beam sensor module (101) according to claim 7,

characterized in that the beam elements (108, 108 ', 108 ^yy ) semiconductor lasers (108, 108 ^y , 108 ^yy ) of different wavelengths in the wavelength range from 900 nm to 1700 nm are, in particular with intensity maxima at the wavelengths 980 nm and / or 1310 nm and / or 1550 nm.

9. Radiation sensor module (101) according to at least one of the claims 7 and 8,

characterized in that a radiation power of the at least two beam elements (108, 108 ^y , 108 ^{/ y} ) each does not exceed 1 mW, wherein the radiation power is determined in particular on an outer side of the windshield (102).

10. Radiation sensor module (101) according to claim 9,

characterized in that the radiation power is delivered pulsed.

11. Radiation sensor module (101) after at least one of

Claims 9 and 10,

characterized in that the detector element (104) one of the windshield (102) in the radiation sensor module (101) is consistent retro-reflected portion of the radiation power load and the radiation sensor module (101) based on the back ^¬ reflected portion of the radiation power on the outside of the windshield (102 ) regulates.

12. Radiation sensor module (101) according to at least one of claims 7 to 11,

characterized in that the radiation sensor module (101) for each beam element (108, 108 ^y, 108 ^{/ y)} en De ^¬ tektorelement (104) whose respective sensitivity analyzes tätsmaximum the wavelength of the maximum intensity of the respective beam element (108, 108 ^y, 108 ^{/ y} ).

13. Radiation sensor module (101) according to at least one of claims 7 to 12, characterized in that the De ^¬ tektorelement (104) (104) photodiode, in particular an indium gallium arsenide based photodiode (104) or a germanium based photodiode (104).

14. Radiation sensor module (101) according to at least one of claims 7 to 13, characterized in that the

The radiation sensor module (101) further comprises a visible light barrier filter (105) shielding the detector element (104).

15. Radiation sensor module (101) after at least one of

Claims 7 to 14,

characterized in that the radiation sensor module (101) further comprises at least one converging lens (111) which focuses the reflected sensor beams (115) onto the at least one detector element (104).

16. Radiation sensor module (101) according to at least one of claims 7 to 15,

characterized in that the radiation ^{sensor module} (101) comprises a connection (117) to a vehicle bus and in ^¬ particular information about a detected road condition on at least one further vehicle system continues.

17. Radiation sensor module (101) according to at least one of claims 7 to 16,

characterized in that the at least two beam ^¬ elements (108, 108 ^y , 108 ^{/ y} ) emit no radiation power in a vehicle standstill.

18. Radiation sensor module (101) after at least one of

Claims 7 to 17,

characterized in that the radiation sensor module (101) carries out a method according to at least one of claims 1 to 6.