WO2015070965A1

WO2015070965A1 - Method for determining a value for a height

Info

Publication number: WO2015070965A1
Application number: PCT/EP2014/002992
Authority: WO
Inventors: Christoph Göhrle; Andreas Schindler; Andreas Unger; Oliver Sawodny
Original assignee: Audi Ag
Priority date: 2013-11-13
Filing date: 2014-11-07
Publication date: 2015-05-21
Also published as: DE102013018926B4; DE102013018926A1

Abstract

The invention relates to a method for determining a value for a height of a position (12) of an underlying surface (10) to be driven on by a motor vehicle (4) with respect to a level (16), wherein the position (12) is observed from at least two different perspectives by at least one sensor (6) for sensing an environment of the motor vehicle (4), wherein at least one value for the height is measured for the position (12) from each perspective, wherein one perspective is defined as the main perspective and at least one further perspective is defined as the secondary perspective, wherein at least one value measured from the at least one secondary perspective is transformed into at least one value measured from the main perspective, and wherein the value for the height of the position is calculated from a value which is accumulated from all values from all perspectives.

Description

Method for determining a value for a height

The invention relates to a method for determining a value for a height of a location of a subsoil, a method for detecting a profile of a height profile of a portion of a subsoil and a system for determining a value for a height of a location of a subsoil.

A profile of a surface of a road to be traveled by a motor vehicle can be measured by a sensor arranged on the motor vehicle and thus detected. By knowing the profile it is u. a. possible to prepare a chassis of the motor vehicle on the future to be traveled surface.

The publication DE 10 2009 033 219 A1 describes a method for determining a height profile of a road ahead based on image data which is detected by a sensor arranged on a motor vehicle, for example by a video camera or by a laser sensor. In this case, an estimated height profile of the road is combined with an estimating device to form a continuous height profile that is independent of a proper movement of the motor vehicle.

Against this background, a method having the features of claim 1, a method having the features of claim 12 and a system having the features of claim 3 are presented. Further embodiments of the invention will become apparent from the dependent claims and the description.

The method according to the invention is provided for determining a value for a height of a ground to be traveled by a motor vehicle with respect to a level to be defined or defined or to a reference plane to be defined or defined, wherein the location consists of at least two different perspectives of at least one Sensor is detected for detecting an environment of the motor vehicle. At least one value for the height is measured for the position from every perspective. sen, wherein a perspective as a main perspective and at least one further perspective is defined as a secondary perspective, and wherein the at least one sensor for detecting the environment of the motor vehicle relative to the location takes a respective perspective. At least one value measured from the at least one secondary perspective is transformed, usually taking into account a transformation, into at least one value measured from the main perspective and adapted to the value measured from the main perspective. The value for the height of the position is calculated from a value, for example an average, which, for example, is accumulated via a statistical method from all the values from all perspectives, ie the main perspective and the at least one secondary perspective. Thus, values dependent on different perspectives are accumulated and / or summarized.

This means in an embodiment that for determining the accumulated value, the value measured from the main perspective and the at least one value measured from a secondary perspective, which is transformed into a value measured from the corresponding main perspective, are taken into account. All stated values, d. H. The value measured from the main perspective and the at least one value measured from the at least one secondary perspective, which is transformed to a corresponding value from the main perspective, are summed, for example. A sum formed from these values is divided by the number of all values.

Several values measured from a perspective form a vector. A vector of a secondary perspective is transformed by turning and / or shifting into a vector of a main perspective taking into account an inertial or sensor-strong coordinate system. To determine a transformation, three shifts and three angles can be considered. A vector of a secondary perspective is transformed by a rotation matrix formed of angles, for example Euler angles, and translated.

In an embodiment, a value from the secondary perspective in the transformation is changed as if it were measured from the main perspective. The value measured from the main perspective and the transformation into the main perspective. te, but values measured from the secondary perspective are generally the same except for a measurement noise.

The at least one value of the height measured from the at least one secondary perspective is transformed taking into account the transformation to the at least one measured value from the main perspective, the transformation regarding a transition of an observation of the position by the sensor from the at least one secondary perspective to an observation of the Position determined by the sensor from the main perspective.

In addition, a perspective of the at least one sensor is in each case dependent on a position at which the sensor is arranged relative to the location and on a viewing angle under which the value of the height of the location is measured. To determine the transformation, a spatial difference between a first position taken by the at least one sensor relative to the location at a first perspective becomes a second position that the at least one sensor occupies relative to the location at a second perspective , considered. In addition, a spatial transformation and thus a spatial difference between a first viewing angle, which the at least one sensor assumes relative to the location in the first perspective, becomes a second viewing angle, which the at least one sensor occupies relative to the location in the second perspective, considered.

Accordingly, the value for the height of the steepness is determined for the ground to be driven by a motor vehicle, for example for a road, wherein the at least one sensor for detecting the surroundings is arranged on the motor vehicle and transported during a movement of the motor vehicle.

In addition, the at least one sensor may take different perspectives relative to the location at different times.

The transformation between different perspectives occupied by the at least one sensor relative to the location is derived from a movement of the motor vehicle relative to the location, the movement being positionally determined. and / or time-dependent of at least in addition a sensor of the motor vehicle, for determining a kinematic variable of the motor vehicle, for. B. whose position, speed and / or acceleration is configured is determined. This additional sensor for determining a kinematic variable may alternatively or additionally be designed to measure a pitch rate, a roll rate or a lift acceleration of the motor vehicle as kinematic variable and / or a wheel suspension for each wheel of the motor vehicle.

Due to the at least one kinematic variable, in addition to the movement of the motor vehicle, a movement of the at least one sensor for detecting the surroundings is to be derived, for example, estimated. In a refinement of the method, a movement of the at least one sensor for detecting the surroundings is derived from the movement of the motor vehicle and the transformation between two perspectives based on values or data of the sensor is determined from this movement of the sensor for detecting the surroundings.

Thus, with at least one additional sensor of the motor vehicle, which is designed to determine a kinematic variable of the motor vehicle, detects a movement of the motor vehicle and derived therefrom a movement of the at least one sensor for detecting the environment. The transformation between two perspectives is determined as a function of the movement of the sensor between two different perspectives. Furthermore, the transformation is also determined based on the values detected by the sensor for detecting the environment.

In an embodiment, a sensor-resistant coordinate system can be defined for the at least one sensor, from the transformation between different perspectives the transformation is derived as a function of a respective position and a respective viewing angle of the at least one sensor.

The method may be performed for a location of the ground in the direction of which the motor vehicle is traveling. In this case, the motor vehicle assumes different perspectives at different times, with a Distance of the at least one sensor to the point from time to time reduced. In addition, a value of the viewing angle, insofar as it is related to a vertical axis perpendicular to the ground, in this case from time to time becomes smaller.

The at least one secondary perspective relative to the location can be taken by the at least one sensor for detecting the environment at a time before the main perspective is taken by the sensor. Alternatively or additionally, the at least one secondary perspective of the at least one sensor for detecting the environment relative to the location can be taken at a time after the sensor has taken the main perspective.

For any perspective occupied by the at least one sensor for detecting the environment relative to the location, a balance geometry, i. H. a balance line or level, to which a value for the height of the position determined from the respective perspective is referred to and / or projected. The method presented above can also be used for a method for detecting a profile of a height profile of a section of a subsoil having a plurality of locations. In this case, a value for their height is determined for each of these points by the method for determining the value of the height of a respective point, wherein the profile of the heights is composed of the values of the heights of the points.

The system according to the invention is designed for determining a value for a height of a location of a ground traveled by a motor vehicle with respect to a level or a reference geometry, for example a reference plane or a reference line, and comprising at least one sensor for detecting an environment of the motor vehicle and a controller, wherein the at least one sensor is configured to observe the location from at least two different perspectives and to measure at least one value for the height from each perspective, one perspective as a main perspective and at least one additional perspective as a side perspective is to be defined by the controller. The controller is also adapted to the at least one value measured from the at least one secondary perspective, possibly taking into account a transformation, to transform at least one value measured from the main perspective and thereby adapting it to the at least one value measured from the main perspective. The value for the height of the position is to be calculated from a value to be accumulated from all the values from all perspectives.

This system is designed to carry out at least one step of the method according to the invention.

The system has at least one sensor for detecting a kinematic variable of the motor vehicle, which is designed to detect a movement of the motor vehicle train. The control unit is designed to derive from a detected movement of the motor vehicle a movement of the sensor for detecting the environment and to determine therefrom the transformation between two different perspectives. A calculation of this transformation is supplemented by information of the road detected by at least one sensor by comparing a detection of the road between two times.

In addition, the system is designed to detect a profile of a height profile of a section of a road having multiple locations, to determine from the system for each of these locations a value for their altitude and to compile the profile of the altitude profile from the values of the heights of the locations is.

Taking into account the dimensions determined in the context of the method, u. Ä. Be implemented a scheme for a predictive chassis of the motor vehicle.

The motor vehicle has the at least one sensor, ie a mono-sensor and / or stereo sensor and / or laser sensor for detecting the environment or the surroundings of the motor vehicle. This at least one sensor is designed to detect, for example, using laser beams, video recordings or radar, the road located in front of the motor vehicle. For the At least one sensor can be defined as a sensor-fixed coordinate system, which is moved relative to the road during a movement of the motor vehicle, which is dependent inter alia on a stroke, a pitch or roll of the motor vehicle.

At least one place and thus the section, d. H. If necessary, a large part of the road formed as a ground, is repeatedly measured by the at least one sensor for detecting the environment from different perspectives redundant and thus detected. In this case, a point of the road to be observed is acquired at different points in time from different perspectives, wherein the points of time, which are spaced apart from one another by regular time intervals, follow one another. In this case, from each perspective, an area of the road extending over a certain length of the road is detected. Positions which the sensor-oriented coordinate system occupies depend also on a speed of the motor vehicle. If at least one sensor after a time interval of z. B. 30 ms new information over a length of 4 m to 15 m along the road are provided, with the motor vehicle moves at a speed of 50 km / h, the motor vehicle sets during the time interval of 30 ms about 0.4 m back. Accordingly, the same portion and / or same location of the road is detected at several consecutive times, wherein the road from the at least one, with the motor vehicle moving sensor at any time from another perspective, d. H. from a different position and / or angle.

By repeatedly, redundantly measuring the same location and / or the same section, different values of a height of the same location of the street are detected, wherein the values acquired at different times are computationally accumulated, for example averaged. Such a computational averaging of the values can improve accuracy in determining the height of the point to be detected. The averaging can also be carried out by statistical methods, such as a predictor-corrector method or a median method. Usually, older values or data measured at a previous time point are viewed from a secondary perspective transformed into the values or data measured at a current time. Thereafter, the accumulated value, for example the mean value, is formed from all the values. Typically, older values collected from a secondary perspective are transformed to younger values captured from the main perspective. Consequently, it is envisaged to transform older values from a secondary perspective as if they were measured from the newer main perspective or position of the sensor. The older values from the secondary perspective are accumulated and contain information of all older secondary perspectives for the section of the underground. When accumulating in an inertial coordinate system, new values are transformed from a secondary perspective into older values of a main perspective.

In a first variant of the method, the values for the height measured at different times are accumulated in the sensor-oriented coordinate system. Here, old, already measured values are transformed to new, current values and all values are subsequently accumulated, usually averaged.

In this case, it is possible at any time to use a straight line and / or compensation plane, ie. H. generalizes a compensation geometry to provide for the amount of raw values captured by the site. This z. B. smallest error squares between the raw values or the raw data and the compensation geometry are determined. The values for the height of the location will continue to be calculated with respect to this compensation geometry.

In a second, alternative or supplementary variant z. B. when starting an engine of the motor vehicle, a reference plane set as a level for the height. The values of the height recorded at the following times are measured, calculated and accumulated with respect to the reference level provided as a level. In this case, a value acquired at a current time from a sub-perspective to a value acquired at a prior time from a main perspective is transformed with respect to the inertial coordinate system and subsequently accumulated, using between the inertial coordinate system and a sensor-sensitive coordinate. can be distinguished. An inertially fixed reference plane of a coordinate system can be reset at certain intervals, if, for example, the values for the height become too large.

A transformation is independent of a used coordinate system and is determined by combining the kinematically measured quantities and sensory values to the elevation profile of the ground from the different perspectives. Usually, the different perspectives are taken by the sensor for detecting the height profile at different times, which are each spaced apart by a time interval.

In both variants, either the old, previously sensory acquired values can be transformed into the values acquired at the later, later time or the values acquired at the more recent time into the values recorded at the old time. In the variant of the intertial fixed reference plane, the new values are transformed into the old values. Regardless thereof, at least one additional sensor of the motor vehicle for detecting at least one kinematic variable of the motor vehicle, for example, its location or position, speed, acceleration, pitch rate, roll rate, Hubbeschleunigung, and / or Radeinfederung measured and based on a first estimate for a movement of the sensor for detecting the environment and thus a transformation between different perspectives of the at least one sensor for detecting the environment are performed. A further, more accurate determination of a transformation of the values which are detected at different times is determined by evaluating the data of the at least one additional sensor with which the road ahead of the motor vehicle is measured, three angles and three translations in which Values that are transformed depending on the time point fit together as well as possible.

The height profile of the ground is detected by the at least one sensor for detecting the environment from different perspectives. To determine the transformation, a first estimate may be performed, where EP2014 / 002992

10 te for kinematic sizes, z. As for a position, speed or acceleration of the motor vehicle or for a Radeinfederung, are used, these values change from perspective to perspective. For this purpose, a model of the motor vehicle with information about a mass, a spring stiffness of a spring or a damper force of a damper of the motor vehicle or a control of an actuator of the motor vehicle can be taken into account. This estimation is improved by information of the at least one sensor for detecting the environment, wherein a predictor correction method with a Kalman filter can be used.

For implementation, a so-called vertical model of the motor vehicle may be used which includes information on its structure, mass, spring rigidity, damper characteristic or properties of the tires used. It is also taken into account how actuators of the motor vehicle are currently activated during its movement. In addition, a condition of the traveled ground is roughly known by at least one detection from a perspective. From this it is predicted from a sensory detected speed of the motor vehicle its own motion. In addition, the acceleration of the motor vehicle and a Radeinfederung can be used to determine the proper motion. Furthermore, the proper motion can be supplemented and thus corrected, taking into account the sensory environment of the motor vehicle.

In a further variant, the model of the motor vehicle can be dispensed with. For this purpose, a linear or non-linear optimization can be performed.

By minimizing error squares, a linear equation system can be provided taking into account a linear regression. In this case, a plurality of perspective and / or time point-dependent detected values for a height profile of the section can be compared with one another and adapted to one another by shifting one another. Another possibility is to look at values for randomly determined sections of the section and for different points in time and these values taking into account the respective perspective by turning and / or shifting to each other, so that the values of the height of the location detected at the different times fit well together.

To determine the transformation between two perspectives, a rotation and a displacement of a height profile acquired from a secondary perspective are searched, so that this height profile along a portion of the background and the height profile from a main perspective are oriented in the same coordinate system. For this purpose, an error between the two two-dimensional height profiles can be calculated, for. B by forming the sum of the error squares between lines for each point of the background. If the sum is small, both height profiles fit well together. Thus, a suitable rotation and / or displacement for the transformation can be determined taking into account the sensory values detected for the height profile and the kinematic variables.

The raw values detected by the at least one sensor for detecting the environment at a first time and at a second time are processed by transformation to each other and by accumulation. A composition of a profile of a height of the road can be carried out in a sensor-resistant and / or inertial coordinate system.

Further advantages and embodiments of the invention will become apparent from the description and accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

The invention is schematically illustrated by means of embodiments in the drawings and will be described schematically and in detail with reference to the drawings. Figure 1 shows a schematic representation of an embodiment of a system according to the invention when carrying out a first embodiment of a method according to the invention.

Figure 2 shows the presented with reference to Figure 1 embodiment of the system according to the invention in carrying out a second embodiment of the method according to the invention.

Figure 3 shows a schematic representation of the presented with reference to Figures 1 and 2 embodiment of the system according to the invention in carrying out a third embodiment of the method according to the invention.

The figures are described coherently and comprehensively. Like reference numerals designate like components.

The embodiment of the system 2 according to the invention shown schematically in all FIGS. 1 to 3 is intended for a motor vehicle 4 and comprises a sensor 6 which detects an environment of the motor vehicle 4 using electromagnetic waves, for example video, laser or radar-based , is formed, and a control unit 8.

In detail, it is provided that the motor vehicle 4 travels in the first embodiment of the method, a first, designed here as a road surface 10. In this case, the motor vehicle 4 is shown with the complete system 2 only in Figure 1a. In this case, the sensor 6 assumes a first perspective relative to a point 12 of the substrate 10 in FIG. 1 a at a first point in time, which is defined by a position of the sensor relative to the point 12 and a viewing angle of the sensor 6 relative to the point 12 , FIG. 1 b merely shows the background 10 with respect to a level to be defined or a reference line 16 (dashed line) taking into account the first perspective. In Figure 1 c, only the sensor 6 is shown, which occupies a second perspective when driving the motor vehicle 4 in comparison to the first perspective of Figure 1 a at a second time relative to the point 12, which also by the position and the angle of view of the sensor 6 is defined relative to the point 2. Both FIGS. 1 a and 1 c additionally show a viewing region 14 of the sensor 6. FIG. 1 d shows the background 10 and the level 16 taking into account the second perspective. The perspective of the sensor 6 changes depending on a movement of the motor vehicle 4 on the substrate 10.

When carrying out the first embodiment of the method according to the invention by the system 2, it is provided that the first perspective taken by the sensor 6 at the first time is called a secondary perspective, whereas the perspective taken by the sensor 6 at the second time is relative to the location 12 is called main perspective. In addition, all FIGS. 1 a to 1 d show the level 16 defined in the context of the method, which is illustrated here by a dashed line.

In the first embodiment of the method, a value of a height of the location 12 with respect to the level 16 is set. Here, as Figure 1a and Figure 1 b indicate, starting from the first perspective or secondary perspective of the sensor 6 at the first time for the height of the point 12, a first value determined. Thereafter, at the second time point, starting from the second perspective or main perspective of the sensor 6 relative to the point 12, a second value for the height of the point 12 relative to the level 16 is determined. In a transition of the sensor 6 from the first perspective to the second perspective, its position relative to the location 12 and its viewing angle relative to the location 12 are transformed. In this case, values for usually three coordinates for describing a transformation of the position and / or values for, as a rule, three angles for describing a transformation of the viewing angle are determined.

To determine the transformation, among other things, values for at least one kinematic variable, ie location, speed, acceleration, pitch rate, roll rate, stroke acceleration and / or wheel suspension of the motor vehicle 4, from a further sensor 9 of the motor vehicle 4, with the at least one kinematic variable of the motor vehicle 4 is to be used. Thus, with the additional or additional sensor 9 for determining at least one kinematic variable of the motor vehicle 4 to detect its movement, from in turn, a movement of the sensor 6 for detecting the environment of the motor vehicle 4 is derived. A transformation between two different perspectives depends on a movement of the sensor 6 for detecting the environment.

Based on the transformation between the two perspectives of the sensor 6 relative to the point 12, the values for the height of the point 12, d. H. the value determined from the first perspective or secondary perspective is transformed according to an indicated by an arrow 18 and dependent on the movement of the sensor 6 for detecting the environment transformation on the second time from the second perspective detected value of the height of the point 12. These two values are accumulated, for example averaged, whereby an accumulated value, for example the mean value, is formed as the value to be detected of the height of the point 12 from values which are acquired from different perspectives.

Usually, many values are sensory measured at one time, e.g. B. for a front of the front axle of the motor vehicle 4 lying portion of the substrate 10. These values are stored. A vector of values of an old time step contains all information from previous time steps because of averaging previously acquired values. These values are transformed so that the altitude values coincide with the altitude values of the current time step except for the measurement noise. Thus, the values of the old secondary perspective are transformed as if they were measured from the current main perspective.

FIGS. 2 a, 2 b, 2 c and 2 d show a second example of a base 20, which is also used here by the motor vehicle 4 equipped with the embodiment of the system 2. It is provided here, when performing the second embodiment of the method also to determine a height of a point 22 with respect to a defined level of the ground 20. In this case, the motor vehicle 4 with the complete system 2 is shown only in FIG. 2a. In Figure 2c, only the sensor 6 of the system 2 is shown schematically. In this case, the sensor 6 in FIG. 2 a assumes relative to the position le 22 of the ground 20 to be traveled at a first time a first perspective, here a secondary perspective, a. In contrast, the sensor 6, as indicated with reference to Figure 2c, at a second time relative to the point 22, a second perspective, here a main perspective, a.

When carrying out the embodiment of the method, different values for the height of the point 22 relative to the level are also determined here from different perspectives. In addition, a transition and thus a transformation of the first perspective or secondary perspective of the sensor 6 (FIG. 2a) toward the second perspective or main perspective (FIG. 2c) of the sensor 6 are taken into account. In FIGS. 2a to 2d, a compensation geometry 26 designed as a straight line of compensation is indicated by a dashed line. The level or the reference line is calculated by the balancing line or compensation plane. In the case of a transformation of the height of the point 22 detected from the first perspective, indicated here by an arrow 28, to the value of the height detected from the second perspective, the compensation geometry 26 is used. In this case, the values from both perspectives are accumulated, for example averaged, whereby the value of the height of the point 22 is calculated from an average value of all the values.

In both embodiments, old values are transformed from a minor perspective into new values from the main perspective. In this case, a sensor-resistant coordinate system dependent on the movement of the motor vehicle 4 is used with the embodiment described in FIG. In the embodiment described with reference to FIG. 2, the coordinate system is determined by the compensation geometry 26. In this case, the compensation geometry 26 or compensation straight line is laid through the values of the height profile, with a reference line or zero line of the level generally lying on the substrate 20.

The compensation geometry 26 or equalization line is the one with the least error squares. In this case, raw data from a field of view of the sensor 6 are used. The regression line is determined by solving a linear equation system, taking into account that a sum of squared Values of the height at each point of the best-fit line to the values detected by the sensor 6 becomes minimal.

In the third embodiment of the method according to the invention, which is likewise carried out here by the already presented embodiment of the system 2 according to the invention, it is provided that the vehicle equipped with the system 2 drives over a third example of a substrate 30. In this case, the sensor 6 assumes different perspectives along the substrate 30 relative to the substrate 30, as indicated with reference to FIG. 3a.

Here, values for a height profile of the ground 30 are accumulated in an inertially fixed coordinate system. In addition, once a reference plane is set or updated at certain intervals and the values accumulated with respect to this reference plane. For this purpose, FIG. 3 shows the main perspective and a following secondary perspective.

Claims

claims

A method for determining a value for a height of a location (12, 22) of a ground (0, 20, 30) to be traveled by a motor vehicle (0, 20, 30) with respect to a level (16), said location (12, 22) comprising at least two different perspectives of at least one sensor (6) for detecting an environment of the motor vehicle (4) is observed, wherein at least one value for the height is measured for the point (12, 22) from each perspective, with a perspective as the main perspective and at least one further perspective is defined as a secondary perspective, wherein at least one value measured from the at least one secondary perspective is transformed to at least one value measured from the main perspective, and wherein the value for the height of the location is calculated from a value that comprises all the values all perspectives is accumulated.

2. The method of claim wherein the at least one value measured from the at least one minor perspective is transformed taking into account a transformation to the at least one main-perspective measured value, the transformation relating to a transition to observation of the site (12, 22) the at least one secondary perspective to an observation of the location (12, 22) is determined from the main perspective.

3. The method of claim 1 or 2, wherein in each case a perspective of the at least one sensor (6) from a position at which the sensor (6) is arranged, and from a viewing angle, below which the value of the height of the location (12 , 22) is dependent.

4. The method according to any one of the preceding claims, wherein the at least one sensor (6) for detecting the environment on the motor vehicle (4) is arranged and during a movement of the motor vehicle (4) is transported.

5. The method according to any one of the preceding claims, in which of the at least one sensor (6) at different times relative to the point (12, 22) different perspectives are taken.

6. The method of claim 1, wherein the transformation between different perspectives that the at least one sensor occupies relative to the location is derived from a movement of the motor vehicle relative to the location ,

7. The method according to any one of the preceding claims, which for a point (12, 22) of the substrate (10, 20, 30) is carried out in the direction of the motor vehicle (4) moves.

8. The method according to any one of the preceding claims, wherein the at least one secondary perspective of the at least one sensor (6) is taken at a time before by the sensor (6) the main perspective is taken.

9. The method according to any one of the preceding claims, wherein the at least one secondary perspective of the at least one sensor (6) is taken at a time after the sensor (6) the main perspective was taken.

10. A method according to any one of the preceding claims, wherein for each perspective occupied by the at least one sensor (6) relative to the location (12, 22), a balancing geometry (26) is defined to which the at least one of the respective ones Perspective determined value for the height of the body (12, 22) is related.

1 1. The method according to any one of the preceding claims, wherein at least one additional sensor (9) of the motor vehicle (4), which is designed to determine a kinematic size of the motor vehicle (4) detects movement of the motor vehicle (4) and from it a movement of the at least one sensor (6) for detecting the environment is derived, wherein the trans- formation between two perspectives depending on the movement of the sensor (6) between two different perspectives is determined.

12. A method for detecting a profile of a height profile of a portion of a substrate (10, 20, 30) having a plurality of locations (12, 22), wherein for each of these locations (12, 22) a value for their height by a method according to one of claims 1 to 1 is determined, wherein from the values of the heights of the points (12, 22) the course of the height profile is composed.

13. A system for determining a value for a height of a location (12, 22) of a motor vehicle (4) to be traveled surface (10, 20, 30) with respect to a level (16), wherein the system (2) at least one sensor (6) for detecting an environment of the motor vehicle (4) and a control unit (8), wherein the at least one sensor (6) is adapted to observe the location (12, 22) from at least two different perspectives and for the location (12, 22) to measure at least one value for the height from each perspective, wherein one perspective is to be defined as a main perspective and at least one further perspective as a secondary perspective, wherein the control device (6) is designed to at least one of the at least one secondary perspective to transform the measured value to the at least one value measured from the main perspective, and to calculate the value for the height of the location (12, 22) from a value consisting of all the values of all n is to accumulate perspectives.

14. System according to claim 13, which is adapted to carry out a method according to one of claims 1 to 12.

15. System according to claim 13 or 14, comprising at least one sensor (9) for detecting a kinematic variable of the motor vehicle (4), which is adapted to detect a movement of the motor vehicle (4)

16. System according to claim 15, wherein the control unit (8) is adapted to a detected movement of the motor vehicle (4) Derive movement of the sensor (6) for detecting the environment and to determine the transformation between two different perspectives.

A system according to any one of claims 13 to 16, adapted to detect a profile of a height profile of a portion of a ground (10, 20, 30) having a plurality of locations (12, 22), the system (2) thereto is formed, for each of these bodies (12, 22) to determine a value for the height thereof by a method according to one of claims 1 to 10 and to compile the course of the height profile from the values of the heights of the points (12, 22).