METHOD FOR RADAR-BASED MONITORING OF A REARWARD AREA

Abstract

A method for radar-based monitoring of a rearward area of a truck. The truck comprises a radar device and at least one semitrailer. The method comprises the steps of ascertaining various objects and their position using the radar device, determining an alignment of the trailer relative to the radar device, determining the objects that, based on their position, are concealed for the radar device as a result of the alignment of the semitrailer, and ascertaining, on the basis of the alignment of the semitrailer and an ascertained reflection of the radar waves on the semitrailer, the true position of the objects ascertained as concealed.

Claims

1. A method for radar-based monitoring of a rearward area of a truck including a radar device and at least one semitrailer, the method comprising the following steps: ascertaining various objects and a position of the various objects using the radar device; determining an alignment of the semitrailer relative to the radar device; determining objects of the various objects that, based on the position of the objects, are concealed for the radar device as a result of the alignment of the trailer; and ascertaining, based on the alignment of the semitrailer and an ascertained reflection of radar waves on the semitrailer, a true position of the objects ascertained as concealed.

2. The method according to claim 1, wherein the alignment of the semitrailer relative to the radar device is ascertained by evaluating odometry data of a tractor of the truck and static parameters of the semitrailer.

3. The method according to claim 1, wherein the alignment of the semitrailer is determined via radar detection.

4. The method according to claim 3, wherein the semitrailer is detected based on a relative speed of the semitrailer relative to the tractor so that radar values of which the relative speed is zero are assigned to the semitrailer.

5. The method according to claim 1, the radar device is an FMCW radar device.

6. The method according to claim 1, wherein the ascertained various objects are transmitted to a driver assistance system.

7. A device for radar-based monitoring of a rearward area of a truck including a radar device and at least one semitrailer, the device comprising: the radar device including at least one radar sensor; and a computing unit; wherein the device is configured to: ascertain various objects and a position of the various objects using the radar device, determine an alignment of the semitrailer relative to the radar device, determine objects of the various objects that, based on the position of the objects, are concealed for the radar device as a result of the alignment of the trailer, and ascertain, based on the alignment of the semitrailer and an ascertained reflection of radar waves on the semitrailer, a true position of the objects ascertained as concealed, using the computing unit.

8. The device according to claim 7, wherein the radar device is arranged on at least one exterior mirror of the truck.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 shows a first exemplary embodiment of the present invention.

[0022] FIG. 2 shows a second exemplary embodiment of the present invention.

[0023] FIG. 3 shows a third exemplary embodiment of the present invention.

[0024] FIG. 4 shows an exemplary embodiment of the method according to the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0025] FIG. 1 shows a first exemplary embodiment of the present invention. This figure shows a truck 14 which has a tractor 18 and a semitrailer 22 arranged behind the tractor 18. In this exemplary embodiment, a radar device 30, which has a radar sensor, is arranged on an exterior mirror 26 of the tractor 18. The radar device 30 substantially monitors a rearward area of the truck 14, as is illustrated by the field of vision 34 of the radar device 30 shown in the figure. In order to evaluate the radar results, a computing unit 38 is arranged in the tractor 18.

[0026] The figure furthermore shows two objects O.sub.R, O.sub.V detected by the radar device 30, which objects are here shown as cars. In this case, the object O.sub.R is a real object which has been detected via the radar wave R1. The object O.sub.V, on the other hand, is a virtual object, which, due to the course of radar beam R2 assumed to be the radar beam shown as R2* is detected behind the semitrailer 22. The longitudinal side 42 of the semitrailer 22 arranged on the side of the radar device 30 here forms a mirror plane 44 for the radar beam R2. As a result, the radar beam R2 is reflected on the longitudinal side 42 of the semitrailer 22. The radar beam R2 therefore does not travel as radar beam R2* as assumed. The radar beam R2 thus likewise detects the object O.sub.R.

[0027] Based on the position of the virtual object O.sub.V and of the semitrailer 22, it is recognized in computing unit 38 that this object O.sub.V could not have been detected since it is concealed by the semitrailer 22. In order to ascertain the true position of the object O.sub.V, the computing unit 38 ascertains the alignment of the mirror plane 44 formed by the semitrailer 22. The real object O.sub.R is subsequently determined by a reflection on the longitudinal side 42 of the semitrailer 22 so that erroneous measurements can thereby be eliminated.

[0028] FIG. 2 shows a second exemplary embodiment of the present invention. In this exemplary embodiment too, a virtual object O.sub.V, which is located behind the semitrailer 22 and thus not visible to the radar device 30, is ascertained. In this exemplary embodiment, direct detection of the associated real object O.sub.R by means of a radar wave R1 is not possible since the real object O.sub.R is concealed for the radar wave R1 by a further object O.sub.W. Here too, the computing unit 38 recognizes that the object O.sub.V is not a real object O.sub.R since it is located behind the semitrailer 22. Based on the alignment of the semitrailer 22 and the reflection on the longitudinal side 42, the computing unit 38 thus calculates the real position of the object O.sub.R.

[0029] As a result of this procedure, it is possible to detect objects O.sub.R that normally could not have been detected by the radar device 30. As a result, the detection of objects O.sub.R is improved.

[0030] FIG. 3 shows a third exemplary embodiment of the present invention. A concealment 48 is shown in this figure. This concealment 48 may be another truck, a wall or the like. As a result, it is impossible to detect the objects O.sub.R directly with the radar waves R1. Here, the truck 14 is engaged in a parking maneuver with the aim of parking in a rearward direction 50 next to the concealment 48. Here too, the longitudinal side 42 of the semitrailer 22 serves as a mirror plane 44. The computing unit 38 recognizes here that the objects O.sub.V ascertained behind the trailer 22 are virtual objects and calculates the real position of the objects O.sub.R based on a reflection on the longitudinal side 42 of the semitrailer 22. As a result, detection in a non-visible region is improved.

[0031] FIG. 4 shows an exemplary embodiment of the method according to the present invention for radar-based monitoring of a rearward area of a truck 14. In a first step A, various objects O.sub.R, O.sub.V, such as cars, pedestrians or cyclists are ascertained in the rearward area by means of the radar device 30. In a next step B, the alignment of the semitrailer 22 relative to the radar device 30 is determined. This is ascertained, for example, by means of the odometry data of the tractor 38 and the static parameters of the semitrailer 22, such as the width of the semitrailer 22 and the distance from the tractor 18. Subsequently, in a next step C, the objects O.sub.V that, based on their ascertained position and the alignment of the trailer 22, are behind the trailer 22 are determined. The radar device 30 would thus actually not be able to ascertain these objects O.sub.V.

[0032] In step D, the true position is ascertained for the objects O.sub.V ascertained as concealed. For this purpose, a reflection of the radar waves on the semitrailer 22 is calculated on the basis of the ascertained alignment of the semitrailer 22. In this case, the true object O.sub.R corresponds to an object O.sub.V mirrored on the mirror plane 44 formed by the longitudinal side 42 of the semitrailer 22. The thus ascertained true position of the object O.sub.R is subsequently transmitted in step E to a driver assistance system for further evaluation.