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EP-3935403-B1 - VEHICLE TARGET WITH PANELS FOR AVOIDING RADAR REFLECTIONS INSIDE THE VEHICLE TARGET

EP3935403B1EP 3935403 B1EP3935403 B1EP 3935403B1EP-3935403-B1

Inventors

  • HAFELLNER, REINHARD
  • FRITZ, MARTIN

Dates

Publication Date
20260506
Application Date
20200302

Claims (9)

  1. Vehicle target (100) for testing radar sensors of vehicle driver assistant systems, the vehicle target (100) comprising an outer skin (101) defining the outer geometry of the vehicle target (100), wherein the outer skin (101) at least partially surrounds an inner volume (Vi), a panel (112) comprising a basic body (103) and a radar absorbing layer (105) attached to the basic body (103), wherein the panel (112) is mounted to the outer skin (101) such that the radar absorbing layer (105) has an offset (109) with respect to the outer skin (101) in the direction to the inner volume (Vi), wherein the panel (112) is arranged between a front wheel (107) and a rear wheel (107) of the outer skin (101), wherein the panel (112) is arranged between a movable bottom platform (120) onto which the vehicle target (100) is arranged and a bottom of the outer skin (101) and is arranged for covering a space between the bottom platform (120) and a bottom of the outer skin (101), so that the panel (112) is distanced and spaced apart to edges of the outer skin (101) with a panel-to-edge offset in the direction to the inner volume (vi), wherein the panel-to-edge offset defines a distance between the panel (112) and an outer contour of the outer skin (101), characterized in that the radar absorbing layer (105) is arranged to the basic body (103) of the panel (112) at inner surfaces (114) of the basic body (103) directing to the inner volume (Vi).
  2. Vehicle target (100) according to claim 1, wherein the panel (112) is detachably coupled to the outer skin (101) or an inner support structure of the vehicle target (100) by respective detachable fixing elements, such as hook-and-loop fasteners, zip fasteners and/or screw connections.
  3. Vehicle target (100) according to claim 1 or 2, wherein an outer surface (113) of the panel (112) is wave-shaped.
  4. Vehicle target (100) according to one of the claims 1 to 3, wherein an outer surface (113) directing to the environment of the vehicle target (100) has a grey and/or mat color.
  5. Vehicle target (100) according to one of the claims 1 to 4, wherein the basic body (103) comprises a side surface (115) connecting the inner surface (114) with the outer surface (113) of the basic body (103), wherein the radar absorbing layer (105) is arranged onto the side surface (115) of the basic body (103).
  6. Vehicle target (100) according to one of the claims 1 to 5, wherein the absorbing layer (105) extends non-parallel with respect to a vertical direction.
  7. Vehicle target (100) according to one of the claims 1 to 6, wherein the outer skin (101) comprises a wheel section (107) which comprises an optical representation of a real wheel, wherein the outer skin (101) comprises a gap (116) around the wheel section (107) for representation of a wheel arch, and wherein a further panel (102) is mounted in the gap (116) to the wheel section (107) and/or to an inner surface of the outer skin (101) opposite to the wheel section (107).
  8. Vehicle target (100) according to one of the claims 1 to 6, wherein a further panel (102) is arranged to a bottom surface of the vehicle target (100) and extends between two opposing sides of the vehicle target (100).
  9. Method of manufacturing a vehicle target (100) for testing radar sensors of vehicle driver assistant systems, the method comprising providing an outer skin (101) defining the outer geometry of the vehicle target (100), wherein the outer skin (101) at least partially surrounds an inner volume (Vi), and attaching a panel (112) comprising a basic body (103) and a radar absorbing layer (105) to the basic body (103), wherein the panel (112) is mounted to the outer skin (101) such that the radar absorbing layer (105) has an offset (109) with respect to the outer skin (101) in the direction to the inner volume (Vi), wherein the panel (112) is arranged between a front wheel (107) and a rear wheel (107) of the outer skin (101), wherein the panel (112) is arranged between a movable bottom platform (120) onto which the vehicle target (100) is arranged and a bottom of the outer skin (101) and is arranged for covering a space between the bottom platform (120) and a bottom of the outer skin (101), so that the panel (112) is distanced and spaced apart to edges of the outer skin (101) with a panel-to-edge offset in the direction to the inner volume (vi), wherein the panel-to-edge offset defines a distance between the panel (112) and an outer contour of the outer skin (101), characterized in that the radar absorbing layer (105) is arranged to the basic body (103) of the panel (112) at inner surfaces (114) of the basic body (103) directing to the inner volume (Vi).

Description

Field of invention The present invention relates to a vehicle target for testing radar sensors of vehicle driver assistant systems. Furthermore, the present invention relates to a method for manufacturing a vehicle target for testing radar sensors of vehicle driver assistant systems. Art Background Crash-objects like vehicle targets for testing sensors of vehicle driver assistant systems are usually very light weight and have a hollow structure with an inner volume. The vehicle targets are movable and cross a predefined path of a vehicle comprising the driver assistance systems to be tested. The vehicle targets are mounted to a drivable platform by a support structure which is arranged in the space between the bottom surface of the vehicle target and the surface of the platform. Hence, there is no free space between the bottom of the vehicle target and the surface of the drivable platform. However, in contrast to this, a real vehicle is arranged on the street by wheels, wherein between the wheels, the bottom of the vehicle and the streets, as free area is provided. To avoid that e.g. radar-sensor of sensor systems of vehicle driver assistant systems are confused by the design of the vehicle target and specifically by internal reflection of waves, in particular optical and/or radar waves, inside a vehicle target coming from the hollow structure of the vehicle target, the lower part/bottom area of the vehicle target is covered by e.g. a plate like element/panel comprising a radar absorbing or reflecting material/layer. US 2018/0010984 A1 discloses a dummy vehicle formed from a plurality of beams to form a support frame. A flexible envelope is arranged around the support frame, which has the shape of a vehicle to be simulated. Furthermore, side, front and rear skirts are disclosed. The side, front and rear skirts prevent the penetration of radar waves into the lower area of the dummy vehicle. Summary of the Invention Hence, there is a need to provide an improved vehicle target for testing radar sensors of vehicle driver assistant systems. This need is met by the subject-matter of the independent claims 1 and 9. The vehicle target comprises the outer skin defining the outer geometry of the vehicle target. The skin defines the outer shell of the vehicle target. The outer skin may be made of several self-carrying foam panels which are mounted together for forming the desired shape and design of the outer skin representing for example a car. The vehicle target is arranged onto a movable bottom platform which is configured for being driven along the ground. Between the bottom platform and the bottom side of the vehicle target, the panel is arranged between a front wheel and a rear wheel of the outer skin. The outer skin further comprises for example transparent sections for simulating windows of the car or a light of the car. Furthermore, the outer skin comprises a wheel section simulating a real wheel of the car. The real section may simply optically show a non-rotating wheel. For example, the wheel section may be generated by painting or by stickers glued onto the outer surface of the outer skin. Between the wheel section and the surrounding part of the outer skin, a gap may be formed by e.g. a groove, wherein along the outer circumference a wheel arch may be simulated, for example by paint, stickers or by additional foam elements. For example, additional elements, such as reflectors simulating lights of the vehicle may be arranged to the outer skin. The outer skin may be mounted to an inner supporting structure which comprises for example beams that are mounted onto the drivable platform. The panel comprises a basic body to which a radar absorbing layer is attached. If the layer is made of an absorbing material, radar waves can be absorbed. Hence it can be assured, that no radar waves are reflected for example by an inner supporting structure of the vehicle target which fixes the vehicle target to a platform or the like. For example, if no panel or a transmissive panel would be used below the outer skin, radar waves would radiate below the outer skin and would be reflected by elements, such as the supporting structure, in the inner volume, which would cause a measurement of the respective radar sensor of the driver assistant system. However, if the layer comprises a reflecting material, which is not part of the invention as claimed, a predefined reflection direction can be controlled by the alignment of the panel. For example, the panel may be adjusted such that radar waves would not be reflected 180° such that although the radar waves are reflected, no error measurements are caused. Hence, by the panel, a reflection of radar waves reflected from a structure below the vehicle target to the radar sensors can be reduced or prevented. Hence, although supporting structures and the like are arranged below the vehicle target, a free space below the vehicle target can be simulated for the radar sensors, such that a sim