Vehicle destination with plates to prevent radar reflections inside the vehicle destination

Description

Field of invention

[0001] 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

[0002] 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.

[0003] 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.

[0004] 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

[0005] Hence, there is a need to provide an improved vehicle target for testing radar sensors of vehicle driver assistant systems.

[0006] This need is met by the subject-matter of the independent claims 1 and 9.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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 simulation of a real vehicle having a free space below its bottom is possible.

[0012] The radar absorbing material may be made of foam materials in particular without a homogeneous surface. For example, the foam materials may have surface with a nub structure. Furthermore, the absorbing material may be made of polymer material comprising electrically conductive particles, such as electrically conductive carbon or soot particles. Specifically, the absorbing material may have destructive interference characteristics.

[0013] The radar reflecting material, which is not part of the invention as claimed, may have an electrically conductive surface which support the reflection characteristic for in particular radar waves.

[0014] The basic body forms the supporting structure for the radar absorbing layer. The basic body may be formed of hard foam and comprises for example a coupling element for being coupled to the outer skin of the vehicle target.

[0015] According to an example, which is not part of the invention as claimed, below the front bumper and below the rear bumper respective panels are arranged. Additionally, behind the wheel sections respective panels may be arranged.

[0016] According to the present invention, the panel, that is arranged between the front wheel and the rear wheel, comprises an offset in the direction to the inner volume of the vehicle target and the outer skin, respectively. The offset defines a distance between the panel and an outer contour of the outer skin, respectively. Specifically, the panel is distanced and spaced apart to the edges of the outer skin.

[0017] Hence, the shape of the shadow generated by the outer skin including its edge is not influenced by the panel, because the panel is located further inside and spaced apart from the edge. Hence, the confusion of optical sensors of the driver assistance system between the real vehicle and a vehicle target is reduced, since no artificial shadow is generated by the radar absorbing panels.

[0018] Accordingly, as an example which is not part of the invention as claimed, to provide and display the natural shadow of the vehicle target, which is important for sensors to be tested, e.g. camera sensors, radar sensor, etc., the outer side / outer edges of the panel may have a geometrical offset from the outer skin in direction to the interior volume of the vehicle target with respect to the other exterior surfaces (doors, mud guards, front and rear bumper). Hence, no edges or other parts of the panel protrude from the outer geometry (e.g. the skin and the other exterior surfaces, such as reflectors) of the vehicle target, so that natural shadow of the vehicle target 100 is not influenced by the panels.

[0019] According to an example, which is not part of the invention as claimed, at least two panels are pivotably coupled together. In other words, the vehicle target comprises a further panel which is pivotably coupled to the panel, for example by a hinge. The further panel may comprise a radar reflective or absorbing layer arranged on a further basic body. Hence, in case of a deformation of the outer skin due to a crash, the panels may pivot around the hinge in order to prevent deformation of the panels.

[0020] According to an example, which is not part of the invention as claimed, at least two panels are detachably coupled together by respective detachable fixing elements, such as hook-and-loop fasteners, zip fasteners and / or screw connections.

[0021] According to further exemplary embodiment. the panel is detachably coupled to the outer skin or an inner support structure of the vehicle target by respective detachable fixing elements, such as hook-and-loop fasteners, zip fasteners and / or screw connections.

[0022] Additionally or alternatively, the panels may be coupled to the outer skin or an inner support structure of the vehicle target by elastic elements, such as elastically deformable belts or strips (e.g. rubber straps). The elastic elements may be coupled to the panel and the outer skin or support structure of the vehicle target in such a way that upon an impact of the vehicle target with a further subject (such as a vehicle to be tested) the elastic elements still connect the panels to the vehicle target. Hence, if for example the detachable fixing elements, such as the hook-and-loop fasteners, release the panels from the outer skin upon impact, the elastic elements still hold the panels in the vicinity of the vehicle target. Hence, a faster reassembly of the vehicle target after a crash may be provided, since the detached panels are still in the vicinity of the vehicle target.

[0023] As an an example, which is not part of the invention as claimed, the basic body is, at least partially, transparent for waves, in particular optical and / or radar waves.

[0024] According to further exemplary embodiment an outer surface of the panel is wave-shaped. Hence, the risk of a direct reflection of radar waves which may cause an error measurement of the radar sensors may be reduced. Additionally, or alternatively, the outer surface of the panel may have a plurality of protrusions and grooves or holes in order to reduce the risk of direct reflection of radar waves to the respective sensors. Hence, the outer surface of the panel may not be a plain surface to reduce optical reflections.

[0025] According to further exemplary embodiment, an outer surface of the panel directing to the environment of the vehicle target has a grey and / or mat color. Hence, in particular reflection of optical waves may be reduced in order to reduce the risk of an error measurement of optical sensors of the driver assistant system may be reduced, which is an example not part of the invention as claimed.

[0026] According to the invention, the radar absorbing layer is arranged to the basic body of the panel at inner surfaces of the basic body directing to the inner volume. In particular the inner surfaces are opposite surfaces with respect to the outer surface. Specifically, the inner surface of the basic body comprises a normal which directs into the inner volume of the outer skin. The radar absorbing material is located at the inner side (i.e. the inner surface) of the panels and the basic body, respectively. To the inner surface of the basic body, the layer of radar absorbing material is arranged.

[0027] According to further exemplary embodiment, the basic body comprises a side surface connecting the inner surface with the outer surface of the basic body, wherein the radar absorbing layer is arranged onto the side surface of the basic body. Hence, a more comprehensive absorbing of the radar waves is provided.

[0028] According to a further exemplary embodiment, the absorbing layer extends non-parallel with respect to a vertical direction. In other words, the absorbing layer comprises a normal which is non-perpendicular to a horizontal direction. In other words, the vehicle target is arrangeable onto a supporting plane which is generally parallel to the horizontal plane. A normal of the supporting plane may be parallel to a vertical direction.

[0029] According to further exemplary embodiment, the outer skin comprises a wheel section which comprises an optical representation of a real wheel, wherein the outer skin comprises a gap around the wheel section for representation of a wheel arch. The panel is mounted in the gap to the wheel section and / or to an inner surface of the outer skin opposite to the wheel section. the offset of the panel mounted to the wheel section may be determined by the distance between a front edge of the outer skin to the panel arranged to the front wheel section and / or by a distance between the rear edge of the outer skin to the panel arranged to the rear wheel section.

[0030] According to an example, which is not part of the invention as claimed, the panel is arranged to a bottom surface of the vehicle target and extends between two opposing sides of the vehicle target. The panel may extend between a front end and a rear end of the vehicle target, wherein the panel may be spaced by the offset from a front edge and a rear edge of the vehicle target and the outer skin, respectively. According to the invention, the panel is arranged between a front wheel and a rear wheel of the outer skin. Hence, radar waves arriving to a space below the vehicle target from the side of the vehicle target are absorbed, such that error measurements can be reduced.Brief Description of the Drawings

[0031] Fig. 1 to 4 show exemplary embodiments of the car target according to the present invention. Fig. 5 show a schematic view of a vehicle target having panels on wheel sections according to an example, which is not part of the invention as claimed. Fig. 6 shows a schematic view of a back side of a vehicle target according to an example, which is not part of the invention as claimed. Detailed Description of Exemplary Embodiments

[0032] The illustrations in the drawings are schematic. It is noted that in different figures similar or identical elements are provided with the same reference signs. Fig. 1 shows a side view of a vehicle target 100 according to an exemplary embodiment of the invention.

[0033] The vehicle target 100 is provided for testing radar sensors of vehicle driver assistant systems. The vehicle target 100 comprises 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. The vehicle target 100 further comprises at least one panel 102, 112 comprising a basic body 103 and a radar absorbing layer 105 attached to the basic body 103, wherein the panel 102, 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.

[0034] The vehicle target 100 comprises an outer skin 100 defining the outer geometry of the vehicle target. For example, additional elements, such as reflectors 106 may be arranged to the outer skin 101 for defining the outer geometry. Additionally wheels 107 may be formed to the outer skin 100.

[0035] The skin 101 defines the outer shell of the vehicle target 100. The panel 102, 112 comprise an offset 109 in the direction to the inner volume vi of the vehicle target 100. The offset 109 defines a distance between the panel 102, 112 and an outer contour of the outer skin 101, respectively. Specifically, the panel 102, 112 flushing with the edges of the outer skin 101. So that the offset 109 may be small.

[0036] Specifically, below the front bumper and below the rear bumper respective panels 102 are arranged. Additionally behind the wheels 107 respective panels 102 may be arranged. Additionally, two panels 102 may be flexibly mounted together by hinges 110. Hence, in case of a deformation of the outer skin 101 due to a crash, the panels 102 may pivot around the hinge 110 in order to prevent deformation of the panels 102.

[0037] The vehicle target 101 is arranged onto a bottom platform 120 which is configured for being driven along the ground. Between the bottom platform 120 and the bottom side of the vehicle target 100, the panel 112 is arranged between the front wheel and the rear wheel 107.

[0038] As an example which is not part of the invention as claimed, to provide and display the natural shadow of the vehicle target 100, which is important for sensors to be tested, e.g. camera sensors, radar sensor, etc., the outer side / outer edges of the panel 102 may have a geometrical offset 109 from the outer skin 101 in direction to the interior volume Vi of the vehicle target 100 with respect to the other exterior surfaces (doors, mud guards, front and rear bumper). Hence, no edges or other parts of the panel 102, 112 protrude from the outer geometry (e.g. the skin 101 and the other exterior surfaces, such as reflectors 106) of the vehicle target 100, so that natural shadow of the vehicle target 100 is not influenced by the panels 102. Additionally the outer surface 113 of the panel 102, 112 may not be a plain surface to avoid optical reflections. Preferably, the outer surface 113 of the panel is wave-shaped and has a grey / mat color.

[0039] The radar absorbing material 105 is located at the inner side (i.e. the inner surface) of the optical panels 102, 112.

[0040] To the inner surface of the basic body 103, the layer of radar absorbing material 105 is arranged.

[0041] The panel 102, 112 comprises a basic body 103 to which a radar absorbing layer 105 is attached. The basic body 103 forms the supporting structure for the radar absorbing layer 105. The panels 102, 112 comprise offsets in the direction to the inner volume vi of the vehicle target 100 and the outer skin 101, respectively. The offset 109 defines a distance between the panel 102, 112 and an outer contour of the outer skin 101, respectively. Specifically, the panel 102, 112 is distanced and spaced apart to the edges 501, 502 of the outer skin 101. The offset 109 specifically defines the distance between an edge of the panel 102, 112 at the contact position with the outer skin 101 and an edge 501, 502 of the outer skin 101 from which the bottom surface and a side surface of the outer skin 101 extend.

[0042] As can be taken from Fig. 1, the panel 112 extends from the front to the back of the vehicle target 100. Hence, the panels 102, 112 covers the space between a platform 120 and the bottom of the outer skin 101. The panel 112 has an offset 109 (not shown for panel 120) in the plane of projection and has a respective offset 109 from the side wall of the outer skin 101. Accordingly, panel 112 is arranged further inside and behind the respective wheel sections 107. A perspective view of the panel 112 can be taken from Fig. 3.

[0043] Accordingly, the panel 102 provides a respective offset 109 with respect to the side wall of the outer skin 101. Additionally, the panels 102 comprising offset 109 from the bottom surface of the outer skin 101 as shown in Fig. 1. the panels 102 are arranged at an inner side of the outer skin 101 and / or with an offset 109 above the bottom edge 108 of the outer skin 101. Specifically, the panels 102 extend between the inner sides of opposing front wheel sections 107 or opposing rear wheel sections 107, respectively.

[0044] As can be taken by the front and rear panels 102, at least two panel parts are pivotably coupled together. The two panel parts are pivotably coupled by a hinge 110. Hence, in case of a deformation of the outer skin 101 due to a crash, the panel parts may pivot around the hinge 110 in order to prevent deformation of the panel parts.

[0045] The radar absorbing layer 105 is arranged to the basic body 103 of the panel 102, 112 at inner surfaces 114 of the basic body 103 directing to the inner volume vi. In particular, the inner surfaces 114 are the opposite surfaces with respect to the outer surface 113. Specifically, the inner surface 114 of the basic body 103 comprises a normal which directs into the inner volume vi of the outer skin 101. The radar absorbing layer 105 is located at the inner side 114 (i.e. the inner surface) of the basic body 103.

[0046] As can be seen in Fig.2, the panel 112, the panel 112 comprises a (e.g. vertical) offset 109 from the side surface of the vehicle target 100. As can be further taken by the panel 112 in Fig. 2, the panels 102, 112 may have a basic body having a trapezoid or almost triangular cross-section. Along to side surfaces of the panels 102, 112, which side surfaces direct to the inner volume Vi of the vehicle target 100, respective radar absorbing layers 105 are arranged. Hence, radar waves 111 are prevented from entering the inner volume Vi.

[0047] Specifically, the basic body 113 may have a wedge-shaped cross-section, wherein the tip of the wedge-shaped cross-section is spaced apart from the bottom of the outer skin 101 and the larger side surface 115 is coupled for example to the outer skin 101 or a bottom structure of the vehicle target 100. Specifically, between the side surface 115 of the basic body 103 and the outer skin 101, a section of the radar absorbing layer 105 may be arranged. Furthermore, further part of the radar absorbing layer 105 is attached on the inner surface 114 of the basic body 103. As illustrated by the arrow 111, radar waves radiating below the outer skin 101 are absorbed by the panel 112, so that an error measurement of the radar sensors of a vehicle driver assistant system can be prevented.

[0048] As can be taken from Fig. 3, the panel 112 is offset from the outer skin 101 in the direction to the in the volume Vi of the vehicle target 100. Hence, as can be taken from Fig. 3, the shadow of the vehicle target 100 is not affected by the panel 112.

[0049] Hence, the shape of the shadow generated by the outer skin 101 including its edges is not influenced by the panels 112, because the panel 112 is located further inside and spaced apart from the edge. Hence, the confusion of optical sensors of the driver assistant system between the real vehicle and a car / vehicle target according to an example not part of the invention is reduced, since no artificial shadow is generated by the radar absorbing panels 112. Fig. 4 illustrates a schematic view of a vehicle target 100 comprising the outer skin 101. As can be taken from Fig. 4 the outer skin 101 may additionally comprise wheel sections 107 which simulates a real wheel of a real vehicle. However, the wheel sections 107 may be not rotatable in comparison to a real wheel. The wheel section 107 may be formed by a sticker which is glued onto a skin surface of the outer skin 101 or by a specific paint layer. Furthermore, a wheel arch 117 may be formed. Between the real section 107 and the wheel arch 117, a gap or groove 116 may be formed inside the outer skin 101.

[0050] Fig. 5 shows a schematic view of a vehicle target 100 having panels 102 on wheel sections 107 according to an example, which is not part of the invention as claimed. 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 117. The 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. the offset 109 of the panel 102 mounted to the wheel section 107 may be determined by the distance between a front edge 501 of the outer skin 101 to the panel 102 arranged to the front wheel section 107 and / or by a distance between the rear edge 502 of the outer skin 101 to the panel 102 arranged to the rear wheel section 107.

[0051] 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 a radar absorbing or reflecting material / layer 105 is arranged onto the side surface 115 of the basic body 103. Hence, a more comprehensive reflection or absorbing of the radar waves is provided.

[0052] Specifically, the panel 102 is arranged to an interior side of the wheel section 107 and extends for example between two opposing wheel sections 107. Hence, the panel 102 has an offset 109 from the front or rear edge 501, 502 and a further offset 109 from a side surface of the outer skin 101. Hence, radar waves 111 which radiates from the backside or the front side of the vehicle target 100 below the outer skin 101 can be absorbed or reflected by the panel 102. Furthermore, the panel may have a curved shape which can be adapted to the circumferential extension and (bending) radius, respectively, of the wheel section 107.

[0053] Fig. 6 shows a schematic view of a back side of a vehicle target 100 according to an example, which is not part of the invention as claimed. A absorbing / reflecting layer 105 extends non-parallel with respect to a vertical direction. In other words, the absorbing / reflecting layer 105 comprises a normal which is non-perpendicular to a horizontal direction. In other words, the vehicle target 100 is arrangeable onto a supporting plane 601 which is generally parallel to the horizontal plane. A normal n of the supporting plane 601 may be parallel to a vertical direction. In other words, the absorbing / reflecting layer 105 may have an angle a between 1° and 89° to the normal n of the supporting plane 601. Furthermore, the panel 102 extends from the edge 502 of the outer skin 101 in the direction to the supporting plane 601 and further along a vertical direction to the inner volume vi. Hence, radar waves 111 directed to the panel 102 are reflected in the direction to the supporting claim 601.

[0054] Specifically, the panel 102 is arranged to a bottom surface of the vehicle target 100 and extends for example between two opposing sides of the vehicle target 100. Hence, the panel 102 has an offset 109 from the rear edge 502 and a further offset 109 from a side surface of the outer skin 101. Hence, radar waves 111 which radiate from the backside of the vehicle target 100 below the outer skin 101 and the vehicle target 100, respectively, can be absorbed or reflected by the panel 102. The panel 102 can be formed similar to the panel 102 shown in Fig. 5.Reference numerals

[0055] 100 car target 101 skin 102 panel 103 basic body 105 radar absorbing layer 106 reflector 107 wheel, wheel section 108 lower part of vehicle target, bottom edge 109 offset 110 hinge 111 waves, particular optical and / or radar waves 112 further panel 113 outer surface of panel 114 inner surface of panel 115 side surface of panel 116 gap 117 wheel arch 120 driven platform 501 front edge 502 rear edge 601 supporting plane

Claims

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).