Technical Bulletin

Global Vehicle TargetSpecification
Version 1.0

May 2018
TB 025TitleVersionDocument NumberAuthor
Date
Related Documents
StatusApplication Date

Global Vehicle Target Specification
1.0TB025
Euro NCAP Secretariat
May 2018
AEB C2C Test Protocol, LSS Test Protocol
Information
May 2018

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1INTRODUCTION

Based on the outcome of the several Global Harmonization workshops organized by Euro
NCAP, the National Highway Traffic Safety Administration (NHTSA), and the InsuranceInstitute for Highway Safety (IIHS), as well as the pre-studies from Dynamic Research, Inc. thefollowing specification defines a 3-dimensional vehicle target called the Global Vehicle Target(GVT).
The Euro NCAP AEB C2C & LSS Test Protocols require the use of the Global Vehicle Target(GVT).
This document provides the technical specification for the GVT, which is designed to be an
accurate surrogate for a passenger vehicle from almost any horizontal direction and in almost
any conflict scenario while minimizing the potential for damage to the vehicle under test (VUT)
and to minimize the risk to the VUT occupants.
All targets used for official Euro NCAP tests will meet these requirements, which are verified
by the lab at the start of a test series.

1.1 Abbreviations
GVTIRLiDARLPRVPMD
RADAR
RAMRCS
VUT

Global Vehicle Target
InfraredLight Detection And Ranging
Low Profile Robotic Vehicle
Photonic Mixer Device
Radio Detection And Ranging
Radar Absorbing Material
Radar Cross Section
Vehicle under test

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2

VEHICLE TARGETThe GVT shall be comprised of representative vehicle attributes relevant to the target detection
sensors used in the VUT. The required sensor-relevant GVT attributes for a system test are
determined by the vehicle manufacturer and must be implemented in the manner specified inthis document. The GVT must be detectable by following automotive sensors technologies:
RADAR, Video, LiDAR, PMD, and IR.

1.1 Vehicle Target Features
The GVT representing a vehicle, whose purpose is to activate sensor systems, consists of atarget structure and optionally a target carrier, representing a vehicle having the necessary
features to be recognised from any direction (3D vehicle target).
and shall be lightweight and flexible so as to minimize the load imparted to the VUT body
panels in the event of a collision. The GVT should also have radar-reflective and infraredreflective materials that meet the specifications in sections 1.3 and 0.
The GVT shall provide a safe mounting location for a GPS antenna within the structure suchthat the radar reflective (i.e., metallic) fabric of the GVT does not interfere with the GPS satellite
reception required by the robotic platform responsible for supporting, and moving whenappropriate, the GVT during a VUT evaluation.

Figure 1: Global Vehicle Target

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1.2 Vehicle Target Dimensions
The dimensions of the GVT provided in Tables 1 and 2 are shown in Figures 2 and 3,respectively. Note that the vertical measurements are based on a typical ground clearance of themotion platform of 20 mm.

Table 1: GVT Longitudinal and Vertical Dimensions

No.

Description

Dimension

Tolerance

1234*

Overall length
Front ground clearance
Front skin height
Hood height4023 mm
173 mm
488 mm
290 mm± 50 mm± 25 mm± 25 mm± 25 mm56789*
10*
1112*
131415

Side ground clearance
Rear ground clearanceOverall height
Tire diameter
Front skin angle
Rear skin angle
Hood length
Side mirror position
Side mirror length
Side mirror clearance
Side mirror height

185 mm
323 mm1427 mm
607 mm
6.4 deg
1.0 deg
792 mm1140 mm
229 mm
892 mm
132 mm± 25 mm± 25 mm± 50 mm± 10 mm± 2.0 deg
± 0.5 deg
± 25 mm± 25 mm± 10 mm± 25 mm± 10 mm

16Wheelbase

2565 mm± 50 mm* Optional reference measurements

Figure 2: GVT Longitudinal and Vertical Dimensions

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Table 2: GVT Lateral Dimensions

No.

Description

DimensionTolerance

1234

Overall width (excluding mirrors)
Roof width
Overall width (including mirrors)
Tire Width

1712 mm
1128 mm
1798 mm
206 mm± 50 mm± 50 mm± 50 mm± 10 mmFigure 3: GVT Lateral Dimensions

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1.3 Visible and Infrared Properties
Dimensionally, and from the perceptive of the sensors installed in the VUT, the GVT shall be
representative of a white hatchback passenger vehicle. The IR reflectivity of the GVT surfaces,
specified in Table 3, shall be in the wavelength range of 850 to 910 nm. Each of the visual areasof interest, as indicated in Figure 4, shall be measured in accordance with the procedure outlinedin Appendix A1.

Figure 4: IR Areas of Interest

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Table 3: IR Reflectivity

No.

Area of Interest

IR Reflectivity

12
3
4
56
7
8910

White Vinyl (no graphics)
Windshield, dark area
Windshield, light area
Side Mirror Face(1)Side Panel(1)Side Windows
Tire, wall and tread(1)Rear bumper, black
Rear window, light area
Black fabric (RAM skirts, wheel wells)> 70%
40% - 70%
> 70%
> 70%
> 70%
> 70%
10% - 40%
< 10%> 70%< 10%

Note 1: Most of these objects have large variation in graphics. IR reflectivity should be averaged
over many sampled areas.

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1.4 Radar Properties
The radar reflectivity characteristics of the GVT shall be similar to a passenger vehicle of thesame size.
1.4.1 Radar Cross Section (RCS)The radar cross section of a vehicle may vary significantly with observation angle. Theoreticallythere is no RCS variation with the distance. However, due to the limited field of view of theradar sensor and the implemented free space loss compensation, the measured RCS
significantly varies over distance, and in near distances the vehicle is not scanned over its
complete height. The measured RCS is also influenced by geometrical effects (i.e., multi pathwith constructive and destructive interferences). Therefore, in this document RCS refers to themeasured RCS by a given radar sensor with its specific parameter set, while recognizing that it
does not necessarily correspond to the physical RCS. The method of measuring the GVT RCS
is described in Appendix A2.

1.5 Mounting and Guidance SystemProvisions must be made to ensure the GVT is fully supported and at the correct vertical height.
Providing sufficient support is particularly critical for the wheel blocks which are relatively
heavy and are located at the corners of the GVT footprint. In general, the following guidelines
should be followed.
• All visible parts of the motion platform should be colored in grey.
• It must be ensured that the GVT mounting does not influence radar return. Where
needed, RAM skirts shall be used to ensure the radar reflections from the motion
platform are minimized.
• Reproducible positioning of the GVT is achieved by aligning the GVT with the motion
platform mounting locations to within 2 cm.

1.6 Vehicle Target Weight and Collision Stability•••

Maximum relative velocity of the VUT into the GVT: 120 km/h, (to prevent damage tothe VUT).
Maximum GVT weight: approximately 110 kg
The GVT must continue to meet the specified requirements after repeated collisions.

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APPENDIXA1 Measurement of the IR reflectivity
The measurement of the GVT shall be made in accordance with the following procedure.
Required measurement equipment:• A spectrometer capable of covering wavelengths from 850 to 910 nm, such as theOcean Optics Flame-S-XR1 spectrometer (shown in Figure A1) or the JazMiniaturspektrometer,• A light source• A 45-degree probe• A calibration standard
The spectrometer should be calibrated using the calibration procedure specified by the device
manufacturer. The calibration shall then be confirmed using a calibration standard with a knownreflectivity.

Figure A1. IR Measurement Equipment

The IR measurements shall be taken at three locations for each feature to be measured, and shallbe averaged across the three measurements for wavelengths in the range of 850 to 910 nm.
Figure A2 and Figure A3 show the averaged results for the various areas of interest, which arelisted in Table 3 (previously shown in Section 1.3).

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Figure A2. Example IR Measurements (1-6)

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Figure A3. Example IR Measurements (7-10)

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A2 Measurement of Radar Reflectivity
Measuring RCS at a fixed distance can produce misleading results because the sensor might beexperiencing either cancellation or amplification due to the multi-path effect. Therefore, it isnecessary to measure RCS by moving the sensor towards the object, such that the sensor will
be moving into and out of the cancellation and amplification regions. Also, to reproduce theeffect of decreasing RCS at close range, the radar reflectivity of the GVT must be distributed
over the whole body causing the RCS to decrease at shorter distances due to partial visibility ofthe GVT by the sensor. The method of measuring the GVT RCS is described in Appendix A2.
The instantaneous measured RCS of a vehicle or target can experience cancellation due to theradar multi-path effect at various ranges. These cancellation regions will result in very lowRCS relative to the typical RCS at certain distances (see examples in Appendix A3). Reducing
the lower RCS boundary to account for these cancellation regions could allow for a target witha low average RCS to be deemed acceptable. Therefore, the RCS of the GVT is specified using
a curve fit to the measured RCS data as a function of range, as well as tolerance bounds on thecurve fit.
The RCS curve fit characterizes both the far-field RCS and the near-field RCS which, as notedabove, decreases with range. The form of the curve fit RCS, as shown in Figure 4, is:
RCSFIT = RCSFAR – KDEC x min(R - RFAR, 0)2

where KDEC ≥ 0

The RCS curve fit is calculated by determining the parameters, RCSFAR and KDEC, such that thesum of the square of errors between the RCS curve fit and the raw RCS data is minimized. Theparameter RFAR is dependent on several factors, including the sensor parameters. For thisanalysis it is assumed to be fixed for a given sensor.

Figure 4: Form of the Average RCS Curve

The RCS curve fit of the GVT should stay within a defined range, defined by upper and lowerbounds. For the GVT, the equations defining the bounds are given below for a Bosch LRR3sensor and a Continental ARS 408-21 sensor, using the calibration and measurement methods
described in Appendix A2.
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RCSBOUNDS,BOSCH = 16 – 0.004 x min(R - 48,0)2 ± 6

for the Bosch sensor

RCSBOUNDS,CONTI = 16 – 0.015 x min(R - 34,0)2 ± 6

for the Continental sensor

A slightly different definition must be made for each frequency and sensor variant since theRCS reduction at close range is a function of the sensor parameters.
Depicted in Figure 6 are the RCS boundaries for measurements with these two commerciallyavailable 77 GHz sensors. If other sensors are used or the mounting position deviates from that
described in Appendix A2 or the test surface differs from the description in this appendix, otherRCS values may be obtained. In that case an additional verification/adaption of the boundaries(Figure 6) may be necessary for validation of the GVT. These boundaries are valid for a rearapproach measurement from 180 degrees with 100% overlap.

Figure 5: Vehicle target RCS boundaries for measurements at 77GHz

Radar reflectivity measurement of the GVT shall be made in accordance with the following
procedure.

Recommended Measurement Setup
A reference measurement with a corner reflector calibrated to 10 dBsm is required. The cornerreflector shall be positioned at a vertical height of 500 mm +/- 10mm. The average RCS,
calculated as the median RCS in m2 but reported in decibels per square-meter, shall be used tocalculate the correction factor to be applied to the output of the sensor as needed.
Sensor Configuration and Orientation• 77 GHz wavelength with performance similar to either of the following:o Bosch LRR3o Continental ARS 408-21• Vertical height above the ground: 500 mm +/- 25mm
• Horizontal alignment: +/-1 deg to center line
• Vertical alignment: +/-1 deg to center line

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Sensor Motion Device
The radar sensor shall be moved towards the object being measured (i.e., the corner reflector
reference or GVT). The sensor may be attached to a vehicle or to a specialized measurement
cart (e.g., like that shown in Figure A4). Alternatively, the GVT could be moved towards astatic sensor, as long as the relative motion between the sensor and GVT is the same as thespecified scenario. In any case, the requirements below are applicable:• Angular deviation (relative to the direction of motion): <0.5 deg• Positioning measurement accuracy (longitudinal/lateral): < 50 mm

Figure A4. Example Radar Measurement CartTB 025-15/21

Vehicle Target• Positioning accuracy (longitudinal/lateral): < 20 mm• Angular orientation deviation (relative to direction of sensor motion): < 1 deg

Test Environment• No additional objects/buildings in the area indicated as “Free space” in Figure A5• Proving ground surface completely covered with tarmac, asphalt, or concrete andcompletely flat within 5m of the path of the sensor or GVT• Ground conditions: flat and dry• No metallic or other strong radar-reflecting parts within the area indicated as “Freespace” in Figure A5

Free spaceGVTSensor

Figure A5: Test Environment

Measurement Scenario•••••

Static GVT with moving measurement device
Initial distance: 100 m to 5mApproaching speed: 3-5 km/h
Approach aspect: 180 deg (i.e., the sensor faces the rear of a static GVT)
Perform 3 approaches
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Figure A6: Measurement Scenario

Data Analysis

During each of the three approach measurements, the range and RCS of the GVT shall berecorded. The curve-fit RCS shall then be calculated by minimizing the sum-squared error,ESS, between the raw RCS data and the curve-fit RCS. In other words, the parameters RCSFAR
and KDEC shall be optimized to find the solution that minimizes the error term ESS, whereESS = ∑(RCSAVG(R) – RCSMEAS(R))2
RCSFIT (R) = RCSFAR – KDEC x min(R - RFAR, 0)2(KDEC ≥ 0)

Note: As a point of reference, the RFAR values for the sensors previously described in Sensor
Configuration and Orientation are as follows:• Bosch LRR3: 48 m
• Continental ARS 408-21 : 34 m

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A3 RCS Measurement Examples
The example data in this appendix were measured during the GVT Familiarization event, hostedby Thatcham Research in Upper Heyford, United Kingdom on 12-13 April 2018.
Figure A7 provides an RCS measurement example of the calibration measurement (10 dBsmtrihedral) for the Bosch LRR3 and Continental ARS 408-21 sensors. The depicted data has beenscaled based on the known RCS of the measured object.

Figure A7: Example RCS measurement of trihedral calibration object using theBosch (top) and Continental (bottom) sensors

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Figures A8 through A10 provide RCS measurement examples for the GVT using the evaluation
methodology defined in Appendix A2 for the Bosch LRR3 and Continental ARS 408-21
sensors, respectively. The raw data depicted in the figures below were captured during threemeasurement scenarios.
Figure A8 provides an example RCS measurement of the GVT on a robotic platform. Figure
A9 provides an example RCS measurement of the GVT on a foam stand used for static test
scenarios. Figure A10 provides an example RCS measurement of the previous version(Revision E) GVT with a Retrofit Kit. The Retrofit Kit is designed to ensure the radar
characteristics of the Revision E GVT are similar to the latest GVT.

Figure A8: Example RCS measurement of GVT on Platform using theBosch (top) and Continental (bottom) sensors

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Figure A9: Example RCS measurement of GVT on Foam Stand using theBosch (top) and Continental (bottom) sensors

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Figure A10: Example RCS measurement of GVT (Revision E with Retrofit Kit) on Platformusing the Bosch (top) and Continental (bottom) sensors

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