ADAS & Autonomous Vehicle Engineering - July 2023 - 16

Testing
of view of the radar sensor.
If the tested radar sensor and the radar echo generator
are configured with the same unique Doppler
shift, it is also possible to filter out undesired echoes
from multipath propagation, such as radar echoes with
different Doppler shifts from other test stands or from
other tests being performed in parallel.
The EMS test system can automatically perform
Figure 2: The target positioning system allows ± 55° angular
motion from the central position in front of the VUT.
The target positioning system situated
in front of the test vehicle.
radiated and conducted EMS measurements in line
with ISO 114511-2. It consists of a signal generator with
multiple amplifiers and antennas for different frequency
bands to generate the necessary field strengths for EMS
measurements on the vehicle. Figure 3 shows an example
test setup with a test system (shaded dark gray) for
frequencies from 9 kHz to 3.2 GHz. The system's EMC
test software enables automatic EMS measurements and
can also monitor the electronic devices under test. The
software additionally controls the radar echo generator
and the positioning system for the automatic ADAS tests.
target-positioning system, they also check the behavior
of the ADAS system.
To test ADAS functionality, the radar echo generator
simulates a vehicle driving ahead of the VUT,
which the VUT must detect at predefined distances
and at different speeds. The test engineer can set up
to four individually configurable test distances on the
echo generator. It also enables a controlled Doppler
shift, as well as settable radar cross-sections.
The target positioning system additionally simulates
a lane change from left to right or right to left. It allows
±55° angular motion from the central position in front
of the VUT (Fig. 2). With these two devices, the test
engineer can generate scenarios to check whether the
VUT correctly performs automatic speed adjustments
and autonomous emergency braking when adaptive
cruise control is activated.
The EMS test system also feeds electromagnetic
disturbances into the VUT so that performance
impairments can be detected. Movable absorber walls
are used to screen the radar system under test from
the signals of other targets without restricting the field
Test sequence
First, an engineer tests the radar sensors at the front of
the vehicle and the ADAS functions - ACC and AEB
- without additional disturbance signals, in order to
eliminate unforeseen problems before the EMS test
and to ensure that the system generally is working
properly. Next, the EMS signals are fed into the test
scenario. They should simulate typical EMS measurements
on vehicle radios and achieve a maximum field
strength up to 30 V/m.
For the functional tests, the VUT operates
on the vehicle test stand with the respective ADAS
function activated. The system records any anomalies
or malfunctions that occur due to electromagnetic
disturbances. The response of the VUT is determined
by the wheel speed on the test stand, the brake lights
and the results displayed by warning lights or on the
screen of the driver's console; an EMC camera is placed
in the vehicle to record the cabin warnings.
To test the ACC function, a vehicle 15 meters in
front of the VUT is simulated and initially travels at the
same speed as the VUT on the test stand. The simulated
object should be shown on the driver's screen.
The simulated vehicle then brakes slightly and accelerates
again. The VUT must adjust its speed accordingly,
16 July 2023
ADAS & AUTONOMOUS VEHICLE ENGINEERING
Rohde & Schwarz
Rohde & Schwarz
ADAS & Autonomous Vehicle Engineering - July 2023

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