Radar sensors are key components in autonomous driving. The number of radar sensors in vehicles is growing since, in addition to long-range radars required by NCAP (New Car Assessment Program), an increasing number of corner radars are installed that can also monitor objects moving laterally.
The latest generation of radar sensors comes with integrated RF antennas and signal processors for object recognition accommodated on the same chip. That is why the objects to be recognised need to be simulated over the air in radar sensor tests. The new R&S RTS – consisting of the R&S AREG800A backend and the R&S QAT100 antenna array frontend – is a target simulator that generates dynamic radar echoes that can be used at all stages of automobile radar sensor testing – from pre-development through hardware-in-the-loop lab tests to validation of ADAS/AD functions integrated in the vehicle.
The backend can simulate a large number of independent artificial objects and dynamically vary their range, size (radar cross section) and radial velocity. With an instantaneous bandwidth of 4 GHz between 76 GHz and 81 GHz, it covers the typical frequency range of current and future automotive radar sensors.
The frontend uses up to 192 independently switchable antennas to simulate objects moving laterally to the car’s direction of movement, providing very fine resolution, high switching speed and high repeatability. Electronic switching of the antennas does not cause any wear to RF cables and other moving parts, as is otherwise encountered with mechanical antenna motion used in traditional test systems. An optional transmit array makes it possible to simulate two objects very close together and moving laterally to the car. The small patch antennas and the absorber-lined surface provide a low-reflection RF frontend with a very small radar cross section. This reduces the sensor’s noise floor and suppresses close-range targets and potential multipath reflections. The antenna spacing of just 3.7 mm delivers very fine angular resolution. Multiple frontends can be combined to cover larger fields of view of radar sensors. An angular resolution of less than 0.5° is possible.
Starting from simple scenarios such as automatic emergency breaking (AEB), the R&S RTS can be extended to cover very complex scenarios with multiple radar sensors thanks to its modularity and scalability. Any number of R&S QAT100 frontends and R&S AREG800A backends can be combined. One of the backends synchronises all the components installed in the setup. A graphical user interface with a touchscreen makes it easy to configure the test setup.
For test automation with industry-standard tools, the R&S RTS comes with a hardware-in-the-loop (HiL) interface conforming to the ASAM Open Simulation Interface specification.