Test system for automated validation and calibration of mass-produced automotive radar sensors, which directly contributes to the high safety level of radar-based driver assistance systems in assisted or automated vehicles.
Radar far-field tests in the smallest of spaces (CATR)
Interference-free testing of the entire radar sensor due to large quiet zone
Distances, speeds, and sizes of radar targets can be changed continuously
Automated, reproducible test scenarios
The end-of-line (EOL) test bench for mass-produced automotive radar sensors is required to test the functionality of finished assemblies and to calibrate them automatically in a particularly compact and low-reflection absorber chamber by means of radar target simulation. The measurement of radar sensor operating parameters and their calibration is carried out in a defined test sequence in which the radar sensor (radar under test, RUT) is rotated around its radiation center in the horizontal and vertical directions by means of high-precision drives.
The test solution, developed by dSPACE GmbH in cooperation with NOFFZ Technologies GmbH, enables precise, reliable, and efficient testing of any automotive radar sensor and only requires a small footprint. It is based on the CATR (compact antenna test range) method, which allows for the calibration of sensors with a large far-field distance in a particularly compact setup. The test system is therefore especially suitable for the calibration of modern radar sensors, such as 4-D radars and imaging radars.
The CATR-EOL test solution combines the industry-proven leading-edge solutions of two recognized vendors:
The device under test, or RUT, is placed manually or by robot into the RUT fixture protected by a light curtain. There, the sensor is mounted, the sensor type is checked by means of a barcode, and the sensor position is checked. Subsequently, the electrical connections are contacted mechanically, the sensor is moved into the absorber chamber, and the absorber chamber is sealed by means of an absorber bulkhead.
The absorber chamber contains a robot that performs relative motion around its radiation center, a reflector with a parabolic surface, and the transmit/receive antenna of a target simulator at the reflector's focus center.
The reflector focuses the radar waves emitted by the radar sensor and redirects them to the receiving antenna of the target simulator. The radar target simulator imprints targets on the radar waves and thereby returns the manipulated waves as echoes to the test object via the reflector. The resulting plane wavefront is independent of the sensor-specific far-field distance, which is why CATR methodology enables a compact design instead of a very large test chamber (often over 10 m long).
During testing and calibration of the radar sensor, it is rotated horizontally (azimuth) and vertically (elevation) around its center of radiation, thus capturing the antenna pattern with its power levels at the respective angle. The transmit and receive antennas of the radar sensor are characterized and measured. Functional results such as correctly detected targets and their properties can be output as test results, as well as the detection characteristics of the respective test object.
Automated end-of-line inspection of radar sensors
Compact design thanks to 3GPP-compliant CATR method1
Fast set-up times when changing the type of radar sensor to be tested, by means of quick-change adapter
Validation of the entire radar transmission channel (antennas and electronics) via over-the-air approach
Up to four simultaneous test targets (same direction of arrival)
Real-time simulation of radar targets with parameterizable distances, velocities, and sizes
Programmable, reproducible tests
Calibration of 3-D and imaging 4-D radar sensors by bandwidth up to 5 GHz
Optimized RUT handling by means of parallel RUT mountings for accelerated test throughput
1) The 3rd Generation Partnership Project (3GPP) unites several telecommunications standard development organizations.