Here are brief descriptions of each system component and communications connection/bus:
• Radar Engine Control Unit (ECU)—The main task of the radar sensor is to detect objects and measure their velocity and position relative to the movement of the host radar-equipped vehicle. The radar sensor is a monostatic multimodal radar and uses the 76 GHz frequency band with six fixed radar antennas. The sensor can detect other vehicles at roughly 250 meters. The radar is equipped with a heated lens that ensures full sensor availability, even in poor weather conditions such as snow and ice. The relative speed of objects is measured using the Doppler effect—change in frequency between the reflected and transmitted signals—and distance to the object can be determined by the time lag.
The ECU handles the sensor fusion with the information from the camera and is responsible for functions such as ACC and AEB.
• Camera ECU—The Camera ECU acquires images of the surrounding environment and provides several pieces of information such as distance from lane lines and other objects. This information is sent to the Radar ECU for sensor fusion, but in some cases (for example, road signs and lane keeping), the Camera ECU works alone. In this case, it sends CAN messages on the Vehicular CAN.
• Video Scenario Generation—Video Scenario Generation is a simulator that includes a vehicle system that receives input from PXI-8512/2 through CAN communication and transmits info about the simulated environment. Radar data such as distance, radar cross section (RCS), angle of arrival, and speed is generated during simulation and is calculated in real time based on the video scenario. Through the control panel in the second screen, it is possible to handle connection with PXI-8521/2, change weather conditions, adjust radar position, and spawn a new vehicle with defined speed and distance.
Figure 5. Vehicle Communication Emulation
This simulator has been developed using the Unity 3D Graphic Engine, a cross platform game engine by Unity Technologies. Using a modularized approach, the video scenario can be easily integrated with every third-party platform, plugin, or device like the Logitech G29 shown in the previous image.
Figure 6. ADAS HIL Test Environment
The radar object simulator is used in the HIL system for test and measurements. The flexibility, modularity, and scalability of the NI system enables users to easily integrate it with other I/O as part of a comprehensive HIL tester for radar design and test applications and to use the same system for both target emulation and radar device measurements, lowering the cost of device and system test.
The system is capable of:
• RF measurements for sensor performance verification
• Signal analysis: equivalent isotropically radiated power ( EIRP), noise, beam width, and frequency
• Chirp analysis: linearity, overshoot, recording, and tagging
• Radar target simulator for sensor functional verification
• Single and multiple targets
• Fixed and variable distance
• Multiple object scenarios (distance, velocity, size, and angle of arrival)
• Customizable target scenarios
Figure 7. Two-Target, One-Angle System Architecture
In Figure 7, the setup with one PXIe-5840 vector signal transceiver and one mmWave head can generate two targets with the same angle of arrival. Thanks to the PXI platform flexibility, the system could be easily extended to cover multiple targets with multiples angles of arrival. In Figure 8, the configuration with four PXIe-5840 devices and four mmWave heads can simulate up to eight different targets with four angles of arrival.
Figure 8. Eight-Target, Four-Angle System Architecture
The radar object simulator chassis can be integrated with standard automotive bus communication (CAN or LIN) and other types of industrial communications required for the HIL system. The modularity of the solution allows car makers to test complex real-world scenarios with the possibility of handling multiple angles of arrival. Standard maneuvers provided by the New Car Assessment Program (NCAP) guidelines can be tested automatically, saving test time and effort.