Car radar are generally more reliable

The received signal is also low-cost innovative designs. Through the acquisition of position information to collect the reflected signal the need for mechanical scanning antenna or phased array antenna, and a combination of digital bunching algorithm. Antenna behind the general homodyne receiver with a lot of channels, this is the antenna design - for the simple rotating antenna, an array of 16

 Reuter said: "The receiver output is a baseband signal of the DC-20-MHz band." Design with good azimuth resolution of the system will be channels 8-16, 8-16 high-speed analog-to-digital converters (ADC ).

Digital baseband signal from each channel into the fast Fourier transform (FFT) module to achieve lengths of up to 2K sampling of the transformation. Reuter said: "In the past, perform an FFT means that requires a lot of FPGA Today, the trend is integrated floating-point DSP accelerator 32-bit microcontrollers." Bunching system can use two FFT scope and speed of data extracted from the signal shown in Figure 3.

In fact, multiple-FMCW analog channel, the formation of this front-end processing unit processes the input digital bit stream of the azimuth / range / speed of the array. This data stream into one or more CPU cores, the software will be supported by other accelerators are infer whether there are objects around the vehicle, location and attributes of the object.

Reuter explained: "You need to identify goals, to separate them from the background, select the most critical one. You may need to deal with 200 goals, therefore, the calculation will be very complex, especially to extract angle information.

The physical configuration of the system have become increasingly complex. Reuter said that the processing of the sensor itself. In contrast, ADC dedicated analog interface, a dedicated digital signal car dvd player and in car dvd player processing hardware interface for the FFT, the microcontroller interface to extract the target, and its classification. Target information is input to the vehicle control area network (CAN) or FlexRay bus, the central CPU cluster, their interpretation and analysis.

The entire pipeline has a lot of bandwidth and delay requirements. Reuter CPU interpretation of the data generally presents a graphical display to the driver, that is, able to observe him through the windshield to the front of the multifunction display. This mixed display a maximum of 50-ms update interval, as well as more challenging 50-ms delay. Otherwise, the image will be very stable, there will be lag through the windshield of the image, it may lead to driver misjudgment.

With the system developed to support the function of the bunching multiple sensors from one sensor, in order to achieve camera data fusion, the Internet architecture has also changed. Reuter said: "use Ethernet to reduce the cost of demand." However, the system still requires real-time, brought how to ensure that the Ethernet real-time nature of the problem.