The most advanced radar today is 100% Digital Beamforming (DBF). Although the analog radar still excels in performance, due to its high cost, high power consumption architecture and complexity, the automotive industry has abandoned analog green laser pointer radar (such as phased array antennas). The automotive industry has always been very sensitive to costs, and the cost of signal processing will eventually continue to fall. Just like other microchips with calculations (Moore’s Law), DBF is still an attractive option.
But the resolution and speed of DBF are still limited. The military is more focused on performance, and analog radars are still used for ballistic missile detection and tracking. For autonomous driving, cost is not and should not be a top priority, performance and safety are the most important!
It’s slow. The time DBF uses to scan the scene requires milliseconds of waiting. Signal processing in the digital domain is very important. To achieve an acceptable signal-to-noise ratio (SINR), an integration time on the order of milliseconds is required. Processing a series of complex analog-digital circuits and the allocation of digital weights for running DBF will cause a higher computational workload and cause slow operation.
Lack of resolution-it cannot see narrow objects or pedestrians. It is not a “real” beamforming architecture, and complete beamforming is impractical. Because it requires a large number of antennas to achieve high resolution. First, many antennas are very expensive to implement, requiring multiple ports (non-traditional) on the green laser pointer radar chipset. In addition, this will require more snapshots to get an acceptable SINR (because all-round noise will overload the system). With the traditional three transmit ports and four receive ports, the resolution is not clear enough to see pedestrians. It is suitable for cars (good trade-offs between resolution, SINR, and range), but not for non-metallic objects.