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The development status and industry trend of millimeter wave anti-collision radar

in the process of the development of vehicles to advanced assisted driving and automatic driving, the automatic/assisted driving function will gradually replace people's initiative. Among them, the most important technology is the anti-collision system that senses the surrounding environment of the vehicle. Millimeter wave radar has the characteristics of high measurement accuracy, simple structure, low price and so on. It is suitable for short-range accurate measurement, and is being used in automobile anti-collision system on a large scale

1 technical scheme of automobile anti-collision system

at present, the technical scheme of automobile anti-collision system includes millimeter wave radar, laser radar, infrared radar, camera, etc. Millimeter wave radar is less affected by the natural environment and has a moderate detection distance. It is the most cost-effective in the field of vehicle mounted radar, but it is difficult to identify pedestrians, traffic signs, etc; Lidar measurement accuracy is high, which can be used to establish spatial 3D map in real time, but the cost is high, and the electronic universal experimental machine below 30t in rain and snow has more advantages, and the effect is poor in fog; Infrared radar has high measurement accuracy, mature technology and low cost, but the short measurement distance (less than 10m) greatly limits its application scenarios; The camera has low cost and can recognize objects. It is an indispensable sensor for lane departure warning, traffic sign recognition and other functions, but it has the disadvantages of relying on light, failure at night and extreme weather, and difficulty in accurate ranging. Various technical schemes have their own advantages and disadvantages in measuring distance, accuracy and adapting to the environment. At present, the multi-sensor fusion solution is basically used in all kinds of assisted driving/driverless solutions, but no matter which solution, millimeter wave anti-collision radar plays an important role

2 millimeter wave radar development status

at present, millimeter wave radar is mainly 24GHz and 77GHz

24ghz is short (5-30m), which is mainly used in the rear of cars; The 77GHz radar has a long measuring distance (30-70m), which is mainly used in the front and both sides of the car. Millimeter wave radar mainly includes three parts: radar RF front-end, signal processing system and back-end algorithm. Among the existing products, the patent licensing fee of radar back-end algorithm accounts for about 50% of the cost, the RF front-end accounts for about 40% of the cost, and the signal processing system accounts for about 10% of the cost

2.1 RF gold assay polymer stretching front end

RF front end obtains intermediate frequency signals by transmitting and receiving millimeter waves, and extracts distance, speed and other information. Therefore, the RF front-end directly determines the performance of the radar system. At present, the RF front-end of millimeter wave radar is mainly planar integrated circuit, which has two forms: hybrid microwave integrated circuit (Hmic) and monolithic microwave integrated circuit (MMIC). Among them, MMIC RF front-end has low cost and high yield, which is suitable for mass production. In the production process, the device processes such as epitaxial MESFET, HEMT and HBT are generally used. Among them, GaAs based HEMT process is the most mature and has excellent noise performance

2.2 signal processing system

signal processing system is also an important part of radar. By embedding different signal processing algorithms, it extracts the IF signal collected from the RF front-end to obtain specific types of target information. The signal processing system usually takes DSP as the core to realize complex digital signal processing algorithm and meet the real-time requirements of radar

2.3 back end algorithm

back end algorithm accounts for the highest proportion of the whole millimeter wave radar cost. For millimeter wave radar, domestic researchers have proposed a large number of algorithms from the frequency domain, time domain and time-frequency analysis, and the accuracy of offline experiments is also high. However, domestic radar products mainly use the fast Fourier transform based on frequency domain and its improved algorithm for analysis, which has certain limitations in measurement accuracy and scope of application, while foreign algorithms are strictly protected by patents and are very expensive

3 millimeter wave radar industry trend

the development trend of millimeter wave radar technology is modularization and accuracy, while reducing the cost and facilitating large-scale assembly into cars. In the radar RF front-end, SiGe based technology replaces GaAs based technology, which can make the RF front-end smaller while ensuring bandwidth. In terms of signal processing system, mcu+dsp and fpga+dsp dual core architecture also appear. Secondly, it can meet the higher requirements of signal processing. In the millimeter wave radar market, by 2016, the world's top three manufacturers Bosch (accounting for 22% of the market share), the mainland (accounting for 22% of the market share) and Haila (accounting for 13% of the market share) had accounted for more than half of the global market share if the pest control treatment was not in place. In the Chinese market, millimeter wave radars are all imported, and there is no independent radar product yet. However, domestic manufacturers, such as Huayu automobile, Suntech and Hangzhou Zhibo, have completed the laboratory development of 24GHz radar. In addition to the basic ranging and speed measurement functions, they can also realize blind spot detection, Lane switching assistance and other functions, and solve the localization problem of product form. The corresponding products are expected to appear at the end of 2017

4 conclusion

millimeter wave anti-collision radar has become the main solution for vehicle anti-collision with its balanced performance. At present, millimeter wave anti-collision radar is mainly installed in American and German high-end vehicles. However, in the future, millimeter wave anti-collision radar will be an essential sensor for basic vehicle models of domestic and foreign manufacturers. China is still in the stage of catching up and learning in the development of millimeter wave anti-collision radar, but the progress of research and development is very rapid. As more enterprises enter the field of millimeter wave radar, it is expected that the technical level of domestic manufacturers will reach the international leading level in the near future