Research On The Freeway Automotive Anti-collision Radar

With the rapid population of the freeway, the accident of automotive collision occurs now and then, which has been aroused considerable attention all over the world. So it is essential to find out an effective way to solve the automotive anti-collision on the expressway. Aims at this actuality, this article introduces a radar system of automotive anti-collision. This radar is mainly applied to prevent the vehicle from rear-end collision under the fog weather condition, with no consideration of the other obstacle's anti-collision before the vehicle. The design had been finished a basic function of forward looking anti-collision for danger detecting and collision alarming. This article adopts a technical ripeness and easily realizable automotive anti-collision, which employs centimeter wave and measures distance by beam radiation. To compensate centimeter wave's short-comings such as broad beam and short effective range, a transponder is added in the back of target automotive. This secondary radar measures range in the way of responding. With the illustrations of many block diagrams, circuit schematics and waveform figures, this paper expatiates the system architecture, working principle and working flow of the automotive anti-collision radar. According to the different employing system of radar, this article designs two schemes, one is pulse radar, the other is phase code pulse compression radar. Both schemes have the same radio frequency(RF) channel and displaying terminal , which RF channel part is introduced in the chapter of pulse radar scheme, moreover the displaying terminal as unique chapter. For pulse radar scheme, the article expatiates it's RF channel and intermediate frequency(IF) modulation and demodulation parts. Because the use of direct judgment to receiving pulse can be easily brought on an error, so pulse echo is sampled firstly with high-speed and then synchronous accumulation, that the quality of back pulse and the ratio of signal to noise can be improved. At the same time, the article expatiates how to realize pulse accumulation by A/D,FPGA and D/A. For the phase code pulse compression radar, the article gives emphasis to introduce its working principle and realizing method.