| Automobile,as a means of transportation and traffic, becomes an indispensable tool in social life.Automotive collision avoidance radar system should be preferred FMCW (Frequency Modulated Continuous-wave radar) system.The biggest advantage of the LFMCW (Linear Frequency Modulated Continuous-wave radar) method is that it can easily calculate the relative distance and the relative velocity between the target,according to the frequency difference between the transmitting singals and receiving signals.The shortcoming in the LFMCW modulation is that launch waves had leakage to reflected waves and there are much disturbance and noise in actual traffic environment, which is difficult to achieve high precision.The received radar signal is not fixed.The signal changed with the speed and the distance of the goal. At present, the radar signal processing algorithm is for the fixed signal, so there are defects in practical applications.In order to solve the above problems, in this paper first the mathematical model of vehicle crash and millimeter-wave automotive anti-collision radar signal were analyzed. The wavelet analysis was adopted for the method of signal processing. Wavelet thresholding method was used for the signal denosing.Based on the regular soft and hard thresholding methods, the threshold rules were improved. The simulatin results of MATLAB showed that the new method is effective in denoising.A millimeter-wave automotive anti-collision radar system was designed. The digital signal processors chip TMS320LF2407 was the calculation core of the millimeter-wave automotive anti-collision radar system. The millimeter-wave automotive anti-collision radar system was designed including the front-end circuit, the power supply module, the clock and replace circuit, the signal acquisition and processing module, the external extended ROM/RAM, the D/A conversion circuit, the serial interface, the CAN communication protocol interface and man-machine interface etc. The software design of the system was based on CCS and realized the basic functions of data processing and transmission. C language has better transplantation. The whole system was tested and the results were satisfied. |
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