Research On Signal Processing For LFMCW Radar Based On Channelization Structure

Linear frequency modulated continuous wave(LFMCW) radar obtains the information of distance and velocity by the way of modulating the frequency of continuous wave. It has been widely concerned for its no distance blind spots, high range resolution, low transmitting power, simple structure and so all, its theoretical research, key technologies and applications has been developed rapidly. Nowadays, the research of signal processing in LFMCW radar is mainly focused on small target detection in strong background, and methods of distance-speed decoupling of moving target etc. It is emphasis of the paper too.This thesis studies a traditional algorithm for the signal processing of LFMCW radar based on Beat Fourier-Frequency Domain matching. For a single sweeping LFMCW radar, there is a shift in the distance and speed of a target, in this method A symmetrical triangle frequency modulated continuous wave is used as the transmitting signal, the distance-speed coupling of moving targets is eliminated by matching the beat spectrum of the same target in the upper and lower sweeping frequency bands, for the reason of that the spectrum offset of moving targets in the upper and lower sweeping frequency bands is symmetrical. The method is simple structure, easy achieved, but it is easy to lose small target in detecting beating signal of multiple targets with large dynamic range.For the problem existing in Beat Fourier-Frequency Domain matching, a new way for signal processing in LFMCW radar based on channelization structure is approached in this paper. Firstly, the traditional Beat Fourier structure is replaced by the channelization structure, and then completing the match after beat signal frequencies of different targets were detect. Finally, realize of dynamic target distance speed decoupling. For the losing of small target in detecting beating signal of multiple targets with large dynamic range, the detection of small target is achieved through channelization structure based on higher stop-band attenuation prototype filter.Finally, the effectiveness of the method in this paper is simulated through MATLAB, compared with traditional ways based on Beat Fourier on small target detection, the simulation results show that in a multi-target environment, the method proposed in this paper can measure the distance and speed of each target accurately. When the prototype low-pass filter stop-band attenuation meet the requirement, the method can be used for the detection of small target and achieve good results.