Research Of The Multi-target Detection Technology Based On Trapezoidal Wave FMCW Radar

Since FMCW radar has strong anti-interference ability, non-distance blind areaand high sensitivity, so it is widely applied in various areas and has great prospect.FMCW makes the use of the frequency difference between the transmitted signaland the echo signal to determine distance and speed. This research is about arelatively new FMCW modulation method, namely trapezoidal wave modulation.The modulation has obvious advantages comparing with traditional triangle wavemodulation and sawtooth wave modulation, especially in the multi-target distanceand speed test, it can better inhibit the emergence of false targets and solvedistance-velocity coupling more easily. Besides, it also operates more simply in thesignal processing than the traditional modulation. This paper firstly states theresearch status of FMCW radar and analyzes its advantages and disadvantages. Thenit introduces the basic working principles of trapezoidal wave FMCW radar andmakes a comparison with traditional modulation. After that, there is a derivation ofthe radar transmit signal, the echo signal and the beat signal, and then a research oftheir time-domain and frequency domain to get a calculation of individual targetdistance and speed. At last, in the case of multi-target, this paper studies the beatsignal and proposes several multi-target distance and velocity approaches,concluding that trapezoidal modulation has advantages in the multi-target detection.Based on the above research and analysis, in order to meet the project’s request,this paper develops a transceiver front-end module of trapezoidal wave FMCW radar.The following is its operation principle: DDS generates a trapezoidal modulatedcontinuous wave, and then the wave mixes twice with a single-frequency point ofPLL to achieve the required up-conversion frequency band, after filtering andamplification, ultimately get the desired modulation waveform. In this research, Imakes a comparison of equipment and designs the whole system. Furthermore, theauthor continuously designs, programs and debugs the DDs, PLL frequency sourcecircuit, finally develops radar transceiver for future research.