| The life-detection radar works aiming for the process and recognition of the weak echo signals of the low velocity moving targets. Strong clutter overwhelms desired signals because of the low signal to clutter ratio, and the frequency spectrum of life signals overlaps those of clutter, therefore the key technology of life-detection radar is the processing of the weak signals of the low velocity moving targets. According to the analysis of numerous experimental data and investigations of the characteristics of life signals and clutter of the life-detection continuous-wave radar, we build the harmonic model which is based on life signals as well as the model of clutter which obey Gaussian distribution. Two recognition method based on characteristic values of human states and high-order cumulants of the harmonic model are analyzed theoretically while experimentally. A new recognition method of human states based on the chaotic oscillator, which is sensitive to certain signals and immune to noise at the same time is proposed. From the simulation results, when the signal to noise ratio is low, the methods base on the high-order cumulants of the harmonic model and chaotic oscillator perform considerable efficiency and stabilization. |
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