Phase Compensation Transform for Human Detection with LFMCW Radar

Abstract Efficiently accumulating the power of human echo using a linear frequency modulated continuous wave radar is difficult owing to the spread of micro-Doppler due to the varying velocity of human body motion. Consequently, the detection performance for human targets degrades. A coherent integration algorithm called phase compensation transform (PCT) is proposed to solve this issue. In PCT, the beat signal of a human target is derived for an LFMCW radar based on the Boulic model. The nonlinear phase characteristic of the beat signal caused by micro-Doppler from human motion is analyzed. The phase compensation signal is constructed to compensate the nonlinear phase from micro-Doppler during a coherent processing interval. The compensated range cell is fast Fourier transformed, and the Doppler spread resulting from periodic micro-Doppler is integrated. The performance of PCT is evaluated and compared with that of other methods. Simulation results show that PCT exhibits higher integration efficiency than moving target detection (MTD) and optimized nonlinear-phase methods. Experiment results from the LFMCW radar system demonstrate that the detection signal-to-noise ratio of PCT increases 5dB compared with that of MTD method. Besides, PCT can estimate human motion parameters simultaneously, including average radial velocity, gait frequency, and torso initial phase.