Micro-motion period estimation of coning target using four-point method

Doppler sideband modulation is induced by the micro motion of targets carried on radar echoes. Time-frequency diagram of coning target with multiple scattering centers consists of multiple sinusoidal curves with different amplitudes and initial phases. The time-frequency curves are separated by the associativity among points; then a four-point method is proposed to estimate the period of micro motion, and it is proved to be an unbiased estimation. The simulation results using echoes of ideal scattering centers show that the four-point method has high estimation precision and can be applied to low signal-to-noise ratio conditions.