P is totally removed and the blue curve becomes flat. However, due to mismatching, the signal of B P is still modulated by the micro-motion and the red curve in Fig. 3(c) fluctuates. If Fourier transform is directly performed on A P in the azimuth direction after micro-motion compensation, the imaging result of A P will be degraded because of the interference caused by micro-motion of B P , as shown in Fig. 3(d). Therefore, signal separation must be performed by removing the micro-motion effect to guarantee the imaging quality.
III. BASIC IDEA OF SIGNAL SEPARATIONSince the time-frequency characteristics of various scatterers are different, imaging needs to be performed scatterer by scatterer.