Ambiguity Function Based High-Order Translational Motion Compensation

Micro-Doppler feature plays an important role in cone-shaped target recognition and parameter estimation. However, translational motion causes shifting, tilting, and aliasing in micro-Doppler spectrum and influences the extraction of micro-Doppler features. Most existing methods do not consider higher order translation compensation. In this article, a high-order translational motion compensation method is proposed. First, the high-order ambiguity function (HAF) of a periodical polynomial phase signal exhibits periodicity along the lag axis and reaches the peak concentration when the lag is equal to the micromotion period. The micromotion period can be obtained by searching the peak concentration of echo's HAF. Then, the translational jerk and acceleration are, respectively, compensated by searching the peaks of the second- and third-order HAFs. Last, convolution is operated on the frequency spectrum to find the symmetric center located at the Doppler shift frequency, and the residual translational velocity can be estimated. Experimental results based on electromagnetic computation data show that the proposed method can accurately achieve high-order translational compensation.