Abstract:

Ｍidcourse ballistic target (MBT) possesses two motion features of high velocity and micromotion. Hereby, the measured Doppler shift is ambiguous and modulated by the microDoppler components. That makes it difficult to estimate the microDoppler bandwidth of MBT and extract its micromotion parameters. Taking the motion features of MBT into account, its wideband echo mathematical model is established and investigated at first. Then, the velocity compensation technique is put forward based on simplified fractional Fourier transform (SFRFT). In order to prove the asymptotic validity of the method, the parameter estimation error variance of initial frequency and slop of the signal in azimuth is derived. Simulation results show that the advanced method can present accurate parameter estimation and perform effective compensation for translation Doppler shift. Even in low signal to noise ratio case, the simulated outcomes prove it still work well. This technique provides the precondition for microDoppler feature extraction.