Radar echo envelope extraction using Teager energy operator and wavelet transform

As for the projectile with slots at the bottom, the amplitude envelope of monochromatic Doppler radar echo contains the information of the flying attitude. Owning to the nonlinear movement of the projectile, the echo can be modeled as an amplitude modulation (AM) and frequency modulation (FM) signal. To extract the envelope of radar echo scattered from the slotted projectile and separate the amplitude from frequency modulation effectively, a hybrid method is proposed based on the Teager energy operator and wavelet transform. First, the echo model was presented and its characteristics were analyzed briefly. Next, the Teager nonlinear energy-tracking operator was introduced and exerted to the echo. However, the envelope obtained was seriously corrupted by the noise. Then stationary wavelet transform was adopted to suppress the noise. The comparison between the denoised envelope and the radar cross section measured in the static state validates the effectiveness of the hybrid technique.