Doppler profile estimation in VHF radar signals using wavelets

The wind profile estimations are the fundamental objective of the Indian MST radar with the received signal ranging from nearly 3.5-25 Km height. A widely accepted narrow band model is considered, for the analysis of the signal received. Though the received signal SNR is stronger at lower altitudes, as the height progresses the strength becomes feeble and the noise dominates the received signal. The classical Time-Frequency analysis is made on the received signal from different altitudes and observed that the zero Doppler influence is significant at higher altitudes along with the noise. A Hilbert transform based DC bias removal is proposed in contrast with the existing 3 point MA technique. To handle the noise, in particular at higher altitudes a wavelet based adaptive denoising is proposed and found satisfactorily for the spectral cleaning of the Doppler spectrum. The validation of the proposed algorithm is made with the GPS data.