Pulse Doppler Weather Radar Signal Processing System

This thesis discusses the Pulse Doppler (PD) weather radar signal processing system including digital intermediate frequency (IF) receiver, especially on the application of IF sampling and digital demodulation technique in PD weather radar signal processing system, the influence of amplitude and phase unbalances of in-phase and quadrature channels on weather radar echo spectrum estimation,ground clutters elimination algorithms and a typical engineering realization scheme of PD weather radar signal processing system.Firstly, we introduce the Radar equation of weather radar, the basic principles of detection weather targets, the time and frequency domain properties of weather radar echo and its simulation methods. Then, we introduce the basic structure of PD weather radar signal processing system and their function of each subsystem, mainly including intermediate frequency receiver, clutter elimination, range correcting and smoothness, ambiguity resolution and spectrum estimation.Secondly, we discuss the application of IF sampling and digital demodulation technique in PD weather radar signal processing system. First of all, the mathematical development and extensive computer simulation are used to analyze the influence of amplitude and phase unbalances of in-phase and quadrature channels on weather radar echo spectrum estimation. The theoretic analysis and computer simulation results reveal that this influence can't be ignored. Because the IF sampling and digital demodulation technique can improve amplitude and phase unbalances of in-phase and quadrature channels, we apply it in the PD weather radar signal processing system and select several digital demodulation algorithms, which are easier to implement, for this system.Thirdly, we study several ground clutters elimination algorithms combining the properties of ground clutters and we get the conclusion that the frequency domain algorithm has better performance through extensive analysis and comparison.Finally we proposed a typical PD weather radar digital signal processing system realization project including the software and hardware implementation.