Millimeter-wave Interferometer Signal Processing

The measurement of the velocity of projectile in interior ballistics has an important guiding significance on the development of weapon system. The millimeter-wave interferometer can get the instantaneous frequency of moving target in use of doppler effect, and measure the velocity of projectile precisely.Traditional signal analysis method-Fourier transform can only analyze the signal in time domain or frequency domain. Fourier transform lacks of the method of conjoint analysis from both time domain and frequency domain, can not compute instantaneous frequency of signal precisely.Time-frequency analysis is a hot spot in area of signal processing in recent year. It is a powerful tool for analyzing non-stationary signal. This method provides conjoint distribution information in both time domain and frequency domain, so it can describe the relationship between time and frequency.The paper introduces the knowledge of time-frequency analysis. Some detailed methods are introduced, such as Short Time Fourier Transform(STFT), Wigner-Ville Distribution(WVD),Wavelet Transform(WT) and Hilbert-Huang Transform(HHT). These methods are deeply researched on the application of signal processing.In the end, the millimeter-wave interferometer's composition structure is introduced. The actual signal acquired by interferometer is analyzed in use of time-frequency analysis based on STFT and HHT. The precise measurement of the velocity of projectile in interior ballistics is realized.