Non-linear Frequency Modulated Radar Signal Parameter Estimation Algorithm

Time-frequency distributions were introduced as a means of representing signals whose frequency content is varying with time, and for which both time domain representation and frequency representation are inadequate to describe the signal appropriately. This dissertation is intended to study the parameter estimation methods of PPS(polynomial phase signal) and sin-frequency modulation signal by using time-frequency distributions. The main work and achievements of this dissertation are included:(1) Study and analyze the structure of PPS, based on phase parameter method, signal phase is expressed by a finite order polynomial, the frequency estimation is then translated into polynomial coefficient estimation. The least square method is used to get the coefficient and order, through which the instantaneous frequency is then obtained.(2) A method is discussed to extract the instantaneous frequency of PPS signal in wavelet domain. The usage is made of the relationship between the maximum of wavelet modulus and the wavelet function. This method is suitable for the signal with time-variant spectrum.(3) Time-frequency distributions have been used to restrain noise except for the use of parameter extraction. Since the Wigner-Ville distribution can entirely remain the signal information at the frequency f = 0, it becomes an available method to avoid the affection of noises. According to this, wavelet ridge is then used to get the instantaneous frequency.(4) Compared with traditional solutions that try to analyze signals received by single sensor, it possible to improve time-frequency representation of signal received by array. Thus, the extraction of time-frequency characters of sin-frequency modulation signal, and the methods to estimate its instantaneous frequency are discussed.