A new dechirp method for wideband radar direct IF sampling signal

Analog dechirp can effectively reduce the sampling frequency of wideband radar receiver and the computation load of the pulse compression. However, the amplitude and phase distortion, the frequency modulated nonlinearity and the distortion introduced by the mixer may reduce the quality of received signal. These problems can be avoided by adopting pulse compression after direct IF (Intermediate frequency) sampling. But the pulse compression based on matched filtering need to fulfill ultra-long points FFT/IFFT in real-time, which caused great difficulties to its application. Combining the benefits of this two methods, a digital dechirp method is proposed in this paper. By theoretical analyzing, the mathematical model is obtained. The data decimation and filter design is also analyzed in detail for its realization. Simulation and analysis based on real data proves the effectiveness and efficiency of the proposed strategy.