DC offset and low frequency noise compensation for direct-conversion receiver in pulse compression radar

In this paper, we replace low-pass filter (LPF) in traditional direct-conversion receiver (DCR) in pulse compression radar (PCR) by pre-defined filter (PDF) to directly filter direct-current offset and low frequency noise. We also accordingly propose an algorithm for compensating the distance range resolution degradation caused by PDF´s effect on low frequency components of received linear frequency modulation (LFM) signals. Based on the theoretical understanding on how the low frequency band influences the pulse compression, a set of newly deduced equations are used to calculate the compression, and the range resolution degradation can be recovered based on the priori knowledge of the employed LFM signal and filters. This method can be used in all pulse compression radars where pre-defined continuous radar signals are employed.