A Two-Stage Method for Screening Pulse RFI in SAR Raw Data Alternating the Use of Time and Frequency Domains

Abstract

In the increasingly complex electromagnetic environment, the spectrum is becoming more and more crowded. Synthetic aperture radar (SAR) is more susceptible to be affected by the radio frequency interference (RFI) in the same frequency band when receiving echo signal. Pulse RFI (PRFI) is a common form of RFI and often has time-varying characteristics, which will deteriorate the SAR images quality and hinder image interpretation. To effectively suppress the PRFI, the serial number of the pulses in SAR raw data containing PRFI need to be screened out with high precision. A two-stage method for screening PRFI in SAR raw data alternating the use of time and frequency domains was proposed in this article. First, range-cell level difference screening is performed in the time domain and frequency domain, respectively, to initially screen the PRFI. Then, the preliminary screening results are accumulated along the range direction, and the accumulated results are classified using a clustering algorithm to perform pulse-level screening to obtain the serial number of the pulses containing PRFI. Compared with the traditional PRFI screening methods, the proposed approach boasts a remarkable ability to circumvent missed screening and false alarm when screening weak-energy PRFIs. It possesses exceptional sensitivity and accuracy, offering fresh perspectives and innovative solutions to the PRFI screening challenge. The effectiveness and superiority of the proposed method are verified by the simulation data and measured data experiments.