RFI Suppression for SAR Systems Based on Removed Spectrum Iterative Adaptive Approach

Abstract

A synthetic aperture radar (SAR) system can be seriously contaminated by radio frequency systems because of working in the same microwave frequency bands, which would degrade the SAR image quality and affect the accuracy of image interpretation. In this paper, a novel radio frequency interference (RFI) suppression approach including RFI identification, band-stop filtering and a removed spectrum iterative adaptive approach (RSIAA) is proposed. First, the smoothing process is added before RFI signal detection to improve the RFI detection capacity. Afterwards, the band-stop filtering with a broaden factor is proposed to mitigate the residual RFI, and it ensures the accuracy of the following removed spectrum recovery by the RSIAA. Finally, the removed spectrum components are estimated from available adjacent spectrum data by the RSIAA in turn to obtain the desired range spectra. Compared with the conventional range frequency filtering method for RFI suppression, the capacity of the weak RFI signal detection is improved, and the increased sidelobes due to the discontinuous spectra are well suppressed. Simulation experiments on both simulated SAR raw data, Gaofen-3 and Sentinel-1 SAR raw data validate the proposed RFI suppression approach.

Joint Radio Frequency Interference and Deceptive Jamming Suppression Method for Single-Channel SAR via Subpulse Coding

“…In terms of RFI suppression methods, they This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/ can be roughly divided into three categories: nonparametric [9], [10], [11], parametric [12], [13], [14], [15], and semiparametric [16], [17], [18], [19], [20], [21], [22], [23]. Among them, nonparametric methods normally focus on the setting of notching filters in the frequency domain, which can greatly suppress RFIs.…”

“…This impact is especially evident when RFIs are wideband. Although a removed spectrum IAA is proposed in [11] to recover the damaged SAR signal spectrum, even so, when bandwidths of RFIs are relatively large, SAR signals are still difficult to be recovered perfectly. The common basic idea of parameter methods is the subspace projection.…”

Suppression of Jammer Multipath in GNSS Antenna Array Receiver

“…Global navigation satellite system (GNSS), represented by global position system (GPS), is a space-based navigation and positioning system, which is widely used in various fields such as land, sea and air navigation, aerospace, geodesy, and other national defense construction and national economy with its full space coverage, all-weather work, and high positioning accuracy [1][2][3]. When the navigation signal arrives at the ground, the signal is already very weak, so it is susceptible to various intentional or unintentional interferences [4][5][6]. For military or core civilian areas, anti-jamming performance is an important indicator to evaluate the navigation receivers [7,8].…”

MCSNet: A Radio Frequency Interference Suppression Network for Spaceborne SAR Images via Multi-Dimensional Feature Transform

“…Chang et al [17] found that the trap filter had a significant effect on the side flaps of the system response, which may be considered as a false target; Wu et al [18] combine the advantages of traditional notching filtering and Eigen-subspace projection methods to reduce false alarm rates providing a more accurate determination of thresholds and gap weights. Instead of the method for processing data in the time and time-frequency domains, Xu et al [19] proposed an adaptive spectral iteration method to obtain the desired range spectra from the available neighbourhood spectral data. In a nutshell, the non-parametric method requires less computation and permits easier implementation [20], but faces the problem of spectral loss in the echo signal, which usually presents some significant side flaps in the image [21].…”