Adaptive Radio Frequency Interference Mitigation for Passive Bistatic Radar Using OFDM Waveform

Zhixin Zhao,Sihang Zhu,Sheng Hong,Yuhao Wang,Siyuan Cheng

doi:10.1155/2016/1892512

Abstract

High frequency passive bistatic radar (HFPBR) is a novel and promising technique in development. DRM broadcast exploiting orthogonal frequency division multiplexing (OFDM) technique supplies a good choice for the illuminator of HFPBR. HFPBR works in crowded short wave band. It faces severe radio frequency interference (RFI) problem. In this paper, a theoretical analysis of the range-domain correlation of RFI in OFDM-based HF radar is presented. A RFI mitigation method in the range domain is introduced. After the direct-path wave rejection, the interference subspace is constructed using the echo signals at the reserved range bins. Then RFI in the effective range bins is mitigated by the subspace projection, using the correlation among different range bins. The introduced algorithm is easy to perform in practice and the RFI mitigation performance is evaluated using the experimental data of DRM-based HFPBR.

Highlights

HF passive bistatic radars (HFPBR) are a subset of bistatic radars exploiting noncooperative HF transmitters of opportunity
The results provide a theoretical basis for radio frequency interference (RFI) mitigation in the range domain
The RFI issues in HFPBR with orthogonal frequency division multiplexing (OFDM) waveform are investigated in this paper

Summary

Introduction

HF passive bistatic radars (HFPBR) are a subset of bistatic radars exploiting noncooperative HF transmitters of opportunity. RFI is introduced in HF radar since the frequency band 3–30 MHz is shared by many radio services It is inevitable for HFPBR because DRM broadcasts have to share the usage of the current equipment and frequency bands of the analog transmission systems over a period of time called transition period. For HFPBR systems with OFDM waveform, RFI will show different characteristics, because the radar waveform of PBR is new and different, which exploits OFDM technique and is originally designed for broadcasting. A theoretical analysis of the range-domain correlation of RFI in OFDM-based HF radar is presented.

Range-Domain Correlation of RFI in OFDM-Based PBR

RFI Mitigation

Real Data Results

Conclusions