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International Journal of Antennas and Propagation
Volume 2017, Article ID 7514916, 16 pages
https://doi.org/10.1155/2017/7514916
Research Article

MIMO High Frequency Surface Wave Radar Using Sparse Frequency FMCW Signals

1National Laboratory of Radar Signal Processing, Xidian University, Xi’an 710071, China
2Collaborative Innovation Center of Information Sensing and Understanding, Xidian University, Xi’an, China

Correspondence should be addressed to Baixiao Chen; nc.ude.naidix@nehcxb

Received 14 March 2017; Revised 28 May 2017; Accepted 6 June 2017; Published 14 August 2017

Academic Editor: Ana Alejos

Copyright © 2017 Mengguan Pan and Baixiao Chen. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The heavily congested radio frequency environment severely limits the signal bandwidth of the high frequency surface wave radar (HFSWR). Based on the concept of multiple-input multiple-output (MIMO) radar, we propose a MIMO sparse frequency HFSWR system to synthesize an equivalent large bandwidth waveform in the congested HF band. The utilized spectrum of the proposed system is discontinuous and irregularly distributed between different transmitting sensors. We investigate the sparse frequency modulated continuous wave (FMCW) signal and the corresponding deramping based receiver and signal processor specially. A general processing framework is presented for the proposed system. The crucial step is the range-azimuth processing and the sparsity of the carrier frequency causes the two-dimensional periodogram to fail when applied here. Therefore, we introduce the iterative adaptive approach (IAA) in the range-azimuth imaging. Based on the initial 1D IAA algorithm, we propose a modified 2D IAA which particularly fits the deramping processing based range-azimuth model. The proposed processing framework for MIMO sparse frequency FMCW HFSWR with the modified 2D IAA applied is shown to have a high resolution and be able to provide an accurate and clear range-azimuth image which benefits the following detection process.