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.
Highlights
High frequency surface wave radar (HFSWR) refers to a classification of radar which operates in the HF band (3–30 MHz) and utilizes the surface wave mode of propagation
A signal bandwidth of several tens of kilohertz is common in typical HFSWR system which corresponds to a range bin of several kilometers
For our proposed multiple-input multiple-output (MIMO) sparse frequency frequency modulated continuous wave (FMCW) radar system, the receiver and the signal processor are deramping processing based, and the orthogonality is surely achieved by the frequency offset of different channels
Summary
High frequency surface wave radar (HFSWR) refers to a classification of radar which operates in the HF band (3–30 MHz) and utilizes the surface wave mode of propagation. In MIMO radar systems, orthogonal signals are transmitted by different sensors, resulting in a uniform distribution of the radiation energy in space This meets the demand of HFSWR system for continuous whole spatial space surveillance. For our proposed MIMO sparse frequency FMCW radar system, the receiver and the signal processor are deramping processing based, and the orthogonality is surely achieved by the frequency offset of different channels. Following crucial step is the range-azimuth processing which synthesizes a wideband signal and a narrow beam associated with the large virtual array This step is the synthetic impulse and aperture processing (SIAP) in conventional SIAR systems [22, 23].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
