Radio and Clutter Suppression Algorithm Based on Spatial Multiple Beams for Small-Aperture HFSWR

Abstract

Radio and clutter that cover a certain number of range-Doppler-angle cells have a major impact on the detection performance of a high-frequency surface wave radar (HFSWR) system. Especially for a small-aperture array, the angle spectrums of radio and clutter suffer from severe broadening, so the targets that are more easily submerged in the broadened radio and clutter can be hardly detected. To tackle this issue, this paper proposes an algorithm for radio decontamination and clutter suppression to enable detection of the submerged targets. First, the spatial correlation of the array is derived, and the characteristics of radio and clutter are analyzed based on angle-Doppler joint eigenvector. Then owing to the analysis, the information of radio and clutter in the main beam can be accurately estimated from that in the auxiliary beams and eliminated by subtracting it. The results of simulations and measured data indicate that the proposed method offers a significant performance improvement and has a strong robustness against the array amplitude-phase errors.

Space-Time Cascaded Processing-Based Adaptive Transient Interference Mitigation for Compact HFSWR

“…δ a and δ d denote the number of the selected angle units and Doppler units in the ADLR. According to [23,27], δ d and δ a are both set to 3. The ADLR in the compact HFSWR is shown in Figure 2.…”

“…For example, if the antenna gain loss is 0.423 dB, the factor T 0 should be set to 1.05. The square norm of the weight w a (γ) in Equation ( 26) can be written as Equation (27), and it decreases monotonically as γ increases:…”

“…In a HF radar system, the distribution characteristics of interference and clutter are significantly heterogeneous [15,27]. Based on the above analysis, the mitigation of interference performance depends on the accuracy of the selected training samples, and the SLDs can reflect the homogeneity between the reference unit and test units.…”

Ionospheric Clutter Model for HF Sky-Wave Path Propagation with an FMCW Source

“…Thus it is necessary to develop a mathematic model to quantify the impact of the ionosphere. Many investigations have been made on the characterization of ionospheric clutter and suppression of ionospheric clutter [6][7][8][9][10][11]. These ionospheric clutter mitigating techniques include many complicated adaptive signal processing algorithms or additional antennas.…”