An Improved Oblique Projection Method for Sea Clutter Suppression in Shipborne HFSWR

Abstract

Sea clutter has a major impact on the detection performance of a shipborne high-frequency surface wave radar (HFSWR) system. Due to the platform motion of shipborne HFSWR, the Doppler spectrum of the first-order sea clutter suffers from some broadening so that the targets submerged in this broadening Doppler spectrum can be hardly detected. In this letter, an improved oblique projection (IOP) method, combining the oblique projection (OP) algorithm and the method of sea clutter suppression in the Doppler domain, is proposed to suppress sea clutter in both Doppler domain and spatial domain for shipborne HFSWR. Compared with the OP and the orthogonal weighting algorithms, the proposed IOP algorithm is shown to give far superior suppression results in the Doppler domain and can achieve better azimuth estimation results based on real data.Index Terms-Oblique projection (OP), sea clutter suppression, shipborne high-frequency surface wave radar (HFSWR).

A Single-Dataset-Based Pre-Processing Joint Domain Localized Algorithm for Clutter-Suppression in Shipborne High-Frequency Surface-Wave Radar

“…Figure 11 gives the comparison between the conventional clutter-suppression algorithms and the proposed algorithm (fast Fourier transform and digital beamforming (FFT–DBF), improved orthogonal weighting [ 26 ], improved oblique projecting [ 27 ], conventional JDL [ 24 ], and proposed algorithm) with three simulated targets and one real target, respectively.…”

“…The training samples which are similar to the CUT counts more and the proportion of unrelated training samples are weakened. An improved orthogonal weighting (IOW) algorithm [ 26 ] and an improved oblique projection (IOP) algorithm [ 27 ] were proposed, despite significant progress in the direction of arrival estimation, these JDL-like methods use samples in Doppler domain to estimate the CCM and suffer from the same drawbacks as the conventional JDL algorithm.…”

A Knowledge-Based Auxiliary Channel STAP for Target Detection in Shipborne HFSWR

“…, D are the Doppler frequency and the azimuth of the clutter patches, respectively. They satisfy Equation (9). The quantity of auxiliary channels, denoted by D, is discussed as follows.…”

“…SCNR Improve = SCNR after − SCNR before (dB). Figure 9 illustrates the comparison of Doppler profiles with simulated targets between the existing clutter-suppression algorithms (conventional JDL [7], IOW [8], IOP [9]) and the proposed algorithm. The FFT-DBF method was set as the reference.…”

“…Space-time adaptive processing (STAP) has been proven to be an effective clutter suppression algorithm for this kind of clutter. Some direct-from STAP methods like joint domain localized (JDL), improved orthogonal weighting (IOW), and improved oblique projection (IOP) have been proposed for clutter suppression in shipborne HFSWR [6][7][8][9][10][11][12]. Except for the direct-form processor structure, like the methods above-mentioned, the STAP algorithm can be implemented in the generalized sidelobe canceler (GSC) structure [13].…”