This paper presents a joint method of Doppler Beam Sharpen (DBS) imaging and Signal Subspace Processing (SSP) to achieve Ground Moving Target Indication(GMTI) for along- track dual-antenna airborne radar. When the err...This paper presents a joint method of Doppler Beam Sharpen (DBS) imaging and Signal Subspace Processing (SSP) to achieve Ground Moving Target Indication(GMTI) for along- track dual-antenna airborne radar. When the error of the two antennas (also refers to channels) changes pulse to pulse, the method SSP is used to precisely calibrate the two antennas’ DBS images, then to detect the ground moving targets in the difference image of the two calibrated images. The method DBS-SSP is proved to offer performance improvement on the actually measured data and simulated data.展开更多
This paper focuses on the problem of adaptive blind source separation (BSS). First, a recursive least-squares (RLS) whitening algorithm is proposed. By combining it with a natural gradient-based RLS algorithm for nonl...This paper focuses on the problem of adaptive blind source separation (BSS). First, a recursive least-squares (RLS) whitening algorithm is proposed. By combining it with a natural gradient-based RLS algorithm for nonlinear principle component analysis (PCA), and using reasonable approximations, a novel RLS algorithm which can achieve BSS without additional pre-whitening of the observed mixtures is obtained. Analyses of the equilibrium points show that both of the RLS whitening algorithm and the natural gradient-based RLS algorithm for BSS have the desired convergence properties. It is also proved that the combined new RLS algorithm for BSS is equivariant and has the property of keeping the separating matrix from becoming singular. Finally, the effectiveness of the proposed algorithm is verified by extensive simulation results.展开更多
A novel space-borne antenna nulling method is presented on rejecting strong multi-interference from the ground and air. Immune Genetic Algorithm for searching for the multi-extremum of maximum likelihood function has ...A novel space-borne antenna nulling method is presented on rejecting strong multi-interference from the ground and air. Immune Genetic Algorithm for searching for the multi-extremum of maximum likelihood function has been developed, which is based on injecting vaccine pick-up adaptively. GA has the capability of the whole searching and is not limited by the selection of initial parameter. And the Immune algorithm possesses the advantage of availing oneself of characteristic information. The proposed method, combining GA with the Immune algorithm, can converge at the global optimum quickly and offer high resolution null point. Simulation examples, based on the spot survey data, are shown to illustrate the effectiveness and robustness of the proposed algorithm.展开更多
This paper analyzes some properties of the alternating separation (AS) and alternating projection (AP) algorithm. The analysis shows that AS converges to the optimal point steadily but slowly, while AP converges to th...This paper analyzes some properties of the alternating separation (AS) and alternating projection (AP) algorithm. The analysis shows that AS converges to the optimal point steadily but slowly, while AP converges to the optimal point quickly but is prone to immersing into the local extreme of the maximum likelihood (ML) criterion. To avoid their disadvantages and make use of their advantages, ASAP, which is the combination of AS and AP, is proposed. Simulation results show that the ASAP algorithm has the ability of estimating the direction of arrival more accurately and converging to optimal point more quickly.展开更多
文摘This paper presents a joint method of Doppler Beam Sharpen (DBS) imaging and Signal Subspace Processing (SSP) to achieve Ground Moving Target Indication(GMTI) for along- track dual-antenna airborne radar. When the error of the two antennas (also refers to channels) changes pulse to pulse, the method SSP is used to precisely calibrate the two antennas’ DBS images, then to detect the ground moving targets in the difference image of the two calibrated images. The method DBS-SSP is proved to offer performance improvement on the actually measured data and simulated data.
文摘This paper focuses on the problem of adaptive blind source separation (BSS). First, a recursive least-squares (RLS) whitening algorithm is proposed. By combining it with a natural gradient-based RLS algorithm for nonlinear principle component analysis (PCA), and using reasonable approximations, a novel RLS algorithm which can achieve BSS without additional pre-whitening of the observed mixtures is obtained. Analyses of the equilibrium points show that both of the RLS whitening algorithm and the natural gradient-based RLS algorithm for BSS have the desired convergence properties. It is also proved that the combined new RLS algorithm for BSS is equivariant and has the property of keeping the separating matrix from becoming singular. Finally, the effectiveness of the proposed algorithm is verified by extensive simulation results.
文摘A novel space-borne antenna nulling method is presented on rejecting strong multi-interference from the ground and air. Immune Genetic Algorithm for searching for the multi-extremum of maximum likelihood function has been developed, which is based on injecting vaccine pick-up adaptively. GA has the capability of the whole searching and is not limited by the selection of initial parameter. And the Immune algorithm possesses the advantage of availing oneself of characteristic information. The proposed method, combining GA with the Immune algorithm, can converge at the global optimum quickly and offer high resolution null point. Simulation examples, based on the spot survey data, are shown to illustrate the effectiveness and robustness of the proposed algorithm.
文摘This paper analyzes some properties of the alternating separation (AS) and alternating projection (AP) algorithm. The analysis shows that AS converges to the optimal point steadily but slowly, while AP converges to the optimal point quickly but is prone to immersing into the local extreme of the maximum likelihood (ML) criterion. To avoid their disadvantages and make use of their advantages, ASAP, which is the combination of AS and AP, is proposed. Simulation results show that the ASAP algorithm has the ability of estimating the direction of arrival more accurately and converging to optimal point more quickly.
