This paper proposes a new signal noise level estimation approach by local regions. The estimated noise variance is applied as the threshold for an improved empirical mode decomposition（EMD） based signal denoising me...This paper proposes a new signal noise level estimation approach by local regions. The estimated noise variance is applied as the threshold for an improved empirical mode decomposition（EMD） based signal denoising method. The proposed estimation method can effectively extract the candidate regions for the noise level estimation by measuring the correlation coefficient between noisy signal and a Gaussian filtered signal. For the improved EMD based method, the situation of decomposed intrinsic mode function（IMFs） which contains noise and signal simultaneously are taken into account. Experimental results from two simulated signals and an X-ray pulsar signal demonstrate that the proposed method can achieve better performance than the conventional EMD and wavelet transform（WT） based denoising methods.展开更多
This paper establishes the classic linear model of signal of the MIMO radar system with distributed apertures. Based on this model, the design principle and detection performance of MIMO radar detector is investigated...This paper establishes the classic linear model of signal of the MIMO radar system with distributed apertures. Based on this model, the design principle and detection performance of MIMO radar detector is investigated under conditions of Gaussian colored noise and partially correlated observation channels. First, the research on design principle of detector shows that the clutter suppression and matched filtering can be independently implemented at each receiving aperture, which greatly reduces the difficulty in implementation of these detectors. Based on these results, a Max detector is proposed for the case where partial channels are disabled due to strong noise and stealth techniques. The second part is the performance analysis of detector. The Fishier divergence coefficient and the statistical equivalent decomposition of limit statistics are used to theoretically analyze the detection performance of AMF detector, and then the analytical expressions of the detection performance of the AMF detector is derived. Analysis results show that both the colored nature of noise and the correlation among observation channels can reduce the capability of spatial diversity of the MIMO radar system, change the target RCSs among observation channels from quick fluctuation to slow fluctuation, and degenerate the detection performance of this radar system into that of the phased array radar system at high signal-to-noise ratio.展开更多
基金supported by the China Aerospace Science and Technology Corporation’s Aerospace Science and Technology Innovation Fund Project(casc2013086)CAST Innovation Fund Project(cast2012028)
文摘This paper proposes a new signal noise level estimation approach by local regions. The estimated noise variance is applied as the threshold for an improved empirical mode decomposition（EMD） based signal denoising method. The proposed estimation method can effectively extract the candidate regions for the noise level estimation by measuring the correlation coefficient between noisy signal and a Gaussian filtered signal. For the improved EMD based method, the situation of decomposed intrinsic mode function（IMFs） which contains noise and signal simultaneously are taken into account. Experimental results from two simulated signals and an X-ray pulsar signal demonstrate that the proposed method can achieve better performance than the conventional EMD and wavelet transform（WT） based denoising methods.
基金the Program for New Century Excellent Talents (Grant No. NCET-05-0912)the National Natural Science Foundation of China (Grant Nos. 60672140, 60802088)
文摘This paper establishes the classic linear model of signal of the MIMO radar system with distributed apertures. Based on this model, the design principle and detection performance of MIMO radar detector is investigated under conditions of Gaussian colored noise and partially correlated observation channels. First, the research on design principle of detector shows that the clutter suppression and matched filtering can be independently implemented at each receiving aperture, which greatly reduces the difficulty in implementation of these detectors. Based on these results, a Max detector is proposed for the case where partial channels are disabled due to strong noise and stealth techniques. The second part is the performance analysis of detector. The Fishier divergence coefficient and the statistical equivalent decomposition of limit statistics are used to theoretically analyze the detection performance of AMF detector, and then the analytical expressions of the detection performance of the AMF detector is derived. Analysis results show that both the colored nature of noise and the correlation among observation channels can reduce the capability of spatial diversity of the MIMO radar system, change the target RCSs among observation channels from quick fluctuation to slow fluctuation, and degenerate the detection performance of this radar system into that of the phased array radar system at high signal-to-noise ratio.
