An array extension method in a noisy environment was proposed to improve angular resolution and array gain. The proposed method combines the FOC (fourth-order cumulants) technique with the ETAM (extended towed array m...An array extension method in a noisy environment was proposed to improve angular resolution and array gain. The proposed method combines the FOC (fourth-order cumulants) technique with the ETAM (extended towed array measurements) method to extend array aperture and suppress Gaussian noise. First, successive measurements of a virtual uniform linear array were constructed by applying fourth-order cumulants to measurements of uniform linear array; Gaussian noise in these measurements was also eliminated. Then, the array was extended by compensating phase differences using the ETAM method. Finally, the synthetic aperture was extended further by the fourth-order cumulants technique. The proposed FOC-ETAM-FOC method not only improves angular resolution and array gain, but also effectively suppresses Gaussian noise. Furthermore, it inherits the advantages of the ETAM method. Simulation results showed that the FOC-ETAM-FOC method achieved better angular resolution and array gain than the ETAM method. Furthermore this method outperforms the ETAM method in Gaussian noise environment.展开更多
This paper proposed a method for blind estimation of underwater channels in shallow water environment by using received data at a single hydrophone or from single beam. First, the received signal is used for source si...This paper proposed a method for blind estimation of underwater channels in shallow water environment by using received data at a single hydrophone or from single beam. First, the received signal is used for source signal reconstruction by means of signal-dependent TF （Time-Frequency） distribution, in association with instantaneous frequency estimation and TF inversion. Then the shallow-water channel estimation is achieved via WRELAX technique by use of the received signal and the estimated source signal. Finally, the results of numerical simulation and experimental test from real data taken in South China Sea trial have proved satisfactory. It is shown that the proposed method is useful for underwater channel estimation.展开更多
基金Supported by the National Science Foundation of China (No.60872146)
文摘An array extension method in a noisy environment was proposed to improve angular resolution and array gain. The proposed method combines the FOC (fourth-order cumulants) technique with the ETAM (extended towed array measurements) method to extend array aperture and suppress Gaussian noise. First, successive measurements of a virtual uniform linear array were constructed by applying fourth-order cumulants to measurements of uniform linear array; Gaussian noise in these measurements was also eliminated. Then, the array was extended by compensating phase differences using the ETAM method. Finally, the synthetic aperture was extended further by the fourth-order cumulants technique. The proposed FOC-ETAM-FOC method not only improves angular resolution and array gain, but also effectively suppresses Gaussian noise. Furthermore, it inherits the advantages of the ETAM method. Simulation results showed that the FOC-ETAM-FOC method achieved better angular resolution and array gain than the ETAM method. Furthermore this method outperforms the ETAM method in Gaussian noise environment.
基金This work was supported by the National Natural Science Foundation of China(60472073)(10304015)and by the Doctor Research Foundation of Ministry of Education of China(20020699010)by the Natural Science Fundamental Research Foundation of Shaanxi province(2005F40).
文摘This paper proposed a method for blind estimation of underwater channels in shallow water environment by using received data at a single hydrophone or from single beam. First, the received signal is used for source signal reconstruction by means of signal-dependent TF （Time-Frequency） distribution, in association with instantaneous frequency estimation and TF inversion. Then the shallow-water channel estimation is achieved via WRELAX technique by use of the received signal and the estimated source signal. Finally, the results of numerical simulation and experimental test from real data taken in South China Sea trial have proved satisfactory. It is shown that the proposed method is useful for underwater channel estimation.
