空间色噪声下信号频域检测方法性能分析

水下小孔径阵列的应用环境是色噪声环境,针对超增益波束形成方法在色噪声环境下噪声协方差矩阵估计偏差使阵列空间增益不能达到最大的问题,提出了一种频域超增益波束形成方法(FSD, Super-Directive beamforming in Frequency domain),该方法将宽带接收数据分成多个子带,在每个子带内分别估计噪声协方差矩阵,降低了噪声协方差矩阵的估计偏差,并使用估计得到的噪声协方差矩阵对接收数据解相关.最后使用空间谱检测器检测微弱目标信号.实测噪声数据的仿真结果表明,空间有色噪声环境中FSD方法的检测性能优于传统的时域超增益波束形成方法(TSD, Super-Directive beamforming in Time domain)2 dB,优于频域最小方差无畸变响应(FMVDR, Minimum Variance Distortionless Response in Frequency domain)波束形成方法2 dB.

Performance analysis for frequency domain detection method in spatial color noise background

Underwater noise environment of small aperture array is spatial color noise background.A super-directive beamforming in frequency domain(FSD) method was proposed to solve the problem that the array gain of super-directive beamforming cannot reach maximum when there exists error in the estimated noise matrix under color noise background.The wideband received data were divided into many subbands,and noise covariance matrix in each subband was estimated,which reduces the error of estimated noise matrix.Estimated noise covariance matrix was used to de-correlate the received data.At last,spatial spectrum detector was employed to detect weak signal.Experimental results show that the detection performance of FSD is better than super-directive beamforming in time domain(TSD) and minimum variance distortionless response in frequency domain(FMVDR) of 2 dB and 2 dB respectively.