Abstract:

In order to meet the requirements of precise direction finding of radar weak target signal under the influence of complex interference and array error factors, an algorithm of constructing virtual beam based on uniform linear array to replace the array received signal for fourth-order cumulant (FOC) direction of arrival (DOA) estimation is proposed.The algorithm includes two key steps: one is to extract the main information component of the signal by using the method of feature decomposition of the array received signal, and calculate the FOC matrix with the constructed virtual beam as the input. The other aiming at the fluctuation outside the lobe of the principal component virtual beam, is to use Gaussian window to modify the beam pattern to further improve the estimation accuracy of the spatial spectral function. The simulation results show that under the non ideal factors of array error, the DOA estimation accuracy of the target signal in the complex electromagnetic interference scene is more than 150% higher than that of the existing FOC method. Especially when there are multiple non equal power source signals in the field at the same time, the proposed method has obvious advantages in improving the DOA estimation accuracy of the target with low signal-to-noise ratio, and has higher DOA estimation accuracy and stronger adaptability in the complex interference environment.

Key words: direction of arrival (DOA) estimation, array errors, fourth-order cumulant (FOC), virtual beam forming (VBF), Gaussian distribution window, non-equal power sources