Research On Interference Mitigation Methods Based On The Asymmetric Array Singal Processing

Weak singal processing has great importance for improving the performance of radar system and increasing the efficiency of radio astronomy efficiency. However, frequency interference brings great chanllenges to the work of weak signal observation in more and more electromagnetic environment. On the interfence mitigation for weak singal processing, The Interference mitigation methods based on the asymmetric array have unique advantage. Against this background and with full consideration of requirement of weak signal observation, this paper focuses on the evaluation criteria of the anti-interference processing, post-correlation interference mitigation algorithm and adaptive beamforming algorithm for interference mitigation.Firstly, As the basis of research on the interference mitigation methods and aiming at the requirement of radio astronomy application, this paper establishes the overall evaluation criteria of anti-interference processing according to property of noise signal, interference suppression and pattern rumble, and analyses the influence of typical interference mitigation algorithm to the radio astronomy observation. Based on it, combining with the characteristic of array receiving system, the effect of anti-interference processing on the statistical property of the noise signal is evaluated, as the basis of the following work.Secondly, aiming at the application of Interferometer array, the post-correlation interference mitigation algorithm based on the asymmetric array was proposed. With the eigen structure of the desired signal and correlation data of the asymmetric array, the signal space was reconstructed, and based on it, the the estimation accuaacy of desired signal subspace is improved to construct the filtering matrix. The simulation result shows improvmance of the performance on the interference mitigation of the proposed algorithm.Finally, aiming at the application of radio telescope of phased array, the oblique projection adaptive beamforming algorithm for interference mitigation based on the asymmetric array was proposed. With parameter estimation of interference from the auxiliary antenna, the pseudo-inverse of interference convariance matrix is acquired for increasing the depth of interference nulling. The simulation result shows the proposed algorithm improves the performance on interference mitigation under the actual conditions, and the effect of anti-interference processing on the statistical property of the noise signal is under acceptable range.