Aiming at problems that interpolated array has large amount of computation and high sensitivity to transformation angle and interpolated step, a new array extension algorithm which is symmetric extension steering vector is proposed. In this paper, two properties of the conjugate of received data and the source covariance matrix being a real diagonal matrix are exploited to extend the dimensions of the covariance matrix. However, the essence of this extension method is the symmetric extension of the steering vector. The high complexity and degradation of the performance of interpolated array beamforming caused by the sensitivity of angle and interpolated step are improved. Numerical simulations confirm the validity of the proposed algorithm. Compared with existing algorithms, the proposed algorithm is not affected by the angle range of transformation and interpolated step. Besides, the complexity of array extension using this proposed algorithm is much lower than the interpolated transformation method.
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