Abstract:

A new approach is proposed for resolving the direction ambiguity by using twice virtual array transformation, which makes use of the nonuniform time delay to generate virtual transformation matrix. Due to the random variation in time interval of nonuniform time delay, the transformation based on nonuniform time delay matrix is equivalent to altering the relative distance between sensors. This means that the plane wave impinges a virtual uniform linear array with a time-varying array element interval. Therefore, a larger array aperture is available without anglular ambiguity, which enhances resolution and accuracy of the direction-of-arrival (DOA) estimation. Simulation results show that the proposed algorithm is effective for DOA estimation, and capable of improving estimation performance
at low SNR.

Key words: virtual array transformation, direction-of-arrival estimation, nonuniform time delay, resolving ambiguity