DOA Estimation for Directional Antenna Based Uniform Arc Array With Incomplete Array Manifold Information

In the directional antenna element-based uniform arc array (DA-UAA), the conventional spatial spectrum estimation algorithms such as multiple signal classification could not be utilized to find the direction-of-arrival (DOA) of an incident electromagnetic wave because of the incomplete information about the radiation pattern and polarization characteristics of each array element. In this article, a collection of DOA estimation algorithms for cases with incomplete DA-UAA manifold information is proposed. First, the received signal model of the DA-UAA is analyzed, and an active calibration method for array receivers, incorporating de-embedding equalization filtering to address the interchannel amplitude and phase inconsistencies, is proposed. Based on the traditional omni-directional amplitude-comparison DOA estimation method, the cosine-series expansion-based multiantenna amplitude-comparison DOA estimation method is adopted by the DA-UAA. Second, the low-order Legendre polynomial-based difference-sum amplitude-comparison DOA estimation algorithm and the Legendre-series-based root-seeking amplitude-comparison DOA estimation method are proposed to combine computational complexity and direction-finding accuracy. Third, an eigen subspace projection-based successive suppression amplitude-comparison DOA estimation strategy is designed to handle multiple incident waves with the same frequency. Finally, the effectiveness and accuracy of these proposed algorithms are verified through numerical simulations and field experiments, with the Cramér-Rao Lower Bound analyzed simultaneously.