2D DOA Estimation of UCA Correlative Interferometer Based on One Dimensional Sorting Lookup Table-Two Dimensional Linear Interpolation Algorithm

Abstract

In order to improve the direction-finding efficiency of the correlative interferometer and reduce the size of the lookup table, this paper proposes the one dimensional sorting lookup table-two dimensional linear interpolation (1DSLUT-2DLI) algorithm. Firstly, the uniform circular array (UCA) model is established and the direction finding (DF) theory of the correlative interferometer is analyzed. A new lookup table is obtained by proceeding the ascending order for the first dimensional phase differences and a one dimensional iterative filtering method is used to look up the new table to get the direction of arrival (DOA) estimation. Compared to the exist methods, the 1DSLUT algorithm can reduce the computational complexity greatly. Considering the burden of a big lookup table, this paper proposes the 2DLI algorithm. Through the Taylor expansion, the conclusion that the phase difference is approximately linear in a small angle range is obtained. So, the linear interpolation can be applied to calculate the phase differences in the azimuth direction and elevation direction. On this basis, we conclude the equations to get the DOA estimation using the 2DLI algorithm. In this way, the size of the lookup table is reduced greatly, which decreases the computational complexity greatly also. The numerical simulations verify the effectiveness of the 1DSLUT-2DLI algorithm and it can obtain a pretty high DOA estimation precision with a low computational complexity and a small lookup table.