Maximum cross-correlation method for DOA estimation with an ESPAR antenna

We propose a fast convergence direction-of-arrival (DOA) estimation scheme, with a very small error margin, employing an electronically steerable passive array radiator (ESPAR) antenna. The proposed scheme maximizes the cross-correlation between a reference signal and the antenna output by using a conjugate gradient algorithm. Simulation results show that DOA estimation is performed with an average error margin within 2.22° and average convergence within 21 iterations. The performance of the DOA estimation is not affected by interference signals when non-correlated pilot symbols are used, and the best efficiency is achieved when orthogonal codes such as Walsh codes are used. Comparisons with current techniques show the superior performance of our proposed scheme. Accordingly, the proposed scheme yields a big improvement over adaptive control of ESPAR antennas in the aspects of convergence speed and DOA estimation precision, and thus it can be a practical approach to small-size and low-cost smart antennas for mobile terminals and location detection applications.