Angle-of-Arrival Estimation Technique for Fast Beamforming Using Monopulse Signal in the Antenna Array Systems

In this paper we propose an anlge-of-arrival (AoA) estimation technique using the monopulse signal to achieve a reliable link for the ground-to-unmanned aerial vehicle (UAV) or UAV-to-UAV. We first find the exact statistical characteristics of the monopulse signal, which is the random variable as a form of the ratio between the uncorrelated quadratic random variables with non-zero means. Specifically, we derive the probability density function (PDF) and the cumulative distribution function (CDF) of the monopulse signal in antenna array in closed-form. Then using the statistical characteristics of the monopulse signal, we develop the adaptive AoA estimator, which can be applied to fast beamforming with high accuracy. Based on our exact analytical results, we derive the mean squared error (MSE) performance of the proposed method. We show from our simulations that the proposed method achieves better performance with relatively less complexity and overhead than other conventional methods.