Parameter-constrained DOA estimation for directional uniform circular arrays with plane-reflection effect

Abstract

A new multi-parameter direction-of-arrival (DOA) estimation model with image pattern factor is proposed for directional uniform circular arrays (UCAs) in the presence of plane-reflection effect. Firstly, to accurately formulate the characteristics of the radiation pattern impacted by the plane-reflected effect, a modified multi-parameter 3D radiation pattern with image pattern factor is derived on the principle of sources reconstruction. This model is well verified in theory by comparing it with the pattern of the practical log-periodic dipole antenna (LPDA). Secondly, having introduced this radiation pattern into the response vectors, the DOA estimation method with the constrained height-to-wavelength ratio (HWR) is then formulated, which is aimed to improve the achievable estimated accuracy within the full spatial coverage. Unlike the most existing models, it is well suited to the situation when there are reflected signals impinge on the response array. Thirdly, in order to evaluate the DOA performance with the constrained parameters, the deterministic Cramer-Rao Bound (CRB) function is derived. The qualitative analysis on CRB is referenced in the design of the available parameters of antennas on the premise of the uniform DOA estimation performance. Finally, the relationships between the DOA performance and the various constrained parameters are demonstrated in the simulations. The simulation results indicate that the DOA method using the proposed model has a superior estimation performance comparing to the traditional models when reflected signals exist.