Angle-of-arrival estimation with array in a Line-of-Sight indoor UWB-IR

Antenna array is useful in direction-finding because of its spatial-spread signal profile. Conventional array processing for narrowband is not suitable for ultra-wideband impulse radio (UWB-IR) because of the wideband spectrum and large off signal period. This paper addresses the utility of uniform circular array for AOA estimation in a line-of-sight (LOS) UWB-IR channel. Maximum likelihood (ML) estimation of AOA is obtained through minimizing the error function. Energy-capture capability (EC) is proposed as the weighted factor in the error function. It can indicate peak signal-to-noise ratio (SNR) and phase noise level, which is thought to be the reason for accuracy improvement. When all sensors lie in almost equal SNR environment, the key factor to degrade EC is the different RF impairments level, and phase noise caused by jitter and spike noise belong to this. Measurements are conducted to verify the weighted least square error (LSE) estimator's improvement in performance. Its accuracy is compared to the performance using uniform weighted estimator.