On the unimportance of phase-coherent measurements for beampattern-assisted positioning

Accurate indoor radio positioning requires high-resolution measurements to either utilize or mitigate the impact of multipath propagation. This high resolution can be achieved using large signal-bandwidth, leading to superior time resolution and / or multiple antennas, leading to additional angle resolution. To facilitate multiple antennas, phase-coherent measurements are typically necessary. In this work we propose to employ non-phase-coherent measurements obtained from directional antennas for accurate single-anchor indoor positioning. The derived algorithm exploits beam patterns to jointly estimate multipath amplitudes to be used in maximum likelihood position estimation. Our evaluations based on measured and computer generated data demonstrate only a minor degradation in comparison to a phase-coherent processing scheme.