Specular multipath model for an optimal anchor placement evolutionary algorithm

A multi-objective evolutionary algorithm for optimal anchor placement of an infrared indoor positioning system is proposed. As a novel contribution the multipath error, a severe cause of inaccuracies (up to some tens of cm), is taken into account as an objective together with precision in a genetic algorithm. Multipath error and precision of the estimated position are assessed as scalar functions of the client position within an entire region of interest using models of the phase-based measurements and their propagation into estimated position. The precision is assessed using the trace of the covariance matrix of the estimated coordinates assuming position-dependent variances. A specular model is applied to calculate the respective multipath errors, and the appropriate number of multipath components to be included is analyzed. The method is applied to a geometrically simple scenario using realistic system parameters and environmental parameters to demonstrate the feasibility and highlight the impact of multipath on optimization of anchor placement. The results are sets of quasi-optimal configurations within a non-restricted anchor-location space.