Investigations on Cramér-Rao-Bound Conscious Optimization Strategies for Antenna Design Aimed at Phaseless Direction of Arrival Estimation

We present the result of a novel optimization strategy for the design of the antenna front-end for indoor positioning system based on the Cramér-Rao bound sensitivity analysis. The positioning system considered relies on the direction of arrival estimation via space division multiple access which in turn is enabled by a smart antenna operating a 2.45 GHz. The antenna is designed via an optimization process driven by an invasive weed optimization algorithm. This is based on a multi-objective cost function relying on an ad-hoc implementation of the Cramér-Rao analysis of the antenna beam set. The use of the Cramér-Rao analysis to drive the optimization represents the novelty of this manuscript. To prove the effectiveness of the approach, the antenna front-end is limited to the essential components, albeit suitable to cover almost 180° degrees of observable area. The localization performance – validated with a simulated experiment – outperforms the results found with similar results in real life. In detail, the mean dilution of precision ranges from 0.78° to 2.71°, with an average of 1.63° and a standard variation of 0.41°. The worst case of the best-set exhibits a maximum error below 4.67°. The 95% coverage is equal to 2.22°, with a range spanning from 1.87° to 2.52°, corresponding to a spread of 0.6°. Anyhow, a full statistics over the whole Pareto set and the whole cloud of antenna geometries is presented, to validate the choice of the sub-set of best solutions chosen.