This paper presents a novel Time Difference of Arrival-based approach suitable for single-anchor positioning systems, implemented by phase wrapping-impaired array antenna. With the latter being a typical occurrence in large Switched Beam Antenna (SBA) operating in the low microwave range. The proposed method takes advantage from the large bandwidth of radio link, established between the anchor and the positioning target, by generating an unambiguous equivalent phase relationship between antenna array elements. The technique is validated by adopting a relatively large SBA antenna operating in the 4.75–6.25 GHz bandwidth, and capable to position a target in a 3D domain. Experimental data, carried out in the 4–7 GHz frequency bandwidth, show that by dealing properly with the inherent constraint of phase wrapping issues, it is possible to get a significant improvement on the elevation angle with respect to methods not capable to deal with phase reconstruction and thus operating in a phase-less context. Combining range and angle errors, the associated cumulative distribution function error in 90% of cases shows an error of 0.13 m.

The present paper analyzes the performance of localization systems, based on dual-band Direction of Arrival (DoA) approach, in multi-path affected scenarios. The implemented DoA estimation, which belongs to the so-called Space and Frequency Division Multiple Access (SFDMA) technique, takes advantage of the use of two uncorrelated communication carrier frequencies, as already demonstrated by the authors. Starting from these results, this paper provides, first, the methodology followed to describe the localization system in the proposed simulation environment, and, as a second step, describes how multi-path effects may be taken into account through a set of full-wave simulations. The latter follows an approach based on the two-ray model. The validation of the proposed approach is demonstrated by simulations over a wide range of virtual scenarios. The analysis of the results highlights the ability of the proposed approach to describe multi-path effects and confirms enhancements in DoA estimation as experimentally evaluated by the same authors. To further assess the performance of the aforementioned simulation environment, a comparison between simulated and measured results was carried out, confirming the capability to predict DoA performance.

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