Theoretical study of signal and geometrical properties of Two-dimensional UWB-based Indoor Positioning Systems using TDoA

Abstract

This document is the author's post-print version, incorporating any revisions agreed during the peer-review process. Some differences between the published version and this version may remain and you are advised to consult the published version if you wish to cite from it.

Analysis and Accuracy Improvement of UWB-TDoA-Based Indoor Positioning System

“…The CRLB analysis is crucial for estimating the precision of the positioning system across the domain of measurements, although the analysis does not consider regions in the measurement domain where failure occurs due to geometrical constraints [ 38 , 41 ]. For instance, IPSs suffer from a well-known problem of geometrical origin called flipping uncertainty [ 39 , 40 ].…”

“… Precision level sets and colourmaps for symmetric and random anchors. The magenta trapezoid is the convex hull of four anchors (modified from [ 38 ], with permission). …”

“…Examples include the calculation of bounds for ToA [ 31 , 32 ], anchor time synchronisation [ 33 , 34 , 35 ], and AoA [ 36 ]. Such work is of critical importance, as the performance of UWB-based IPSs tends not to be homogenous across the measurement domain [ 37 ]; thus, characterising its performance is crucial to understanding the limits of the system and potentially optimising its design and/or layout [ 38 ].…”

“…CRLB analysis is widely accepted for positioning systems in which the tagged object to be localised/tracked is not in close proximity to the anchors; in such scenarios, localisation algorithms tend to fail due to flipping uncertainty , a well-known problem of geometrical origin [ 39 , 40 ]. Regions in the measurement domain where failure occurs due to geometrical constraints are not considered in the CRLB analysis [ 38 , 41 ]. Furthermore, the possibility of signal degradation due to the anisotropic signal transmission properties of the anchors is almost never considered, even though it is an important property that many antenna optimisation studies have accounted for [ 42 , 43 , 44 , 45 ].…”

“…More specifically, it is concerned with the planar localisation performance within a homogeneous medium with negligible interference and reverberation, while taking into account the anisotropic radiation pattern of an actual DWM1000 antennae module rather than simply assumming ideal signal distributions. A rigorous analysis of system performance is carried out in terms of precision , failure , and accuracy , informed by previous work reported in [ 38 , 39 , 40 , 46 , 47 , 48 , 49 , 50 ]. To summarise, the contributions of this paper are as follows: A theoretical study of the precision of the position estimates is performed based on a CRLB analysis for round-robin scheduling and an anisotropic representation of the signal-to-noise ratio function of the 3D radiation pattern of the anchor antennas.…”