A Full-Body Wireless Wearable UWB-Based Human Motion Capture and Gait Analysis System - E-Healthcare Systems and Wireless Communications - page 448

Figure 2. ZZLB in the IEEE 802.15.6a CM3 UWB channel model for seventh order Gaussian pulse with
optimal and suboptimal templates, quadrature analog correlator (QAC), and CRLB (cm)(Shaban 2010).

LOCALIZATION shows a simplified schematic representation of the

proposed system, and Figure 3(b) shows a block
diagram of the ranging and localization stages.
Specifically, we assume that the localization data
processing is performed at an off-body centralized
node (typically a PC). The node arrangement, ini-
tial and core localization stages will be explained
in further details in the following sub-sections.

In our system we assume two localization phases,
namely the initial and core phases. This section
introduces the employed node arrangement, and
initial and core phase localization stages. In the
initial phase we assume a low-complexity local-
ization approach, which is linear least-squares
(LS) with possible reference-nodes. For the core
phase, we assume a more complex localization
approach, namely the classical multidimensional
scaling (C-MDS) localization with no reference-
nodes. This is typically because at the initial stage
we can have reference nodes, whereas at the core
phase all nodes are mobile with no reference nodes.
This makes it require a more complex localization
technique for providing high localization accuracy.
Each localization stage is preceded by a ranging
stage with a ranging accuracy dependent upon
the system requirements at that stage, as will
be described in further details later. Figure 3(a)

Node Arrangement

Generally, gait analysis is based on markers lo-
cated according to a standard arrangement, termed
marker-set. There are several standardized marker-
sets like Helen Hayes, modified Helen Hays, and
Vicon marker-sets. These marker sets are typically
based on substantial work for developing sets that
track each segment taking into consideration the
degrees of freedom (DOF) associated with the
movement of each segment (Thomas, Salim et
al. 2009).