**3.2 Reliability of UWB technology**

Four studies [16–18, 20] aimed to assess the reliability of LPS based on UWB technology. Hoppe et al., (2018) assessed the reliability calculating the differences between the KINEXON ONE UWB devices of each positioning system (i.e. the between device reliability) though typical error. They found typical errors between 0.1 (criterion variable of 10 m jogging with jump) and 1.7 (criterion variable of 129.6 m entire circuit). The LPS revealed good reliability for the entire distance covered, walking over 10 m and sprinting with change of direction, sprinting over 30-m, sprinting over 5–20 m and theoretical maximal force and horizontal power [20]. In addition, Hoppe et al., [20] compared the results of GPS and UWB, and despite some contradictorily results, comparisons of reliability between the GPS and LPS was mainly favorable to LPS [20].

Regarding to the other commercial UWB based device from RealTrack Systems was tested for its intra- and inter-unit reliability [17]. These tests assisted with understanding the degree of error and the amount of variation between the units. A Mann– Whitney U test was performed to compare differences in the differently designed routes and between devices (i.e. the variation in data measured in one participant or another). Inter-unit reliability (i.e. the difference in using one device or another) was determined using Hopkins's reliability spreadsheet to calculate the percentage typical error of measurement and the intra-class correlation coefficient (ICC) values. The intra-unit reliability of UWB in mean velocity varied between 0.895 and 0.999 of ICC (95% of confidence interval) and the low and upper (for inter-unit variability) ranged between −0.09 and 0.42%. In the case of distance covered, the typical error of UWB varied between 0.94 and 4.87% and the lower and upper bias was between


**97**

**Ref.** Bastida- Castillo, et al., [18]

• • • • • • •

Drill: (1) perimeter of the field; (2) halfway

line; (3) centre circle; (4) perimeter of the

penalty area; (5) semicircle penalty area;

(6) *SSG* (7 vs. 7).

Pino-Ortega

• • • • • • • course).

**Table 3.**

*Studies that assess validity or reliability of Realtrack systems´ UWB (Almería, Spain) (adapted from Rico-González et al. [9]).*

Drill: over the lines of the court (linear

Gold Standard: real measurement.

• ence the reliability results.

Besides, inter-unit, test–retest and inter-subject analysis did not influ-

Sampling frequency: 33 Hz.

Number of anchors: 8

• coming back and in total.

It is remarkable that %CV was less than 1% in all cases, in going,

Algorithm: TDOA.

Environment: indoor.

Aim: accuracy/reliability.

•

The MD was less than 4 cm and in 95% of the cases was between 1 cm

•

An eight antennae UWB system can be

considered suitable for locomotion and

positioning in an indoor environment.

and 7 cm, the reference being the real measure. The magnitude of the

differences was expressed as 0.28% with real measures as the refer-

ence. %CV was less than 1% in all cases.

et al., [16]

Gold Standard: GIS.

Sampling frequency: 18 Hz.

Number of anchors: 6

Algorithm: TDOA.

Environment: outdoor.

Aim: accuracy.

**Article's information**

**Outcomes**

> •

• reached 8.31% (ES = 0.11).

MAE = 9.57 ± 2.66 cm (x coordinate) and 7.15 ± 2.62 cm (y coordinate).

*SSG:* For tactical variables, differences between UWB and GPS

**What this Document Add?**

•

UWB-20 Hz has been recommended as

accurate technology for estimating position

of players on the pitch, while GPS-10 Hz has

substantial limitations.

•

Significance differences reported in tactical

analysis between GPS and UWB that the

error of using one system or another can

mean a difference of more than 8%.

•

Test–retest reliability and inter-unit reliability were good for the two systems assessed.

*Review of Ultra-Wide Band in Team Sports DOI: http://dx.doi.org/10.5772/intechopen.94591*

