## 2 Materials and Methods
### Data Processing  
Data was collected during the Atidas Next Generation Basketball Tournament, part of the 2016-2017 season, at the \"Sinan Erdem Dome\" Sport Arena (Istanbul, Turkey). To investigate the accuracy of the UWB system for monitoring players' positions on the court, the data were transformed into raw position data (x and y coordinates) using software (S PRO, RealTrack Systems, Almeria, Spain). The reference system to compare the results was projected in the software using a GIS mapping application. To do this, the set of points obtained by step 4 in the procedure were downloaded into the software. The centroid of each set of points was calculated as the point of reference (the four corners) to project onto the template of the court (Figure 3B). The standard deviation of the centroids calculated in all sets was \(\pm\) 2.2 cm and \(\pm\) 2.9 cm for coordinate x and y, respectively.  
The GIS mapping application allows representation of geometrical shapes, such as polygons or circles, with millimeter accuracy. In this way, the routes selected with their real measurements (measured by trundle wheel) were introduced on the template created before. And then, the x and y  
Figure 4: (**a**) Arrangement of sides and axes for the analysis of the movements made by participants and design of the different routes followed: (**b**) Perimeter markings of court, (**c**) middle line of court; (**d**) exterior perimeter of the painted lines, (**e**) center circle and (**f**) 6.75 m line.  
coordinate data of the UWB system were introduced and compared. The distance errors of each axis (coordinate) were reported. Of all the data entered, only those that corresponded to the execution of the routes were selected, according to registers obtained using ANT+ technology and photocells at the beginning and end of each test. The protocol to register the beginning and the end of the test was described in a previous study (see that study for more information) [28].  
In routes (b), (c) and (d), a number was assigned to each edge of the projected rectangle, so in each test the software automatically calculated the distance of the participant's position between the court line where the displacement occurred (y coordinate) and the opposite court line (x coordinate). In lanes (e) and (f), the centroid of the projected circle was assigned, so in each test the software automatically calculated the distance of the position of the participant from the indicated centroid (coordinate x). The calculation of the distance of the participant's position according to the reference element was made every 0.5 s, obtaining a total of 8344 samples. The reference distances were as follows:  
* Perimeter markings of court. (1) Baseline: 28 m with respect to the opposite baseline (coordinate x) and 0 m with respect to the displacement baseline (coordinate y). (2) Lateral line: 0 m with respect to the displacement lateral line (coordinate x) and 15 m with respect to the opposite lateral line (coordinate y).
* Middle line court. 14 m with respect to the baseline (coordinate x) and 0 m with respect to the center line (coordinate y).
* Exterior perimeter of the painted lines. (1) Baseline/front-line of the paint: 5.8 m with respect to the baseline or the front line of the paint (coordinate x) and 0 m with respect to the displacement line of the paint (coordinate y). (2) Lateral line of the paint: 0 m with respect to the displacement line of the paint (coordinate x) and 4.9 m with respect to the opposite lateral line of the paint.
* Centre circle. 1.8 m with respect to the centroid of the center circle (coordinate x).
* 6.75 m line. 6.75 m with respect to the centroid of the three-point line (coordinate x).  
The estimation of error was considered as the difference in the distance between the UWB devices' tracking data (x and y coordinate) and the reference distance described previously.