## 3 Methodology
### Experiment Plan
#### 3.5.3 Impact of LoS/NLoS Conditions  
Measurements were performed using a GTEM cell, simulating LoS/NLoS conditions. Additionally, tests of the influence of the supplied supply voltage on the measurement accuracy were also carried out in the GTEM chamber. Then, in a further stage, measurements were taken with various basic obstacles occurring in the real environment (concrete walls, glass walls, and wooden doors), and all cases were analyzed and compared.  
Measurements were conducted over a duration of 300 s for each data point, yielding aggregated outcomes for each specific use case. During the static case, this extended measurement period (300 s) allowed us to average out short-term variations and noise, providing a more reliable assessment of the UWB beacon's performance under stable conditions. It allowed for the collection of a significant number of samples, which improved the statistical reliability of the measurements. In all cases, research was carried out, and use cases were selected by analyzing those proposed in previous studies. The inspiration to carry out tests under static and dynamic conditions was derived from [80], which evaluated the performance of UWB in varying environmental dynamics. The precision and accuracy were assessed based on the x, y, and z positions, revealing divergent precision across the axes. The impact of beacon positioning and antenna range was thoroughly analyzed in [81], where significant differences in measurement were attributed to both antenna placement and the model of the equipment used [82]. Measurements related to the supplied energy were introduced in [83], which sought a compromise between energy consumption and the accuracy and precision of distance measurement. Distance measurement errors for devices with a low-power implementation were found to exhibit a bias and standard deviation that were at most 12 cm higher in line-of-sight propagation, and a spread 2-3 times greater in non-line-of-sight conditions compared to devices with typical power consumption. UWB has a substantial potential to reject multipath interference signals; however, NLoS issues still form the basis of many studies [84,85], and assessing their impact is a key element before implementing a UWB beacon-based localization system.  
Based on these considerations, we divided the evaluation indicators into three categories:  
* Accuracy of the device;
* Durability/reliability of the device;
* Adaptability to a dynamic environment.  
Accuracy pertains to the deviation in distance (or error) between the estimated location value of the system and its true location value. The durability of navigation devices denotes their reliability in consistently delivering precise and dependable position values, particularly in regions where signal strength and/or data acquisition may encounter challenges. The capability to adapt to a diverse environment refers to the inherent disparities within indoor settings (including the existence of materials like glass, wood, concrete, or steel) that impact the visibility of the signal source and/or disrupt readings, thereby complicating the assurance of consistent positioning system performance.