Comparison of Accuracy and Precision Between Two Real-Time Location Systems (RTLS) Systems for Indoors Positioning

The purpose of this study was to compare two different indoor real-time location systems RTLS, for bias, precision, and environmental ruggedness within a simulated workspace. One system is based on RF trilateralization algorithm of ultra-wide band (UWB) radio waves and the second is based on RF wave phase ratios of RF near-field electromagnetic ranging (NFER). The UWB system was used in a pilot study called Chemical Exposure monitor with Indoor Positioning (CEMWIP), data from this study was used to compare to the NFER system. Both systems were assessed using comparisons to true locations premeasured with laser distance measurer. Tests were conducted to compare bias, precision, and wall penetration between systems as well as the stability of the NFER system. The NFER system showed to have superior bias than UWB system in most circumstances and the UWB system showed superior precision than the NFER system. When it comes to working environments, there can be a variety of factors that influence the ability of RTLS that use RF to track. More research on how different work environments with water or have high levels of noise and how it affects the positioning of RF-based RTLS is needed.