Indoor positioning with trilateration using orientation-based FSPL model selection

With the rise of Industry 4.0, wireless sensor networks (WSN) are increasingly vital, particularly in indoor positioning applications using various positioning techniques. Radiocommunication-based technologies such as WiFi and Bluetooth Low Energy (BLE), Ultra-Wideband (UWB) technologies are receiving growing attention in this area. The Free Space Path Loss (FSPL) model establishes a relationship between signal attenuation during propagation and distance. Previous studies have demonstrated that considering the angle between individual modules, i.e., their orientation, can significantly impact the accuracy of distance estimation. In this paper, an orientation-based positioning method is proposed. The appropriate FSPL model is selected based on the orientation of both the anchors and the station unit to compute the distance, followed by position determination using trilateration. This method was compared to a generalized FSPL model approach. In the tested scenario, the proposed orientation-based method demonstrated superior performance, achieving a 13% relative improvement in the average of the Mean Absolute Error (MAE).