Design of a Wireless Indoor Tracking System for Multi-Sensor Data Acquisition with BLE Channel Sounding

This thesis presents the design and development of a wireless indoor tracking system that integrates multi-sensor data acquisition with Bluetooth Low Energy (BLE) Channel Sounding for precise short-range localization.The system combines distance estimation based on Inverse Fast Fourier Transform (IFFT) and Phase-Based Ranging (PBR) with real-time environmental sensing, enabling both positioning and contextual monitoring in indoor environments.The thesis is structured into three main parts.The first part introduces the theoretical background of radio propagation, BLE technology, and channel sounding principles, emphasizing the advantages of IQ-based phase and delay measurements over traditional RSSI approaches.The second part focuses on the hardware and software design, including the development of a custom PCB built around the nRF54L15 SoC, integration of environmental and inertial sensors, and implementation of firmware supporting both sensor data transmission and channel sounding procedures.The third part presents an experimental evaluation of the system through a series of controlled indoor tests, including stepped-distance measurements, single-link ranging, and local error field visualization.The results demonstrate that the proposed system achieves sub-metre accuracy under realistic indoor conditions, with the IFFT-based estimator providing the most stable and accurate distance estimates compared to PBR.The overall performance validates the feasibility of BLE Channel Sounding as a practical ranging method for cost-effective indoor localization and sensor fusion applications.This work establishes a modular foundation for future extensions toward multi-anchor positioning, autonomous mapping, and context-aware tracking in industrial and IoT environments.