Research on Centimeter-Level RFID Positioning Method for Electrical Safety Tools Based on Phase Measurement

Conventional RFID positioning methods face difficulties in achieving centimeter-level accuracy due to phase distortion and cycle ambiguity coupling caused by multipath reflections in metal-enclosed power equipment cabinets, failing to meet the requirements of intelligent management and control of electrical safety tools. This paper proposes a robust PDoA positioning method based on frequency-hopping phase difference. A fast ambiguity resolution strategy with non-uniform frequency hopping is constructed, combined with a signal-to-noise ratio weighted least squares algorithm using a 2×2 antenna array to achieve optimal spatial coordinate estimation. An adaptive Kalman filter is introduced to suppress dynamic observation outliers and improve dynamic positioning stability. Experimental results show that the proposed algorithm achieves an average positioning error of 6.8 cm under metal occlusion conditions, a dynamic positioning accuracy rate of 91%, a 90% confidence error below 9.5 cm, and a single-frame computation time of 12 ms.