Indoor 5G Differential Positioning With Audio Constraints

Abstract

Three-dimensional positioning in large indoor environments poses a significant challenge for achieving high-precision 5G positioning. This letter proposes an indoor 5G differential positioning solution, which is constrained by the ranging measurements from a low-cost audio anchor. The method first eliminates receiver and 5G base station clock biases using double-differenced 5G time of arrival (ToA) and carrier phase observations. It then incorporates a single high-precision audio range measurement. Extended Kalman filtering is employed to estimate the float solution, followed by a ratio test to validate the resolution of the ambiguity and obtain the fixed solution. When the 5G ToA accuracy is 0.4 m, the proposed method improves positioning accuracy by 44.4% under static conditions and 29.2% under dynamic conditions compared to using five 5G base stations, achieving a positioning accuracy of approximately 0.10 and 0.17 meters, respectively. Our findings further demonstrate that the audio constraints facilitate 5G carrier phase ambiguity resolution, thereby accelerating positioning convergence. This letter presents a comprehensive analysis of how high-precision audio ranging significantly enhances the accuracy and ambiguity resolution of 5G carrier differential positioning, thereby offering a novel approach to indoor positioning.