Indoor Positioning System Based On Audio Beamforming Signal Strength Fingerprint

With the rapid development of the Internet and the Internet of Things(Io T),the demand for location-based services has been increasing.However,compared to wellestablished outdoor positioning technologies,the progress of indoor positioning technology has been relatively slow.While research on indoor positioning,including Ultra Wide Band(UWB)and Wireless Local Area Network(WLAN)technologies,exists,most indoor positioning techniques cannot be directly applied to user terminals,such as smartphones,due to hardware platform limitations.In this regard,audio-based positioning technology emerges as a promising solution,eliminating the need for additional hardware and offering ease of use in practical scenarios.This paper proposes an innovative indoor positioning system based on the unique fingerprint features derived from audio beamforming signal strength.The system operates as follows: directional audio beamforming signals are emitted by the audio base station in various directions within the target area,creating spatially diverse beamforming signal strength distributions.The user terminal captures and analyzes the audio signals,extracting the audio beamforming signal strength fingerprint features.These features are then matched with the database for accurate positioning.The feasibility and practical implementation of the proposed positioning system were investigated.Through a combination of modeling simulations and real-world tests,it was demonstrated that the audio beamforming technique produces significant spatial diversity in signal strength distributions,confirming the theoretical and practical viability of the proposed system.Furthermore,the hardware implementation involved employing a piezoelectric audio signal transmitter as a superior alternative to traditional speakers,enabling the generation of high-quality and directional audio beams.The contributions of this study are as follows:(1)Integration of audio beamforming at the signal transmission end,reducing multi-path interference and enhancing system robustness.This approach opens up new avenues for audio positioning systems by utilizing beamforming technology.(2)Active enhancement of the spatial diversity of fingerprint features through beamforming,improving base station utilization,and providing a new reference solution for fingerprint positioning systems employing Bluetooth and geomagnetic technologies.(3)Hardware optimization through the use of a piezoelectric audio signal transmitter as a replacement for traditional speakers,providing a valuable implementation solution for generating high-quality and strong beamforming audio signals.Comprehensive indoor positioning tests were conducted to evaluate the system’s performance.Under a fingerprint density of one per square meter,the static and dynamic positioning tests employed the k-nearest neighbors(KNN)feature matching method.The results revealed static average mean absolute errors(MAEs)below 0.7m for various device models,while dynamic MAEs were below 1.1m.Additionally,cross-device positioning tests using fingerprint databases from different models achieved static MAEs below 0.9m and dynamic MAEs below 1.2m.The proposed positioning system exhibited strong accuracy,robustness,and usability.In conclusion,this paper presents an innovative indoor positioning system based on audio beamforming signal strength fingerprint features.The system demonstrates high positioning accuracy,robustness,and introduces novel advancements in the field of indoor positioning technology.