Bluetooth, Floor-Plan, and Microelectromechanical Systems-Assisted Wide-Area Audio Indoor Localization System: Apply to Smartphones

During the past decade, there has been an increasing interest in the audio-based indoor localization approach, which has benefited from the high precision, high privacy, and high security of the passive time difference of arrival positioning. However, the limited bandwidth and complexity in real-time ID encoding and decoding make it difficult to achieve wide-area (>1500 m
²
) localization in off-the-shelf smartphones. Plenty of previous work applied to a single region localization only with a small range. In this article, a hybrid acoustic signal transmission architecture based on frequency division multiple access, time division multiple access, and space division multiple access is perfected to cover the acoustic signal to a wider range. With the prior information of the Bluetooth and floor-plan, smartphones estimate which cell themselves are located in accurately. An enhanced particle filter algorithm, along with the microelectromechanical systems-based pedestrian dead reckoning and the floor-plan restraint, was proposed to make the smartphones tracking smarter and more robust. The proposed prototype system provided submeter-level localization accuracy and stable 1-Hz update rate in several typical wide indoor environments with less infrastructure, which demonstrates some values of reference and application owing to the work of this article.