Precise, Low-Cost, and Large-Scale Indoor Positioning System Based on Audio Dual-Chirp Signals

Existing indoor positioning systems, such as WiFi, Bluetooth and ultra-wideband based solutions, have difficulty achieving a balance among cost, accuracy and coverage simultaneously. In this article, we present a precise, low-cost and large-scale (>1000 m(2)) indoor positioning system based on audio dual-chirp signals and some inexpensive commercial devices that consists of four basic transmitters and supports unlimited receivers. In this system, the transmitters can be easily deployed on the sidewall or the ceiling indoors, and the receivers can be easily integrated or placed on moving targets, such as trailers, badges and helmets. In addition, this system has a better ability to assist the localization drift caused by Doppler shift by relying only on acoustic signals. To fully evaluate the performance of the proposed system, such as the positioning accuracy, coverage and robustness, experiments were conducted in a field environment, and a comparative experiment based on an ultra-wideband solution was presented. All experimental results show that the proposed prototype positioning system can achieve decimeter-level localization accuracy, a stable 4 Hz update rate and good robustness with less infrastructure, which is sufficient for mobile device positioning and tracking in actual indoor environments.