Pressure-Pair-Based Floor Localization System Using Barometric Sensors on Smartphones.

Wonik Choi,Youngjun Jeon,Ling Liu,Chungheon Yi

doi:10.3390/s19163622

Wonik Choi, Youngjun Jeon + Show 2 more

Open Access

https://doi.org/10.3390/s19163622

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Abstract

As smartphone technology advances and its market penetration increases, indoor positioning for smartphone users is becoming an increasingly important issue. Floor localization is especially critical to indoor positioning techniques. Numerous research efforts have been proposed for improving the floor localization accuracy using information from barometers, accelerometers, Bluetooth Low Energy (BLE), and Wi-Fi signals. Despite these existing efforts, no approach has been able to determine what floor smartphone users are on with near 100% accuracy. To address this problem, we present a novel pressure-pair based method called FloorPair, which offers near 100% accurate floor localization. The rationale of FloorPair is to construct a relative pressure map using highly accurate relative pressure values from smartphones with two novel features: first, we marginalized the uncertainty from sensor drifts and unreliable absolute pressure values of barometers by paring the pressure values of two floors, and second, we maintained high accuracy over time by applying an iterative optimization method, making our method sustainable. We evaluated the validity of the FloorPair approach by conducting extensive field experiments in various types of buildings to show that FloorPair is an accurate and sustainable floor localization method.

Highlights

Ever since smartphones were equipped with barometers, starting in 2012, numerous research efforts on floor localization have tried to improve the accuracy of identifying a smartphone user’s floor location in a multi-floor building
We proposed a pressure-pair-based floor localization method called FloorPair that aims at determining the exact number of the floor on which smartphone users are located
We had the following three goals for the floor localization problem: first, we construct a relative pressure map with minimum costs; second, using the relative pressure map, we provide near 100%

Summary

Introduction

Ever since smartphones were equipped with barometers, starting in 2012, numerous research efforts on floor localization have tried to improve the accuracy of identifying a smartphone user’s floor location in a multi-floor building. Most of those efforts have succeeded only in detecting floor changes or the number of floors changed instead of determining the exact floor number. MEMS barometers have low power consumption, low cost, and very high-performance sensors. Because of these beneficial characteristics, barometers are found in an abundance of mobile devices, including smartphones and tablets. The floor localization problem remains a big challenge, since no existing methods identify a floor number with near 100% accuracy—a critical requirement for various applications, such as emergency location service, worker location tracking service, and clinical monitoring applications

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