Abstract

The motivation of this work is to help outpatients find their corresponding departments or clinics, thus, it needs to provide indoor positioning services with a room-level accuracy. Unlike wireless outdoor localization that is dominated by the global positioning system (GPS), wireless indoor localization is still an open issue. Many different schemes are being developed to meet the increasing demand for indoor localization services. In this paper, we investigated the AoA-based wireless indoor localization for outpatients’ wayfinding in a hospital, where Wi-Fi access points (APs) are deployed, in line, on the ceiling. The target position can be determined by a mobile device, like a smartphone, through an efficient geometric calculation with two known APs coordinates and the angles of the incident radios. All possible positions in which the target may appear have been comprehensively investigated, and the corresponding solutions were proven to be the same. Experimental results show that localization error was less than 2.5 m, about 80% of the time, which can satisfy the outpatients’ requirements for wayfinding.

Highlights

  • With the popularity of mobile devices, such as smartphones, smartwatches, tablets, as well as some wearable devices, wireless localization has spawned numerous location-based services (LBS)to facilitate our daily life in the fields of emergency services, navigation, healthcare, geofence, social networking, entertainment/gaming, asset tracking, etc. [1,2,3,4,5,6]

  • No matter where the target locates around the two access points (APs) and no matter which pairs of the angle of arrival (AoA) are used, the results show that the equations are essentially consistent and that solutions are the same

  • In order to provide room-level localization services for hospital outpatients using their own mobile devices, this paper proposed an efficient AoA-based wireless indoor localization algorithm that uses the coordinates and the angles of the arrival, provided by commercial Wi-Fi access points, to estimate the target’s position

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Summary

Introduction

With the popularity of mobile devices, such as smartphones, smartwatches, tablets, as well as some wearable devices, wireless localization has spawned numerous location-based services (LBS). ToF, ToA, and TDoA are very sensitive to timing error, relying on highly synchronized timers They usually need work under line of sight (LOS) conditions to get accurate ranging. The nearby mobile devices detect the signal from the beacon and calculate the approximate distance to the beacon It needs to deploy a mass of beacons to obtain an accurate location. Since the RSSI can be obtained by common mobile terminals, such as smartphones, Wi-Fi devices, Bluetooth beacons, ZigBee sensors, and so on, it is widely used to study wireless localization in range-based and range-free schemes. We propose an efficient AoA-based wireless indoor localization method for the outpatients’ wayfinding, in hospital, using mobile devices, such as tablets, smartphones, smartwatches, and so on.

Related Work
Methodology
AoA-Based Localization with Two Known APs
All Possible Positions of the Target around the APs
Roaming Strategy
Experimental Setup
The Impact of the Distance and Direction
Comparison with RSSI Range-Based Method
Localization Accuracy
Conclusions and Discussion
Full Text
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