Geomagnetism-Aided Indoor Wi-Fi Radio-Map Construction via Smartphone Crowdsourcing

Abstract

Wi-Fi radio-map construction is an important phase in indoor fingerprint localization systems. Traditional methods for Wi-Fi radio-map construction have the problems of being time-consuming and labor-intensive. In this paper, an indoor Wi-Fi radio-map construction method is proposed which utilizes crowdsourcing data contributed by smartphone users. We draw indoor pathway map and construct Wi-Fi radio-map without requiring manual site survey, exact floor layout and extra infrastructure support. The key novelty is that it recognizes road segments from crowdsourcing traces by a cluster based on magnetism sequence similarity and constructs an indoor pathway map with Wi-Fi signal strengths annotated on. Through experiments in real world indoor areas, the method is proved to have good performance on magnetism similarity calculation, road segment clustering and pathway map construction. The Wi-Fi radio maps constructed by crowdsourcing data are validated to provide competitive indoor localization accuracy.

MagPP: Combining Particle Filters and Pedestrian Dead Reckoning Algorithm with Geomagnetism for Indoor Positioning Using Smartphone

“…Moreover, the Wi-Fi technology used additionally in Ref. 8 is affected by the signal distance. In the method proposed in recent studies, it is difficult to determine the direction of the magnetometer and the simultaneous attachment of the IMU and the magnetometer to the foot.…”

“…However, owing to the limitations of positioning time, positioning accuracy, and complex indoor environments, GPS, BDS, and other GNSS technologies cannot be used for indoor positioning. Therefore, experts and scholars have proposed various indoor positioning technology solutions, such as the use of Wi-Fi, (2)(3)(4) bluetooth, (5) magnetic field, (6)(7)(8)(9) visible light, (10) ultrasound, (11) wireless radio frequency signals, (12) inertial navigation systems (INS), (13) and simultaneous localization and mapping (SLAM). (14) Among all the mentioned positioning technologies, the positioning method based on geomagnetic fingerprints has become a more effective solution to solve the problems in indoor positioning.…”

“…To solve this problem, we have focused our research on geomagnetism that does not require the deployment of additional infrastructure. However, studies (6,8,17) show that magnetic fingerprints may not be unique in large indoor spaces, so it is difficult to estimate the area where the magnetic field distribution changes little in a building and the area where the magnetic field excessively fluctuates, as shown in Fig. 2.…”

Real-Time Indoor Positioning Approach Using iBeacons and Smartphone Sensors

“…These methods are not suitable for smartphone since its low-cost sensors may not meet the requirement of high accuracy. In contrast, current fusion solutions for smartphone include the combinations of WiFi and PDR [6], geomagnetism/WiFi/PDR [7,8], or WiFi/Bluetooth [9]. Their typical positioning methods include fingerprinting and trilateration based on RSSI of WiFi and/or Bluetooth device.…”

Feasibility Analysis of Magnetic Navigation for Vehicles

“…The magnetic map can be constructed by adding supplementary magnetic sensors to a street-view collection system like Google Maps and Baidu Maps [5]. The crowd-source based approach can also be used to create magnetic maps [6,7]. During the online phase, which is the actual positioning phase, only magnetic data are collected.…”