Calibration of Wi-Fi-Based Indoor Tracking Systems for Android-Based Smartphones

Abstract

With the growing development of smartphones equipped with Wi-Fi technology and the need of inexpensive indoor location systems, many researchers are focusing their efforts on the development of Wi-Fi-based indoor localization methods. However, due to the difficulties in characterizing the Wi-Fi radio signal propagation in such environments, the development of universal indoor localization mechanisms is still an open issue. In this paper, we focus on the calibration of Wi-Fi-based indoor tracking systems to be used by smartphones. The primary goal is to build an accurate and robust Wi-Fi signal propagation representation in indoor scenarios.We analyze the suitability of our approach in a smartphone-based indoor tracking system by introducing a novel in-motion calibration methodology using three different signal propagation characterizations supplemented with a particle filter. We compare the results obtained with each one of the three characterization in-motion calibration methodologies and those obtained using a static calibration approach, in a real-world scenario. Based on our experimental results, we show that the use of an in-motion calibration mechanism considerably improves the tracking accuracy.

Simplified Indoor Localization Using Bluetooth Beacons and Received Signal Strength Fingerprinting with Smartwatch

“…There are also approaches to indoor tracking and indoor localization that use Wi-Fi instead of Bluetooth [5][6][7]24,28,29]; however, the approach is very similar and involves comparing the RSSIs of Wi-Fi broadcasters from different positions in an area. One of the issues that can be encountered with these approaches is that reading Wi-Fi data consumes more battery usage when compared to Bluetooth [30].…”

“…In addition to focusing on the algorithms and hardware used for this research, reducing the number of access points or reference points is also a concern. Although there have been approaches with less than 50 reference points [6,7], there have been approaches with over 100 [4,8], or even over 2000 [5] reference points. Because our approach is focused on room-based or region-based localization, we are able to utilize only one AP and one RP per region in the household.…”

“…However, many of these approaches require an extensive and time-consuming setup that would be difficult and expensive for the average end user of ambient assisted living technology. Having many calibration points, as many other approaches do [4][5][6][7][8], is one of the factors which makes it time-consuming, particularly if the system requires re-calibration. Approaches that use a form of received signal strength indicator (RSSI) need to be re-calibrated occasionally, as signal broadcasting power levels can drift and change over time [9].…”

Smartphone-Based Indoor Localization Systems: A Systematic Literature Review

“…Although GPS has been the most extensively used outdoor localization tool, no standard method exists for indoor localization [1]. Indoor localization and tracking are, therefore, important topics for discussion in the academic domain [14][15][16].…”

A CSI-Based Indoor Positioning System Using Single UWB Ranging Correction

“…Though Global Navigation System (GNS), including Chinese BeiDou Navigation System (BDS) and American Global Positioning System (GPS), can provide high-accuracy positioning results in open-air scenarios [2], they are limited in indoor environments such as basements, tunnels, and even high-density building areas, due to attenuation and distortion of electronic signals on the surface of blocking objects [3]. Therefore, many positioning technologies have been proposed or improved to satisfy various indoor localization requirements including technologies such as Wi-Fi [4], UWB [5], Bluetooth [6], Zigbee [7], Ultrasonic [8], and more [9]. Broadly, current indoor positioning technologies can be classified into two types: fingerprinting-based methods and ranging-based methods.…”