GSM indoor localization

Abstract

Accurate indoor localization has long been an objective of the ubiquitous computing research community, and numerous indoor localization solutions based on 802.11, Bluetooth, ultrasound and infrared technologies have been proposed. This paper presents the first accurate GSM indoor localization system that achieves median within floor accuracy of 4 m in large buildings and is able to identify the floor correctly in up to 60% of the cases and is within 2 floors in up to 98% of the cases in tall multi-floor buildings. We report evaluation results of two case studies conducted over a course of several years, with data collected from 6 buildings in 3 cities across North America. The key idea that makes accurate GSM-based indoor localization possible is the use of wide signalstrength fingerprints. In addition to the 6-strongest cells traditionally used in the GSM standard, the wide fingerprint includes readings from additional cells that are strong enough to be detected, but are too weak to be used for efficient communication. We further show that selecting a subset of highly relevant channels for fingerprinting matching out of all available channels, further improves the localization accuracy.

Montage: Combine frames with movement continuity for realtime multi-user tracking

“…One category of existing methods are based on fingerprints, e.g., [4], [6], [17], [23], [28], which achieve room-level (meterlevel) accuracy. Those methods, however, are typically labor intensive and environment restrictive during fingerprint collection stage.…”

Coarse In-Building Localization with Smartphones

“…However, when we enter a building the reception of GPS signals become weak or is lost causing the inability to determine additional location information within the building. Existing solutions for indoor localization include techniques that use WiFi [4], RFID, Bluetooth [2], ultrasound [16], infrared [19] and GSM [17] [13] etc. Many of these solutions rely on external infrastructure or a network of nodes to perform localization.…”

Collaborative Cellular-Based Location System

“…First, unlike previous works that relied on special hardware for retrieving the signal-strength for multiple cells [13,14], our approach allows nearby mobile phones to exchange the signal-strength information for the cell they are connected to, the only information that can be accessed using the existing APIs in common mobile devices. The use of the signal-strength from multiple cells is essential for providing good location results.…”

“…Second, even for special hardware without the previous software limitation, it is usually only possible to obtain information for the cells of a single operator [13,14]. As it has been previously noticed [3], using weak signal strengths tends to make more harm than good.…”

“…The system works only with a specific phone able of providing to the applications the signal strengths of multiple GSM towers. Other works on GSM location also tend to use specific phones [3,14]. These works served as inspiration to UCLS.…”