Overview

The tools presented here (Loclib, Loctrace, Locana, and Loceva) are part of the ongoing mobile business research project at the University of Mannheim, Germany. The mobile business research group focuses on location-based and context-aware applications.
Our paper entitled "Loc{lib,trace,eva,ana}: Research Tools for 802.11-based Positioning Systems" describes our research methodology and tools in more detail.

During recent years we have seen considerable improvements in down-sizing computer hardware and in increasing the capacity of rechargeable batteries, as well as the advent of wireless networks for the mass markets. These technologies allow manufacturers to build mobile devices that have a similar performance as desktop computers had several years ago. The benefit of mobile devices can be leveraged by so-called location-based services: Applications that act differently depending on the location of the user, or, even better, proactively offer location-dependent information to the user. Location-based services are currently a hot topic in research, and are considered to be a promising market.
Many recent research activities focus on IEEE 802.11-based positioning because almost everywhere, especially in occupied areas of developed countries, 802.11 network infrastructure is available for data communication. Universities, offices and many private homes utilize 802.11 networks to get rid of wires. As a reaction to the proliferation of 802.11, almost all modern mobile devices ranging from smartphones to laptops are shipped with built-in 802.11 network interfaces. 802.11 networks are not only used in indoor scenarios; even outdoors, many universities and coffee shops support nomadic users. Furthermore, 802.11 radio waves tend to travel outside the intended area covering adjacent regions as well. For instance, an access point deployed at a private home is often detectable while passing by. Finally, 802.11-based positioning systems show sufficient positioning accuracy to be useful for a wide range of applications.
The most promising 802.11-based positioning systems utilize the so-called fingerprint approach. This technique comprises two stages: An offline training phase and an online position determination phase. During the offline phase, the signal strength distributions are collected from access points at pre-defined reference points in the operation area. They are stored in a table together with their physical coordinates. An entry in this data-set is called a fingerprint. During the position determination phase, mobile devices sample the signal strengths of access points in their communication range and search for similar patterns in the fingerprint data-set. The best match is selected, and its physical coordinates are returned as position estimate.
We provide the tools to the community hoping that they will be widely used in the future. The benefit for the community is considerable: First, researchers can save time because the software to trace signal strength and process data are already in place. Second, the confidence in the correctness of the tools increases because everyone is able to confer the source code and fix bugs. Third, a unified process of collecting data and processing it makes research results mutually comparable. And finally, we hope other researchers extend our set of tools.

The head of the research team is Thomas King. However, a large number of students contributed to the project:

• Alexander Biskop
• Sabine Baumann
• Andreas Färber
• Hendrik Lemelson
• Christian Lubberger
• Mehmet Suerue
• Alexander Hanschke
• Philip Mildner

All tools presented on these websites (Loclib, Loctrace, Locana, and Loceva) are released under the GNU General Public License. Please respect our work and abide the license.