awiloc®

Fraunhofer Institute for Integrated Circuits

How It Works

Baustelle

awiloc® technology by Fraunhofer IIS enables a continuous positioning by recognizing surrounding wireless LAN stations.

The self-positioning of mobile devices is based on a method known as fingerprinting. For this purpose signal measurements are taken at reference points, including all received wireless LAN stations and their corresponding receipt information. This receipt information only contains the measured signal strength of the existing wireless LAN base stations at the reference point.

Positioning through signal strengths patterns

The resulting fingerprint of the receipt information at reference points is then stored in a data base and used on the mobile device as a basis for its self-positioning. The Fraunhofer IIS positioning algorithm implemented on the mobile device calculates the current position continuously and independently by matching the measured receipt information with the reference information. Thus only the user knows the position.

The so-called MAC address serves for a technical distinction of measured signal strengths of wireless LAN stations. The SSID, assigned and possibly disabled by the user, is an uncertain information in terms of positioning. Therefore the positioning through awiloc® technology by Fraunhofer IIS is not hooked on the SSID as well as other information sent by wireless LAN stations, e.g. their encryption status – they are not needed and therefore not stored. A data exchange with the wireless LAN station is not performed. The position of the wireless LAN access point is unimportant and not determined.

Positioning in cities and buildings

Our stand-alone wireless LAN positioning in cities considers both commercial wireless LAN hot spots and private wireless LAN access points and works without registration or access to the data network. A robust positioning algorithm ensures a high degree of immunity to distorting influences such as the addition, removal, or relocation of wireless LAN access points.

Thus, positioning accuracy is totally unaffected by the addition of wireless LAN access points and it will be influenced only if the number of wireless LAN access points in a common city surrounding is reduced by more than 50%. While accuracy will be diminished if access points are moved, continuous positioning means that there will be no major errors or dropouts.

The solution developed by Fraunhofer IIS enables continuous positioning even in multi-story buildings or underground facilities. By the use of an environment model it is possible to integrate semantic information and to add functionality such as structural feature identification. Indoor positioning accuracy usually varies between 1 and 5 meters (depending on the type of environment, e.g. office building or production facility). Outdoors, positioning accuracy averages around 10 meters while also varying with the environment: The more densely built up an area, the better the performance of Fraunhofer IIS's wireless LAN positioning technology – a characteristic that makes this solution the ideal complement to GPS.

The implementation

awiloc® technology by Fraunhofer IIS for wireless LAN positioning is a purely software-based solution that can be easily integrated into mobile devices. Location Based Services are feasible both as local services on the mobile device and as network-based services.