Mapping From Wi-Fi "Fingerprints" Could Improve Indoor Navigation

Korean researchers build maps from Wi-Fi signals collected by mobile devices, even if GPS signals are lacking

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Mapping From Wi-Fi "Fingerprints" Could Improve Indoor Navigation

With outdoor mapping tools widely available and generally successful (Apple’s recent mapping debacle being the exception that proves the rule), technologists are pushing forward the state-of-the-art in indoor navigation, likely to be a hot area for advances throughout 2013.

This week, KAIST, The Korea Advanced Institute of Science and Technology, announced a development that definitely is a step, so to speak, in the right direction: a new method to build a map from Wi-Fi radio signals without accompanying GPS tags or manual inputs of map coordinates. Most current systems need GPS signals to fully interpret the data coming from Wi-Fi routers.

Dong-Soo Han, a professor in KAIST’s Department of Computer Science, and his research team used software embedded in smartphone apps to upload a Wi-Fi fingerprint, that is, information about the current set of Wi-Fi signals and signal strengths available to the mobile device at that moment. Users were asked to input their home and office addresses. The mapping system developed linked the geographic coordinates of those locations to the Wi-Fi fingerprints most frequently collected by the smartphones, combining that information with those from other users to create an overall Wi-Fi radio map of a selected geographic area. Such maps could be used as the basis of indoor navigation or indoor location-based services (that, for example, send a coupon when you pass a particular restaurant in a shopping mall). Han’s team tested the system in four areas of Korea with mixed residential and commercial locations.

In a press release, Han is quoted as saying, "Although there seem to be many issues like privacy protection that have to be cleared up before commercializing this technology, there is no doubt that we will face a greater demand for indoor positioning system in the near future."

Mike Stanley, a systems engineer at Freescale Semiconductor, told Spectrum that “Using measured Wi-Fi signal strengths to develop Wi-Fi fingerprints is an area that has been receiving attention from researchers, and is certainly a valid approach for indoor environments."

Stanley grimly questioned, however, one possible use of Wi-Fi mapping information envisioned by the researchers, that is, for emergency rescue operations. It could be difficult, he pointed out, to find victims under piles of rubble using Wi-Fi fingerprints when the rubble “may very well contain the remains of the Wi-Fi base stations upon which they based their fingerprint analysis.”

Image: ST Microelectronics

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