I am returning to mobility problems in this post and especially for indoor environements. One of the most pressing issues for mobility impaired and vision impaired persons is the issue of getting around in unknown indoor environments. Getting lost, disoriented and even getting “trapped” in some circumstances can be quite a stressful situation for them.
Lately, a number of positioning techniques have been developed for indoor environments (e.g., the methods based on Wireless Local Area Networks (WLAN), Bluetooth, Radio Frequency Identification (RFID), Ultra Wideband (UWB), infrared and ultrasound, etc.). Among these techniques, the approach on the basis of exploiting 802.11 WLAN (Wi-Fi) is attractive, which is expected to yield a cost-effective and easy-accessible solution. All modern smartphones have Wi-Fi built in, and wireless networks are common enough in indoor spaces that an app could easily scan for known access points and calculate your position using trilateration . This is currently enabled in open operating systems of smart phones, e.g. in Android ones. As an alternative, there are some Wi-Fi installations in buildings, such as the ones based on Cisco MSE that can determine the location of any wireless device in the building. The Wi-Fi access points receive the Wi-Fi signals created by the mobile phone and then estimate its position via trilateration. Read the rest of this entry »