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.
The American Museum of Natural History has developed their own interactive Museum explorer that can be downloaded in an iPhone and based on Wi-Fi based positioning and navigation (see previous section for more info on this technology) to find your current location within the Museum, explore an interactive map, listen to digital guides and get real-time directions to your next exhibit, a café, or anywhere else in the Museum using the quickest route.
Also Google announced in November 2011 the new version of its Maps app for Android. The mapping and navigation software got indoor maps and navigation, allowing you to find your way around malls, airports, IKEAs and the list is expanding. Google Maps 6.0 is also said to be able to detect on what floor of the building you are and adjust the map data appropriately, so you will only be seeing what’s around you. According to the developers, the location algorithm is finely tuned, so it should work as well indoors as it does outdoors. In this way, there are already applications developed that can give spoken walking directions from Google maps (e.g. Walky Talky, Intersection Explorer) and can be of tremendous help to people with sight loss or navigation problems such as elderly people with dementia, Alzheimer or people with learning disabilities.
Given the widespread use of Wi-Fi in indoor spaces an indoor positioning solution based on Wi-Fi might be more feasible and cost effective than the one presented earlier based on sensors. It demonstrates that in order for an indoor navigation system to be successful there are two critical parameters.
- Not requiring any additional installation by using existing infrastructure on a building.
- Not requiring special devices and sensor systems on the client.
Although solutions like Wi-Fi positioning and navigation seem to be ideal for indoor spaces especially when it comes to public spaces, large stores, shopping malls, museums, theatres, airports etc. there are still a number of issues to deal with in the next years. Current location cannot be estimated accurately by indoor positioning systems based on trileration; therefore systems developed for indoor navigation should be designed in a way to compensate for that. This could be done by using data from other sensors like accelerometers, compasses etc. but in any case there is a need for further research in that direction to improve indoor positioning. Given that new mobile devices are usually sensor-packed and with better more powerful processors I guess that indoor posistioning systems based on combining all these data will start appearing soon.
This will certainly benefit persons with disabilites but not only them. It could also become a valuable gadget for everyoone else who’s sense of orientation gets messed up in indoor environments.