occupancy location sensor with wifi?

[completelyhis]

I have a friend in the medical industry who told me they use a wifi and software solution that can pinpoint the location of any wifi device. it measures signal strength from multiple access points and determines the location of the device. he told me to check out

http://www.arubanetworks.com/

and

http://www.ekahau.com/?id=4500


Is anyone familiar with this? I'm sure it would be way too expensive for the average bear, but I thought it was interesting.

[anogee]

Yes, I know the company (Aruba) and application well. I've spoken to the company since I follow this technology.

The devices are relatively expensive and they support voice calling as well as location. They require a fair number of access points to determine location and it has to be their access points with controllers, but since hospitals already have Wi-Fi, hospitals need all these access points anyway, so they are used for dual purpose; Wi-Fi access and employee location and communication.

[Stevech]

I too am familiar with these and a couple of other companies' products. Have purchased/used some.

Problem with signal-strength based approaches are:
1) requires heavily overlapped coverage among 3+ access points. Uncommon as it wastes money
2) relies on a survey of signal strengths using a reference device. Later, if there are large changes in furniture/walls/cubicles, the survey has to be re-done.
3) none of these do an adequate job of estimating the floor no. correctly.

the time-of-arrival (TOA) based approaches, e.g., Aeroscout, work better indoors, in some situations.

Same ideas are done with UWB rather than WiFi bu Ubisense and Time Domain.

all are $$$$$$$$$$$$