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How Wi-Fi Location Works in PERS Devices

Nov 27, 2019 8:00:00 AM

How good would a fall detection device be if EMS couldn’t locate the user? Not very useful. Location services, and more specifically, Wi-Fi location help pinpoint where the user is in the event of a fall. But how exactly does Wi-Fi location work?

What is Wi-Fi location?

You might be thinking that GPS is the technology that finds your location. While that statement isn’t wrong, it’s not the only way to determine a user’s location. Wi-Fi access points can also be used to pinpoint a user’s location, especially when indoors. GPS can struggle with obstructions such as buildings or bad weather, making it harder to determine a user’s location. Sometimes PERS devices, along with any technology for that matter, can simply become old and outdated, and the GPS in those devices might begin to fail. Wi-Fi location can help step-in and allow for the location of the user to still be determined.

How Wi-Fi Location Works

Networks can use Wi-Fi access points such as SSID and MAC addresses to narrow down where a user is located. What happens is the device scans local networks for public information to determine which network it is. This information is recorded and can be used for later use.

When a user is indoors, Wi-Fi can be used in four different ways to help determine the position of a user:

  • Signal intensity - Depending on the strength of the signal, RSSI technology can determine where the user is in relation to the access point.
  • Fingerprinting - This is a term used when signal strength location is stored and can later be used to determine a user when networks are offline.
  • Angle of arrival - This uses multiple access points and antennas to determine the path of the signal and triangulate the location of the user.
  • Time of flight - This processes measure when the signal was received and can estimate the distance and position of the device from the access point.

So, what does that mean? Let’s use a real-world example to explain. A person wearing their PERS device goes to a department store (people still shop offline). If the device has GPS, it might have trouble locating the device because the building is obstructing the signal path from the satellite to the device. Bad weather can also cause interruption in GPS signaling. But since the device has been storing known Wi-Fi access points, the user can still be found using that information.

One thing to keep in mind is that if there isn’t any Wi-Fi around, Wi-Fi location services will not work.

Why Wi-Fi Instead of GPS

The header is not suggesting that you should ditch your GPS enabled device for Wi-Fi location services. Instead, the two technologies can work in tandem with one another, picking up where the other leaves off. If you have a PERS device, but you like to often go outside and far away from urban areas – on hikes for instance – it’s a good idea to have a GPS enabled device to track your location when out in the open. Where Wi-Fi can really assist is indoors. Like the scenario above, where GPS struggled, Wi-Fi can help fill in the void. This location service can be exceptionally useful in a multi-story building. Wi-Fi can locate where a user is in a multi-story building and give EMS a better indicator on where the user is located as opposed to GPS, which is unable to do so.

Check to see if your PERS device has Wi-Fi location or both GPS and Wi-Fi location. And if you are looking for a company to monitor those PERS devices, reach out to AvantGuard, one of the industry leaders in monitoring security, IoT, PERS and fire.

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