What are the technologies available for Real Time Location Systems (RTLS)?

And what are some considerations for using one over another?

I’ll start with the active tags. Active tags usually are pulling location data from some infrastructure in the ceiling - which is much like wireless access points, except they are just sending out timing pulses for the most part. An active tag can cost anywhere from $10 to $100, depending on whose you’re buying.

Then you have to put an infrastructure in, typically on the ceiling, sometimes on the walls, that the tags can then talk to. We call them anchors. And the anchors can talk to each other and configure each other, or you can have to manually set that up. It really depends on system architecture.

Active systems are typically for bigger customers because the installation and configuration is more expensive than the system components. And of course the whole thing is based on needing to get all that information, to a local server to drive some local process. If you’re looking for an active system, you’re probably a Fortune 500 kind of company doing a business intelligence kind of deployment.

If anybody is interested in that kind of thing, the first place I would go - knowing you’re going to write a check with a lot of zeros - is to Seimens. They have, what I consider, the best technology out there. When it’s operating at 2.4 GHz, you can get to around a 1 - 2 meters very consistently. And then, if you actually need better than that accuracy, which a lot of Seimens’ customers do, it can switch to 5.6 GHz - and you can get centimeter type accuracy. It’s a real deployment, for big corporations that are doing major installations.

So that’s active tags.

The first real time location systems used WiFi. And WiFi is actually still valid if you have a campus and you just want to know which building a certain physical asset is in. The ROI on it is actually very good.

You get what is called a location engine that would bolt right into the high end routers. Then you put the WiFi tags on whatever your assets are and they basically just keep track of what access point it was attached to. A big campus will have lots of access points and they could tell you fairly accurately where you can go find, for example, the x-ray machine.

WiFi-only systems didn’t pan out. In the mid-1990s to mid-2000s it didn’t have accuracy for places like hospitals. Just knowing it was on this wing and that building was not accurate enough for a lot of applications out there.

And then what most people are talking about these days is self-meshing Bluetooth technology.

Basically what you do is create a Bluetooth beacon. And they cost literally anywhere from $3 to $12, with decent quantities getting you somewhere in the $7 to $10 range.

With self-meshing Bluetooth, you don’t need an infrastructure throughout your building. You can just stick these buttons up, on every pole or whatever doesn’t move, and they become the fixed part of the mesh. And then you attach the same beacons to objects you want to track, and the magic code that does the self meshing also then allows a gateway to collect the topology of that meshing and give you location data.

It turns out to be very economical. The installation couldn’t get simpler. You get a guy with a roll of double stick duct tape and a box of buttons, and you send him out there to stick them on every pole and anything that doesn’t move.

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