A Gentle Intro to Indoor Positioning

Indoor Positioning, a fast-growing branch of the Internet of Things, has the power to remap the way we think about indoor spaces.

- Thanks to GPS, we always know exactly where we are.

We take this technology for granted today, but prior to the year 2000, when President Clinton permanently ended the military’s ability to reduce the accuracy of GPS for non-military users, people carried paper atlases in their cars and often had to stop for directions. It was a different world.

All that ends when you enter a building, though. GPS can’t see through roofs, so buildings – especially large and labyrinthine ones – are persistent reminders of what it was once like to navigate in the 20th Century.

Mapping indoor spaces

But Indoor Positioning, a fast-growing branch of the Internet of Things, has the power to remap the way we think about indoor spaces. With the right sensors, cameras, beacons, and software, we can track people and products everywhere you care to know about them.

As an example, consider MapsIndoors, an indoor mapping solution that marries Google Maps with common IoT indoor positioning beacons to let people locate themselves on a map in such places as convention centers, corporate offices, stadiums, and other venues.

Not all indoor positioning solutions are about finding people; there are a lot of important use cases for tracking products or other objects instead.

Amazon Go is Amazon’s retail industry experiment that does away with checkouts and lines, not unlike Apple stores. But unlike Apple – which still forces customers to flag down sales staff to ring up purchases, Amazon Go stores let you simply put products in your bag and walk out the door – in fact, “just walk out” is part of the company’s marketing message for the stores.

Finding the right solution

So how does indoor positioning work? Many solutions depend on some kind of RF transmission – like Wi-Fi or Bluetooth, for example – with software that triangulates positions based on parameters like signal strength or the time it takes the signal to be received.

But there are a lot of other positioning technologies as well. Ultra-wide band and ultrasonic tracking systems are on the rise. And physical items can be tracked with RFID tags or even computer vision – it’s really a matter of what your use case happens to be and the nature of the physical environment you’re configuring.

Wi-Fi, for example, is inexpensive to implement because Wi-Fi infrastructure is so ubiquitous. It also offers a long range and fast data transfers. Wi-Fi isn’t especially accurate, though, which means you can’t use it to locate people or objects in an indoor space with high precision.

At the opposite end of the spectrum you’ll find ultrasonic tracking. Ultrasonic doesn’t penetrate walls easily, so it’s especially good at precisely locating people and objects in a large multiroom structure.

Aiming for accuracy

Many other positioning solutions, like ultra-wide band and even RFID suffer the same kind of “bleed-through” problems as Wi-Fi, where it can be ambiguous which room something is in if it’s registering near a wall or door.

Computer vision has its own advantages – particularly accuracy – but uses an enormous amount of bandwidth compared to most RF beacons. Not only do you need to capture video, but a machine learning algorithm needs to process the image to understand what it is.

But if you’re wondering how Amazon knows what product a customer has put in their shopping bag, the answer is that it’s using, at least in part, computer vision to mind the store. Overhead cameras read a unique pattern of dots on the packaging to know what a customer has taken.

Which suggests that the indoor positioning solution for your facility depends in large part on the requirements for your use case.

No one size

Like any part of the IoT, indoor positioning is not one size fits all. You need to assess what you want to track: retail products, warehouse inventory, customers, and so on. The environment of the facility is also critical. Is it multi-room or multi-floor? Does the layout frequently change?

And, you’ll want to catalog your success criteria. You need to know the desired accuracy, if the data needs to be available in real time or processed later, and what kind of coverage you need in the facility.

There are a lot of factors to consider when implementing an indoor positing solution, but like the birth of GPS, it can completely revolutionize the way you approach your business within four walls.