How the ultra wideband technology that locates your objects works

With the officialization of its Airtag tags, Apple has put the spotlight on a technology hitherto largely unknown to the general public, ultra wideband (UWB). We explain to you what is behind this abstruse term.

The Beacon War has begun. With the officialization of AirTag, these small accessories supposed to help you find your keys or your wallet, Apple is settling in a new sector where competition is already tough.

Until now dominated by the American Tile, which markets accessories of the same name, the connected beacon industry has seen a second breath in recent years with the arrival of Samsung’s SmartTag + then Apple AirTags.

How to explain this sudden resurgence of interest in these small accessories? Well, it’s because the industry is rediscovering an old, very practical radiocommunication standard: ultra wideband (UWB or Ultra Large Bande in good French) which theoretically allows ultra-precise indoor localization. We tell you all about this technology that equips the new generation beacons from Samsung or Apple.

What is the Ultra Wide Band?

For simplicity, UWB is a radio communication technology just like Bluetooth or Wifi. Used since the 1960s, this technology has long remained unknown to the general public, who rather discovered the joys of wireless Internet via Wifi or remote communication via Bluetooth. It is only recently that consumer accessories have started to use this system.

But unlike these two technologies which uses the 2.4 GHz band, the UWB is spread over a very wide band (hence its name) ranging from 3.1 to 10.6 GHz. This specificity allows it to be very versatile and not to be disturbed by other domestic waves.

What’s the point ?

Until now the UWB has been widely used in industrial environments to locate goods in warehouses. Because the major interest of this technology is to offer a very fine indoor location, where the GPS waves are much less precise.

The Samsung tag like that of Apple offers an augmented reality view to find your objects // Source: Samsung

It is this aspect of the UWB that is talked about a lot today. The technology has left the warehouses to find its way into the Samsung and Apple beacons that promise to help you find your most precious possessions, thanks to ultra-precise location (to the nearest fifteen centimeters) and capable waves. to cross obstacles.

How it works ?

« UWB works a lot like walrus. A transmitter will send pulses in the form of a wave and this wave will then be read by a receiver which will interpret the data »Explains Mickael Delamare, doctoral student, mechatronics engineer and author of scientific publications on the UWB. « Unlike wifi waves which will be sent as a continuous wave, the UWB sends a short pulse on several frequencies, so that even if some frequencies are “lost” the others will reach the receiver. And depending on the time it took for the signal to reach the receiver, the distance separating it from the transmitter can be evaluated. »

This calculation method called “time of flight” is already used on some smartphone cameras. A laser on the back of the mobile sends an infrared signal and measures the time required for its return to create a harmonious background blur (the longer the signal takes to return, the farther the target is and therefore the more dense the blur will be. ).

What are the advantages ?

Unlike Bluetooth and Wifi, which are designed to transport a lot of data, but over a fairly short distance, the UWB does not transport much data over long distances.

« Areas of up to 50 square meters can be covered very precisely », Specifies Mickael Delamare. On top of that ” as soon as a beacon is in direct line of sight, 15 cm of precision is reached “And not to spoil anything UWB objects (beacons and telephones) are at the same time transmitters and receivers, result” the more objects there are, the more precise the location will be thanks to triangulation »Adds the doctoral student.

Apple’s solution to efficiently find your belongings // Source: Apple

It is this cocktail of characteristics that allows Apple to sell its lost and found system, which potentially has hundreds of millions of mesh points. In addition to showing you how far you are from a beacon, the UWB can also show you the direction, making it easier to find lost keys. Samsung and Apple also rely on the camera of their smartphones to indicate in augmented reality where your belongings are.

Does it work with everything?

Non. Interoperability is unfortunately one of the weak points of the UWB. No standard has yet been imposed, which leaves the field open to manufacturers to operate their own in-house implementation. As a result, the precise location of an Apple beacon cannot be read by a Samsung phone despite the fact that the brand’s latest high-end mobiles do indeed have a dedicated chip for the UWB.

« The UWB is a closed system to know who sends what information», Specifies Mickael Delamare. In the case of Apple and the Airtag, it is the famous U1 chip present in the latest iPhones which is responsible for this decoding.

But then, is it the future?

On paper the UWB therefore has many advantages, but its price remains high for the moment and the lack of interoperability risks complicating its deployment. Apple’s entry into this sector could, however, reshuffle the cards, rekindle interest in this technology, and who knows, perhaps make it a cornerstone of the mobile world in the near future.

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