AirTag’s Technology: Ultra-Wideband, Bluetooth Low Energy, Near Field Communication, and Find My iPhone.
What Technology Does AirTag Use?
Apple’s new AirTag is a location tracker that uses iPhones to help find lost objects. Unlike cheaper trackers that only chirp, the $29 gadget relies on a distributed network of iPhones to locate an object.
That means that Apple’s installed base of 1 billion iPhones is a physical network that is constantly looking for your stuff. So what technology does the AirTag use to do this?
Ultra-wideband, also known as UWB, is a wireless communication technology focused on precise ranging and tracking. It uses low energy and operates on a wide portion of the radio spectrum, allowing devices to send pulses of radio signals to each other very frequently.
AirTags use this technology to communicate with your iPhone and transmit the location of the tag to your app. This is how your app can find lost keys or pets, for instance.
Like sonar, UWB calculates a device’s location by measuring the time it takes for short pulses of radio signal to travel from the transmitter, bounce off an object, and return to the receiver. The difference in time between the two measurements is then used to determine a device’s distance. Because of this, UWB is a very efficient and accurate way to locate items. It also allows for the use of small and inexpensive sensors.
Bluetooth Low Energy (BLE)
BLE is a wireless communication standard that consumes significantly less energy than traditional Bluetooth connectivity (classic Bluetooth) devices. It’s also a common feature of smartphones and mobile operating systems, so it doesn’t require specialized compatible hardware to use.
It’s the basis for retail geofencing, fitness wearables, smart home applications, and even Apple’s iBeacon offering on new iPhone models. Unlike classic Bluetooth, which only transmits data in packets over short distances, BLE sends periodic broadcast messages that allow nearby devices to detect the signal.
AirTag BLE signals are also picked up by the user’s iPhone, which uses a combination of network analysis and the U1 Ultra Wideband chip to zero in on an accurate location within about three feet. This makes it easy for event management companies to use the technology in ways that enhance the attendee experience. This could include gamification or auto check-ins, or providing recommendations during their visit to an attraction. The possibilities are endless.
Near Field Communication (NFC)
AirTags pair with their owners’ iPhones or Macs, sharing a cryptographic seed. They then start broadcasting Bluetooth Low Energy (BLE) advertisements every two seconds, like smoke signals, to anyone nearby with a compatible device.
The first couple of bytes in those messages indicate to iPhones and Macs that the message belongs to an AirTag, and those devices then relay those AirTag messages up to Apple’s ‘Find My’ network. They also grab any other relevant data such as GPS, Wi-Fi and the device’s battery status, encrypting and bundling it with the AirTag messages before relaying them up to the network.
All of this is powered by the swarm of iPhones around the world, which give AirTags amazing range and accuracy. Anyone who finds a lost item with an AirTag can tap it with their phone to get the owner’s contact information so they can reunite them. That’s a powerful use case for Apple’s custom U1 chip.
Find My iPhone
Apple’s Find My feature works by relying on a network of iPhones and iPads running iOS 14.5 and later to share location data with one another. When an AirTag emits a BLE signal, it automatically connects to iPhones in the Find My network and shares its location with them. The feature has been criticized for potentially being used to stalk people, but Apple has introduced a security update that notifies users of an unknown AirTag that is “following” them.
When a new AirTag pairs with its owner iPhone, it shares a secret public key and begins broadcasting time-sensitive BLE advertising messages every two seconds that can be picked up by anyone with an iPhone in the vicinity. This crowd-sourced location data is stored in iCloud and shared among Apple devices. When a device is missing, owners can open the Find My app to locate it by tapping on the AirTag and following the onscreen instructions.