Ultra-wideband (UWB)
Also known as: UWB, ultra wideband, ultrawideband
Ultra-wideband (UWB) is a short-range wireless technology that sends very brief pulses across a wide range of radio frequencies, letting devices measure distance and direction to each other with accuracy down to roughly 10 centimetres.
It powers precision finding for item trackers, digital car keys that unlock as you approach, and quick sharing between nearby phones. While UWB is far more precise than Bluetooth for locating things, it uses more power and needs both devices to have UWB chips.
Ultra-wideband (UWB), explained at three levels
At home
Imagine finding a friend in a dark room by clapping and timing how long the echo takes. Ultra-wideband does something similar with radio. Your phone sends extremely short radio pulses to a tag, the tag replies, and the phone measures the round trip in billionths of a second. Because radio travels at a known speed, that timing shows the distance to within about 10 centimetres.
At work
Ultra-wideband is a short-range radio technology built for measuring distance and direction precisely, rather than for moving lots of data. Businesses use it to track tools, equipment, and people indoors, and for digital keys that unlock a door or car only when the authorized phone is truly nearby. It matters where knowing the exact spot of something saves time or prevents theft.
At home
Normal radios send a steady signal on a narrow band of frequencies. UWB sends pulses lasting about two nanoseconds, spread over a band at least 500 MHz wide, usually around 6.5 or 8 GHz. Those sharp pulses make it easy to time exactly when a signal arrives, even in rooms full of reflections. Phones with several antennas also measure the tiny difference in arrival time between them, which gives direction, not just distance.
At work
UWB location systems work in two main ways. In two-way ranging, a phone or tag exchanges timed messages with another device, which is how digital keys and item finders work. In real-time location systems, fixed anchors on walls listen for tags, and a server compares arrival times, called time difference of arrival, to compute positions. The IEEE 802.15.4z standard adds scrambled timestamp sequences that make distance readings hard to fake, which blocks relay attacks on car keys.
At home
While UWB's precision makes finding keys easy, it also makes item trackers good at following people. Apple's AirTag and similar tags rely on nearby phones over Bluetooth to report location widely, and UWB adds the final few metres of precision. That combination led Apple and Google to roll out shared unwanted-tracker alerts in 2024 that work across iPhone and Android. In my opinion, those alerts are an important safety feature, and worth leaving on.
At work
A UWB deployment's accuracy depends on geometry. Anchors need clear lines of sight and good spacing, typically every 10 to 30 metres, and metal shelving or bodies cause reflections that skew readings. Tags trade update rate against battery life. UWB channels overlap Wi-Fi 6E and Wi-Fi 7 in the 6 GHz range, and power limits and allowed channels vary by country, including under ISED rules. FiRa certification aims to make different vendors' devices work together, and tracking employees needs a clear privacy policy.
Real-world examples
At home
Thomas misplaced his keys in his Saskatoon apartment. His phone pointed an arrow toward the couch and showed the tracker was under a cushion two metres away.
At work
Fatima manages operations at a Mississauga hospital. A UWB tracking system lets staff find infusion pumps and wheelchairs instantly, cutting time spent searching for equipment.
How it compares
| feature | Ultra-wideband (UWB) | Bluetooth Low Energy |
|---|---|---|
| Location accuracy | Around 10 cm | Metres |
| Direction finding | Yes, precise | Limited |
| Power use | Higher | Very low |
| Device support | Newer high-end phones | Nearly everything |
UWB pinpoints. Bluetooth gets you in the neighbourhood.
For analysts
For asset tracking, I'd only pay for UWB's precision if knowing the exact spot matters. Bluetooth tags often deliver most of the value for a fraction of the cost.
History & origin
Pulse-based radio ideas date back to early radio experiments, and UWB was studied for military radar for decades. The US FCC authorized unlicensed commercial UWB use in 2002, and the technology was first pitched for fast wireless USB connections, which failed commercially. IEEE standards for precise ranging, 802.15.4a in 2007 and 802.15.4z in 2020, refocused UWB on location. Apple put its U1 UWB chip in the iPhone 11 in 2019, and Samsung added UWB to Galaxy phones in 2020. The FiRa Consortium formed in 2019 to promote interoperability, Apple's AirTag launched in April 2021, and carmakers began adopting UWB digital keys under the Car Connectivity Consortium's Digital Key 3.0 specification. In my view, UWB is a great example of a technology that failed at its first job and found a better one.