The best-known use of UWB today is probably connected with smart phones. Those of you who own an iPhone 11 or later have a UWB module in your phone that can communicate with other UWB radios through a standard protocol known as IEEE 802.15.4z.
The ability to communicate is not what sets this radio apart from the other half-a-dozen radios present in your phone. It’s the ability to accurately measure the distance to another UWB radio that justifies adding another standard to your phone.
More precisely, the ability to determine a maximum distance accurately and securely between two radios (often called “secure range bounding” or “secure distance bounding”).
This ability is crucial for applications such as keyless entry systems for cars or buildings, and for contactless payment terminals where customers can pay without entering PINs or other credentials. But it requires active radios on both sides, often known as “anchors” and “tags”.