Ultra-Wideband Positioning

Using extremely short radio pulses to measure signal flight time, for centimeter-level indoor ranging and positioning.

Ultra-wideband (UWB) is a low-power radio technology that occupies a very wide frequency band, defined by the US FCC as a bandwidth exceeding 500 MHz or 20% of the center frequency, whichever is smaller. Its pulses are extremely narrow, which allows precise measurement of signal flight time and makes it well suited to ranging: common approaches are two-way ranging (TWR) or time difference of arrival (TDoA), where a tagged device measures its distance to several fixed anchors, and geometry is used to solve for its coordinates, reaching centimeter-level accuracy, though this degrades with occlusion and multipath reflection. GPS doesn’t work indoors, so UWB is commonly used for warehouse robot localization, follow-me robots, and relative localization between multiple robots; phones from the iPhone 11 onward, and Apple’s AirTag, also have UWB built in.

ExampleUWB anchors are mounted in the four corners of a warehouse, and a transport robot carries a UWB tag; it measures its distance to each anchor in real time, solves for its position in the warehouse, and fuses that with wheel odometry.

Also called

UWB, UWB Ranging

Related

Multi-Sensor Fusion · State Estimation · Wheel Odometry · GNSS / Real-Time Kinematic Positioning · Autonomous Mobile Robot · Kalman Filter

Sources

Ultra-wideband - Wikipedia