Ultra Wideband (UWB)
While Bluetooth Low Energy is currently the most widely used technology for indoor position tracking, a new technology is making substantial progress in transforming the space. Ultra Wideband (UWB) is already being utilized for applications in which radio frequency interference occurs.
UWB was originally used for personal area networks, and appeared to be WiFi’s competitor. However, the technology is now being used as an affordable and low-energy solution for indoor positioning. UWB operates at a frequency greater than 500 MHz. The FCC limits the range for commercial use from 3.1 GHz to 10.6 GHz in the United States. UWB is unique in that it uses frequent pulses at specific time intervals to carry information rather than power, frequency or phase modulation to encode the messages carried by the signals. This prevents interference with other radio signals in the same spectrum by allowing for transmissions across a wider bandwidth.
UWB tracks location by using Time Difference of Arrival (TDOA). A UWB system can be designed such that a minimum of three networked receivers for 2D locations and four for 3D locations can be placed at various points throughout the building. Once assets are embedded with UWB transmitters, they can be tracked using the omnidirectional signals that are emitted. The distance from the transmitter to the receiver causes the signals to arrive at the receiver units at different times. The location is then pinpointed by comparing the varying times of signal arrivals and distances.
UWB’s design enables large amounts of data to be transmitted using much less power. While the transmissions have a shorter range, UWB can be used alongside multiple well positioned receivers for indoor position tracking.
The technology promises to give users the ability to see through walls and other obstacles. UWB radar can recognize the presence of people or objects on the other side of barriers by detecting distortions to the reflected radio waves caused by breathing or heartbeats. An interesting application of UWB radar could be as an on-board sensor for cars as part of a traffic management system. The signals would not interfere with each other so many could operate within close proximity of each other.
While the technology is not as widespread as other wireless standards, it’s important to consider UWB when designing an indoor positioning solution.