Introduction to Bluetooth Direction Finding

Locating items or navigating indoors are functionalities with huge potential. Both have been possible with Bluetooth Low Energy for a long time using Bluetooth Beacons, but with limited accuracy. To improve accuracy and interoperability, the Bluetooth SIG introduced new features to the Bluetooth Core Specification.

The Bluetooth SIG introduced support for Direction Finding in the Bluetooth 5.1 specification. There are two major flavors, Angle of Arrival (AoA) and Angle of Departure (AoD). Both flavors provide angle information between a usually static and larger multi-antenna antenna array and a moveable single antenna unit. Nordic added full production support for both AoA and AoD with both transmitter and receiver options in nRF Connect SDK version 2.1.1. This support can be extended to build a full Bluetooth Direction Finding solution.