Bluetooth Angle of Arrival (AoA) and Angle of Departure (AoD) are new technologies that establish a standardized framework for indoor locationing. With these technologies, the fundamental problem of locationing comes down to solving the arrival and departure angles of radio frequency signals.

In this paper, we explain the basics of these technologies and give some theory for estimating direction of arrival. Currently the Bluetooth AoA/AoD specifications are in a mature state but not yet public. Therefore, this paper will only cover the general concepts without going into the details of the specification.