Abstract: A beacon uses a plurality of co-located, unidirectional antennas each to transmit angular and/or ranging reference signals from substantially the same point. In some embodiments, two such antennas transmit the reference signals in substantially opposite directions, and in some embodiments four such antennas transmit in directions that are substantially at right angles to each other. In some embodiments, the transmitted signals overlap so they can be received at a single receiver. Some implementations include a receiver that interprets the reference signals from two or more of the co-located antennas to determine the direction of the receiver is in relative to the beacon or the location of the receiver relative to the beacon. Another implementation uses an omnidirectional antenna to provide ranging information and a rotating, unidirectional antenna to provide directional information. In some of these implementations, the antennas are co-located, while in others, they are separated in space.