Direction-of-Arrival Estimation Using a Low-Cost, Portable, Software-Defined-Radio-Based Phase Interferometry System [Education Corner]

This article presents the design of a portable, compact radio system for locating transmitters in real time. The system is based on the concept of a multibaseline additive interferometer and has a custom interferometric antenna configuration using a single low-cost, software-defined radio (SDR) as the receiver. It can tune to frequencies within the 5 GHz industrial, scientific and medical (ISM) band (5.725-5.875 GHz) and is capable of switching the antenna configuration between either of the two baselines or a single antenna. The system can be used to reliably locate a transmitter and compute the delay-spread profile of a received signal.