On the Use of Unmanned Aerial Vehicles for Antenna and Coverage Diagnostics in Mobile Networks

The capability of in-situ antenna measurement and diagnostics using a compact low-cost unmanned aerial system is presented. An onboard power sensor collects amplitude-only measurements, which are processed by means of an iterative phase retrieval technique. This technique allows recovering an equivalent currents distribution, which characterizes the antenna under test (AUT). These currents can be used for antenna diagnostics as well as to evaluate the field radiated by the AUT. In the field of mobile networks, the proposed system is of interest for rapid assessment of the antenna's operational conditions, providing radioelectric coverage within the mobile network cells and allowing the evaluation of antenna failures, such as incorrect tilt or beamforming/ feeding network malfunction. A proof of concept of the system is conducted for testing a commercial base transceiver station antenna under normal and malfunctioning operation conditions, discussing the extension of the system to allow measurements at millimeter-wave frequency bands.