In-Flight Calibration of the Measurement System for UAV-Based Near-Field Antenna Measurements

The measurement systems used for outdoor unin-habited aerial vehicle (UAV)-based near-field measurements are typically sensitive to environmental influences, such as temperature. These factors manifest as a drift in the measured signal over time. To detect and compensate such variations in UAV-based near-field measurements, we propose an in-flight calibration approach. This approach involves a near-field interpolation based on local measurements taken repeatedly around fixed reference points, eliminating the need for precise UAV positioning. The interpolation is achieved by solving an inverse source problem. Based on this interpolation technique, which is verified through several simulations, we give a flight strategy that allows for monitoring possible changes in the received signal. We test the effectiveness of the interpolation method using real measurement data.