Fully Automated HF antenna pattern measurements using low cost UAVs

Sammanfattning

HF (High Frequency) is an important component in long-range communications. As sizes on practical HF antennas are very large, measuring the far-field properties of these antennas presents inherent challenges. The traditional method has been to use helicopters carrying a receiver to measure the antennas far field radiation pattern, but this is a very expensive process. More and more studies are made revolving the use of small efficient unmanned aerial vehicles (UAVs) as a substitute for the older practice, however still expensive due to the receiver’s weight. Recently, it has been confirmed with the reciprocity theorem that using a small and affordable UAV carrying a light-weight transmitter to measure the radiation pattern of a stationary antenna with a receiver is feasible. Nonetheless, the data collection and processing has been handled manually, therefore not applicable for measurements with large amount of data points. In this thesis, the automation using computer processing is introduced. By implementing a combination of the extracting digital signal strength measurement from the receiver, image meta-data, and waypoint system, an automated measurement without any manual step in data collection and processing can be made. While the automation works as intended, several problems appeared to have an affect on the accuracy of test results. These issues and their possible solutions are discussed in the discussion part of this thesis.