Using Small Unmanned Aerial Systems and Helium Aerostats for Far-Field Radiation Pattern Measurements of High-Frequency Antennas

A new methodology is described for performing near-free space far-field radiation pattern measurements of high frequency and very-high frequency antennas to be employed as part of the radar science instrument system onboard NASA's planned Europa Clipper mission to Jupiter's moon Europa. Adapted from land-based measurements, this test methodology involves hoisting the antenna under test using a helium-filled aerostat above the earth to minimize ground interactions while flying a small unmanned aerial system (sUAS) with onboard RF measurement equipment package to map the far field radiation pattern. Prior to testing the technique using both airborne platforms - the aerostat and the sUAS - measurements are performed on the ground using the sUAS and a fixed VHF dipole over a ground plane to verify the methodology prior to incorporating the flying aerostat for airborne measurements of the HF dipole. These initial measurements have produced promising far-field pattern results with work remaining to fully adapt the fixed VHF antenna measurements to the dynamic HF antenna test setup that uses two airborne platforms (sUAS and aerostat) for measurements.