Radar cross section measurement of unmanned aerial vehicles

A radar cross section (RCS) measurement method is developed in a far-field antenna range. Through rigorous calibration measures and comparisons with targets of known RCS values, the tangible RCS levels can be reduced to a small value that the unmanned aerial vehicles (UAV), which is in general retain a small RCS, can be assessed. A UAV of plastic chassis is measured. Its sizes are 30 × 30 × 20 cm3. The measurement results, as expected, suggest the back scattering RCS of a UAV is a function of the incident angle. According to its angular variation, reflections from a compact UAV are mainly contributed by its battery pack and its system board. However, ripples are observed in gated frequency domain results, which suggest the presence of multiple scatters. By considering the fading effect of multiple sources, the UAV RCS values can be estimated, which are between -15 to -5 dBsm in the X-band range.