Development of circularly polarized synthetic aperture radar on-board UAV JX-1

We developed L band (frequency 1.275 GHz) circularly polarized synthetic aperture radar (circularly polarized SAR) on-board unmanned aerial vehicle (UAV). This paper explains the configuration of system, antenna, and car-based experiment of circularly polarized SAR. The comparison of circularly polarized SAR and linearly polarized SAR by full polarimetric scattering experiment in anechoic chamber was done and discussed. The result shows circular polarization has less effect of orientation angle of target and could avoid the misalignment of transmitter and receiver antenna during UAV operation. Axial ratio and ellipticity images are also derived and introduced as novel classification technique in microwave remote sensing field using circularly polarized SAR or ellipticity characteristic of scattering wave.