Range-Doppler Mapping of Space-Based Targets Using the JRO 50 MHz Radar

The Jicamarca Radio Observatory (JRO) two-dimensional square array radar system operating at ~ 6-m wavelength was used to study the Moon and low Earth orbit satellites using the Range-Doppler inverse synthetic aperture radar technique also known as Delay-Doppler imaging. The radar data was collected on Oct 21, 2015. A circularly polarized coded pulse was transmitted from a quarter-array antenna segment during lunar transit over JRO. Dual-linear polarization receive systems were employed on two quarter-array segments and on two 1/64th array modules giving the longest possible baselines across the transit path. A Range-Doppler mapping technique that uses the rotational motion of the targets and an autofocusing motion and ionospheric delay compensation technique has been implemented to generate the two-dimensional maps of the point-target (Satellite) and range-spread target (Moon). A review of our technique and the maps obtained from these observations is presented herein. Range-Doppler maps of the Moon and satellites are instructive with regards to possible further improvement of the technique, especially regarding ionospheric compensation.