Implementations of Coherent Software-Defined Dual-Polarized Radars

Software-defined radio (SDR) platforms represent a compelling solution for low-cost, flexible, dual-polarized radar systems. However, the phase coherency requirements of a dual-polarized radar system between the transmit ports and between the receive ports as well as between transmission and reception, are difficult to attain in popular SDRs. In this paper, we provide high-level overviews of SDR radar systems, dual-polarization radars, and system phase calibration procedures found in literature. The method adopted to achieve coherency involves a manual calibration procedure, which is applied to four dual-polarized radar system configurations designed around commercial off-the-shelf SDR platforms. The implemented, calibrated designs were exercised in a laboratory setting to determine the coherence performance of the SDR-based radar architectures in characterizing a fixed target's full-polarization scattering matrix.