Measurement of Transmitted Differential Phase on Polarimetric Radars

A measurement procedure to determine the transmitted differential phase between horizontally and vertically polarized radiation of a dual-polarization radar is presented. It applies to radars that transmit and receive simultaneously horizontally and vertically (SHV) polarized waves. The method relies only on power measurements and leverages the capabilities of polarimetric radars with independent transmitters per polarization to estimate the differential phase of transmission. Measurements using this method by ground and airborne systems are conducted, and results are validated using a software-defined radio (SDR) that provides true phase measurements. The differential phase estimate produced with the proposed method for the PX-1000 (X-band) radar is
$-105\,\,^{\circ }$
, while that produced with the SDR is
$-104.47\,\,^{\circ }\,\,\pm $
4.43 °. The proposed method with a simple power sensor achieves a precision of ±2.5 °.