The RADARSAT Constellation Mission (RCM) launched on the 12 th of June 2019 is equipped with three SAR satellites (RCM1, RCM2 and RCM3) flying in a constellation configuration. Each SAR is equipped with Compact polarimetry (CP) capabilities. It is now admitted that the actual SAR technology does not permit the generation of a perfectly circular polarization and this may significantly affect CP information [1], [2]. Recently, a new CP calibration model [2], which explicitly takes into account the non-circularity of transmitted polarization, in addition to polarimetric antenna distortion matrix and channel imbalances, was introduced and validated using ALOS2 CP data. In this study, the Touzi CP calibration model [2] is extended to the RCM. The extended Freeman-Van Zyl calibration method introduced in [3] is used for the measurement of the RCM polarimetric distortion matrices using RCM data collected over (3.5m) corner reflectors (CR) deployed at the CSA calibration site (Saint-Hubert, Québec). It is shown that the three RCM satellite antennas are highly isolated with a cross-talk lower than -40 dB. This permits a simplification of the Touzi CP model and its use as the basis of a convenient method for measurement of RCM CP axial ratio (AR) using Amazonian rainforests. The Touzi CP calibration model is used to setup the requirements on CP calibration. Since the baseline RCM CP calibration method is based on the Freeman calibration model [4], which assumes that the transmitted circular polarization is perfectly circular, the new requirements setup on CP calibration leads to the conclusion that the current RCM calibration meets the CP requirements for all the RCM beams with AR lower (or equal) than 0.5 dB (5m-CP2-to-14, and 30mSC beams within the incidence angle range 20°-to- 43° ). A new calibration method based on the Touzi RCM CP-calibration model is developed (and validated) for the correction of the non-circularity of RCM CP beams with AR larger than 0.5dB.