Kavli Affiliate: Jeffrey McMahon | First 5 Authors: Maximilian H. Abitbol, David Alonso, Sara M. Simon, Jack Lashner, Kevin T. Crowley | Summary: We quantify the calibration requirements for systematic uncertainties for next-generation ground-based observatories targeting the large-angle $B$-mode polarization of the Cosmic Microwave Background, with a focus on the Simons Observatory (SO). We explore […]