Fig. 9
From: Investigation of geomagnetic reference models based on the Iridium\(^{\circledR }\) constellation
Main field and secular variation spectra for the 6-satellite Iridium model and the quasi-definitive observatory model. Left panels show the spectra at the 2018 model epoch and right panels show the spectra for the models extrapolated to 2013. The dashed lines indicate spectral differences with respect to CHAOS-7.2