Mean equivalent source shift as a function of angular distance from the nearest calibrator caused by inference errors from the ground truth for panel a: remote stations (RS; > 3 km from the reference antenna) at nominal conditions (30 calibrators for 12.6 deg² and 1 mTECU noise), panel b: core stations (CS; < 2 km) at nominal conditions, panel c: RS with sparse-and-noisy conditions (10 calibrators for 12.6deg² and 2.6 mTECU noise), and panel d: CS with sparse-and-noisy conditions. The solid line styles are the best competitor models (see text), the dashed line styles are the physical model. The red lines are dawn ionospheres, and the blue lines are dusk ionospheres.