Systematic effects are modeled to improve the localization and its precision. Effects that are not modeled are empirically included using a dataset of pulsars and FRBs with a known position. In the following, the correction for systematic effects is described.

Temperature correction

Variations in temperature cause a thermal expansion of the cylinders along the S-N axis. As a consequence, formed beams point in different y-directions than expected. This is solved by measuring the temperature at CHIME at the time of a specific event and correcting for the expansion here. In the equation for the expansion, the coefficient has been measured by the Cosmology team (Seth, private comm.). The initial temperature has been evaluated with the pulsar test sample described below.

Temperatures at CHIME are measured by (to be continued...)