Average systematic bias, the expected thermal noise and the error on the thermal noise as a function of observation time for three different regions in the 2D power spectrum space: The foreground dominated region in panel 1 (k_∥-bins < 0.2 h Mpc⁻¹), the short baseline region, where diffuse Galactic emission is prominent in panel 2 (k_∥-bins > 0.2 h Mpc⁻¹ and k_⊥-bins < 0.1 h Mpc⁻¹) and the noise dominated region in panel 3 (k_∥-bins > 0.2 h Mpc⁻¹ and k_⊥-bins > 0.1 h Mpc⁻¹). In orange we show the expected thermal noise, in dashed black the error on the thermal noise as a function of integration time and in blue and purple the systematic bias for matched PSO and mismatched sky model calibration, respectively.