Redshift of the source (filled red circles) and that of the high-velocity blueshifted absorber (filled green symbols), against their input values in the simulations. Ten source redshifts are drawn from a uniform distribution between 2.4 and 2.6, while ten blueshifts are added from a uniform distribution bounded between −0.3 and −0.05. A large velocity broadening normalized to 3000 km s⁻¹ has been assumed for the high-velocity absorber. The spin of the source is assumed to be 0.5. For the reflection parameters, we assumed R_f = 1, A_Fe = 1. The flux of the source is 2 × 10⁻¹³ ergs cm⁻² s⁻¹, and the integration of the spectrum is 100 ks. See Sect. 4 for details. The 90% confidence level errors are plotted. The errors are less than 0.001 and 0.01 for the source redshift and UFO velocity, respectively.