  The Muon Ionization Cooling Experiment (MICE) will perform a detailed study
of ionization cooling to evaluate the feasibility of the technique. To carry
out this program, MICE requires all of its detectors to reconstruct space
points in a globally consistent fashion. The beam-based alignment constants
were found to be more accurate than the survey for the scintillating-fibre
trackers lodged inside the bores of the superconducting magnets. This alignment
algorithm can achieve unbiased measurements of the trackers rotation angles
with a resolution of 6 mrad/$\sqrt{N}$ and of their position with a resolution
of 20 mm/$\sqrt{N}$, with $N$ the number of selected tracks.
