Tracker Alignment Strategy in CMS and Experience with Cosmic Ray Data

Aligning the CMS silicon tracker is an unprecedented challenge due to the more than 15~000 modules that it is composed of. Besides high precision mounting, survey measurements and the laser alignment system, track based alignment is needed to reach the envisaged precision. The first successful full scale alignment study on simulated data uses a fast global minimisation procedure implemented in the Millepede~II program. Tracks from cosmic ray muons and the inclusion of prior knowledge are key ingredients. Experience beyond simulation studies is gained analysing real data from cosmic ray muons.