The CMS alignment system

The optimal reach on momentum resolution for high-energy muons requires a precision in the alignment of the CMS muon stations with respect to each other as well as a global alignment of the muon system with respect to the inner detector with precisions that run from 100 to 500 μm. Due to the considerable movements and deformations originated by magnetic forces, heavy loads and thermal effects foreseen, the implementation of an online monitoring system is needed.