Performance test of the CMS link alignment system

We have presented the conceptual principle of the CMS Link Alignment System and the details of the experimental set-up, installed at the 14 ISR hall, at CERN to validate the design. The experimental set-up reproduces one half of a Φ CMS alignment plane with the final dimensions and covers a surface of 20x17 m2. We have described the different instrumentation present in the system (including calibration procedures and results), the DAS and the reconstruction software. The set-up includes a network of reference points that are accurately measured by levelling and photogrammetry survey techniques. Link System measurements are compared with the survey data. Results from this first global test performed with all the link elements running validates the conceptual optomechanical design. Spatial and angular reconstruction precisions reached in the present experimental set-up are already close to the CMS requirements. (author)