ATLAS inner detector alignment

ATLAS is one of the four experiments under preparation for the LHC accelerator at CERN in Geneva. The reconstruction of charged particle tracks will be performed by the Inner Detector, consisting of silicon-based and drift-tube-based detectors. To achieve the physics goals of ATLAS, the system with its almost 36000 degrees of freedom must be aligned to a precision of a few micrometers. The algorithms which are used for aligning the Inner Detector with tracks have been exercised on several challenges with simulated as well as testbeam and real data. Results from these challenges are presented, showing that track-based alignment is feasible using the implemented techniques. In order to fulfill the requirements from the computing model, it is foreseen that a dedicated alignment and calibration data stream enables the software to produce updated alignment constants 24 hours after recording the corresponding data