Real-time alignment procedure at the LHCb experiment for Run 3

The LHCb detector at the LHC is a general purpose detector in the forward region with a focus on studying decays of c- and b-hadrons. For Run 3 of the LHC, LHCb will take data at an instantaneous luminosity of 2x10^33 cm^-2s^-1. To cope with the harsher data taking conditions, LHCb will deploy a purely software based trigger with a 30 MHz input rate. The software trigger at LHCb is composed of two stages: in the first stage the selection is based on a partial event reconstruction, while in the second stage a full event reconstruction is used. This gives room to perform a real-time alignment and calibration after the first trigger stage, allowing to have the most precise detector alignment in the second stage of the trigger. The framework and the procedure for a real-time alignment of the LHCb detector in Run 3 are discussed from both the technical and operational point of view. Specific challenges of this strategy and foreseen performance are presented.