Tracking and Alignment of the LHCb detector

The LHCb experiment is designed to study $B$-decays at the LHC. This purpose is achieved by means of an outstanding track momentum resolution and excellent particle identification. The performance of the detector exceeds expectations, and the physics program of the collaboration is extended to the study of charm decays, QCD and electroweak physics. Both tracking and alignment play a key role for obtaining these results. The tracking efficiency in this high-occupancy environment has been measured during LHC Run I (2010-2012) to be larger than 95% over a wide range of momentum and pseudo-rapidity. The alignment of the detector is based on a Kalman filter fit of the tracks and provides an uncertainty on the momentum scale below 1 x 10$^{-4}$ and a momentum resolution of about 0.4%. These results allowed one to achieve high-precision mass measurements of many charm and $B$ hadrons so far. Starting from Run II of the LHC, the running conditions will continue to push the performance of the detector to its limits. An upgrade of the detector will therefore take place in 2018 to extend its reach. A fast tracking will be a fundamental part of the upgraded detector as well. In light of this, the prospects for the recently proposed upgrade will be discussed.