  The physics goals the Belle II experiment require an exceptionally good
alignment of all the components of the Belle II tracker. The Belle II tracker
is composed of the DEPFET based pixel silicon detector, four layers of double
sided silicon strip detector, a low material budget drift chamber, all three
operating in a solenoidal 1.5 T B field, which is affected by the final
focusing system of the accelerator. Each component of these three components
must be aligned with an accuracy significantly better than the point resolution
of the detector that for the PXD is order of 10 microns. The Belle II alignment
software is based on the Millepede II package and uses cosmics and collision
data to constrain the weak modes. The performance of the alignment algorithms
was tested on the phase 2 collision data collected during spring 2018. Good
alignment of the vertex detector was essential to demonstrate the nano-beam
collision scheme of the accelerator and check the quality of the impact
parameter resolution, which is essential for time-dependent CP violation
studies at the B factory.
