  The Dark Energy Spectroscopic Instrument, consisting of 5020 robotic fiber
positioners and associated systems on the Mayall telescope at Kitt Peak,
Arizona, is carrying out a survey to measure the spectra of 40 million galaxies
and quasars and produce the largest 3D map of the universe to date. The primary
science goal is to use baryon acoustic oscillations to measure the expansion
history of the universe and the time evolution of dark energy. A key function
of the online control system is to position each fiber on a particular target
in the focal plane with an accuracy of 11$\mu$m rms 2-D. This paper describes
the set of software programs used to perform this function along with the
methods used to validate their performance.
