  The ATLAS muon spectrometer is designed to measure muon momenta with a
resolution of 4% @ 100 GeV/c rising to 10% @ 1 TeV/c track momentum. The
spectrometer consists of precision tracking and trigger chambers embedded in a
2T magnetic field generated by three large air-core superconducting toroids.
The precision detectors provide 50 micron tracking resolution to a
pseudo-rapidity of 2.7. The system also includes an optical monitoring system
which measures detector positions with 40 micron precision. This paper reports
on the calibration and performance of the ATLAS muon spectrometer.
