• M.D. Hildreth
  University of Notre Dame, Notre Dame
• A.S. Aryshev
  Royal Holloway, University of London, Surrey
• S.T. Boogert
  JAI, Egham, Surrey
• Y. Honda, T. Tauchi, N. Terunuma
  KEK, Ibaraki
• G.R. White
  SLAC, Menlo Park, California

The demonstration of the stability of the position of the focused beam is a primary goal of the ATF2 project. We have installed a laser interferometer system that will eventually correct the measurement of high-precision Beam Position Monitors used in the ATF2 Final Focus Steering Feedback for mechanical motion or vibrations. Here, we describe the installed system and present preliminary data on the short- and long-term mechanical stability of the BPM system.