Global Feed-Forward Vibration Isolation in a km scale Interferometer
  Using a network of seismometers and sets of optimal filters, we implemented a feed-forward control technique to minimize the seismic contribution to multiple interferometric degrees of freedom of the LIGO interferometers. The filters are constructed by using the Levinson-Durbin recursion relation to approximate the optimal Wiener filter. By reducing the RMS of the interferometer feedback signals below \sim10 Hz, we have improved the stability and duty cycle of the joint network of gravitational wave detectors. By suppressing the large control forces and mirror motions, we have dramatically reduced the rate of non-Gaussian transients in the gravitational wave signal stream. 
Ryan DeRosa, Jennifer C Driggers, Dani Atkinson, Haixing Miao, Valery   Frolov, Michael Landry, Joseph Giaime, and Rana X. A...
physics.ins-det