I have created the FIR filters for the GDS calibration during ER7.  The filters are based on the following models:

Total_Actuation = Actuation * AI * ActuationTimeDelay
Total_Sensing = Sensing * AA * OMCWhiteningPoles * SensingTimeDelay

These models follow directions given in LHO alog #18769.  

Actuation is model(2).par.A.total from aligocalibration/trunk/Runs/PreER7/H1/Results/DARMOLGTFs/2015-06-01_LVLNDriver_DARMOLGTF.mat.  

Sensing is model(2).par.C.total from aligocalibration/trunk/Runs/PreER7/H1/Results/DARMOLGTFs/2015-06-01_LVLNDriver_DARMOLGTF.mat.

AA is the antialiasing filter, which is model(2).par.C.antialiasing.total loaded from aligocalibration/trunk/Runs/PreER7/H1/Results/DARMOLGTFs/2015-06-01_LVLNDriver_DARMOLGTF.mat.

AI is the anti imaging filter, which is model(2).par.A.antiimaging.total loaded from aligocalibration/trunk/Runs/PreER7/H1/Results/DARMOLGTFs/2015-06-01_LVLNDriver_DARMOLGTF.mat.

OMCWhiteningPoles are the super-Nyquist-frequency poles of the OMC whitening.  This is model(2).par.C.uncompensatedomcdcpd.c from aligocalibration/trunk/Runs/PreER7/H1/Results/DARMOLGTFs/2015-06-01_LVLNDriver_DARMOLGTF.mat.

The ActuationTimeDelay is model(2).par.t.actuation from aligocalibration/trunk/Runs/PreER7/H1/Results/DARMOLGTFs/2015-06-01_LVLNDriver_DARMOLGTF.mat (in seconds), and the SensingTimeDelay is model(2).par.t.sensing + model(2).par.t.armDelay from aligocalibration/trunk/Runs/PreER7/H1/Results/DARMOLGTFs/2015-06-01_LVLNDriver_DARMOLGTF.mat in seconds.

To generate the FIR filters, run create_td_filters_ER7.m in aligocalibration/trunk/Runs/ER7/Common/MatlabTools/.  I've attached plots of the frequency response of the actuation and inverse sensing FIR filters compared to the models they are based on.  In the plots, the left column shows the FIR frequency response in blue and the original frequency model in red (magnitude on top, phase on bottom).  The right column shows the relative error in magnitude on top and the phase error in degrees on bottom.

In addition, I performed a test where I took some random DARM_CTRL and DARM_ERR data and calibrated in the time domain with the FIR filters and in the frequency domain with the original frequency models.  I've also attached a plot of the comparison between this frequency domain calibration and the time domain calibration.