I've updated the blend filter for the SR3 yaw estimator, v2 is called "skinnynotch". v1 was "doublenotch". I have not yet updated the installation scripts for it. It's based on the yaw fits by Ivey at the end of July. There are more recent fits, but they seem very similar, so I'm going to post this and let folks use if for the prediction calculations.

The new blend is a based on putting a simple notch in the model path at each lightly-damped resonance, and then rolling off the model at low frequency. The goal is to use the OSEM signal at the resonance and for the position info. (NOTE - The damping loop is AC coupled, so the estimator probably doesn't need the real OSEM signal at DC, but for now I'm leaving it in place so that the OSEM signal and the estimator signal will be as similar as possible for comparison reasons.)

Figure 1 shows the MODEL path of the blend vs. the plant model. The dashed lines are at the plant resonances. The notch width is chosen by-eye. The minimum notch transmission is 0.2, so we would expect 0.2 of the signal from the model, and 0.8 from the OSEM. However - note the phase at the botom of the third notch is about 15 deg, instead of 0. This means, see later, that the peak of the complimentary OSEM signal is slightly shifted. For -v3 I think we should try to make peaks for the OSEMs instead of notches for the models, because I think this will be better. Ivey and Edgard have some math to look at the performance

Figure 2 and 3 show the complementary filters, figure 3 is a zoom around the resonances

Figure 4 compares the plant model with the OSEM path. 

I've also attached a pdf of the four plots.

Design script: Estimator_blend_skinnynotch_SR3yaw_20250723.m 
in the SUS_svn at  .../HLTS/Common/FilterDesign/Estimator/   (revision 12586)

The first blend and its installation are described in LHO log 84004.