aLIGO SEI Actuators and Sensors Change of Basis (Transformation, Orientation, Matrix)

Document #:

LIGO-T1000388-v17

Document type:

T - Technical notes

Abstract:

The objectives of this document are:
- To describe the instruments location and orientation

- To define which scripts have been used to calculate the change of basis matrices (must define clear location in the svn)

- List the matrices values (for the X and Y directions)
Specify where the matrices are stored in the svn and the Structures names

- Specify which scripts to use to load the matrices (populate...)

Files in Document:

• T1000388 SEI Sensors Location.pdf (file is not accessible)

Other Files:

• D2100066-v1_OpticalTableSurface_to_HorzActuatorPlane_2...png (file is not accessible)
• T1000388 SEI Sensors Location.pptx (file is not accessible)

Topics:

• Seismic Isolation

Authors:

• Fabrice Matichard
• Jeffrey Kissel
• Celine Ramet

Notes and Changes:

We flipped the T240 orientation used to calculate the change of basis matrices.

We agreed that we would assume that inertial instruments point in the same direction as the position sensors for the purpose of the matrix calculation, and flip the signs in the "symetrization" filters where necessary.

While at LHO, Rich reminded me that there are know symmetrization filters for the T240s. So the orientation used to calculate the matrices as to match with the actual orientation.

Therefore I had to flip the sign of T240 Xi and Yi (for i=1 to 3), so that the orientation used for calculation match with actual orientation.

- The program has been modified:

https://svn.ligo.caltech.edu/svn/seismic/BSC-ISI/Common/Basis_Change_BSC_ISI/aLIGO_BSC_ISI_Matrices_Input_Values.m

- The m file and mat file have been committed in the svn (same folder, please update your local version).

Related Documents:

• LIGO-D0900124: aLIGO, SEI, HAM ISI Table Assembly