LIGO Document T1000388-v18

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

Document #:
LIGO-T1000388-v18
Document type:
T - Technical notes
Other Versions:
LIGO-T1000388-v17
29 Aug 2024, 11:32
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...)

Notes and Changes:
Added info about HAM-ISI control system Z origin location w.r.t. optical table.

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).

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