Analysis and correction about measurement error of edge sensor caused by guide flexure applied in the support system assembly of Thirty Meter Telescope

The Thirty Meter Telescope (TMT) project will design and build a thirty-meter diameter telescope for research in astronomy in visible and infrared wavelengths. The primary mirror of TMT is made up of 492 hexagonal mirror segments under active control. The highly segmented primary mirror will utilize edge sensors to align and stabilize the relative piston, tip, and tilt degrees of segments. The Support System Assembly (SSA) of segmented mirror utilizes a Guide Flexure to decouple the axial support and lateral support while its deformation will bring in measurement error of edge sensor. We have analyzed the theoretical relationship between the segment movement and the measurement value of edge sensor and proposed an error correction method with matrix. The correction process and the simulation results of the edge sensor will be described in this paper.