Alignment error calculation and measurement method of a compact spaceborne focal plane

Abstract

The thermal and mechanical stabilization of the focal plane assembly (FPA) naturally has a magnificent impact on the performance of space camera. Thermal and mechanical features of the proposed FPA are described first. Special attention is paid to the thermo-structure design of the FPA. Then the fitting methods based on singular value decomposition and least square are proposed to use the finite-element analysis results to predict the relative position changes between charge coupled devices under thermal and mechanical load cases. A comprehensive finite-element model of the FPA has been built, and the alignment errors, which were induced thermal and gravity loads, are predicted based on the proposed fitting method. To further prove that the design of FPA meets the mechanical and thermal stability requirements, an optical bench was developed. Meanwhile thermal cycling and vibration test of the three FPAs were performed; the alignment error measurements of the FPAs after each test were also performed. Both the simulation and tests show a good stability of the FPA design under operational and test environments.