New statistical approach for design optimization and performance assessment of spaceborne optical systems

Abstract

The spot follow-on system is anew CNES Earth Observation program with reduced development cost as a major objective. In order to reach this goal, new methods for design optimization and performances assessment will have to be taken into account, with the aim to decreasing costly design safety margins. Present paper describes an original approach for rational assessment of image quality of spaceborne observation optical systems. This approach is based upon an overall end to end thermal, mechanical, optical modelization of the instrument which is submitted to both ground operations and space environment. Potential presence of ground and/or on-board active control loops can also be taken into account in that global chain. Based on this approach, a simulation tool has been developed, which allows statistical evaluation of the optical performance expressed as the RMS wave front error (WFE) using the Monte-Carlo method. Instrument modulation transfer function statistical budgets, including detector convolution effect, can be finally obtained as a simple post-processing of preceding WFE calculation step. Validation results and application to the 3S TMA instrument will be presented.