Development of the Ball Integrated Telescope Model (ITM)

摘要

As the complexity of telescope systems have increased, system engineering trades related to cost and performance issues have become correspondingly complex. The traditional methodology for end-to-end system modeling depends upon focused analysis and data handoff between disciplines - aptly termed the "bucket brigade" approach. For the last 7 years Ball Aerospace has supported development of an integrated modeling environment for telescope performance modeling and analysis. The Integrated Telescope Model (ITM), a realization of this effort, has been used on several current large telescope programs such as the VLT, NGST, TPF and MAXIM. It permits the user to do both time simulations and analytical work in the spatial/temporal frequency domains. The individual discipline models in structural dynamics, optics, controls, signal processing, detector physics and disturbance modeling are seamlessly integrated into one cohesive model to efficiently support system level trades and analysis. The core of the model is formed by the optical toolbox implemented in MATLAB and realized in object-oriented Simulink environment. Both geometric and physical optical models can be constructed and interfaced to disturbances and detection models. The geometric approach includes ray tracing for exact modeling or sensitivity matrices for rapid execution. Spectral, transmission and polarization information is carried with each ray. The physical optics modules do wavefront propagation for analyzing diffraction effects under either with coherent or incoherent conditions. Coupling of the static offset models, quasi-static thermal deformations and structural dynamics with an optical model allows one to view the full range of disturbance effects on the resulting PSF. This paper addresses the overall model architecture, considerations and issues related to model execution speed, complexity and model resolution/validity. Example of a recent use of the model is reviewed.