Design of ground-based physical simulation system for satellite-borne TDI-CCD dynamic imaging

Abstract

As we know, the existence of image motion has a bad effect on the image quality of satellite-borne TDI CCD camera. Although many theories on image motion are proposed to cope with this problem, few simulations are done to justify the proposed theories on ground. And thus, in this paper, a ground-based physical simulation system for TDI CCD imaging is developed and specified, which consists of a physical simulation subsystem for precise satellite attitude control based on a 3-axis air bearing table, and an imaging and simulation subsystem utilizing area-array CCD to simulate TDI CCD. The designed system could realize not only a precise simulation of satellite attitude control, whose point accuracy is above 0.1° and steady accuracy above 0.01°/s, but also an imaging simulation of 16-stage TDI CCD with 0.1s its integration time. This paper also gives a mathematical model of image motion of this system analogous with satellite-borne TDI CCD, and detailed descriptions on the principle utilizing area-array CCD to simulate TDI CCD. It is shown that experiment results are in accordance with mathematical simulation, and that the image quality deteriorate seriously when the correspondence between the image velocity and signal charges transfer velocity is broken out, which suggest not only the validity of the system design but also the validity of the proposed image motion theory of TDI CCD.