Proceedings Article | 12 March 2008
Proc. SPIE. 6624, International Symposium on Photoelectronic Detection and Imaging 2007: Optoelectronic System Design, Manufacturing, and Testing
KEYWORDS: Optical design, Stars, Imaging systems, Deformable mirrors, Star sensors, Navigation systems, Modulation transfer functions, Missiles, Aerodynamics, Spherical lenses
Star sensor is a special high accuracy photoelectric instrument. It is often used in navigation of aircraft, cruise missiles,
and ballistic missiles, so the imaging quality of the optical system in a star senor is very important. The spherical
windows with a small impact to imaging performance are usually used in traditional star sensors. However, the spherical
surfaces are not ideal aerodynamic surfaces and would cause problems such as high drag. In this paper the conformal
window whose outer shape is neither spherical nor flat is used in a star sensor. Unfortunately, the conformal shape
introduces amounts of aberration which may lead to low imaging resolution. The various correctors can be used to
eliminate the aberrations, for example, the fixed corrector, the arch, Zernike wedges, and the deformable mirror. The
fixed corrector method is selected to decrease aberrations from the conformal window in this paper. The surface of the
conformal window in the star senor is described as the Von Karman equation. The field of view is 17.6°×13.5°, and the
size of the CCD pixel is 6.45 um×6.45um. The optical design program ZEMAX is used to design this system. After the
optimization, under the max frequency of 77.52lp/mm, the MFT can almost achieve 30%. The design results show that
the aerodynamic requirements can be satisfied by the application of the conformal window in the star sensor, and the
aberrations can be corrected by proper ways.
