A proper type for the optical systems design is very important to the performance of a remote sensing or space-borne
surveillance system. In this work, two types of optical systems are designed and compared for space-borne staring IR
sensor systems which are mainly used for point-source detection and identification. The optical design is based on a staring
IR detector with 2K×2K array with 40μm pixel pitch, and capable of high frame rate imaging of multispectral bands from
SWIR to MWIR onto the same FPA. A rotating filter wheel is used for light splitting. Based on the given target parameters,
reflective designs are limited because of packaging limitations, then two types of refractive optical system are selected, one
type has intermediate image, and the other type has not. Different characteristics of the two types of optical systems,
including the size, the maximum aperture of lens, the F number, the MTF, and the encircled energy are compared.
Considering the best balance between size of the lenses, place of the filter wheel, imaging quality, the result of the
integrated comparisons is that the optical system with intermediate image is more suitable for this system. The advantage
of optical system with intermediate image is demonstrated in this application.