Hyperspectral imaging sensor for the coastal environment

摘要

Abstract: Recent advances in large format detector arrays and holographic diffraction gratings have made possible the development of imaging spectrographs with high sensitivity and resolution, ideally suited for space-based remote sensing of earth resources. An optical system composed of dual spectrographs and a common fore-optic has been designed for the visible-near infrared (VNIR) and shortwave bands with 10-nm spectral resolution, providing 30-meter ground resolution from an altitude of 605 km. The spectrograph designs are based on a modified Offner 1-X relay with spherical mirrors and a convex spherical holographic grating for the secondary mirror. The fore-optic is a three-mirror anastigmatic telescope with a 360-mm focal length to match the pixel pitch of the respective 1024 $MUL 1024 visible silicon CCD and SWIR HgCdTe FPAs. The primary advantages of this design are the relatively low f-number (f/3), large flat field (18 mm), and low distortion. Preliminary performance results of a VNIR testbed grating and spectrograph are presented and compared to the design predictions.!16