Large format imaging spectrometers for future hyperspectral Landsat mission

This paper describes a design concept for a Landsat-class imaging spectrometer. The challenge is to match the Landsat data parameters, including a 185 Km swath and a 30 meter ground sample distance (GSD) from a 705 Km sun-synchronous orbit with a sensor that has contiguous spectral coverage of the solar reflected spectrum (400 to 2500 nm). The result is a remote sensing satellite that provides global access imaging spectrometer data at moderate spatial resolution. Key design trades exist for the spectrometer, focal plane array, dispersive element, and calibrator. Recent developments in large format imaging spectrometers at Raytheon are presented in support of a monolithic spectrometer approach. Features of the design include (1) high signal-to-noise ratio, (2) well-corrected spectral fidelity across a 6,000 pixel push-broom field-of-view, (3) straightforward calibration of the data to units of absolute spectral radiance, and (4) real-time simulation of Thematic Mapper bands, vegetation indices, and water vapor maps for direct continuous downlink.