A Prototype Airborne Visible Imaging Spectrometer (PAVIS)

A small, low mass and low power imaging spectrometer for airborne remote sensing of atmospheric and surface properties called the Prototype Airborne Visible Imaging Spectrometer (PAVIS) has been designed, constructed, and field-tested by the Airborne Sensors Initiative team at Ball Aerospace & Technologies Corp. Originally a breadboard spectrometer, PAVIS was developed to validate in the laboratory that a large concave grating on a moderately aspheric surface with minimal scattering could be fabricated, and that both spectral and spatial performance could be optimized simultaneously. The airborne sensor is being developed to demonstrate that useful scientific data approaching the quality of AVIRIS and the MODIS Airborne Simulator whiskbroom scanning spectrometers can be obtained with a compact pushbroom imaging spectrometer. The current prototype has a 200 nm spectral range that may be tuned within the spectral response of the instrument system ranging from approximately 400 to 800 nm and can be set according to the intended target requirements. The instrument has a field-of-view of 3.2°. Data are acquired as 480 spatial pixels by 640 spectral pixels. The optical path of the prototype features an achromatic doublet receiving optic, a 12 × 0.018 mm truncated precision air slit, a holographic grating, a lens assembly, and a small analog CCD camera. A filter can be rotated into the light path for confirmation of spectral calibration in the field. Considerations specific to aircraft flight must be taken into account in the design of the instrument hardware and software.