Use of CAIV techniques to build advanced VIIRS approaches for NPOESS key EDRs

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Visible and Infrared Imager/Radiometer Suite (VIIRS) has responsibility for 23 Environmental Data Records (EDRs), three of them key NPOESS EDRs of highest value to operational users: Imagery, Sea Surface Temperature (SST), and Soil Moisture (primary EDR from the NPOESS conical microwave imager/sounder [CMIS]). The VIIRS design was guided by a set of government requirements priorities, which were topped by key EDR performance. Taking advantage of the MODerate-resolution Imaging Spectroradiometer (MODIS) and Sea-viewing Wide Field Sensor (SeaWiFS) heritage, Raytheon's challenge was to optimize VIIRS system performance using Cost As Independent Variable (CAIV) analyses. The SST key EDR solution combines the traditional long-wave infrared (LWIR) split window with a second split window in the mid-wave infrared (MWIR) 3-4 mum region to offer a globally robust "dual split-window" SST algorithm operable daytime and nighttime with a precision of 0.25K, and an overall uncertainty of 0.35K (intermediate objective) across the entire SST measurement range. This capability was recently validated by the heritage MODIS on NASA's Terra satellite. The imagery key EDR solution permits superb multi-spectral detection and discrimination of cloud presence and type along with substantial ancillary "helper bands" such as the revolutionary 1.38 mum cirrus band now also validated by MODIS. The soil moisture solution is a cross-sensor fusion approach that combines the finer spatial resolution of VIIRS with traditional coarse resolution microwave-derived soil moisture retrievals to achieve objectives under open and partially vegetated scenes. This paper briefly describes the VIIRS sensor design, the key EDR performance, and the CAIV design process with three specific hardware and EDR tradeoff examples. Finally, the paper concludes with a description of the key risk-reduction design processes that led to a relatively low-risk (for advanced space-borne hardware programs) developmental design, which is now approaching hardware realization.