Ultraviolet and Visible Imaging and Spectrographic Imaging (UVISI) Data Processing Center (DPC)

Abstract

The nine sensors and one image processor of the Ultraviolet and Visible Imaging and Spectrographic Imaging (UVISI) instrument aboard the Midcourse Space Experiment (MSX) satellite can potentially generate up to three gigabytes of data of data per day. The UVISI Data Processing Center (DPC) must execute a multitude of complex processing functions in a 24-hour operational window, verify the UVISI data and also provide a compact, quantified record of the verification. The Center additionally must support higher-level data analysis functions. Data processing functions are divided into pipeline processing and data conversion processing. Pipeline processing, which consists of the main pipeline process, Pipeline, and several auxiliary processes is responsible for generating Data Quality Indices (DQI) that summarize sensor performance and Data Measurement Indices (DMI) that summarize sensor measurements. Both sets of indices provide scientists and engineers with a compact, easily-reviewed record of instrument performance. The conversion process, Convert, supports data analysis by converting raw telemetry into scientific/engineering units. On a pixel-by-pixel basis, Convert provides functions for dark-correction, flat-fielding, gain and gate adjustment, non-linearity correction, and count-to-photon conversion. Operating in conjunction with Convert, a pointing utility, Point, is used to determine the locations of selected objects in inertial space. The accomplishment of these myriad tasks relies on a state-of-the-art computer network using multiple workstations. Normal DPC operations are fully automated but remain flexible enough to allow prompt intervention by the UVISI Performance Assessment Team (PAT).