OMPS early orbit dark and bias evaluation and calibration

The dark signal on an Ozone Mapper Profiler Suite (OMPS) charge-coupled device (CCD) results when electrons are thermally emitted into the conduction band of pixels in the active and storage regions. It effectively adds offsets to the photon-generated pixel counts and therefore impacts the Sensor Data Record (SDR) performance. This paper presents OMPS on-orbit results from dark current and electrical bias characterization and calibration on the system level. In particular, data from nominal and diagnostic activities has been collected and analyzed to extract general trends and features about the in-flight detector behaviors. The in-flight dark and bias signals are then compared with the prelaunch on-ground performance for each channel. The South Atlantic Anomaly (SAA) impact and temperature dependency are also addressed. The analysis results have demonstrated that the OMPS CCD performance successfully transferred from ground to orbit; the in-flight timing pattern of the nominal dark measurements are well suited to determine general dark currents of the individual pixels, and data collected during the early orbit calibration are sufficient to perform internal consistency checks of sensor dark and bias parameters and instrument behavior. Results also suggest that to minimize the influence of hot pixels and other effects of CCD lattice damage due to energetic particle hits, the dark current shall be updated on a daily basis rather than the weekly basis as planned.