Post launch quality assurance approaches for high resolution space borne optical sensor data

摘要

Data acquired by space borne systems is subjected to inherent deviations in geometric and radiometric aspects in terms of true representation of observed earth features. Significantly, high resolution data is more sensitive towards its radiometric accuracies and its quality. Raw data is preprocessed incorporating all corrections which are modeled using prelaunch test data. However, it is necessary to estimate post launch performance and its characterization for understanding the deviations in the orbit phase from the lab characterization to produce real world objects accurately in terms of their positional and spectral characteristics. In this paper the emphasis is made w.r.t the early orbit characterization of the Resourcesat-2A, LISS4 multispectral data products which were operationalized during February 2017. The Radiometric characterization is performed through in flight LED Calibration, Non illumination area imaging, global Radiometric Sites, cross calibration with the contemplating sensors. MTF is estimated through edge based artificial targets and vicarious calibration exercises. The Geometric calibration exercises were carried out by estimating positional accuracy consistency through longer paths, different homogeneous and heterogeneous terrains. Assurance of time series data consistency and systematic coverage is estimated after path lock, to provide contiguous data for the support of applications based on larger extents. All the calibrations exercises were carried out in iterative mode and finally achieved the targeted specifications. Over all Image rating is estimated by NIIRS.