Principal Author: Tom Flatley
Title of Paper: On-board Cloud Contamination Detection with Atmospheric Correction
Abstract: The desirability of performing satellite, on-board science data processing and analysis, and the actual production of science data products in space is unquestionably a solution to the often discussed "data glut" problem but the roadmap to get there is rather murkey. An investigation of 2 typical preprocessing algorithms, cloud masking and atmospheric correction, routinely performed during satellite data postprocessing in the Earth Sciences domain is intended to provide some insight on more sophisticated analyses. Central to the issue of realtime data processing in an on-board computing environment is speed, therefore, these 2 algorithms are benchmarked on a variety of commercial microprocessors with the expectation of inferring performance on flight-qualified processors. Intuitively, a sequential processor, especially the lower performance radiation hardened versions essential to some space missions, cannot process and analyze science data fast enough to be practical in a realtime, on-board environment so 2 other computing devices, the Field Programmamable Gate Array (FPGA) and the Application Specific Integrated Circuit (ASIC), which introduce some degree of parallelism, are also investigated with hardware implementations of the 2 algorithms. The embedding of these algorithms in silicon introduces additional parameters other than speed which must also be considered when approaching the issue of sophisticated on board science processing. Gate count becomes equally important as speed since radiation immune FPGAs and perhaps to a lesser extent ASIC's are limited in design space. There is also the issue of acceptable accuracy since in situ data, conventionally required for some preprocesssing algorithms is unavailable.