Nathan Madsen, Brigham Young University
Engineering
A scatterometer is a type of radar used to measure the backscatter of the earth’s surface. In 2014, NASA will launch a new scatterometer, RapidSCAT, and mount it on the International Space Station (ISS). An integral part of the processing code for RapidSCAT is the X-table. X relates the power received by the scatterometer to the backscatter of the surface. It depends on the antenna, processor, and frequency of the sensor, as well as the sensor’s position, velocity, and attitude. The ISS’s comparatively unstable orbit renders previous methods of X-table generation inaccurate. By incorporating position, velocity, and attitude data from a revolution of the ISS, a table that is accurate for that revolution has been produced. This table can be made accurate for up to 8 revolutions of the ISS, by parametrizing variations in X with another variable. Different methods of estimating the relationship between these variables are attempted. Because the table will have to be recalculated repeatedly through the mission life of the sensor, tradeoffs between accuracy and processing time are explored.