Modeling albedo effects in coarse sun-sensor data for a spinning nanosatellite

This paper describes progress made on modeling the effect of Earth albedo for attitude determination on the Local IONospheric Measurements Satellite. LionSat must rely on magnetometer and coarse sun-sensor data (from body-mounted solar panels on all ten faces) for attitude determination. Using data from the Total Ozone Mapping Spectrometer, a simplified albedo database model that averages reflectivity data across all longitudes (and across the 6-month mission lifetime) along with a geometric field-of-view model, one can model the albedo intensity at each panel on the satellite. A sun-vector is calculated using a nonlinear least-squares algorithm, with resulting errors of up to 5 degrees in sun-vector position. Simulations of the attitude determination and control system show that LionSat can achieve acceptable performance for scientific measurements.