Multi-User System for Earth Sensing Spacecraft Attitude Calibration Using International Space Station Attitude Information

The Multi-User System for Earth Sensing (MUSES) spacecraft is an Earth imaging platform onboard the International Space Station (ISS). Its onboard attitude determination sensors comprise of a star tracker and three-axis gyroscopes. The paper first studies how star tracker offsets affect the overall point attitude errors, with specific application to MUSES. Then, a replacement for the original MUSES filter is derived, which integrates the MUSES attitude sensors with the ISS GPS-determined attitude in order to provide a calibration solution for the MUSES star tracker offsets, as well as its gyro biases and scale factors. Both simulated and real results obtained from the spacecraft are presented.