Nano Satellite Attitude Estimation With Magnetometer And Photodiodes Measurements

A method of integrating measurements of a tri-axis magnetometer and body-mounted photodiodes for nano-satellites which require low power consumption and light weight is introduced in this paper. By applying sunlight vector measured by photodiodes and earth magnetic field vector by magnetometer, two observation equations are specifically established for sunlight and umbra areas of the orbit, and attitude estimation is obtained through Kalman filtering. This method is practical in engineering application. Simulation analysis shows that error of estimation by this algorithm is acceptable and does not accumulate over time.