2012.P.1.1 Real-Time Attitude-Independent Three-Axis Magnetometer and Gyro-Bias On-orbit Calibration for Pico-satellites

Author(s)

Tian Xiang (1), Hao Wang (1), Ke Han (1), Tao Meng (1) and Zhonghe Jin (1)

Zhejiang University

Session

P.1 – Poster Session

Keywords

attitude-independent; on-orbit calibration; TAM biases and scale factors;gyro bias; UKF; the ZDPS-1A pico-satellite

Abstract

This article proposes a new real-time algorithm for the three-axis magnetometer (TAM) and gyro bias calibration using both TAM and gyro measurements. As an improvement of previous researches, this method estimates the magnetometer bias vectors, scale factors as well as the gyro biases all based on the unscented kalman filter (UKF) without any attitude information. The scheme mainly consists of three steps: first, the TAM measurement model as well as the gyro model including the scale factors and biases is given. Then the attitude-independent observation model that incorporates the rate information of the gyro is derived. The model mainly relies on a conversion of the magnetometer measurement and its corresponding inertial reference vectors, together with their derivatives. Finally, the UKF is developed to implement the previous two procedures. Simulation results demonstrate that the proposed method is feasible for the calibration of both TAMs and gyros. The convergence time of the gyro bias estimates β is less than 1000s, and the 3σ bounds of them after convergence are 1.5º/hr, 0.45º/hr and 0.94º/hr respectively for each axis. Meanwhile, the magnetometer parameters converge near their true value within 1000s, and the 3σ bounds of the biases b are 0.01mG, 0.012 mG and 0.011 mG respectively for each axis, while those of the scale factors are 4.23×10-5, 5.94×10-5, 4.58×10-5, 4.05×10-5, 3.45×10-5 and 4.12×10-5 respectively for each element of the D matrix.