Spin-Axis Attitude Determination Using In-Flight Data

The paper presents a practical spin-axis attitude determination approach based on the Tanygin–Shuster algorithm. The technique is illustrated by means of sensor measurement data originating from two satellites with very different orbit and attitude characteristics. The most appropriate data intervals are identified using criteria based on measurement sensitivities. A minimum-variance technique is formulated for establishing the Earth aspect angle from the measured chord angles. The chain of covariance transformations from the fundamental sensor measurement errors to the final attitude error is presented. The unit-vector normalization technique, which is an inherent part of the Tanygin–Shuster method, is found to be beneficial for the stability of the attitude determination results under unknown biases, especially in cases in which only a subset of the measurement angles are available.