The absence of a globally nonsingular three-parameter representation of the rotation group forces attitude Kalman filters to estimate either a singular or a redundant attitude representation. We compare two filtering strategies using simplified kinematics and measurement models. Our favored strategy estimates a three-parameter representation of attitude deviations from a reference attitude specified by a higher-dimensional nonsingular parameterization. The deviations from the reference are assumed to be small enough to avoid any singularity or discontinuity of the three-dimensional parameterization. We point out some disadvantages of the other strategy, which directly estimates the four-component quaternion representation.

中文翻译：

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态度估计还是四元数估计？

旋转组没有全局非奇异的三参数表示，这迫使姿态Kalman滤波器估计奇异或冗余的姿态表示。我们使用简化的运动学和测量模型比较了两种滤波策略。我们偏爱的策略估计了由高维非奇异参数化指定的参考姿态的姿态偏离的三参数表示。假定与参考的偏差足够小，以避免三维参数化的任何奇异或不连续。我们指出了另一种策略的缺点，该策略直接估计四分量四元数表示。