ADCS.estimators.quaternion_mean module

Chart-consistent quaternion means for unscented attitude filters.

ADCS.estimators.quaternion_mean.quaternion_mean(values, weights, *, mode)

Solve sum(w_i * chart(q^-1 q_i)) = 0, including signed UKF weights.

Newton steps use rotation vectors, so the solver never retracts an out-of-domain quaternion-vector correction. Backtracking limits each step and reduces the residual, unlike the undamped chart fixed point. Both state and measurement means use this same definition; covariance errors remain in the requested chart. The analytic 3x3 Jacobian avoids repeated state copies and numerical differentiation.

Parameters:

• values (ndarray)

• weights (ndarray)

• mode (str)

Return type:

ndarray