A method and apparatus for estimating a slave payload attitude is
disclosed. The method includes accepting a plurality of slave payload
attitude measurements, deriving a model of the relative attitude of the
slave payload and a master payload attitude at least in part from the
plurality of slave attitude measurements, predicting the relative
attitude between the slave payload attitude and the master payload
attitude using the derived model, and estimating the relative attitude
between the slave payload attitude and the master payload attitude at
least in part from the predicted relative attitude between the slave
payload attitude and the master payload attitude. Furthermore, the
absolute attitude of the slave payload is computed using the relative
attitude and the master payload attitude.