A method of estimating a directional parameter of a downhole component includes deploying a borehole string in a borehole, the borehole string including the downhole component, the downhole component being rotatable, the downhole component including a gyroscope device and a magnetometer device. The method also includes collecting gyroscope measurement data from the gyroscope device and magnetic field measurement data from the magnetometer device during rotation of the downhole component, and estimating, by a processor, the directional parameter of the downhole component, where the estimating includes correcting the gyroscope measurement data based on the magnetic field measurement data.