Hi, I am currently trying to reconstruct three dimensional attitude only by using magnetometer measurements with the knowledge of initial attitude. There have been many research conducted on the attitude reconstruction only by magnetometer (or one vector) measurements. For example, this is a deterministic approach. See "A Method of Determining Attitude From Magnetometer Data Only " by Natanson, McLaughlin & Nicklas. All the methods required the knowledge of tensor of Inertia of the body. But if the information about tensor of Inertia is not available, is it possible to reconstruct attitude with one vector measurements and the knowledge of initial attitude? I think that if the sampling rate of measurements is quite rapid compared to attitude changing speed and if short duration, it would be possible. If someone knows how to do that, could you please help me? Thanks.