Use the Attitude Sensors to Determine the Motion of a Free Rotator,

From the free-body representation of Poinsot and expressions derived therefrom for the behavior of a body free from internal and external torques, the practical determination of the parameters of rocket or satellite motion has been considered. Transient perturbing torques can result in unique free motion patterns. A small number of measurements using rocket-mounted devices can determine free-body motion, with or without knowledge of the moments of inertia. These devices are magnetometers that measure the earths field and telescopic instruments that view stars or the sun. Digital computer programs have proved useful for analyzing signals from rocket-borne attitude sensing devices. These include two scopic sensor across the bright object map and a program which uses magnetometer and star signals to locate the azimuth of a rocket free-body precession cone about the earths magnetic field direction. Author