Magnetic torques on global position system satellites

Using a digital computer simulation of the sun-earth-satellite motion, an estimate of the momentum storage capability of the satellites of the NAVSTAR Global Position System (GPS) is made for torques due to the interaction of the spacecraft magnetic field with the earth's magnetic field. Magnetic torque availability depends strongly on earth/sun pointing requirements and thus is a function of attitude control constraints. Sensitivity to satellite orbit-sun-geometry and vehicle field orientation is determined for 1000 pole-cm spacecraft magnetic field in the presence of the earth's field as represented by the Mead-Fairfield 1972 model.