The platform shown in Fig. I is one of a series of miniature platforms developed for inertial guidance and weighs only 28 lb. It is a three-axis, four-gimbal platform permitting complete freedom of manœuvre without gimbal lock. Three miniature integrating gyroscopes are used for stabilizing the gimbal system (Fig. 2) and three miniature pendulous accelerometers provide voltage outputs proportional to accelerations experienced by the platform.