Abstract: A two-axis gyroscope in which precession may be effected by application of a DC current to the stationary precession windings. The rotor assembly has a pair of ring-shaped permanent magnets with their magnetic vectors aligned parallel with the gyro spin axis. This structure presents a magnetic field to the precession windings which does not change as the rotor assembly rotates. Thus the gyroscope may be precessed by application of a DC current to the precession windings. The precession windings are located along two orthogonal axes to allow precession of the gyro in two orthogonal directions.

Abstract: A scan mirror assembly wherein the scan mirror performs near-linear cyclic two-way scans. During the useful portion of each scan half-cycle, the mirror is acted on only by the torque of the mounting flexural pivots and at turn-around most of the rotational energy of the mirror is returned thereto by a leaf spring bumper arrangement. A clock controlled "closed loop" torquer operates only during the turn-around period to provide for energy losses by adding that amount of energy required to maintain a scan rate equal to the clock rate.