Abstract: Azimuth and elevation information relating to ground based weapons equipment is inputted to a north finding system. The system determines angular azimuth and elevation errors and transmits signals to a display arrangement for indicating the direction to rotate the system so as to eliminate the errors. As the system is aimed, a gyro included in the north finding system measures angular rotation about its input axis and accelerometers measure the change in tilt. The computer projects the rotations to the horizontal plane and determines the change in azimuth. This is a continuous procedure until all errors are eliminated.

Abstract: An optical encoder features a transparent disc having three tracks arranged in a concentric configuration on the face thereof. One of the tracks has opaque markings in a particular pattern for determining a zero or starting angular reference for a rotating member. The other two tracks have opaque markings for providing high resolution, incremental angle information. Light is directed through the disc and light pulses are provided in accordance with the disposition of the markings on the respective tracks. The light pulses are converted to electrical pulses which are processed via suitable interface circuitry and a computer for determining the absolute angle through which the rotating member has rotated.

Abstract: A steerable artillery projectile utilizing electro-optical circuitry to home on a laser designated target where the rear end of the projectile is displaceably coupled to the front end thereof which contains the electro-optical circuitry and munitions is disclosed. The displaceably coupled rear end of the projectile has a plurality of compartments equispaced around its longitudinal axis and each compartment has a gas cartridge which can be activated by the electro-optical circuitry. In flight, a selected gas cartridge may be discharged by the electro-optical circuitry causing the longitudinal axis of the rear end of the projectile to momentarily move out of line with the longitudinal axis of the front end of the projectile resulting in a modification of the flight path of the projectile to home on the laser designated target.