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: A heading indicator is disclosed which utilizes a one degree of freedom platform stabilized by a two degree of freedom dry flexure gyro. The output of one of the sensitive axis is coupled through an amplifier to the corresponding torquer in the gyro and selectively through an another amplifier to the opposite torquer. The other sensitive axis output is coupled through an amplifier to the platform. The indicator initializes at true north and is then switched to a directional gyro mode.

Abstract: A heading indicator is disclosed which utilizes a one-degree-of-freedom platform stabilized by a two-degree-of-freedom dry flexure gyro. The output of one of the sensitive axis is coupled through an amplifier to the corresponding torquer in the gyro and selectively through another amplifier to the opposite torquer. The other sensitive axis output is coupled through an amplifier to the platform. The indicator initializes to true north and is then switched to a directional gyro mode.

Abstract: A combined angular displacement measuring and multiplier system is provided which finds particular application in heading reference units for navigational purposes, but which has general utility, as will become apparent as the description proceeds. The system of the invention includes a bubble tilt or level sensor which measures angular displacements and which, in accordance with the present invention, also serves as a multiplier for a second term, such as azimuth rate (AZ).

Abstract: A self-contained gyrocompassing system providing switch means with coarse align and gyrocompass modes of operation. Starting in the coarse align mode, a north bubble sensor output along with an initial vertical error signal output is applied to an east torquer which coarsely levels the east gimbal. Subsequently, the switch means is placed in the gyrocompass mode and the signal from the north sensor is simultaneously applied to the east gyro and the azimuth gyro loops. A voltage threshold detector determines whether the signal from the north sensor requires low or high rate azimuth torquing. If high rate azimuth torquing is required in the azimuth gyro loop, the east gyro loop is either locked or torqued at a high rate.