Gyrocompass Alignment of an Inertial Platform to Arbitrary Attitudes

Abstract

The vector control equation is derived which dictates the mechanization for aligning an inertial platform to any arbitrary at t i tude by gyrocompassing and leveling techniques. The derivation is based on the assumption tha t the closed loop for some particular at t i tude is known. To illustrate the vector control equation, a north-zenith-east coordinate system is assumed, and the matrix for forming the proper linear combinations of accelerometer outputs to torque the platform gyros is established. Once the form of the matrix for the north-zenith-east orientation is established, the vector control equation can be used to specify the matrix and the block diagram for any other orientations. Two examples are given: one in which the platform is tilted about the east axis and the other in which the platform is tilted and off north.