The Tuning of Gyroscopic Instruments

Abstract

Ever since the fundamental work on this subject by Schuler [24], it has been known that certain navigational instruments, including gravity pendulums, gyro pendulums and gyro compasses, lend themselves to particularly successful tuning when the curvature of the earth is taken into consideration. In this way the instruments can be made to become insensitive to the disturbances that are caused as the result of the accelerations of the carriers along the surface of the earth. The requirement according to which these instruments have to be tuned to an oscillation period of 84.3 minutes (Schuler period) is often referred to as the Schuler principle. In spite of the numerous investigations that have been made as regards the contents and the limits of this principle, the relevant explanations given in many textbooks are rather unsatisfactory. In this chapter it is therefore proposed to use two examples to illustrate some of the particular difficulties that are met in the application of the Schuler principle.