A Theoretical Treatment of Schuler Tuning as Applied to Inertial Navigation Systems

摘要

Two methods of Schuler-tuning an inertial navigation system for motion on a spherical earth were partially investigated under the assumption of perfect components. In each method, differential equations were derived that describe the orientation of the system as a function of time relative to a particular coordinate system. In each case, the particular coordinate system represented the desired orientation of the system. For each method, the differential equations were studied for the special case of motion that cancels the earth's rotation (i.e., the system remains stationary with respect to inertial space); and solutions were found insofar as was possible without recourse to numerical methods. As was expected, both methods lead to systems that are inherently unstable. System B seems to be superior to System A in that it is subject to fewer unstable modes of motion under the conditions studied. Variations in altitude above the earth and the ellipticity of the earth were neglected to permit some solutions to the differential equations. (Author)