Indication of the Vertical from Moving Bases

A comprehensive review is made of the problem of indicating the vertical from moving bases and methods for its solution, both theoretical and practical. This is based on research work carried out at the Instrumentation Laboratory of the Massachusetts Institute of Technology. The concept of Schuler tuning for precise vertical indication is shown to be a particular application of aided-tracking feedback systems in which proper use of the effect of vehicle acceleration can be made to cancel the dynamic tracking error that otherwise would exist. The 84-minute natural period resulting requires accurate instrumentation. A discussion of equipment suitable for this work concludes the paper.