The application of radio altimeters to aircraft approach and landing

Abstract
A brief history of the development and application of pluse and frequency-modulated radio altimeters is given, and a few of the basic principles are mentioned. The paper then discribes in some detail the analysis of the performance of an equipment at very low altitudes and shows how this performance can be improved to make it applicable to the control of landing aircraft. Recorder plots of height and rate of descent are presented.