An analysis of MLAYER: a multilayer tropospheric propagation program

Abstract

MLAYER, a computer program, was developed by the Naval Ocean Systems Center (NOSC) for calculating the signal levels of electromagnetic waves propagating in a multilayer tropospheric waveguide environment over seawater. The program is an extension of the XWVG which is a trilinear ducting program. Modifications of the XWVG were carried out to handle multilayer tropospheric ducts. A number of modifications and improvements on the program made over the past several years were not documented. A detailed documentation of MLAYER was also not available. The object of this thesis is to develop a technical documentation for MLAYER using the program as baseline. The study aims to put together the theoretical formulations (specific to MLAYER) into a complete self- contained document. This is to facilitate potential users with better appreciation of the capabilities, limitations, approximations and assumptions used in the mathematical modelling techniques. As far as possible, the same terminologies and functional variables used by Baumgartner (in the XWVG development) and by Pappert (in the MLAYER development) are adopted to enable one to relate this document to the program. Step-by-step derivation of certain equations was carried out and checked for compatibility with the algorithm in the program.