M-layer: NPS version

M-layer is a FORTRAN program for computing the over-the-horizon propagation factor of an electromagnetic (EM) wave in a stratified atmosphere when ducting is present. The M-layer program developed by the Naval Ocean Systems Center (NOSC) has been substantially revised into a Naval Postgraduate School (NPS) version. The mode locating algorithm was rewritten to take advantage of local analyticity of the mode function. The exponential complex number representation was adopted to simplify multiplication and to improve accuracy when adding two complex numbers which nearly cancel each other. A consistency condition was formulated to assure accurate evaluation of the height-gain function. As a result, this NPS version executes faster with greater stability.<
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