**Fortran Source Code**

####
Fortran is a very old computer language and so are a
lot of the programs available here. They were developed over two
decades and are formated for the Microsoft Fortran version 5 of
the late 1980's. They are presented mainly as templates for more
modern languages, although they can __probably__ be made to compile and run under other compilers.

#### One restriction to the old Microsoft system was the
number of modules that could be linked together. To get
round this restriction, subroutines on a similar topic were grouped together. Most
commons were placed inside "include" files to help prevent errors.
One include (wrdsiz.inc) was used in almost all source code
to set the word size to double precision.

#### Many routines in my library were not included
because they are dependent on specific formats of data and other
local items. These may be added in the future.

#### The source code is grouped by topic in zip files. The zip files are small. The largest is 60 KBytes.

####
These programs are related to atmosphere and
radio propagation though it. Refractive index routines as well as
several subroutines about water vapor are included. The Standard
Atmosphere of 1976 is also here.

####
Several routines to compute radii of the earth,
convert types of latitude are include. There are routines to compute
the nominal gravity in the WGS84 system. A set of routines to compute
geodesics is also included. Great circle routines for a spherical
earth are also here.

####
Routines useful in simple models of satellite orbits
are present. This does not include routines to compute precise
orbits or GPS positions (this needs many support routines that
are dependent of the format of the ephemeris data). This includes
routines to compute the Right Ascension of the Greenwich Meridian. Modified Julian Date (MJD) routines are included here.

####
A wide range of topics are covered. This
includes standard matrix routines, specialized 3 x 3 matrix routines,
estimation theory routines (mean least squares, weighted MLS,
MAP), signal processing (filters, smoothing, residuals of fit to
lines, quadratics), functional values from a table, robust
statistics etc. There is a large set about spherical harmonics.
There are a few main programs for computing
statistics from text files. However the entire set of
supporting routines in note here. Just the mathematics.

####
This catch-all covers things from sorting, setting up
constants (pi etc), signal processing (Kalman alpha-beta tracker)
etc. Some of the items could have been included in other
categories.

####
A few notes on programs and topics. Of special
note are items on spherical harmonics, and the several
conventions used in different fields of science. (The
coefficient load routines in the mathematics section can take several normalizations and convert to the
format used internally.)