TIDE2003 AND RELATED SUBROUTINES

The provided package encludes
tide2003.c
tideutils.c
step1.c 
step2.c 
step3.c
ocean.c
needed routines to compute tide effect and ocean loading at a point, given as inputs:
1) ITRF positions of the point, the Sun and the Moon, 
2) Pole offset and point ocean loading table,
3) epoch.
The computation is performed according to the IERS 2003 Conventions (http://www.iers.org/).
Measurement units and more specifications are given in the source files. 
The routines are C translations of the dehanttideinel.f fortran package of V. Dehant,
published in the website ftp://tai.bipm.org/iers/convupdt/chapter7/.

EXTERNAL LIBRARIES NEEDED BY TIDE2003
None.

TIDEMAIN AND EXAMPLE MAIN
The file main.c includes the routine tidemain.c and an example main:
tidemain computes, for a given point and a given epoch, Sun and Moon ITRF positions; then calls tide2003;
main reads, for a given point and a given time span, the pole offset file EOP-C04-85-04.txt file; 
then calls tidemain and writes the results: you have to modify it according to your point and time needs.
Some utility routines are included in the utils.c file.

EXTERNAL LIBRARIES NEEDED BY THE MAIN TO COMPUTE SUN AND MOON POSITIONS

To compute Sun and Moon positions (in ICRS), the JPL celestial ephemeredes and the JPL fortran PLEPH.F library are needed.
You can freely download them from the JPL ftp://ssd.jpl.nasa.gov//pub/eph/export/ FTP site.
Unfortunately the use of the JPL products requires some ASCII/binary conversion and some source adaptation
that are machine/operative system dependent and (the first time) a little bit complex: 
fortunately, very clear and complete instructions on the use of the JPL products are available: 
ftp://ssd.jpl.nasa.gov//pub/eph/export/README.txt ; strictly follow them!

To transform Sun and Moon positions from ICRS to ITRF some routines of the International Astronomical Union's
SOFA (Standards of Fundamental Astronomy) software collection are needed. Particularly:
anp.f, anpm.f, bpn2000.f, cp.f, cr.f, era2000.f, ir.f, pom2000.f rx.f, ry.f, rz.f, sp2000.f, t2c2000.f, xys2000a.f, zr.f.
You can freely download the routines from the http://www.iau-sofa.rl.ac.uk/product.html website.

LINK BETWEEN THE MAIN AND THE EXTERNAL LIBRARIES

The C code calls the external Fortran routines by the smitrf.f routine,
provided with this package and called by tidemain.c,
according to the GNU C/Fortran calling standards.

BUILDING OF THE WHOLE PACKAGE

The package has been tested in the Linux (Fedora Core 2) environment, 
with the GNU gcc and g77 compilers.
You have to put in the same directory:
1. the provided C and Fortran routines,
2. the JPL JPLEPH and plpeph.f files,
3. the SOFA Fortran routines.
A makefile is available to build the executable. 

AUTHOR AND CONTACT

For any remark/question:
Ludovico Biagi, Politecnico di Milano, DIIAR
ludovico.biagi@polimi.it