## Galileo navigation constellation## http://europa.eu.int/comm/dgs/energy_transport/galileo/# http://europa.eu.int/comm/dgs/energy_transport/galileo/doc/galileo_hld_v3_23_09_02.pdf# Galileo Mission High Level Definition, version 3, 23 Sep 2002.# see section 4.1.1## http://www.aoe.vt.edu/~cdhall/Space/archives/000296.html# The GALILEO constellation will comprise 27 satellites (and four spares)# in circular orbits at 23,616 km altitude, in 56 degree inclined orbits,# with nine operational satellites equally spaced in each of three equally# spaced orbital planes. This configuration is known as a Walker 27/3/1# constellation, where "27" is the number of satellites, "3" is the number# of planes, and "1" is a parameter defining the phasing or mean anomaly# difference between satellites in adjacent planes. The constellation has# the notable property that for any minimum elevation angle, the number of# visible GALILEO satellites is equal to the number of visible GPS satellites# plus one.## this script for SaVi 1.2, by Lloyd Wood (L.Wood@surrey.ac.uk)# http://www.ee.surrey.ac.uk/Personal/L.Wood/constellations/## $Id: galileo.tcl,v 1.3 2004/12/26 14:47:19 lloydwood Exp $# We are excluding all spares.set SATS_PER_PLANE 9set NUM_PLANES 3# setup orbital elementsset a 29994.0set e 0.0set inc 56.0set omega 0.0set T_per [expr 2 * $PI * pow($a,1.5) / sqrt($MU)]# Walker /1 means interplane phasing of 0# table 8 of Mission HLD says:# receiver mask   visible Galileo    visible GPS#  5              13                 12# 10              11                 10# 15               9                  8# ...but is unclear if this includes transmitting spares.# set mask to 0set coverage_angle 0.0satellites GV_BEGINfor {set j 0} {$j < $NUM_PLANES} {incr j} {   set Omega [ expr $j * 360.0 / $NUM_PLANES ]   for {set i 0} {$i < $SATS_PER_PLANE} {incr i} {       set T [expr ($T_per * $i / $SATS_PER_PLANE)]       satellites LOAD $a $e $inc $Omega $omega $T   }}satellites GV_END