/usr/share/savi/data/draim-4.tcl is in savi 1.4.6-1.
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# * THEORETICAL CONSTELLATIONS
# *
# * Draim example 4-satellite elliptical constellation
# *
# * Uses elliptical orbits for continuous coverage.
# *
# * If the Earth is completely enclosed within a tetrahedron,
# * then satellites at the vertices of that tetrahedron can
# * see the whole surface of the Earth.
# *
# * John E. Draim, A common-period four-satellite continuous
# * global coverage constellation, AIAA Journal of Guidance,
# * Control and Dynamics, vol. 10, no. 5, September-October 1987,
# * pp. 492-499. Orbital parameters from Table 1.
# *
# * John E. Draim, Tetrahedral multi-satellite continuous-coverage
# * constellation, US Patent 4,854,527, August 1989.
# http://www.freepatentsonline.com/4854527.html
#
# $Id: draim-4.tcl,v 1.12 2011/09/02 07:59:05 lloydwood Exp $
set NUM_PLANES 4
# apogee altitude 42203 nautical miles - translate to km
set apogee_altitude 78160.0
# perigee altitude 23193 nautical miles - translate to km
set perigee_altitude 42953.5
# setup orbital elements
set a [expr ($apogee_altitude+$perigee_altitude)/2+$RADIUS_OF_EARTH]
# e is approximately 0.263
set e [expr ($apogee_altitude-$perigee_altitude)/(2*$a)]
set inc 31.3
set omega -90
set coverage_angle 0.0
# compute period of orbit
set T_per [expr 2 * $PI * pow($a,1.5) / sqrt($MU)]
satellites GV_BEGIN
for {set j 0} {$j < $NUM_PLANES} {incr j} {
set Omega [expr $j * 360.0 / $NUM_PLANES]
set omega [expr -$omega]
set T [expr $T_per / $NUM_PLANES * $j ]
satellites LOAD $a $e $inc $Omega $omega $T "Draim-$j"
}
satellites GV_END
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