Coordinate Systems for ACE
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The ISTP Project provides a Fortran library for conversion between these
coordinate systems.
A good description of how to make transformations between the different
coordinate systems can be found in a paper by M. A. Hapgood, "Space physics
coordinate transformations: A user guide", in Planetary and Space Science,
Vol. 40, No. 5, pp. 711-717, 1992.
J2000 GCI
Geocentric inertial reference frame using the Julian Epoch of Jan. 1,
2000.
At the Julian Epoch,
X = Earth's mean vernal equinox
Z = Earth's mean spin axis
RTN - Radial Tangential Normal
Spacecraft centered coordinate system.
R = Sun to Spacecraft unit vector
T = (Omega x R) / | (Omega x R) |
where Omega is Sun's spin axis (in J2000 GCI)
N completes the right-handed triad
GSE - Geocentric Solar Ecliptic
X = Earth-Sun Line
Z = Ecliptic North Pole
GSM - Geocentric Solar Magnetospheric
X = Earth-Sun Line
Z = Projection of dipole axis on GSE YZ plane
HSEa - Heliocentric Solar Ecliptic (Inertial)
X = First Point of Aries
Z = Ecliptic North Pole
HSEb - Heliocentric Solar Ecliptic (Earth Oriented)
X = Sun-Earth Line
Z = Ecliptic North Pole
HS - Heliocentric Solar
X = Intersection between solar equator and solar central meridian as
seen from Earth
Z = North Pole of solar rotation axis
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Last Updated: Sep 15, 1998
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