[time-nuts] HP 58503A
jimlux at earthlink.net
Fri Aug 3 13:31:06 UTC 2012
On 8/2/12 6:24 PM, Doug Reed wrote:
> I ran into a wiki description of GPS using WGS84 a couple days ago. It
> included a mention of ESEC and it was something like: Earth Static,
> Earth Centric. I think I was following a link about the Z3801A.
> It referred to the fact that lat-lon is referenced to a static grid on
> the Earth and doesn't change as the Earth rotates on its axis or around
> the sun. Earth static and Earth centric.
Earth Centered Inertial - ECI centered on the earth, doesn't rotate
with earth - very popular with earth orbiting satellites, because their
"center of rotation" is at the center of the earth but their orbital
plane is fixed in celestial terms. like RA/Decl
Earth Centered Earth Fixed - ECEF (or ECF) centered on earth, rotates
with earth. More like conventional lat/lon.
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