Altitude in meters above WGS-84 Geoid ?
Ruben Velasco (heston@arrakis.es)
Mon, 2 Mar 1998 12:43:29 +0100 (MET)
Hi! I've been reading Seesat-L for months. Now it's about time to
participate with this stupid question I have. Here we go:
When you enter your local altitude to a tracking software like Iridflar,
Stsplus, Trakstar... should you enter the metres above the sea level or
above the WGS-84 model? For example, I'm writing this from a place
"oficially" at 9 meters "Above Sea Level". But the sea level stardard
we use here is actually several metres higher than, say, that of the
Indian Ocean near Sri Lanka. In other words, the Earth is not a perfect
spheroid, etc, etc (you already know the story :)
The issue came to my mind a few weeks ago when someone said it was
nonsense to specify your coordinates with a precission of meters or
arcseconds.
So, taking into account that there is a small "bulge" in this part of
the world of about 30 meters, am I right or wrong if I say that my
altitude is really of 39 meters? When people specify their
positions, in their signatures for example, which "altitude" are they
using?
Note: I know that this issue is of no practical interest, with the
errors in the TLE's, the SGP4/SDP4 model, and all that stuff.
It's just curiosity.
Thanks in advance,
--
Ruben Velasco <heston@arrakis.es>
ICBM: 37.3877N 6.0008W +39M UTC+0100 Sevilla, Espa=F1a.
PGP KeyID 37219E45 Fingerprint =3D 96575B8713370081 1BC5D43D324B3F4D