Re: Granat to reenter next year

Björn Gimle (b_gimle@algonet.se)
Sat, 14 Nov 1998 21:08:51 +0100

>Jason Hatton wrote:
>
>>Does anybody know of any software packages
>>which can accurately predict the position of a satellite in a highly
>>eccentric orbit which is subject to significant solar / lunar
>>pertubations?
>
I used Jim Varney's Track16 with Granat elsets for days 314, 310, 293, =
273 and 264
to generate 'fake observations' from lat 40N, long 100E close to the =
epoch times.
Then I used elcor, with weight 0.1 for the Sept/Oct 'observations' (1.0 =
for Nov.)
to generate an elset that 'fits all'

The residuals were less than 5 degrees for the old points, up to 60000 =
km,
and less than two degrees for later positions below 20000 km range.

Since the time frame used is 1.7 lunar orbits, periodic effects can have
distorted the computation. A shorter (or longer) time frame could be =
more
reliable. When/if data for three consecutive perigee passes are =
available,
predictions within a degree ( or minute of time near perigee ) could be
achieved for the next perigee or two ?

GRANAT elcor
1 20352U 89096A   98314.25726220  .00000000  00000-0  10532+4 0 90008
2 20352  64.8178 291.6839 8628333  18.5617 353.4333  0.24434043  5942