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Re: A Question About InstantTrack and AO-40



get the new update for it (1.53?) and then you can put the attitude in as
the ao-40 team posts it. mainly 1/2 -z :)


Scott Elliott
Scott@Pieh0.co.uk
M1SJE / 2E1FJB
----- Original Message -----
From: "Paul Williamson" <kb5mu@AMSAT.Org>
To: "Joel Black" <jbblack1@earthlink.net>
Cc: "AMSAT-BB" <amsat-bb@AMSAT.Org>
Sent: Tuesday, May 07, 2002 5:28 AM
Subject: Re: [amsat-bb] A Question About InstantTrack and AO-40


> At 10:37 PM 5/6/2002 -0500, Joel Black wrote:
> >    "...Note that this type of attitude calculation will only work as
long
> >as AO-40 is in spin mode. After the orbital maneuvers are completed, AO-
> >40 is supposed to go into a 3-axis stabilized mode. InstantTrack 1.50
can't
> >handle that type of attitude mode. Perhaps there will be a
> >new version that can, someday."
> >
> >My question is in regards to the next to last statement.  Is this still a
> >problem with InstantTrack?
>
> Yes it is, and as far as I know this is also a limitation of EVERY other
> satellite tracking program in the world. The problem is that nobody knows
> how the command team will manage AO-40's attitude.
>
> One possibility (at certain times of year) is that they will keep the
> antennas exactly nadir-pointing at all times. InstantTrack can handle
that,
> since it is the same attitude as a gravity-gradient stabilized spacecraft
> (ideally). For this case, enter "L" for "Local Vertical" in InstantTrack's
> attitude coordinates field.
>
> However, they won't be able to keep it that way all the time. Other times,
> perhaps they will have it fixed nadir-pointing during certain MA periods
> near apogee and pointing somewhere else at other times. A practically
> infinite number of other combinations are possible. Until the whole range
> of possibilities is known, software authors will be at a loss to implement
> a suitable attitude prediction mechanism for AO-40.
>
> I imagine that even the command team doesn't know yet. They probably have
> an idea of what they would like to do, but until they have characterized
> the capabilities of the 3-axis stabilization system and gained some
> experience operating it, they won't be able to predict with any certainty
> what the attitude management scheme will look like.
>
> I hope the command team will let us know what they're planning to try,
> somewhat in advance. If they announce the scheme they are writing up for
> the IHU, then software authors have a chance of getting the corresponding
> scheme into tracking programs. I hope and believe that I'll be able to
> update InstantTrack in a timely way to keep up with AO-40.
>
> 73  -Paul
> kb5mu@amsat.org
>
> ----
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