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Re: AO-27 TEPR state explanation



Thanks for the kind suggestion Jeff!  I'll get right on it today.

Any suggestions, comments, or corrections to improved the satellite 
information pages are always welcome.

- Steve N7HPR


At 08:20 AM 11/7/99 -0500, you wrote:
>I'm asked to explain TEPR about one a month. I also noticed that this
>info isn't in the AO-27 spacecraft information area of the AMSAT site. It
>should be added to the schedule and operation area in AO-27  spacecraft
>information.
>
>73 Jeff kb2wqm
>
>
>
>On Sun, 7 Nov 1999 07:51:42 -0500 "Chuck Wyrick" <cwyrick@mediaone.net>
>writes:
> > Here is a reprint of a previous posting explaining the TEPR meaning
> > on
> > AO-27.
> >
> > To summarize:  We set the bird to charge its batteries for "x"
> > number of
> > minutes AFTER it enters the Sun.  This is TEPR state 4 expressed in
> > 30
> > second increments, e.g. TEPR 42 means that the charging time is 21
> > minutes.
> > We then set TEPR state 5 to the length of time, expressed in 30
> > second
> > increments, that the transmitter would be on from the start of TEPR
> > 4 but
> > not on until the completion of TEPR 4, e.g. TEPR 78 means that the
> > transmitter will shut off 39 minutes after the start of TEPR 4, but
> > the
> > transmitter will be on for 18 minutes. (78-42 =36, or 18 minutes)
> >
> > AO-27 TEPR States Explained
> >
> > AO-27 uses a method called Timed Eclipse Power Regulation (TEPR) to
> > regulate the batteries.  In simple terms, TEPR times how long it has
> > been in the eclipse or in the sun and decides what subsystems to
> > turn
> > on or off.
> >
> > The current software onboard AO-27 breaks an orbit into 6 different
> > states as follows:
> >
> > TEPR State 1:  Starts when the satellite enters the Eclipse
> > TEPR State 2:  Starts a programmed time after TEPR State 1 (Still
> > during the Eclipse)
> > TEPR State 3:  Starts a programmed time after TEPR State 1 that's
> > after State 2 (Still during the Eclipse)
> >
> > TEPR State 4:  Starts when the satellite enters the Sun
> > TEPR State 5:  Starts a programmed time after TEPR 4 (Still in the
> > Sun)
> > TEPR State 6:  Starts a programmed time after TEPR 4 that's after
> > State 4 (Still in the Sun)
> >
> > Current Subsystems by State:
> > TEPR 1,2,3 - all unneeded Subsystems turned off (This is why there
> > is
> > no Night time use of the satellite)
> > TEPR 4     - AO-27 Transmitter is turned to exciter power only. All
> > other Transmitters are off.
> > TEPR 5     - AO-27 Transmitter is turned to 0.5 watts (low power)
> > TEPR 6     - all unneeded Subsystems turned off
> >
> > Using this Model, During a descending, day-time pass, AO-27 will
> > enter
> > TEPR 4 after coming out of the eclipse and will start to recharge
> > its
> > batteries.  We program the TEPR 5 time so the satellite will stay in
> > TEPR 4 until the foot print reaches latitudes equal to the Northern
> > United States.  At that time, it changes to TEPR State 5 and the
> > transmitter turns on.  The duration of TEPR State 5 is set for the
> > longest we can leave the transmitter on to keep the batteries in a
> > state that will prolong their life time.  At the current time (June
> > 1999) this is 18 minutes.  If we were to leave it on longer we would
> > start to limit the life time of the satellite.  The TEPR 6 period
> > needs to be long enough to recharge the batteries before we enter
> > the
> > eclipse again (TEPR 1).
> >
> > The time we need to stay in TEPR 6 is what places a limit on the
> > southern latitudes we can work in.
> >
> > 73
> > Chuck, KM4NZ, Acting Control Operator
> >
> >
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>
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- Steve, N7HPR
   n7hpr@tapr.org
   n7hpr@amsat.org

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