[Isocops] [Ibexops] IBEX AUWA Contact DOY 330 @ 1300 UTC

[Steve Montgomery]

Last week (on or about Wednesday 17th Nov)  we did remove two Enertec-3801 units that we were hosting for one of our customers.  An Enertec 3801 is similar to a cortex.  it does commanding, telemetry, and raniging.

These units did use IRIG-B for station timing and the 5-MHz station reference.  Each of these signals was disconnected form the removed units and the associated signal source ports were terminated with 50-ohm loads, per standard practice.

None of this should have affected the Doppler measurement performance on IBEX.  The IBEX support equipment connections remained unchanged.   The distribution amplifiers that carry the IRIG-B adn 5-MHz signalling are common to the IBEX equipment and the removed equipemnt, but it seems unlikely that the equpment remvoal would have caused any changed to the IBEX measurments.

I just wanted to let you know that there was a change to the station, but I don't suspect, nor understand, why such a change would have had any impact on IBEX.  Nothing was changed to the source of the 5MHz reference or the IRIG-B signaling.  That all comes from the GPS recevier via distribution amps to the cortex equipment.   None of the changes made would have impacted the 5MHz freqeuncy stability or the IRIG-B timing stabiltiy.

Regards,

Steve




________________________________
From: Lisa Policastri [lisa at applieddefense.com]
Sent: Friday, November 26, 2010 10:52 AM
To: 'IBEX FDG'; ibexops at lists.sr.unh.edu; Don Gittle; Dan Hobel; 'Sheral Wesley'; 'Tim Perry'; 'Michelle Reno'; jscherrer at swri.edu; 'lockwood.robert'; Steve Montgomery
Subject: IBEX AUWA Contact DOY 330 @ 1300 UTC

Good morning,

Today’s Australia IBEX contact provided Doppler which showed a bias of +2.7 cm/s off of the constant bias of -0.5 cm/s we were using on that station for quite some time.   We likely need to re-baseline Australia once we receive more samples from that station to expect a different, more “up-to-date” constant bias.  At this point we believe the Doppler is not bad, but a slightly larger than typical difference in our predict is showing up upon acceptance of this data.  We’ll call this a successful contact for now.  If information later changes this, I will let you know.

Have a good weekend!
Lisa

Lisa Policastri
IBEX Flight Dynamics Lead
Applied Defense Solutions
lisa at applieddefense.com<mailto:lisa at applieddefense.com>
mobile 443.388.0526



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