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GIAC memo 2001/06/07

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   <title>GIAC Memo: Digital Distortion Anomaly Test</title>

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<td><a href="../"><img SRC="fgcsicon.gif" BORDER=0 height=115 width=110 align=LEFT></a></td>



<td ALIGN=RIGHT VALIGN=CENTER><b><font size=+3>GIAC </font><font size=+2>GPS

Interagency Advisory Council</font></b></td>

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<p>

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<td ALIGN=RIGHT COLSPAN="2">7-September-2001</td>

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<td VALIGN=TOP>GIAC News Flash:</td>



<td VALIGN=TOP>Digital Distortion Anomaly Test</td>

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<pre>
The final test plan for the waveform anomaly test is confirmed 
as September 10-12, 2001:

      Monday     J253/1300 - J254/0306   Configuration 1 
      Tuesday    J254/2003 - J255/0302   Configuration 1 
      Wednesday  J255/2000 - J256/0258   Configuration 2
     
Notes:
     
These dates are julian dates.  Day 253 is September 10.

All times are in GPS time, which is basically equivalent to UTC.  Time 
1300 therefore corresponds to 0900 on the east coast.

In Configuration 1, the NDU Baseband and Processor will re-configured 
to the A-side, and the L1 MOD-IPA will also be configured on the 
A-side.

In Configuration 2, the NDU Baseband and Processor will remain on the 
A-side, while the L1 MOD-IPA will be re-configured to the B-side.
     
Note that transmission of P(Y) on L1 and L2 is at the discretion of 
the test operator (2 SOPS/DOUAN.)
     
Users who do experience problems during the test should report them 
through the Coast Guard 24-hour information watch.  The phone number 
for the watch is (703) 313-5900 and email: nisws@navcen.uscg.mil. 
Pilots who experience problems should contact their nearest flight 
service station to report the details.  Testing will be halted if a 
large number of users detect problems.
</pre>
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<td ALIGN=RIGHT COLSPAN="2">14-August-2001</td>

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<td VALIGN=TOP>GIAC News Flash:</td>



<td VALIGN=TOP>Digital Distortion Anomaly Test</td>

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<p>The PRN 19 Anomaly tests scheduled for August 15-18 have been rescheduled

to September 10-12.&nbsp; I apologize for the short notice, and we are

still working to improve the coordination process.&nbsp; I'm accepting

comments, complaints and criticisms.&nbsp; I will send out the test plan

and detailed schedule when they become available.

<br>Frank Lorge, GPS Civil Test Director, 609-485-4588, frank.lorge@faa.gov

<br>

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<td ALIGN=RIGHT COLSPAN="2">03-August-2001</td>

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<td VALIGN=TOP>GIAC News Flash:</td>



<td VALIGN=TOP>Digital Distortion Anomaly Test</td>

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<p>The new tentative schedule for PRN 19 Anomaly tests is from August 15-18.

We will use the same coordination process for stopping the tests quickly

if users experience severe problems. The point of contact will be the US

Coast Guard 24-hour information watch. The phone number for the watch is

(703) 313-5900 and email: nisws@navcen.uscg.mil.&nbsp;

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<td ALIGN=RIGHT COLSPAN="2">15-June-2001</td>

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<td VALIGN=TOP>GIAC News Flash:</td>



<td VALIGN=TOP>Digital Distortion Anomaly Test</td>

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<p>The planned anomaly test on PRN 19, tentatively scheduled for June 18,

2001, has been delayed indefinitely pending further review by the Air Force.&nbsp;

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<td ALIGN=RIGHT COLSPAN="2">07-June-2001</td>

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<td VALIGN=TOP>GIAC News Flash:</td>



<td VALIGN=TOP>Digital Distortion Anomaly Test</td>

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<p>There are tentative plans to perform a Digital Distortion Anomaly test

on GPS satellite PRN19.&nbsp; The tentative plan is that the test will

begin on June 18, 2001, and will last for 5.5 days (132 hours).&nbsp; The

health bit for PRN19 will be set to �UNHEALTHY� for the duration of this

test.&nbsp; This test is not expected to be noticed with standard GPS receivers,

since such equipment should not process data from unhealthy satellites.

<p>One purpose of this test is to attempt to replicate a signal distortion

observed in 1993 on PRN19.&nbsp; When the distortion first occurred, it

was corrected by switching to an alternative hardware path within the satellite.&nbsp;

If the distorted signal is successfully generated, it will be used to assess

the performance of specialized GPS test equipment known as signal quality

monitors.&nbsp; These monitors are important components in aviation augmentation

systems.

<p>We will update this web site as test plans are finalized.&nbsp; It is

likely that information will also be made available through the <a href="http://www.navcen.uscg.gov/">U.S.

Coast Guard Navigation Center</a>.

<p><font face="Arial"><font size=-1>for information write:</font></font>

<br><font face="Arial"><font size=-1>GPS INTERAGENCY ADVISORY COUNCIL</font></font>

<br><font face="Arial"><font size=-1>FEDERAL GEODETIC CONTROL SUBCOMMITTEE</font></font>

<br><font face="Arial"><font size=-1>NOAA, National Geodetic Survey, N/NGS</font></font>

<br><font face="Arial"><font size=-1>1315 East-West Highway, Room 8657</font></font>

<br><font face="Arial"><font size=-1>Silver Spring, Maryland 20910-3282</font></font>

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Last Updated: Feb 01, 2007 04:09 PM
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