[time-nuts] Fwd: CGSIC: Known Problem With Certain GPS Devices
Magnus Danielson
magnus at rubidium.dyndns.org
Fri May 16 19:01:50 EDT 2014
They can't point official fingers. That's why.
Ask you vendor if they need firmware upgrades to comply in this aspect.
Cheers,
Magnus
On 05/16/2014 12:39 AM, SAIDJACK at aol.com wrote:
> It would be good to understand which receivers are adversely affected by
> this.. the USCG did not list affected vendors/devices..
>
>
> In a message dated 5/15/2014 15:19:51 Pacific Daylight Time,
> magnus at rubidium.dyndns.org writes:
>
> Hi fellow time-nuts,
>
> I think this message is interesting. It shows that some receiver vendors
> have been cheating on an important detail, ignoring the health status
> and being confused as a result.
>
> Cheers,
> Magnus
>
>
> -------- Original Message --------
> Subject: CGSIC: Known Problem With Certain GPS Devices
> Date: Thu, 15 May 2014 21:20:23 +0000
> From: Civil Global Positioning System Service Interface Committee
> (CGSIC) <cgsic at cgls.uscg.mil>
> Reply-To: cgsic at cgls.uscg.mil
> To: cgsic at cgls.uscg.mil <cgsic at cgls.uscg.mil>
>
> All CGSIC:
>
> May 15, 2014
>
> Recently, many GPS users have reported intermittent GPS outages in their
> devices. After investigating, the U.S. government has linked the
> problem to flawed processing of GPS satellite data within certain GPS
> receiver chipsets. The GPS satellite service continues to function as
> designed and is fully operational and available worldwide.
>
> The problem affects only user equipment that erroneously ignores the
> satellite health status information broadcast from every GPS satellite.
> The problem is not related to the April 28, 2014, activation of civil
> navigation messages on the GPS L2C and L5 signals.
>
> Since March 15, 2014, the Air Force has been conducting functional
> checkout on a GPS satellite, designated Space Vehicle Number (SVN) 64.
> SVN 64 broadcasts a data message that clearly indicates SVN 64 is
> unusable for navigation. Nevertheless, the U.S. government has
> confirmed that certain GPS receivers are using data from SVN 64, in
> violation of GPS interface specifications, resulting in outages or
> corrupted, inaccurate position calculations.
>
> The Air Force testing is scheduled to end in mid-May 2014 at which time
> SVN 64 will begin normal operation. At that point, these problems may
> stop occurring. Meanwhile, the U.S. government urges all GPS device
> makers to review their products for compliance with the GPS interface
> specifications, and if necessary, to issue software/firmware updates to
> users as soon as possible. View specifications
> http://www.gps.gov/technical/icwg/
>
> Users experiencing GPS outages should check with their device
> manufacturers for available software/firmware updates. In addition, any
> civil user seeing unusual behavior in GPS user equipment should report
> it to the U.S. Coast Guard Navigation Center (NAVCEN). Aviation users
> should file reports consistent with FAA-approved procedures. Military
> users seeing unusual behavior should report it the GPS Operations Center
> (GPSOC).
>
> Please direct any civil user questions to NAVCEN at (703) 313-5900,
> http://www.navcen.uscg.gov
> Please direct any military user questions to the GPSOC at (719)
> 567-2541, DSN: 560-2541, gpsoperationscenter at us.af.mil
> https://gps.afspc.af.mil
> Military alternate: Joint Space Operations Center, (805) 606-3514, DSN:
> 276-3514, jspoccombatops at vandenberg.af.mil
> ----
> See also:
> Technical explanation for device makers (PDF)
> http://www.navcen.uscg.gov/pdf/gps/GPSOC_PRN 30_Notice.pdf
>
> V/R
> Rick Hamilton
> CGSIC Executive Secretariat
> GPS Information Analysis Team Lead
> USCG Navigation Center
> 703-313-5930
>
>
> _______________________________________________
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>
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> email to: CGLSAdmin at uscg.mil
>
>
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