For all you GPS watchers from c.s.y-2000.
------------------------------
I know you hate long messages but ...
Since we are now less than 2 weeks away from the Aug. 21-22 GPS EOW
rollover, many people may want some background with regard to what kind of
effects might be likely.
Unfortunately, although I have myriad references on this topic, none of them
attempt to come to any bottom line with regard to potential aggregate impact
on the infrastructure. I do have a lot of detail and references though and
this message points to those.
Notably, although NERC alludes to the fact that the electric utilities use
GPS time data, any GPS receiver malfunction is not expected to have any
significant impact on power delivery. There are some supporting references
for this idea below.
-----Original Message-----
From: Harlan Smith [mailto:hwsmith@cris.com]
Sent: Saturday, July 24, 1999 15:56
To: WG - CPSR
Subject: RE: GPS Information; Smith
...
I found tyjcom.bc.ca
This is not a formal reference but provides some interesting comments.
[snip]
Power Grid and Communications Network Concerns
The North American power grid consists of power generating, distribution,
control and monitoring equipment owned and operated by various power
entities. These are all connected in one grid which is phase synchronized at
60 Hz. I expressed concerns to a hydro-electric power engineer regarding
what would happen if generators all lost their timing and began to go out of
phase. I anticipated complete chaos.
He assured me that the physics behind the grid causes each generator to stay
in phase. There is no real need for each generator to be kept in phase once
it is established. Kind of like the Borg Collective takes over peoples minds
in Star Trek ... "resistance is futile".
But it is not that simple. He had more concern about the effect of lost
timing in monitoring equipment which could result in false failure alarms.
These could cause breakers to be thrown which could break up parts of the
grid.
Now here is an interesting twist. He was more concerned about the GPS 1024
Week Rollover event in August this year than the millennial transition. This
is because much of the monitoring equipment derives its timebase from the
GPS satellites. So there may not be power disruptions at the final
transition. These may all occur in the middle of the summer where we just
sweat it out a bit instead of freezing. This could be considered a blessing
in disguise. It is possible that some power entities use equipment that is
GPS 1024 Week Rollover compliant, but not Year 2000 compliant so still be
ready for potential power disruptions.
Power disruptions likely would occur at UTC transition and on the hour as
each time zone locally transitions. These may be minor bumps, brownouts,
fluctuations, but could escalate to major outages if monitoring systems
issue false alarms and throw switches to place systems offline. Hopefully
damage would be minimal and the system will be back up soon. My
hydro-electric engineer contact likely will be on call during the holiday
season.
[There are a lot of complex "subtleties" in the above statements, so that
makes this information very difficult to assimilate without closely
examining the technical issues associated with each potential problem. What
might happen remains rather obscure, without doing that detailed technical
examination.]
hpiers.obspm.fr
[snip]
COORDINATED UNIVERSAL TIME -- UTC
UTC is the time scale that is used worlwide to coordinate technical and
scientific activities. It is a compromise between the highly stable atomic
time and the irregular Earth rotation."
[end snip]
aldridge.com
[snip]
"Weather observations and forecasts are usually reported in UTC, which used
to be known as Greenwich Mean Time (GMT), i.e. the local time at the
Greenwich meridian (zero degrees longitude). This allows weather
observations the world over to have the same time stamp.
Since UTC is ahead of local time in the United States, sometimes weather
data will have tomorrow's date, but it still represents today's data (we are
not THAT good at forecasting the weather).
UTC is 8 hours ahead of Pacific Standard Time (e.g. 0000 UTC is 4 p.m. PST
the previous day, 1200 UTC is 4 a.m. PST the same day), 7 hours ahead of
Pacific Daylight Time (e.g. 0000 UTC is 5 p.m. PDT the previous day, 1200
UTC is 5 a.m. PDT the same day).
UTC is "Coordinated Universal Time", or "Universal Time, Coordinated". It is
UTC instead of UCT because the abbreviation is based on the initials in
French, not English.
[end snip]
GPS 1024 Week Rollover is also a concern to those who depend on pagers and
other mobile communications systems. Many such systems use GPS timing
signals to keep radio modems and transmitters in phase as part of
simulcasting. This is a technique which allows many transmitters to be used
to provide uniform signal coverage without having it disrupted by phase
cancellations. If some of these systems fail to keep sync, the result will
be disrupted communications. Susceptibility to problems will depend on the
products and manufacturers and whether or not updates have been made
available by the vendors, AND INSTALLED by the operating entities. Probably
the least susceptible systems will be the older analogue cellular (and IMTS)
networks and private two-way radio systems. CB radio should work as good as
ever (matter of opinion ;-). Same with amateur radio.
Although I haven't done any specific research on this, there are numerous
synchronous communications protocols in existence, some wireless, some based
on wire, many of which could involve multiple localized clocks all kept in
sync to a master source. In any of these situations, there is possibility of
problems depending on the technology and engineering practices used to
deploy the technology. Both GPS 1024 Week Rollover and Year 2000 Final
Transition "chrono events" are dates to be concerned about with such
systems.
[end snip]
There is a very comprehensive set links at
transity2k.org but none seem to the specific question
of potential GPS malfunctions and their impact at EOW rollover.
Even more comprehensive is "GPS World" magazine
gpsworld.com, but still does not seem to answer your
question.
Very good technical reference, many links
utexas.edu
More technical gpsworld.com
Comparison of timing sources giswww.pok.ibm.com
TrueTime truetime.com
At y2ktimebomb.com
Dick Mills says:
[snip]
Some EMS systems use the timing signals from GPS to establish an accurate
time reference. Some use the WWV radio signal from the national bureau of
standards. If neither of these is available, any source of simultaneous
events can be used to synchronize clocks. The Weather Channel is a good one.
The theme music from National Public Radio's hourly news broadcasts could be
another. Remember that the important point is that all utilities in the grid
synchronize their watches with the same source. The accuracy of the common
source is less important.
If any utilities are concerned that the GPS rollover on August 22, 1999 will
cause any kind of disruption, they should switch to another source of time
reference in advance. In fact, they could switch today and leave it that way
until well after 2000.
[end snip]
Of course I earlier pointed out that NERC indicated that electric utilities
depend on GPS timing signals.
nerc.com
[snip]
Energy management systems -- Control computer systems within the electric
control centers across North America use complex algorithms to operate
transmission facilities and control generating units. Many of these control
center software applications contain built-in time clocks used to run
various power system monitoring, dispatch, and control functions.
Many energy management systems are dependent on time signal emissions from
Global Positioning Satellites, which reference the number of weeks and
seconds since 00:00:00 UTC January 6, 1980.
[end snip]
I tend to believe Dick Mills as above, rather than the NERC planning
document. There should be some work done to reconcile these two, somewhat
conflicting statements.
A Y2K problem is mentioned in that equipment interfaced to GPS receivers
with two digit date output may not handle the two-digit date properly, even
though the receiver output is correct. See
bancomm.com
EOW rollover problems are discussed at: bancomm.com
[snip]
The corrective action to be taken (if any) is indicated in the table at the
end of this report . In general, one of the following five conditions will
prevail:
1. No correction required: This product was built with an awareness of the
GPS Week Rollover event, and a correction is built in.
2. Firmware upgrade: A new PROM will be furnished, or a download to flash
memory will be required to cope with the GPS Week Rollover. There will be
some units with custom firmware that cannot be corrected.
3. Hardware modification: A special microprocessor will process the serial
data stream from the GPS receiver module, make the week number correction
and pass the corrected data to the existing GPS logic. This is a simple
modification that can easily be installed in the field. Datum may elect to
replace the internal GPS receiver module in some products.
4. Replace ACUTIME Antenna/Receiver: Some GPS products use the Trimble
ACUTIME, which is an antenna and receiver packaged together in a single
module to be mounted on a mast. Most of these older units (before 1997) must
be replaced. Newer ACUTIME units have been corrected by Trimble.
5. Unable to correct: Some units that were provided with custom software or
hardware (logic) modifications cannot be corrected. This is also true of the
original Datum GPS Receivers, the Series 9390-5000 and Series 9390-5100.
These units have been obsolete for some time, and parts are simply not
available for them. Units that fall into this category can only be replaced.
[end snip]
Recommended repairs from this vendor appear at
datum.com
Differential GPS - Interesting system sponsored by FAA
The Chrono-log GPS (Global Positioning System) Time Synchronization option
for the K- Series Multi-System Clock/Calendar provides unattended time
synchronization to Coordinated Universal Time (UTC) ... anywhere in the
world! chronolog.com
GPS and a hint of a looming disaster
shineon.org
Detailed Discussion with many links
y2k-status.org
Georgia Tech "Time Server" navobs1.gatech.edu
I'm disappointed that I did not find more information on the potential
impact of EOW rollover on the infrastructure.
There is an opportunity here for a good investigative reporter to check
directly with all the suppliers and users of GPS equipment for both
navigation and time.
Harlan
>-----Original Message-----
>From: 'Doc' Don Taylor [mailto:docdon@pobox.com]
>Sent: Saturday, July 24, 1999 00:13
>To: Simon Leung (HWL - Assist. Mgr, Corporate Systems Co-ordination, GISD);
WG - CPSR
>Subject: RE: GPS Information
>
> If you search at Continuum 21 Foundation
><http://members.visi.net/~certus/yca> you should find some links that
>provide some of this information.
>
>Doc
>
>At 09:48 AM 7/24/1999 +0800, Simon Leung (HWL - Assist. Mgr, Corporate
>Systems Co-ordination wrote:
>>Thanks for the "technical" information provided by Harlan on the GPS. From
>>the general public or ordinary people perspective, what are the risks or
>>impacts by the list of GPS producers for equipment / software with NO
>>information on compliance? Is there any web sites or books that talk about
>>the business applications or equipment / systems usage that would directly
>>or indirectly affect an ordinary citizen? Most of the examples that I
heard
>>were related to the airplanes or ships. Is the solution by simply staying
>>away from these vehicles?
>>
>>Best regards,
>>Simon
-----Original Message-----
From: Harlan Smith [mailto:hwsmith@cris.com]
Sent: Friday, July 23, 1999 11:36
To: WG - CPSR
Subject: GPS Information
This is the most comprehensive GPS information that I have seen
sustainableworld.com
[snip]
GPS Manufacturers
The attached list of manufacturers is included to provide easy access to
information on the ability of specific pieces of equipment to deal
effectively with the rollover. This list is followed by a list of other GPS
equipment suppliers. These lists are in alphabetical order. They will be
revised regularly.
The number of manufacturers posting information on roll-over compliance on
their web sites has increased significantly since early January 1999,
however, many manufacturers are still not providing information. Where
information on rollover compatibility has been found on a site links will be
given for both the home page and the compliance page and the name of the
manufacturer/supplier will be printed in green. This list does not imply an
endorsement of any of the manufacturers nor does it guarantee the accuracy
of any of the information provided. This list is based on information
developed by the Canadian Space Geodesy Forum
gauss.gge.unb.ca, the University of New Brunswick
unb.ca and the United States Naval Observatory . The
original lists can be seen at UNB gauss.gge.unb.ca and
USNO ftp://tycho.usno.navy.mil/pub/gps/gpsou.txt
. Please send inquiries to gpsbug@sustainableworld.com. We will try to find
information on any missing manufacturers, but we cannot research the
compatibility status of any specific equipment. There are three web sites
with additional manufacturer information. GPS MANUFACTURERS
navcen.uscg.mil
ml
contains the addresses and phone numbers of several manufacturers. Mitre
mitre.org provides a list of GPS
manufacturers accompanied by web links (when available) and phone numbers.
The US Department of Defense
laafb.af.mil has a list of
receivers that have been tested for compliance.
Producers of related equipment/software with information on compliance
- Differential Corrections Inc. (DCI)
Home Page -- dgps.com
Compliance -- dgps.com
- GEOSurv, Inc.
Home Page-- geosurv.net
Compliance --http://www.geosurv.net/y2k.htm
- James Associates
Home Page -- csn.net
Compliance -- csn.net
- Resource Industry Associates
Home Page -- ria.com.au
Compliance -- ria.com.au
- TAL Technologies, Inc.
Home Page --http://www.taltech.com/
Compliance --http://www.taltech.com/news/taly2k.htm
- Waypoint Consulting Inc.
Home Page -- waypnt.com
Compliance -- waypnt.com
See sustainableworld.com for
the URLs of the following
Producers of related equipment/software with NO information on compliance
- ACCQPOINT
- Advanced Research Corporation
- The Aerospace Corporation
- AmeriCAD Systems, Inc.
- ASC Scientific
- ATI Networks
- ATX Technologies, Inc.
- Avcan Global Systems Inc.
- Averstar
- BITRONICS, Inc. AVL Management Systems
- The Brunton Company
- CANSEL - Canadian Survey Equipment
- C-Map USA
- ComROAD/Solid Computer Group
- CSL CommTech Ltd.
- Dan Bobyn Engineering Ltd.
- Datachron Inc.
- DCS Corp.
- DeLorme Mapping
- Dorne & Margolin, Inc.
- ELIRIS (Earth, Land and Integrated Resources Information Systems) Inc.
- EnviroTrac Technologies
- Etak, Inc.
- ETE, Inc.
- FieldWorker Products Limited
- Fugro Starfix (Europe) AS
- GeoLine Positioning Systems, Inc.
- Geosystems
- GeoSpatial Solutions Pty. Ltd.
- Géosystèmes Inc.
- Gigatron Associates Limited
- Greenfield Associates
- Hans Trautenberg Software Consulting
- Holst-Weber Enterprises .
- Horizons Technology, Inc.
- Horyzont-KPG Ltd.
- Houston Geoscan, Inc.
- Hydrografix Overseas Consultancy Service.
- Hyperdyne Inc.
- Inmarsat
- INSAT L.C.
- Intelligent Databases International Ltd.
- Intermetrics, Inc.
- Knook Electronic Systems
- K&L Agri Sales, Inc.
- K&L Microwave, Inc.
- Lambda Tech International, Inc.
- Larson Systems, LLC.
- L.A.S. Systems, Inc.
- Liikkuva Systems International, Inc. (LSI)
- Location Technologies
- Lowe Electronics Ltd.
- Manning NavComp
- Marfor Equipment Ltd.
- Mathew Vangel and Associates
- Megapulse, Inc.
- Midwest Traffic Products, Inc.
- Mini-Circuits
- MPN Components
- Navigation Electronics, Inc.
- Navionics
- Navitrak Corp. and Navimap Corp.
- NAVSYS Corporation
- Nobeltec Corporation
- North Coast Resource Management
- Outland Technology Inc.
- Paccomm Packet Radio Systems, Inc.
- Pacific Crest Corporation
- PCI Enterprises Inc.
- Pelorus Navigation Systems, Inc.
- Philsar Electronics Inc.
- Pro Tech Monitoring, Inc.
- QSI Corp.
- Radio Satellite Corporation
- Rockwell International Corp.
- Rockwell Semiconductor Systems
- Stellar Navigation Systems Inc.
- Steve Lieber & Associates, Inc.
- Sunninghill Systems
- Tendler Cellular
- TT Designs Marine Computing
- University Technologies International, Inc.
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