Please can anyone help me on more detailed info about GPS rollover day (22nd August). I am scheduled to fly on that day at 3 a.m. G.M.T. Should I cancel? Is it the sort of problem that will become apparent immediately, as in at midnight G.M.T?What is the latest on fixups for this particular probem? Sorry if I am regurgitating old news but I have only just discovered this forum. Thanks to anyone who cares....Jen

-- Jen Anderson (jenandox@ozemail.com.au), August 03, 1999

Answers

There are 1,000's of articles on the GPS Rollover. Most seem to say that the Satelites are OK and the rollover is fixed in most GPS recievers. I am not a pilot, so don't know if it is a NECESSARY item to naviagtion - BUT are you willing to take the risk that day? I would postpone your trip for several days after the 22nd to BE SAFE.

-- dw (y2k@outhere.com), August 03, 1999.

I just received this today. ----------------------------------------------------------------------

DOT Press Release "End-of-Week" Rollover for GPS

FOR IMMEDIATE RELEASE June 4, 1999 Contact: Bill Mosley Tel.: (202) 366-5571 DOT 80-99

IMPORTANT INFORMATION FOR GPS USERS AND TRAVELERS

Users of the Global Positioning System (GPS) should be aware of two important dates: Aug. 22, 1999, the "End-of-Week" (EOW) rollover; and Jan. 1, 2000 (Y2K).

The Department of Defense (DOD) says the date changes are unlikely to affect the operation of GPS satellites or DOD's ground control center. But GPS receivers that consumers use may be affected by the date change. That can have important safety implications.

Consumers who depend on GPS for geographic locations at sea, on land or in the air, may experience one of the following problems with their receiver:

It will be unable to locate the satellites, resulting in the receiver not working. It will take more time than usual to locate the satellites. It will appear to be working but display inaccurate positions, times or dates.

GPS System Time will roll over at midnight 21-22 August 1999, 132 days before the Year 2000. On 22 August 1999, unless repaired, many GPS receivers will claim that it is 6 January 1980, 23 August will become 7 January, and so on. Accuracy of navigation may also be severely affected. Although it appears that GPS broadcasts do contain sufficient data to ensure that navigation need not be affected by rollover in 1999, it is not proven that the firmware in all receivers will handle the rollovers in stride; some receivers may claim wrong locations in addition to incorrect dates.

Some manufacturers have already solved the problem, but some have not.

What is GPS?

GPS is a satellite-based system that allows consumers who use electronic receivers to determine their location. Recreational boaters and pilots, hikers, campers, hunters, and fishermen are among the consumers who rely on GPS receivers. The military and businesses also use GPS.

End-of-the-Week Rollover and Y2K

The GPS EOW rollover occurs every 1,024 weeks -- about once every 20 years. The GPS system calculates time by counting the number of weeks since Jan. 6, 1980 -- up to a maximum of 1,023 weeks. At midnight between Aug. 21-22, 1999, the GPS week "counter" will roll back to zero weeks. DOD says this will not create problems for the GPS satellites or DOD's GPS ground control center, but it could present a problem for consumers who use older GPS receivers and related applications. That's because after Aug. 21, 1999, receivers could process satellite data incorrectly and display inaccurate information.

As for the Year 2000 date change, DOD has determined that the GPS satellites and its ground control center will operate properly after Dec. 31, 1999. But if consumer GPS receivers and applications are not Y2K-ready, they could process satellite data incorrectly.

What Should You Do?

If you use GPS, check with your receiver manufacturer to find out if your receiver and applications are EOW rollover- and Y2K-compliant. You may want to check the Coast Guard Navigation Center's web site (www.navcen.uscg.mil/gps/geninfo/y2k/default.htm), where the Department of Transportation has posted a list of receiver manufacturers and contacts. You also can call the free Y2K consumer hotline (1-888-USA-4-Y2K) for manufacturer contact information. You will need to tell the manufacturer your receiver's model, serial number, and the firmware version or release date displayed on the startup screen.

webmaster@smtp.navcen.uscg.mil Dated Last Modified: 14 Jun 1999

Sent by: John & Merre Putnam jlp.csp@juno.com ++++++++++++++++++++++++++++++++++

-- BB (peace2u@bellatlantic.net), August 03, 1999.

That's about as concise an answer as I've seen and it corrects me on an other thread. THANKS BB

Chuck

-- Chuck, a night driver (rienzoo@en.com), August 03, 1999.

Jen,

Airliners generaly fit into one of two categories, those that use GPS and those that don't. If it's an older airplane it typically won't use GPS, so, not too much to worry about there. If it's one of the newer generation airplanes they use what is called an FMS(Flight Management System). The FMS as a matter of function samples all available navigation signals and uses what it determines to be the appropriate signal, if the GPS appears unreliable the FMS will not use it for navigation.

IMVHO I don't think there is too much to worry about as far as being on an airplane during the rollover.

Nick

-- Nick Bogaert (hover@tampabay.rr.com), August 03, 1999.

I don't think there will be many problems with commercial airlines. However, there are many private planes sharing same airspace. There's a higher probability that some of these may not have upgraded receivers.

It get's confusing, doesn't it? Here's a statement from one of the biggest GPS manufacturers:

"GPS manufacturers are unable to predict with absolute certainty the precise manner in which GPS and associated firmware, software and systems will actually perform as a result of the Y2K and WNRO events.

Regardless of the manufacturer, Trimble recommends extreme caution in any situation in which a product's failure or inaccuracy would pose any risk of injury, damage or loss to persons, property or critical data.

In these cases, Trimble recommends that GPS not be relied upon at, after, or within the week before the Y2K and WNRO date rollovers, and until robust and accurate performance following the rollovers is conclusively established. Use of GPS products during these events is potentially hazardous. http://www.trimble.com/y2kwnro/policy.htm#noncompliant

Maybe everything's AOK and the attorneys wrote this disclosure.

-- Cheryl (Transplant@Oregon.com), August 03, 1999.

Another interesting article. I still don't expect problems with commercial airplanes though - at least in US.

Government expects problems on weekend of Aug. 21-22, when GPS systems have to change their date settings. http://www.hotcoco.com/news/business/businessstories/jfm30058.htm

EXCERPT

"We do expect this to be an event," said John Loveall, director of quality for Sunnyvale-based Trimble Navigation Ltd., a leading manufacturer of GPS receivers. "We are doing everything we can to minimize the risks. Our general advice (to GPS users) is don't blindly rely on the advice that the receiver is giving (on Aug. 21-22)."

The U.S. Department of Transportation last month issued a warning that "consumers who depend on GPS for geographic locations at sea, on land or in the air may experience  problems with their receiver" on Aug. 21-22 ...

The U.S. military believes the GPS satellites will handle the rollover just fine, but manufacturers expect some garble to occur in many of the receivers that translate the data. Some of the receivers might suddenly flash the date Jan. 6, 1980. Others might provide bogus information about locations. Still other devices might simply shut down briefly after the rollover because they no longer speak the same technological language as the satellites that serve as the system's brains.

At the same time, a huge number of GPS receivers may handle the WNRO without a glitch.

Older GPS receivers are considered the most prone to WNRO trouble, but newer models aren't invulnerable to the problem.....

-- Cheryl (Transplant@Oregon.com), August 03, 1999.

RE GPS Rollover:

Since GPS is used in many different ways, there are bound to be some foul-ups. I personally have viewed the event as a possible trigger point, as in mass awareness. If we experience something major in transport, finance, or utilites, and "if" the media reports, it's possible public awareness may move into a "new phase". Personal preparedness may become more difficult.

Best Regards,

-- Tom McDowell (bullriver@montana.com), August 03, 1999.