GPS Millennium Bugs Disables Many Receivers
No planes fell out of the sky, no ships ran aground. But anticipated problems on the August 22 199 GPS EOW Rollover Day did occur. Some bank services which derived their time from GPS time failed, including credit card transactions. And a sizeable number of GPS receivers were found to have reverted to a date in 1980.

GPS, the Global Positioning System established and run by the US Department of Defense, only became fully operational and world-wide in 1995, but is of ever-growing importance. The use of GPS is becoming vital not only for navigation, but for many applications such as precision farming, in mining, urban planning, and tracking of vessels, vehicles, and containers. News Flash Administrators of Joint Program Office that administers the GPS Program for the US Air Force recently announced the discovery of a bug in the last 36 hours of the current (GPS) millennium which will cause many receivers to reset to their start-up date. This start-up date may be the first date in the GPS millenium in 1980, or a later date in 1984, or it might be the date that the receiver was factory-tested or was first field-operational. This new GPS Millennium Bug, is in addition to the Y2K and the anticipated GPS Bug in receivers due to failure to properly anticipate the EOW roll-over.

Millennium Bug
January 1, 2000
Back in the sixties and seventies, and even beyond, many computer systems used just 2 digits to store year data, so only 99 years can be consistently stored. at the end of the first century lying within the Information age, at January 1, 2000, the problem first arises. Its called the Millennium bug, but really its a century bug.

Millennium Bug
132 days earlier
Satellites are potentially afflicted with a genuine millenium bug, which can emerge on August 22, 1999. This Millenium Bug is based on a digital thousand, 1024, and its also called the GPS EOW Rollover Bug.
GPS system time counts weeks from midnight 5-6 Jan 1980 in modulo 1024 (0-1023) -- a digital millenium of weeks.
The data packets from GPS SV (space vehicles) include all time information, including the week.
At 0000 hours, UTC, 22nd August 1999 the first GPS EOW roll-over occurs.
For details see the article by (US) Lt Al Johnson, GPS Y2K Lead Engineer, MILLENNIUM (Y2K) AND GPS END OF WEEK (EOW) ROLLOVER Major suppliers of GPS navigation devices claim to have prepared their computational systems for this day. However, incidents on the actual GPS EOW roll-over day are possible.

Links to GPS Rollover and Y2k information sites:

Which is the Millennium Satellite ?

The ARIES Satellite will be launched in 2000. FedSat 1 will be launched in 2001. Which of these two Australian satellites is the Millennium Satellite?
Australian Prime Minister John Howard has declared that the next Millennium starts in the year 2001.
The Australian Government support for Australian Space Technology, with its support for FedSat 1 through the CRC for Satelliet Systems, and its indirect support for ARIES will help Australia to new opportunities in space in the next millennium.
But the question remains.
Which of the two Australian scientific satellites about to be launched will truly be the Millennium Satellite?

Australia in Space
a History


Australian Resource Information and Environment Satellite
A low earth orbiting (LEO) microsatellite
ARIES will be equipped with sensors to scan the earth over a range of frequencies, to evaluate ground cover and type, and, especially in arid regions, map rock types and geological data.

FedSat 1
Australia's Scientific satellite launched to celebrate the Centenary of the Federation of Australian states January 1, 1901.
A low earth orbiting (LEO) microsatellite
FedSat 1 is to be the first satellite to be launched by the Australian Cooperative Research Centre on Satellite Systems. The CRCSS aims to foster Australian satellite design, communication, control, and operational engineering skills. FedSat 1 is to use the recently established network of GPS and Glonass satellites to study the ionosphere and atmosphere.
The well known Y2K or millenium bug arrives too early to affect FedSat 1 or ARIES.
At 0000 hours, UTC, 22nd August 1999 there is the GPS EOW roll-over.

Home Page
Quiz on Satellites and GPS
      Enquiries and Comments to the Webmaster   Dr Harvey A. Cohen