Attention all electronic wizards. Has anyone any information on this. (1)When the first GPS units were developed someone decided they should operate for only 1024 weeks. (2)That time is up on August 21. (3)At midnight the GPS system will roll over and revert to its starting date,leaving some units believing the date is January 6,1980. With all the new numbers and positions of satellites what happens at midnight August 21.Do boaties get the year 2000 bug early. ??????????????????????????????????? Greg Comerford M/V "VICTRESS" Australia. Get Your Private, Free Email at http://www.hotmail.com

At 16:39 3/23/99 , Greg Comerford wrote: >Attention all electronic wizards. >Has anyone any information on this. >(1)When the first GPS units were developed someone decided they should >operate for only 1024 weeks. >(2)That time is up on August 21. >(3)At midnight the GPS system will roll over and revert to its starting >date,leaving some units believing the date is January 6,1980. >With all the new numbers and positions of satellites what happens at >midnight August 21.Do boaties get the year 2000 bug early. Here's what I read back in February in a boating magazine whose name escapes me: ............................................. When August 21, 1999 rolls into August 22, every installed GPS will feel a bump in the dark. Most will hesitate and then resume doing their navigational work, but a few will stop cold, perhaps forever. It's known as the end-of-the-week (EOW) rollover issue, and it is something like the 2000 millennium issue for computer software. Basically, the problem is that when the GPS system started operating in January, 1980, it was given the ability to count time in weeks, but only for 1024 weeks. This has to do with the number of bytes in the binary code that are assigned to time keeping. Or something like that. After 1024 weeks, which will be at midnight August 21-22, 1999, the GPS system will start counting weeks over, beginning with week 0000. In a World Wide Web discussion of the date rollover, the Coast Guard said some GPS receivers will interpret the zero week as an invalid date. Some in the industry said a few GPS receivers will look for satellites in the positions they occupied in 1980, and won't find them there. Generally, newer GPS receivers will continue to function. Some will go through the initialization process, and redevelop an almanac. This could take up to 20 minutes. Magellan reports that older models--the Nav 1000, 5000D and DX units with version 1.0 software, and the Nav 5200, 5200D and 5200DX--probably won't work after the date rollover change. New software is available for the 5000DX and DLX, and the Nav 5200, and is being automatically installed whenever those units are serviced. Magellan doesn't know yet if it will have new software for the other affected models. Don Meyer, public relations manager for Magellan, said that if new software can be developed for one series of its product line, it likely can be prepared for others. The firm will know later this year. There are not many of these affected receivers in use. The Magellan 5000 series GPS receivers were expensive ($900 plus) when they first were marketed in the early 1990s, and not many were sold. Meyer estimated only a few thousand are in use today. "In all honesty, we're not quite sure what to expect," Meyer said. GPS satellites will be unaffected by EOW and by the millennium 2000 problem, the Coast Guard said. ### Trimble has information at: http://www.trimble.com/y2kwnro/policy.htm ________________________________________________________________ Jack Haring WhoopeeWagen

You can read Garmin's response to the rollover issue by checking this url: http://www.garmin.com/faqs/1.html In essence, Garmin says their GPS units will not have a Y2K problem, and the newer units shouldn't have any difficulty with the EOW problem. They'll be issuing more informaiton about how particular units will react several weeks before EOW. -- Bob McLeran rmcleran@ix.netcom.com M/V "Sanderling" Docked at Point Patience Marina Hailing port: Wianno MA Solomons, MD Hampton 35 Trawler