I am NOT saying that this is FACT, but it is worth looking into, if GPS is important to you.... FYI: 2-26-2019 mFrom:The Register (British IT News Site)* <Fun fact: GPS uses 10 bits to store the week. That means it runs out... oh heck – April 6, 2019>* *Fun fact: GPS uses 10 bits to store the week. That means it runs out... oh heck – April 6, 2019* Nav gadgets will be Gah, Properly Screwed if you don't or can't update firmware* By Shaun Nichols in San Francisco <Shaun Nichols • The Register> 12 Feb 2019 at 21:37 Older satnavs and such devices won't be able to use America's Global Positioning System properly after April 6 unless they've been suitably updated or designed to handle a looming epoch rollover. GPS signals from satellites include a timestamp, needed in part to calculate one's location, that stores the week number using ten binary bits. That means the week number can have 2^10 or 1,024 integer values, counting from zero to 1,023 in this case. Every 1,024 weeks, or roughly every 20 years, the counter rolls over from 1,023 to zero. The first Saturday in April will mark the end of the 1,024th week, after which the counter will spill over from 1,023 to zero. The last time the week number overflowed like this was in 1999, nearly two decades on from the first epoch in January 1980. You can see where this is going. If devices in use today are not designed or patched to handle this latest rollover, they will revert to an earlier year after that 1,024th week in April, causing attempts to calculate position to potentially fail. System and navigation data could even be corrupted, we're warned. "GPS devices with a poorly implemented GPS Time-to-UTC conversion algorithm may provide incorrect UTC following a week number rollover," US Homeland Security explained in its write-up <https://ics-cert.us-cert.gov/sites/default/files/documents/Memorandum_on_GPS_2019.pdf> (PDF) of the issue this week. "Additionally, some GPS devices that calculate the week number value from a device-specific date rather than the start of the current GPS Time Epoch may provide incorrect UTC at some other device-specific date." As the /Reg/ reader who tipped us off to the shortcoming noted, this could be a significant headache for data centers that use GPS timing for synchronization. "Decent vendors should have patches. But who has been thinking about this?" our tipster told us. "This could be a low-key Y2K style bug all over again, but with companies doing less preparation." Fortunately, devices on sale right now should be prepared for this rollover and handle it gracefully. Uncle Sam's GPS nerve-center GPS.gov says <https://www.gps.gov/cgsic/meetings/2017/powers.pdf> (PDF) receivers that follow the ICD-200/IS-GPS-200 specification should be able to deal with the week number overflow. This basically means newer receivers built after, say, 2010 should be fine, provided they follow the specs <GPS Technical References> and notice the rollover. To put it another way, if your gadget goes haywire in April, it's probably because of this. If it works as normal: brilliant, it's not affected. Consider yourself forewarned. GPS.gov also notes that the new CNAV and MNAV message formats will use a 13-bit week number to solve the epoch migraine right up until the planet becomes uninhabitable via climate change or we all blow ourselves up. For devices unprepared for the counter overflow, a firmware upgrade will be necessary to keep the things working properly. GPS.gov recommends those unsure about their readiness for the turnover, particularly enterprises, should consult the manufacturer of their equipment to make sure they have the proper updates in place. ®
Thanks for the headsup BT. I have a Garmin GPSIII that was manufactured around 1997 - 98. It seems to have a much better receiver than the newer ones, but this could shut it down. Don't think Garmin supports it any more, have to check to see if they have an update on their web site. At least now if it goes bonkers I'll have some idea of what happened.
I have both a III, and a III Plus, that I use for monitoring the Base GPS Signals, when I am planning to do a Differential GPS Survey, or I am looking for Survey Points... Both were Surveyed in, to within a meter or two, and I record their Data Stream over my Network, and then thru Post Processing can get my mobile GPS locations down to inside a 3 Meter Circle... I will be watching them in April and comparing them to my iDevices GPS Locations...
My old Garmin portable for my truck and the Kenwood in dash in my 2005 auto are unsupported and will probably become obsolete, prompting the necessity for me to purchase another $2K in equipment and installation.
lol. My GPS is a compass, maps, and both a sextant and astrolabe I built myself from PDF's in my library. I'm a low tech kinda guy....lol
Folks with a TOM-TOM Check your sextant below Update your navigation device | TomTom The GPS Week Number Rollover (WNRO) occurs every 19 years, with the next rollover taking place on April 6, 2019. Similar to odometers in older cars rolling over from 99,999 miles to 0 miles the GPS WNRO is the resetting of the GPS calendar back to 0. When the calendar resets, it can cause a miscommunication between GPS satellites and GPS receiver chips. As a result, some chips in navigation devices will lose the ability to process certain functions. What does this mean for you? It's time to check your navigation device. Depending on your device, you may need to update or upgrade. Sloth