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GPS Epoch Rollover Findings
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GPS expresses the current time and date with a?? series of binary counters.??
This included a 10-bit binary counter for the current week, meaning that it could only count 1024 (decimal) weeks (just under 20 years) before rolling over from 1111111111 to 0000000000, and starting over.?? This 1024-week cycle is known as an "epoch". The previous epoch ended on April 6th of this year.?? As of April 6th, a 16-bit counter for weeks replaced the 10-bit one.?? This change will put off the NEXT epoch rollover for 65,535 weeks - about 1200 years. Some older GPS hardware (actually firmware) couldn't handle either the rollover from 1023 back to 0000, or couldn't handle the new longer 16-bit counter format.?? Such devices quit working on April 6th of this year. Now that the GPS equivalent of "Y2K" (April 6th) has come and gone, here are my findings testing a bunch of older GPS hardware. -???? Radio Shack "DigiTraveller" (a faceless serial puck-type device that looked like a flying saucer) - DIED -???? Holux GM-200?? USB-connected faceless mouse-type device - DIED -???? Rand McNally serial mouse-type device - DIED -???? 2nd-gen Delorme Earthmate small yellow unit with interchangeable serial and USB cables (not the original large Earthmate) - DIED The Holux and Rand-McNally are visible in this pic on my website: ???????? <> -???? Tri-M "Super Skymaster"?? white hard-mount combo antenna/receiver (shown in the inset photo of the above pic) survived and WORKS.?? This is especially amazing, given that it was the oldest of all these units. - ?? Globalsat BC-337 compact flash/PCMCIA unit - DIED -???? Garmin Foretrex 201 wrist-wearable that is actually a repackaged version of the classic yellow Etrex - WORKS -???? Globalsat BU-353 (USB) and BU-355 (serial) mini-pucks available for USD $30 on Amazon - WORK -???? Various unbranded generic units based on uBLox G7 chipset - WORK -???? Internal GPS of Kenwood TH-D72 APRS handheld - WORKS __________________________________________________________________________________ \Stephen H. Smith?????? wa8lmf (at) aol.com Skype:?????????????? WA8LMF EchoLink: ?? Node #?? 14400?? [Think bottom of the 2-meter band] Home Page:?????????????????? Live Off-The-Air APRS Activity Maps ???? <> Long-Range APRS on 30 Meters HF ???? <> |
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Great report.
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Thank you. Any findings with Garmin eTrex yellow and blue? Joey VA3GOC On Apr 24, 2019, at 12:50, 'Stephen H. Smith' wa8lmf@... [ui-view] <ui-view@...> wrote: |
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All my Earthmate PN Series have their clocks stuck on year 1999 with today's
date accurate. Floyd _____ From: ui-view@... [mailto:ui-view@...] Sent: Wednesday, April 24, 2019 12:28 PM To: ui-view@... Subject: Re: [UI-View] GPS Epoch Rollover Findings Great report. Thank you. Any findings with Garmin eTrex yellow and blue? Joey VA3GOC On Apr 24, 2019, at 12:50, 'Stephen H. Smith' wa8lmf@... [ui-view]<ui-view@...> wrote: counters.?? This included a 10-bit binary counter for the current week, meaning thatit could only count 1024 (decimal) weeks (just under 20 years) before rollingover from 1111111111 to 0000000000, and starting over.?? This 1024-week cycleis known as an "epoch". The previous epoch ended on April 6th of this year.??As of April 6th, a 16-bit counter for weeks replaced the 10-bit one.?? Thischange will put off the NEXT epoch rollover for 65,535 weeks - about 1200 years.rollover from 1023 back to 0000, or couldn't handle the new longer 16-bit counterare my findings testing a bunch of older GPS hardware.looked like a flying saucer) - DIEDserial and USB cables (not the original large Earthmate) - DIED(shown in the inset photo of the above pic) survived and WORKS.?? This is especially amazing, given that it was the oldest of all these units.version of the classic yellow Etrex - WORKSUSD $30 on Amazon - WORK |
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Thank you for collecting that information Stephan. Appreciated.
---In ui-view@..., <wa8lmf@...> wrote : - Globalsat BU-353 (USB) and BU-355 (serial) mini-pucks available for USD $30on Amazon - WORK My Globalsat BU-353-S4 does indeed work. Interestingly *something* got confused as the COM ports have moved. Anyone know how the Bad Elf Pro made out? 73 es sail fast de dave KO4MI |
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On 4/25/2019 7:05 AM, dskolnick@... [ui-view] wrote:
You probably plugged it into a different USB port on the PC. The BU-353 uses- Globalsat BU-353 (USB) and BU-355 (serial) mini-pucks available for USD $30on Amazon - WORK the Prolific USB<-->serial interface chip. The FTDI USB<-->serial chips each have a unique serial number that allow OS drivers to recognize the same device no matter what port it it plugged into.? By contrast, the Prolific driver stupidly treats the same device as a new one if plugged into a different USB port, and proceeds to assign it a different COM number.?? This applies both to root ports directly on the PC, and to different ports on a USB hub. You can force the COM number to be anything not currently in use by other devices. In the Windows Device Manager, locate the driver under "Ports "COM and LPT".? Double-click the entry, then click the tab for "Port Settings".? Finally click the button for "Advanced". ? You will see a drop-down list box at the top of the resulting dialog box for "COM Port Number:". ?? Pull down the list and choose any COM number you want.? You may have to reboot before the new COM number becomes active. Note that for UIview, the COM number MUST be somewhere in the range of COM1 to COM8.? (UIview's internal dialogs don't offer the choice of COM numbers above COM8.) ------------------------------------------------------------------------------- Stephen H. Smith??? wa8lmf (at) aol.com Skype:??????? WA8LMF EchoLink:? Node #? 14400? [Think bottom of the 2-meter band] Home Page:????????? Live Off-The-Air APRS Activity Maps ?? <> Long-Range APRS on 30 Meters HF ?? <> |
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Hello Stephen,
---In ui-view@..., <wa8lmf@...> wrote : On 4/25/2019 7:05 AM, dskolnick@... mailto:dskolnick@... [ui-view] wrote: >> My Globalsat BU-353-S4 does indeed work. Interestingly *something* got >> confused as the COM ports have moved. > You probably plugged it into a different USB port on the PC. You would think that, wouldn't you? *grin* I am a creature of habit. GPS goes in right hand USB port, dAISy2 receiver in left hand back USB port, and powered USB hub in left hand forward USB port. Always. This setup is for backup navigation at sea. Life safety and mission critical systems get extra attention, documentation, and labeling. It is very possible that the COM port change resulted from a big Windows update at the same time as the GPS epoch. Both are odd causation, but it had to be *something.* I don't remember any recent driver updates. Fortunately the navigation software I use supports a wide range of ports so 36 just showed up on their options drop down list. I could have forced the port back from whence it came but it didn't seem worth the effort. My interest in the Bad Elf Pro has the same roots. Bluetooth support for up to five simultaneous connections makes it an interesting option for boats at sea. Nav computer and a couple of tablets and connections to spare. I have email out to customers who are using them but they all seem to be off the edge of the Internet--a couple in the South Pacific, one crossing the Atlantic, and one in the San Blas. On point for this group, the machine on which I use UI-View doesn't use GPS as it doesn't move. *grin* 73 es sail fast de dave KO4MI S/V Auspicious AuspiciousWorks.com P.S. I think I plunked an 'a' into spelling your name in my first message. My apologies. |
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