Changes between Version 23 and Version 24 of pcn

03/28/2019 11:54:04 PM (5 years ago)
Ryan Erbstoesser

add pcn 34 gps rollover


  • pcn

    v23 v24  
     293== PCN34 - April 2019 GPS Rollover  ==
     294 * Date: 03-28-2019
     295 * PCN: On April 6, 2019 there will be a GPS rollover that could affect all GPS / Timing units in the world, regardless of manufacturer.
     297In addition to providing accurate location information, the Global Positioning System provides accurate timing information. It also includes the ability to transmit the proper date and time to a receiver by supplying the receiver with the current week and the current number of seconds into the week. This allows the receiver to translate the date and time into a more typical format – day, month, year, and time of day.
     299The field from the Satellite system that contains the week number is a 10-bit binary number. This limits the range of the week number to 0 – 1023, or 1024 total weeks.
     301GPS week zero started January 6, 1980. The 1024 weeks counter ran out and rolled over on August 21, 1999. The week counter then reset to zero, and it has been recounting ever since. The next time the counter will reach week 1023 and rollover to zero is on April 6, 2019.
     303April 6, 2019 is the 1024th week and unless a GPS module or application has already accounted for this, the date may not report accurately. If the application does not use the date or if there are other sources for the date outside of the GPS module, one may not be affected.
     305Notes for the following GPS devices:
     306 * Wi2Wi GPS
     307  * 02120775: W2Wi W2SG0008i
     308  * Notes: Wi2Wi provided notice indicating that Qualcomm ran extensive simulator testing and that they saw no operational issues.
     309 * u-blox GPS:
     310  * ZOE-M8Q-0
     311  * EVA-M8M
     312  * Notes: As these are newer GPS chipsets, it is not expected they will face any issues. More information is available in the [ u-blox portal]
     313 * Trimble GPS
     314  * 02120512: Trimble Copernicus 63530-00 and Trimble Copernicus 58048-20
     315  * 02120619: Trimble Condor 68674-05
     316  * Notes: Recommended to update application code to accommodate for the week number change from the GPS module. Sample code is available by emailing Gateworks Support.
     319Customers using Gateworks BSPs with gpsd can address this within gpsd if using another time service. Customers not using the GPS time are not affected.
     321For systems that have no RTC GPSD can (does by default?) provide the system time. If you manually set the system clock to a date in the current year before launching gpsd you will get the correct time (gpsd has some sanity check when setting system time).
     323Further information:
     324 * [wiki:gps GPS Wiki Page]
     326Email Gateworks support with any further questions