Major GPS glitch may occur today

Users of critical and essential equipment, whose work depends on the data of the GPS navigation system, are warned of a possible impending failure. It is associated with the mandatory update of such a parameter as "week number". This will happen today, April 6, 2019 at 23:59:42 UTC.

The week number is necessary for a number of operations related to the determination of calendar dates, traditionally it starts counting from the Thursday of the first week in January and can have a maximum value of 52 or 53. In 2019 there will be 52 weeks, in the next 2020 it will be 53. Due to GPS design considerations, this parameter is stored in 10-bit format and must be reset to zero every 1024 weeks.

The countdown has been carried out since January 6, 1980, one zeroing was already 20 years ago, now the time has come for the second. Formally, this is a routine procedure that does not threaten anything with GPS devices supporting the latest IS-GPS-200 and UTC standard. However, in reality, everything is more complicated, and on some devices there is no binding to the general date of January 6, 1980. There are many options for variables, from the firmware date to the release date of a specific instance, so after April 6, 2019, their owners may encounter malfunctions. The week number on these gadgets will still be reset to zero, but it is not known exactly when.

Therefore, it is recommended to check your equipment with reference to GPS, if necessary, contact the manufacturer and clarify the algorithms for zeroing the week number. It is possible to install updates or replace the firmware altogether - in a word, take measures to minimize harm from possible problems.