OEM4 and OEMV Reporting 1994 (Week Roll Over)
GPS Time is reported in weeks since Jan 6, 1980. The GPS ICD defined navigation data format limits the number of weeks before a roll over to 1023. This means that roughly every 19 years the GPS week goes back to zero and starts incrementing again. In order to help the receiver determine the actual calendar date we have historically used a hard coded date as a reference to figure out which GPS "era" we are in (pre 1999 or post 1999). From time to time we would update the baseweek of a new version of firmware and this would provide 10-18 years after that date before the receiver would no longer be able to figure out the correct GPS era. Again, the receiver continues to function but the GPS week is reported as a raw number between 0 and 1023 instead of the number of weeks since January 6, 1980.
With OEMV firmware version 3.200 the last valid date that can be outputted by the receiver is Jul 26, 2014, the latest version (3.907) will output a valid date till Mar. 19, 2033 this can be downloaded here:
With OEM4 firmware version 2.312 the last valid date that can be outputted by the receiver is Jul 26, 2014, the latest version (2.322) will output a valid date till Sep 24, 2022 this can be downloaded here: