The GPS Week Number Rollover (WNRO) will occur at the end of the GPS day on 6 April 2019. GPS provides a current date and time, represented as a week number. The week number parameter is generated via a 10-bit binary number. The valid range for the week number parameter is 0 to 1,023, for a total of 1,024 weeks. After that time, the week number rolls over to 0. The first week number period started when GPS was launched in January 1980, and the last GPS WNRO was 19.7 years ago, on Aug. 21, 1999. The next WNRO occurs on April 6, 2019, when the week number will again reach the maximum value of 1,023 and roll over to 0. Any GNSS receiver that does not account for this rollover will report an erroneous date.
Due to the WNRO, a GPS receiver that does not have compliant firmware will see errors. To guard against this, users are encouraged to make sure they have the latest compliant firmware version for their receiver. Most Spectra GNSS receivers require a firmware update to successfully handle the week number change. Click the link below for the Spectra Geospatial support note with instructions on updating your receiver firmware. On page 2 of the Support Note, users need to download the firmware upgrade needed by clicking on the corresponding link.
Click HERE to download the support note.