GPS Week Number Rollover (WNRO)
SPECTRA GEOSPATIAL

Check to see if your product is compliant:

Most Spectra GNSS receivers require a firmware update to successfully handle the WRNO. To download the firmware version that suits your device, click here.

What is WNRO?
Since its launch, the GPS satellites have transmitted signals that use a 10-bit binary counter to represent the GPS Week Number, a key piece of the date and time information. Every 19.7 years this week number counter reaches its limit and rolls back to zero. The rollover event requires special testing and validation using simulation techniques to ensure that it is properly handled by GPS receivers. A GPS receiver that does not have compliant firmware may experience errors.

The first GPS WNRO event occurred in 1999 and the second  occurred on April 6, 2019, at GPS Midnight.

What is the consequence of the rollover?
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.

What steps should you  take?
Contact your local Spectra Geospatial distributor or reach out  Trimble WNRO Support

More information:
Trimble GPS Week Number Rollover Ressource Center

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