Free GPS Week Rollover Event Files


Our simulations and live recordings of the GPS Week Rollover on 6 April 2019 are an invaluable resource that will allow you to test if your GPS receiver can handle the GPS Week Rollover.

How to test if your device can cope with the GPS Rollover?

Testing your receiver is easy with a LabSat 3.

1) Download the relevant test scenario for your LabSat system.

2) Cold start your GPS receiver and replay the entire scenario.

3) Check if the date shown is 7 April 2019 and if the device is correctly counting up the time.

How to download?

Just fill in the form with your name and email address and you will be redirected to the download page.

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What is a GPS Rollover?

GPS signals from satellites include a timestamp, needed in part to calculate one's location, that stores the week number using ten binary bits. That means the week number can have 210 or 1,024 integer values, counting from zero to 1,023 in this case.

Every 1,024 weeks, or roughly every 20 years, the counter rolls over from 1,023 to zero. 6 April 2019 marked the end of the 1,024th week, after which the counter spilled over from 1,023 to zero. The previous time the week number overflowed like this was in 1999, nearly two decades on from the first epoch in January 1980.

If devices in use today are not designed or patched to handle this latest rollover, they will revert to an earlier year after that 1,024th week in April, causing attempts to calculate position to potentially fail.

If it works as normal: brilliant, it's not affected. For devices unprepared for the counter overflow, a firmware upgrade will be necessary to keep the things working properly.

GPS.gov also notes that the new CNAV and MNAV message formats will use a 13-bit week number to solve the epoch problem for the foreseeable future.

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