The UK Maritime & Coastguard Agency informed operators that use GPS for both position and UTC (Coordinated Universal Time), that the GPS Week Number will be rolling over for the second time, on April 6th, 2019.
This could lead stand-alone GPS receivers and systems using GPS chips, to produce data that is 19.7 years either in the past or future, thus generating errors in both the GPS position and time.
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However, if on board equipment has been installed after August 1999, or has regular firmware updates from the manufacturer, there should be limited of an error. In addition, UK MCA highlighted that not all products will Rollover on April 6th, 2019, as some may Rollover on a different date because of the implementation in the manufacturer’s firmware.
The Week Number is stored as a 10-bit binary number which allows for a maximum of 1024 weeks (19.7 years) before resetting to 0. Since being rolled out in 1980, this will be the second time this has happened, which means most manufactures are aware and prepared.
Nonetheless, there are products that are at a higher risk of going wrong if they are:
- Units older than 10 years;
- Units which have had no firmware updates.
Products are at lower risk if:
- They are relatively new units;
- They are units that are regularly updated with firmware.
In order to be prepared for the Rollover, UK MCA recommends the following actions:
- Make sure all recent firmware updates are completed;
- Check with your GPS manufacturer for further information on GPS-dependent equipment and identify what action, if any is, required by the operator;
- Identify what effect this could have on your current operations, PNT (position, navigation and timing) solutions and potential issues if failure occurred;
- Operators of such equipment should monitor and, wherever possible, verify their equipment for any errors.
