[BobNovas]

"On April 6, 2019, GPS will have a once in a 19.7 year event: the field used to track "weeks" will reset to zero. Basically, GPS transmits a week number so your receiver can calculate the date. The week number is 10 bits long, which works out to 1094 weeks, or 19.7 years. This means every 19.7 years the number must reset to zero. While GPS receivers built in accordance with industry standards should manage the event without incident, the Department of Homeland Security (DHS) encourages you to take steps to ensure your systems are ready. Check if any of your GPS receivers were built before 2010. If so, check with the manufacturer for firmware, hardware or software updates. DHS encourages you to review how time is used in your organization and develop plans for managing your timing requirements. Below are two presentations providing a simplified overview of what the rollover is and steps you should take to prepare. The first document is designed for business leaders to explain why managing timing requirements is important (PDF, 709 Kb < https://ics-cert.us-cert.gov/sites/d...Sheet_508C.pdf >). The second document provides an overview for businesses to follow to identify timing requirements and selecting appropriate timing source(s) (PDF, 1 Mb < https://ics-cert.us-cert.gov/sites/d...Sheet_508C.pdf >). The Department of Homeland Security (DHS) issued the initial notice in April of 2018 (PDF, 212 Kb).