The 50th Space Wing Public Affairs office of the Schriever Air Force Base established and posted guidelines, known as Interface Specification GPS-200 (IS-GPS-200), for receiver manufacturers to ensure continued capability during the GPS Week Number Rollover on Coordinated Universal Time derived from GPS devices.
According to the Schriever Air Force Base, users should be aware of the upcoming GPS Week Number Rollover as it may impact receivers that are not manufactured in compliance with IS-GPS-200 specifications.
The GPS Week Number count began around midnight on Jan. 5, 1980. Since then, the count has been incremented by one each week and years later broadcast as part of the GPS message. One of the GPS week number fields in the legacy navigation message counts from zero to 1,023 weeks. At the completion of every 1,024 GPS weeks, the field rolls from 1,023 to zero and starts counting again. The first occurrence took place the evening of Aug. 21, 1999, and the message field rolled to zero at midnight GPS time. The next similar GPS Week Number Rollover is set to take place April 6.
“We appreciate the 4 billion people around the world who use GPS signals on a daily basis, which is why we are transparent in providing detailed guidance on use for compatibility,” said Lt. Col. Stephen Toth, 2nd Space Operations Squadron commander.
Civil GPS users are encouraged to submit reports of GPS problems to the Coast Guard Navigation Center; civil aviation users are encouraged to report GPS anomalies to the Federal Aviation Administration; and military users should contact the GPS Operations Center.