The Air Force said Sunday a Global Positioning System (GPS) message indexing error was recently identified and had gone unnoticed since 2013.
The error, the service said in a statement, affects a limited number of active GPS IIF series satellites and does not degrade the accuracy of the GPS signal received by users around the globe. The issues appear to be related to the ground software that builds and uploads messages transmitted by the GPS constellation during regular system operations, although the Air Force continues to investigate all possible causes.
Air Force Space Command (AFSPC) has implemented a workaround to prevent further message indexing violations and is taking steps to permanently correct the error.