• Question: have the satellites ever gone wrong on the job?

    Asked by melody to Brian on 14 Mar 2019.
    • Photo: Brian Weaver

      Brian Weaver answered on 14 Mar 2019:

      Yes, the positioning satellites have gone wrong on the job. The satellites send “health” information so we know if they are usable. One problem is when a bad satellite reports that it is healthy.
      Other problems can occur when an old satellite is replaced. For example, a few years ago an old GPS satellite was decommissioned and went offline. This caused a timing error for half of the remaining satellites and disrupted all GPS users until the problem was solved.
      In 2014, two of the European positioning satellites (#5 and #6) were launched into the wrong orbit.
      There are many other examples but those are some of the recent problems.