2014년 4월 2일 GLONASS System 오류발생

2014년 4월 2일 06시부터 17시까지 러시아 위성 시스템인 GLONASS가 전체적으로 오류가 발생하여 GLONASS를 이용한 위치측위에 문제를 일으키는 현상이 발생했다.

4월2일 이 시간대에 GLONASS를 지원하는 휴대폰으로 네비게이션을 사용시에는 경로이탈 혹은 위치 미수신 현상이 많이 발생했을수 있습니다.

- 기사 원문 (http://gpsworld.com/glonass-gone-then-back/)

In an unprecedented total disruption of a fully operational GNSS constellation, all satellites in the Russian GLONASS broadcast corrupt information for 11 hours, from just past midnight until noon Russian time (UTC+4), on April 2 (or 5 p.m. on April 1 to 4 a.m. April 2, U.S. Eastern time). This rendered the system completely unusable to all worldwide GLONASS receivers. Full and correct service has now been restored.

“Bad ephemerides were uploaded to satellites. Those bad ephemerides became active at 1:00 am Moscow time,” reported one knowledgeable source. For every GNSS in orbit, the navigation messages include ephemeris data, used to calculate the position of each satellite in orbit, and information about the time and status of the entire satellite constellation (almanac); this data is processed by user receivers on the ground to compute their precise position.

According to another source, a GLONASS fix could not take effect until each satellite in turn passed back over  control stations in the Northern Hemisphere to be reset, thus taking nearly 12 hours.

During the outage, one U.S.-based GNSS high-precision manufacturer reported “We are currently experiencing calls from customers all over the world who are experiencing GLONASS “outages” and we have advised customers to switch GLONASS tracking off on our receivers. We don’t have any better information on when normal service is likely to resume from GLONASS satellites. If you do, let me know!”

Such a — possibly human, possibly computer-generated — error could conceivably occur with GPS, Galileo, or BeiDou. “Another reason to have backups,” mused Richard Langley of the University of New Brunswick. “And not just other GNSS.”

A recent plot shows all satellites restored to normal service: