NavIC Atomic Clock Failure on IRNSS-1F Explained
Why in the news
ISRO said an onboard atomic clock of IRNSS-1F stopped working. As the satellite belongs to NavIC, India’s regional navigation system, fewer satellites remain fully functional.
Key facts
- Satellite: IRNSS-1F, part of NavIC (Navigation with Indian Constellation).
- An atomic clock counts time via atomic vibrations, usually Rubidium or Cesium.
- Navigation relies on exact timing: a billionth-of-a-second slip can mean a ground error of several metres.
How the clock helps positioning
| Idea | Meaning |
|---|---|
| Atomic resonance | Frequency of radiation emitted or absorbed as electrons change energy level |
| Stable frequency | Atoms vibrate steadily; quartz or mechanical clocks drift |
| Time of flight | Satellite stamps its signal with sending time |
| Trilateration | Receiver compares timings to get distance from several satellites; at least four give latitude, longitude and altitude |
About NavIC
- India’s own regional system, formerly IRNSS.
- IRNSS-1A launched in July 2013; plan was seven satellites by 2016, with replacements later.
- Coverage: India plus about 1,500 km around.
Exam angle
- Earlier name: IRNSS.
- Satellites needed for a 3D fix: four.