NavIC’s Atomic Clock Failure:
ISRO recently reported that the atomic clock on the IRNSS-1F satellite has failed, reducing the number of functional positioning satellites in the NavIC constellation.
- An atomic clock is an ultra-precise timekeeping device that uses the vibrations of atoms (usually Rubidium or Cesium) to measure time. In navigation satellites, these clocks are essential because even a billionth of a second of error can lead to a location inaccuracy of several meters on the ground.
- The clock measures the precise frequency of electromagnetic radiation emitted or absorbed by electrons when they change energy levels within an atom.
- Unlike mechanical or quartz clocks, atoms vibrate at a perfectly constant rate, providing a stable frequency that does not drift over time.
- The satellite sends a signal with a timestamp. By comparing when the signal was sent to when it was received, the receiver calculates the distance.
- By calculating distances from at least four different satellites simultaneously, a receiver can pin-point a user’s exact latitude, longitude, and altitude.
- They are accurate to within one second every few million years.
- Satellites usually carry multiple clocks (often three or four) in case one fails.
- While earlier NavIC clocks were imported, the new generation (NVS series) features India-developed Rubidium atomic clocks.
