Atomic clock on NavIC satellite calls time; ISRO’s ‘GPS’ weakens, Pg9

Key Highlights:

• The atomic clock on IRNSS-1F, a NavIC satellite, failed on March 13, 2026, further weakening India's indigenous navigation system.
• IRNSS-1F, launched in March 2016, completed its designed mission life of 10 years on March 10, 2026.
• As of July 2025, five of the NavIC satellites were completely defunct, with all three clocks in each not working.
• Currently, only three NavIC satellites are reliably providing positional and navigation services.
• ISRO plans to replace the impaired IRNSS satellites with ones containing indigenously developed rubidium clocks.

Detailed Insights:

• NavIC is designed to provide positioning services within India and up to 1,500 km beyond, serving as a backup to global systems like GPS in case of conflicts.
• The atomic clocks in the IRNSS satellites were initially imported from SpectraTime, a Swiss manufacturer.
• NVS-01, a replacement satellite launched in May 2023, features an indigenously developed rubidium atomic clock.
• NVS-02, launched in January 2025, failed to reach its intended orbit, hindering the replacement efforts.
• ISRO aims to launch at least three replacement satellites by the end of 2026 to address the issue of defunct and aging satellites.
• The failure of atomic clocks in NavIC satellites raises concerns about the reliability and accuracy of India's regional navigation system.
• The Union government has been encouraging Indian enterprises to rely on NavIC for determining the Indian Standard Time.

Key Concepts Involved:

• Atomic Clock: A timekeeping device that uses the resonant frequency of atoms to measure time with extreme accuracy.
• NavIC (Navigation with Indian Constellation): India's regional satellite navigation system, designed to provide accurate positioning within India and surrounding areas.
• Rubidium Clock: A type of atomic clock that uses rubidium atoms for timekeeping, offering a balance of accuracy and cost-effectiveness.