India's indigenous Navigation with Indian Constellation (NavIC), officially known as the Indian Regional Navigation Satellite System (IRNSS), has lost its ability to provide standalone positioning services. The system is currently operating with only three active Positioning, Navigation and Timing (PNT) satellites, falling below the minimum requirement of four spacecraft needed for independent location pinpointing.
Standalone Positioning Service Interrupted
The operational shortfall follows the end of mission life for IRNSS-1F, leaving the constellation with IRNSS-1B, IRNSS-1I, and NVS-01 as the sole active satellites. Union Minister of State for Space, Dr. Jitendra Singh, confirmed in the Lok Sabha that while timing services remain functional, the NavIC constellation cannot offer standalone positioning due to the insufficient number of operational satellites.
Calculating a user's precise latitude, longitude, altitude, and time independently requires signals from at least four visible satellites. With only three, this capability is currently compromised.
No Security or Operational Vulnerability
Despite the setback, the government has clarified that users face no security or operational vulnerabilities. NavIC is designed to function seamlessly within a multi-constellation Global Navigation Satellite System (GNSS) environment. This means it operates in conjunction with global networks such as GPS, Galileo, and GLONASS. The Indian Armed Forces, for instance, utilize this hybrid GNSS framework, ensuring their operational capabilities remain uninterrupted.
ISRO's Plans for Constellation Rebuild
The current deficit in the NavIC satellite system follows recent issues within ISRO's second-generation satellite lineup. While NVS-01 was successfully launched in 2023, the subsequent NVS-02 mission encountered propulsion glitches, preventing it from reaching its designated operational orbit.
ISRO is actively working to rebuild the constellation and restore full independent service across India and regions extending approximately 1,500 kilometers beyond its borders. The NVS-03 satellite is reportedly fully prepared for launch, with NVS-04 and NVS-05 currently in advanced stages of realization.
Understanding NavIC: India's Strategic Navigation System
NavIC was developed by the Indian Space Research Organisation (ISRO) to provide accurate position, velocity, and timing (PNT) services. Its primary coverage area includes the entire Indian landmass and extends up to 1,500 km around the Indian boundary. The system aims for an accuracy better than 10 meters for civilian users across its primary coverage and better than 5 meters within the core Indian landmass.
The system offers two main service types:
- Standard Positioning Service (SPS): Accessible to all civilian users, integrated into modern smartphones and vehicle tracking systems.
- Restricted Service (RS): An encrypted signal reserved exclusively for authorized strategic users, including the Indian Armed Forces and security agencies.
Operating in higher Geosynchronous (GEO) and Geostationary (GSO) orbits (36,000 km altitude), NavIC satellites maintain continuous coverage over the Indian region. This orbital advantage means their signals experience minimal blockage from high-rise buildings and mountainous terrain compared to global Medium Earth Orbit (MEO) systems.
India's development of NavIC was driven by the need for strategic autonomy in space-based positioning. The 1999 Kargil conflict, during which foreign navigation access was restricted over the combat zone, underscored the critical importance of a sovereign satellite system for defense applications, critical infrastructure timing, fleet tracking, and disaster management.