India's indigenous satellite navigation system, NavIC, is currently operating with only three satellites capable of providing Positioning, Navigation and Timing (PNT) services, fewer than the minimum four satellites needed to deliver standalone positioning services, the government informed Parliament on Wednesday.
Standalone positioning allows a navigation system to determine a user's location using only its own satellites, without depending on global systems such as GPS.
In a written reply in the Lok Sabha, Union Minister of State for Space Dr. Jitendra Singh said that after IRNSS-1F completed its 10-year mission life, only IRNSS-1B, IRNSS-1I and NVS-01 remain operational for providing PNT services within the NavIC constellation.
The minister explained that at least four operational satellites must be available to calculate a user's latitude, longitude, altitude and time using only NavIC signals.
"To provide basic positioning service, a minimum of four operational satellites are required in orbit. Hence, the NavIC constellation cannot provide standalone positioning service; however, timing service is functional," Singh said.
Despite the reduced number of operational satellites, the government said users are not facing any operational vulnerability because NavIC is currently used as part of a multi-constellation Global Navigation Satellite System (GNSS), alongside systems such as GPS, Galileo and GLONASS.
The government added that the Armed Forces also rely on a multi-constellation GNSS setup, including NavIC, to meet operational requirements.
To rebuild the constellation, ISRO has planned the launch of additional satellites. Singh informed Parliament that NVS-03 is ready for launch, while NVS-04 and NVS-05 are at advanced stages of development.
The update comes as ISRO continues efforts to strengthen the second-generation NavIC network following recent setbacks.
The space agency successfully launched NVS-01 in 2023. However, the subsequent NVS-02 mission faced propulsion-related problems that prevented the satellite from reaching its designated operational orbit.
The upcoming satellite launches are expected to restore NavIC's standalone navigation capability, strengthen the constellation and improve the reliability of India's indigenous satellite navigation system, which provides positioning, navigation and precise timing services across India and regions extending nearly 1,500 km beyond its borders.
