Speaking to reporters after the successful GSLV-F12/NVS-01 mission, Somanath said that only four of the existing fleet of seven NavIC satellites were operational now

India's NavIC (Navigation for Indian Constellation) series of satellites offer a positioning accuracy of three metres, ISRO Chairman Dr S Somanath told WION.

He added that the position accuracy would vary if the signals are weaker and not all satellites are available. However, he said that the navigation, positioning and timing services offered by Indian satellites are superior, considering the architecture being used.

ISRO has the means to make the service global, as and when required.

ISRO recently launched the NVS-01 satellite, a next-generation satellite meant to meet India's requirements of navigation, positioning, and timing.

Launched on Monday, NVS-01 is the first in the series of five satellites that India's UR Rao Satellite Centre in Bengaluru is designing and building. The NVS series will augment India's existing fleet of NavIC satellites.

At present, India uses its Navigation with Indian Constellation(NavIC) series of satellites for civilian and defence navigation, positioning, and timing services within India and even 1500 kilometres beyond its borders.

"NVS series of satellites will sustain and augment the NavIC with enhanced features. This series incorporates L1 band signals additionally to widen the services. For the first time, an indigenous atomic clock will be flown in NVS-01," ISRO had said.

Highlighting the need for the indigenous navigation system, Somanath pointed out India's vast landmass, large population, booming digital services and business opportunities, and stated that it is important to have independent systems for navigation, positioning and timing.

Further, he touched upon the strategic perspective and said that India's armed forces are protecting the nation's borders and they require their own secured services for positioning, navigation and timing, thus giving them strategic autonomy.

ISRO's current series of NavIC satellites were placed in orbit in a phased manner between the years 2013 and 2018 using PSLV rockets. All satellites in the first-generation NavIC series weighed 1,425 kg and carried foreign-origin atomic clocks.

All IRNSS/NavIC series satellites carried two types of payloads – navigation payload and ranging payload. The navigation payload transmits signals for the determination of position, velocity and time. Rubidium atomic clocks are part of the navigation payload of the satellite. The ranging payload of these satellites consists of a C-band transponder which facilitates accurate determination of the range of the satellite.

Speaking to reporters after the successful GSLV-F12/NVS-01 mission, Somanath said that only four of the existing fleet of seven NavIC satellites were operational now.

Instead of replacing the three defunct satellites of the old generation, ISRO is launching a fleet of five next-gen NavIC satellites, of which NVS-01 would be the first, he added.

The rationale behind launching a new fleet of five satellites is due to the fact that the existing constellation would be defunct in a few years (owing to the completion of mission life). Hence, it would not be prudent to replace the old fleet. It is expected that two next-gen NavIC satellites will be launched every year.