Government says NavIC cannot provide standalone navigation after satellite setback
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The government has informed Parliament that India's NavIC satellite navigation system can no longer provide standalone positioning services after the loss of positioning capability from one of its satellites.
In a written reply, Union Minister of State for Space Jitendra Singh said the NavIC constellation currently has only three satellites providing Positioning, Navigation and Timing (PNT) services: IRNSS-1B, IRNSS-1I and NVS-01.
"To provide basic positioning service, minimum four operational satellites are required in orbit. Hence, the NavIC constellation cannot provide standalone positioning service, however timing service is functional," he said.
The Indian Space Research Organisation (ISRO) had earlier announced that IRNSS-1F, launched in March 2016, had completed its mission life and its onboard atomic clock had stopped functioning.
The government said the armed forces continue to use NavIC signals as part of a multi-constellation Global Navigation Satellite System (GNSS), which also uses signals from systems such as the United States' GPS, the European Union's Galileo and Russia's GLONASS.
Responding to concerns about navigation accuracy and real-time mapping, the government said there was no vulnerability for users because NavIC is used in a multi-constellation environment for most applications.
NavIC-enabled applications in aviation, shipping, railways and mobile phones can continue to receive positioning data through other satellite navigation systems, as these devices are equipped with GNSS receivers.
The government said the next NavIC satellite, NVS-03, is ready for launch, while NVS-04 and NVS-05 are at an advanced stage of development.
Although standalone positioning services are unavailable, the constellation continues to provide timing services and can broadcast emergency messages.
The Indian Regional Navigation Satellite System, operationally known as NavIC, was designed as a seven-satellite constellation to provide positioning services across the Indian subcontinent and up to 1,500 km beyond its borders.