According to experts, for a navigation system to run, at least four satellites must be functional. This means that with the IRNSS-1F now completing its 10-year mission life, India\u2019s indigenous navigational system is defunct.\u00a0<\/p>\n
NavIC, once envisioned as India\u2019s answer to the satellite navigation systems run by the US, China, Russia and Europe, has now become a casualty of years of neglect, technical failures, ageing satellites and delayed replacement launches, pushing India further behind in a technology that now underpins both economic competitiveness and modern warfare.\u00a0<\/p>\n
ISRO\u2019s focus on bigger missions like Gaganyaan, India\u2019s first human spaceflight, and the Bharatiya Antariksh Station (BAS), has seemingly distracted the focus from essential strategic missions.\u00a0<\/p>\n
With no confirmation on the launch of the next set of satellites\u2014the only way to revive NavIC to some form of functionality\u2014India\u2019s navigation system is stuck in limbo.\u00a0<\/p>\n
Ajey Lele, deputy director general at the Manohar Parrikar Institute for Defence Studies and Analyses (MP-IDSA), said that a single problem isn\u2019t plaguing NavIC.\u00a0<\/p>\n
India now needs a serious strategy to get back in the race, he said, adding, \u201cIn the initial period, ISRO faced the problem of atomic clocks imported from abroad. Later, we have had problems ranging from the lack of ground support systems to launch failures.\u201d<\/p>\n
In the initial stage of the programme, ISRO had faced troubles with adequate ground support systems to fully realise the potential of the launched NavIC satellites. These ground systems are necessary for catching and translating signals from the satellites in orbit.\u00a0<\/p>\n
How does a navigation system work?<\/p>\n
Satellite navigation systems work on two levels\u2014regional and global.<\/p>\n
For a regional network, at least three to four satellites\u2014usually from medium earth orbit\u2014need to transmit radio signals. This is the bare minimum requirement for operations.<\/p>\n
For global systems such as the US\u2019s GPS or Russia\u2019s GLONASS, this satellite network requires at least 24 to 26 satellites.<\/p>\n
GPS, for instance, has 31 operational satellites operating at a medium Earth orbit (MEO). These satellites operate at about 20,000 km in six orbital planes, inclined at about 50-55 degrees. China\u2019s Beidou also has more than 40 satellites in MEO.<\/p>\n
India\u2019s NavIC, on the other hand, currently has only three operational satellites. In an ideal situation, NavIC requires seven functional satellites to get a decent view of a country\u2019s land and its bordering areas.<\/p>\n
NavIC was initially designed to operate as a regional navigation system, but the ambition was to later expand it for global coverage and use.<\/p>\n
According to ISRO, the NavIC satellite constellation design will have three satellites placed in a geostationary orbit, at about 32.5 degrees E, 83 degrees E and 129.5 degrees E.<\/p>\n
Four more satellites are designed to be placed in inclined geosynchronous orbit with equatorial crossing of 55 degrees E and 111.75 degrees E, with an inclination of 29 degrees. This comes to two satellites in each plane.<\/p>\n
\u201cThe ground network consists of control centres, precise timing facilities, range and integrity monitoring stations, two-way ranging stations, etc,\u201d states<\/a> ISRO in its plan.<\/p>\n The original NavIC design offers two services\u2014Standard Position Service (SPS) for civilian use and Restricted Service (RS) for military use. These services are backed by L5 bands\u2014the most advanced and high-precision global navigation satellite system (GNSS) signal designed for civilian use\u2014and S bands. This helps cover the Indian region and an area up to 1,500 kms beyond the Indian boundary.<\/p>\n \u201cNavIC signals are designed to provide user position accuracy better than 20m (2s) and timing accuracy better than 50ns (2s). NavIC SPS signals are interoperable with the other global navigation satellite system (GNSS) signals, including GPS, Russia\u2019s Glonass, Europe\u2019s Galileo and China\u2019s BeiDou,\u201d the plan states.<\/p>\n