Indian Space Research Organisation (ISRO) chairman K. Radhakrishnan had earlier said, though IRNSS is a seven-satellite system, it could be made operational with four satellites.

On Oct 12, ISRO's Launch Authorisation Board (LAB) gave its nod for the launch. The countdown began Monday morning.

Originally the satellite was scheduled for launch Oct 10, but was put off by a week due to a glitch in the telemetry system.

During the countdown, propellant filling activities would be carried out along with checking of the various systems.

The satellite is part of the Indian Regional Navigation Satellite System (IRNSS) that will have a constellation of seven satellites to provide accurate positioning service for terrestrial, aerial and maritime navigation in 1,500-km area in the Indian peninsula.

The second navigation satellite (IRNSS-1B) was launched April 4 this year from the spaceport. The first one - IRNSS-1A - was launched July 2013.

The Indian system will be similar to the US Global Positioning System (GPS), Russia's Glonass and Europe's Galileo constellation of navigation satellites.

India began its space journey in 1975 with the launch of "Aryabhatta" using a Russian rocket and till date, it has completed over 100 space missions including missions to the Moon and Mars.