NavIC, an acronym for Navigation with Indian Constellation, is an independent regional navigation satellite system developed by the Indian Space Research Organisation (ISRO). It is designed to provide accurate position information service to users within India and up to 1500 km from its boundary. The system utilises a constellation of seven satellites, three in geostationary orbit and four in geosynchronous orbit. This configuration ensures constant coverage of the entire Indian region, providing high availability and accuracy. NavIC operates on dual frequency bands: L5-band and S-band. The L5-band is used for accurate position determination, while the S-band is used for providing messaging services. The system offers two levels of service: Standard Positioning Service (SPS) available to all users and Restricted Service (RS), an encrypted service provided to authorised users for strategic purposes. NavIC is capable of providing position accuracy better than 20 metres in the primary service area. It also provides a time reference accurate to 20 nanoseconds.
