Indian Regional Navigation Satellite System (IRNSS), with an operational name of NavIC (acronym for Navigation with Indian Constellation; also, nāvik 'sailor' or 'navigator' in Indian languages), is an autonomous regional satellite navigation system that provides accurate real-time positioning and timing services. It covers India and a region extending 1,500 km (930 mi) around it, with plans for further extension up to 3,000 km (1,900 mi). An extended service area lies between the primary service area and a rectangle area enclosed by the 30th parallel south to the 50th parallel north and the 30th meridian east to the 130th meridian east, 1,500–6,000 km (930–3,730 mi) beyond borders where some of the NavIC satellites are visible but the position is not always computable with assured accuracy. The system currently consists of a constellation of eight satellites, with two additional satellites on ground as stand-by.

The constellation is in orbit as of 2018. NavIC will provide two levels of service, the "standard positioning service", which will be open for civilian use, and a "restricted service" (an encrypted one) for authorised users (including the military).

NavIC-based trackers are compulsory on commercial vehicles in India, and some consumer mobile phones with support for it have been available since the first half of 2020.

There are plans to expand the NavIC system by increasing its constellation size from 7 to 11.

The system was developed partly because access to foreign government-controlled global navigation satellite systems is not guaranteed in hostile situations, as happened to the Indian military in 1999 when the United States denied an Indian request for Global Positioning System (GPS) data for the Kargil region, which would have provided vital information. The Indian government approved the project in May 2006.

As part of the project, the Indian Space Research Organisation (ISRO) opened a new satellite navigation centre within the campus of ISRO Deep Space Network (DSN) at Byalalu, Karnataka on 28 May 2013. A network of 21 ranging stations located across the country will provide data for the orbital determination of the satellites and monitoring of the navigation signal.

A goal of complete Indian control has been stated, with the space segment, ground segment and user receivers all being built in India. Its location in low latitudes facilitates coverage with low-inclination satellites. Three satellites will be in geostationary orbit over the Indian Ocean. Missile targeting could be an important military application for the constellation.

The total cost of the project was expected to be ₹14.2 billion (US$168 million), with the cost of the ground segment being ₹3 billion (US$35 million), each satellite costing ₹1.5 billion (US$18 million) and the PSLV-XL version rocket costing around ₹1.3 billion (US$15 million). The planned seven rockets would have involved an outlay of around ₹9.1 billion (US$108 million).