Why is Indian Regional Navigational Satellite System (IRNSS) needed ? How does it help in navigation ?

Strategic autonomy

GPS, GLONASS, Galileo and BeiDou answer to their owners, so an encrypted Restricted Service lets India's forces navigate and guide weapons without foreign permission.

Disaster safety

Its messaging service can push cyclone and tsunami warnings to fishermen beyond mobile coverage.

Economy and timing

The AIS-140 vehicle-tracking standard builds in IRNSS receivers, and onboard atomic clocks give a national time reference for power grids, telecom and banking.

Ranging by time

Each satellite broadcasts its position and a time stamp; the receiver turns travel time into distance and, with four satellites, fixes its location and clock error.

Favourable geometry

Three geostationary and four inclined geosynchronous satellites stay constantly visible over India, supporting a designed accuracy better than 20 metres.

Dual-frequency correction

Using both L5 and S bands lets receivers remove ionospheric delay, a large error at low latitudes, while the ISRO Navigation Centre at Byalalu uploads orbit and clock corrections.