IRNSS-1B is the second satellite of India's NavIC navigation system. PSLV-C24 launched it in April 2014.
IRNSS-1B is one of the seven satellites that form the IRNSS space segment, now called NavIC. IRNSS-1B carries two payloads. The navigation payload broadcasts NavIC signals in the L5 and S bands, timed by a rubidium atomic clock. The ranging payload is a C-band transponder that lets ground stations measure the satellite's distance precisely. It also carries corner-cube retro-reflectors for laser ranging. You can see the NavIC fleet's estimated positions on the NavIC tracker.
IRNSS-1B weighed 1,432 kg at lift-off and copies the design of IRNSS-1A. ISRO built it in less than seven months after its predecessor's launch. Two solar panels supply about 1,660 W. A 440 N liquid apogee motor and twelve 22 N thrusters move the satellite, while reaction wheels, magnetic torquers and thrusters keep it pointed, using Sun sensors, star sensors and gyroscopes.
PSLV-C24, the twenty-sixth PSLV flight, launched it from the First Launch Pad at Sriharikota in April 2014, using the PSLV-XL version. Like IRNSS-1A, it works from an inclined geosynchronous orbit crossing the equator at 55° East, tilted 29°. GSAT-8, GSAT-16 and IRNSS-1A share the same 55° East longitude.
The public satellite catalogue carries IRNSS-1B with an operational flag.