The lead centre of ISRO for launch vehicle technology, at Trivandrum in Kerala
Background
The Vikram Sarabhai Space Centre is described by ISRO as the lead centre of ISRO responsible for the design and development of launch vehicle technology. Its address is given as Trivandrum - 695022, in Kerala, India. The Centre works in areas such as propulsion, avionics and structures. ISRO names among its major programmes the Polar Satellite Launch Vehicle (PSLV), the Geosynchronous Satellite Launch Vehicle (GSLV) and the Rohini Sounding Rockets, and lists Reusable Launch Vehicles among its development work. It is therefore the centre where India's launch vehicles are designed, as distinct from the centres that build satellites or operate launches.
In plain words
PSLV Polar Satellite Launch Vehicle — ISRO's workhorse launch vehicle, named on the Centre's own page.
GSLV Geosynchronous Satellite Launch Vehicle — ISRO's launch vehicle for heavier satellites placed in geosynchronous orbits.
Avionics Avionics — The electronic systems that guide and control a rocket or aircraft.