Complex sentence: The CRN-91 Naval gun is gyro stabilized and is directed by an electro-optic fire control system for day and night use, which have been developed and jointly produced by the Ordnance Factory Board (OFB) and Bharat Electronics Limited (BEL).
Split into simpler sentences: The CRN-91 Naval gun is gyro stabilized and is directed by an electro-optic fire control system (FCS) for day and night use. The FCS been developed and jointly produced by the Ordnance Factory Board (OFB) and Bharat Electronics Limited (BEL).