Vietnam is modernizing its S-300 surface-to-air missile system at A29 Factory , that was reported by defense-studies.blogspot.com.
The S-300 air defense missile systems will be upgraded at A29 Factory (Department of Engineering).  Company will repair the system and extend its service life. Currently has self-repair and upgrade different types of radars, including radars 36D6 of S-300PMU1.
Code-named SA-10 Grumble, the S-300PS has an operational range of 90km, and was introduced to the Soviet armed forces in 1985.
The system features 5V55R missiles, and is designed to lock in on a target following launch using an active detection system that steers the missile directly at the target.
Developed by NPO Almaz Bureau, the S-300 is a mobile, long-range air defence system designed to detect, track and destroy incoming cruise missiles, ballistic missiles and high and low-flying strike aircraft.
Different S-300 variants featuring different missiles and improved radars are currently operational with Algeria, Armenia, Azerbaijan, Bulgaria, China, Russia, Ukraine, Venezuela and Vietnam.
