The Full Form of DRDL is‍ Defence Research and Development Laboratory.

Defence Research and Development Laboratory is a Missile System laboratory – under the Defence Research and Development Organisation – with thrust on design, development and flight evaluation of various types of Missile Systems for the Indian armed forces.

The Defense Research & Development Laboratory (DRDL) is India’s premier missile facility. India’s Ministry of Defence initially constituted the Special Weapons Development Team in 1958 to undertake the development of first-generation anti-tank missiles. In 1961, the group was expanded to form the DRDL. Although the DRDL was initially located on the campus of the Delhi Science Centre, it was shifted to Hyderabad in 1962. In the 1960’s, the DRDL was tasked with the design and development of an anti-tank missile for the Indian army. However, the effort was terminated in 1970 when the Indian government decided to manufacture the SSIIBI anti-tank missiles under license from France.

In the 1970s, the DRDL undertook two additional projects. The first, Project Valiant, involved the development of a long-range ballistic missile. The second, Project Devil, was aimed at reverse engineering the Soviet SA-2 surface-to-air missile. Both projects were considered failures and came to be viewed by India’s armed services and the government as competence-building exercises. Project Valiant was terminated in 1974; Project Devil ended in 1980. However, during the period 1972-80, the DRDL developed the infrastructure and facilities to undertake the design and development of missiles. The Indian government revived the missile program during the 1980’s under the rubric of the Integrated Guided Missile Development Program (IGMDP). The IGMDP was launched in 1983 with the objective of developing five missile systems simultaneously. These included:

• Trishul: short-range surface-to-air missile
• Akash: medium-range surface-to-air missile
• Nag: third-generation anti-tank guided missile
• Prithvi: short-range surface-to-surface missile
• Agni-I: intermediate-range surface-to-surface missile (technology demonstrator)