The garrison, when finished, will provide accommodation for more than 3500 army personnel and 700 civilian staff. It ran into problems when the consortium was forced to resubmit a planning application in November 2002.
Enabling works are due to start this month and the main construction work should get under way next year. The scheme is due to be complete in 2008.
Atkins chief executive Keith Clarke expressed relief at the news. He said: "We began working on this project in 1997 – but we have completed some of the design and project service work to enable the project partner to make headway on construction."