Acceleration to 2019 of the deployment of Crowsnest airborne surveillance and control systems will lead to "a significant reduction in costs, as specialist industry personnel will be required for a shorter period of time," the ministry said.
Crowsnest, a high-power radar that is to provide long-range air, maritime and land tracking capabilities, will be an integral part of future carrier operations.
The system will be fitted to the Royal Navy's fleet of upgraded Merlin Mk2 helicopters, including those to be embarked on the Queen Elizabeth-class carriers.
Lockheed Martin UK designs the Merlin helicopter and has been given a $39.3 million contract to run a competition for the design, development and demonstration of the Crowsnest system
The decision to deploy the system 18 months ahead of schedule was made as part of the annual review of MOD's 10-year equipment plan and will save the navy an estimated $36.4 million, the Ministry of Defense said.
The first Queen Elizabeth-class carrier will begin sea trials in 2017 and is expected to reach operational capability in 2020.
"Crowsnest will provide vital surveillance and intelligence to protect the Queen Elizabeth Class aircraft carriers," Defense Secretary Philip Hammond said. "The introduction of Crowsnest 18 months early will ensure HMS Queen Elizabeth has the full range of capabilities when it enters service."