Canada’s defence minister has announced a $548-million upgrade to four more of the country’s military surveillance planes, a project that will extend the life of the CP-140 Auroras into 2030.

The aircraft are already 30 years old. They will be refitted with new tails and wings, along with the latest surveillance equipment. The planes will also be equipped for the first time with the capability to defend against missile attack.

Defence Minister Rob Nicholson made the announcement Wednesday at 14 Wing Greenwood. He was joined by Peter MacKay, the regional minister for Nova Scotia.

The military has spent roughly $1.7 billion since 1998 on upgrading the sensors, surveillance gear and the wing support structures of 10 other Auroras.

The Auroras are used for overland and maritime surveillance, reconnaissance, and search and rescue. The Canadian Forces says the aircraft also help other government agencies fight illegal immigration, illegal fishing, pollution and drug trafficking.

Two Auroras were sent to Libya in 2011 as part of the NATO-led mission. They flew ahead of the CF-18s, which bombed the troops of then-Libyan leader Moammar Gadhafi.