HC Deb 23 March 1988 vol 130 c136W
Mr. Cohen

To ask the Secretary of State for Defence what guidance or position locating systems are to be used by the Vanguard class submarines or their Trident missiles.

Mr. Sainsbury

Vanguard class SSBNs will be equipped with an electrostatically supported gyro navigator (ESGN), a gravity sensing system (GSS) and a range of radio and sonar navigational aids. The Trident D5 missile has a stellar aided inertial reference navigational system.