There is something called: http://en.wikipedia.org/wiki/Inertial_navigation_system http://en.wikipedia.org/wiki/Inertial_navigation_system Not very accurate bu

There is something called: http://en.wikipedia.org/wiki/Inertial_navigation_system http://en.wikipedia.org/wiki/Inertial_navigation_system Not very accurate but should provide enough guidance for the plane to get out of hostile territory.