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Coyne James Christopher: Mole guidance system. January 23, 1973: US3712391 (50 worldwide citation)

A subterranean missile is equipped with three mutually orthogonal coils in its body and a fourth suitably fixed in an articulatable steering member. The missile is guided along any desired underground trajectory defined with reference to a coordinate system including the plane of a dipole-quadrupole ...


2
Coyne James C: Mole guidance system. Bell Telephone Laboratories Incorporated, June 29, 1971: US3589454 (45 worldwide citation)

A subterranean missile is equipped with three mutually orthogonal coils in its body and a fourth suitably fixed in an articulatable steering member. The missile is guided along any desired underground trajectory defined with reference to a coordinate system including the plane of a dipole-quadrupole ...


3