Osterhagen Station 1 was a UNIT run station located in an abandoned fort 60 miles out of Nuremberg, Germany.
During the Dalek Invasion of Earth in 2009, Martha Jones was given the Osterhagen key by General Sanchez before he was exterminated by the Daleks. The Osterhagen Station would activate 25 Nuclear warheads under the earth's crust destroying the earth. Martha transported to this station and made contact with two other stations in China and Liberia.
Martha contacted the Dalek Crucible threatening to use the Osterhagen key but was transmatted out of the station before she could use it. Later when returning her back to earth the Doctor told her to get rid of the key so presumably the remaining stations were abandoned or destroyed. (DW: The Stolen Earth / Journey's End)