Subspace beacon

A subspace beacon was an omnidirectional repeating signal transmitted in the subspace realm.

A standard Starfleet combadge could be modified to emit a subspace beacon.

''In an alternate timeline, Kathryn Janeway activated the subspace beacon in her combadge when she and Tom Paris were thrown back in time on an unknown Class M planet. The senior staff of the USS Voyager used the beacon to locate and attempt to retrieve Janeway and Paris.''

Federation escape pods were equipped with subspace beacons, allowing personnel to track evacuating crew.