Forgotten Perimeter Gateway

Forgotten Perimeter Gateway - Magnetometric
Class 2 Archaeology or Salvage Site
NPCs - Hostiles

First Encounter
Awakened Patroller x4 (Cruiser Class)
Awakened Watchman x1 (Cruiser Class - )

Killing the Awakened Watchman triggers another spawn.

First Wave
Emergent Watchman x2 (Frigate Class - )
Sleepless Patroller x1 (Battleship Class)

Killing the Sleepless Patroller triggers another spawn.

Second Wave
Emergent Patroller x4 (Frigate Class)
Sleepless Escort x1 (Battleship Class)
Sleepless Watchman x1 (Battleship Class)

(Source)