It allows personnel to detect, track and photograph drones at a distance of more than 1km and up to 5km.
Whitehall sources said options for countering the threat included airports deploying their own drones, firing bazookas with projectiles that trapped them in nets, or deploying police with shotguns to shoot them down.
The military team was due to remain at Gatwick until the airport's own defence system was operational, possibly for the two weeks over Christmas.
Stewart Wingate, the chief executive of Gatwick, said: "We are equipping ourselves with capabilities to detect and defeat drones."
A Whitehall source said: "The first thing is to detect when a drone is coming in and having enough distance in which to do that. Second is being able to track the signal."
The Metis Skyperion technology, thought to be used by the military, deploys cameras, laser rangefinders, radar and radio frequency scanners to pinpoint the drone. To install a similar system at a major airport could cost up to £5 million ($9.4m), according to one expert.
To track the drone to its operator would require additional sensors that even the military has not deployed at Gatwick. Finding the culprit becomes easier if they remain in sight of their device.
Gatwick declined to reveal the measures it was considering to "defeat" or "disrupt" any further attacks. Police at Heathrow are testing a SkyWall 100 bazooka, a shoulder-launched weapon that fires a projectile containing a net.
"Some of the airports are putting up enhanced firearms capabilities, most are doing increased police patrols inside and outside," said a Whitehall source.
"Airports are also assessing and monitoring potential launch sites."
Legislation will be rushed through in the new year to enable electronic jamming by airports, bigger drone exclusion zones and new police powers.