Radar

Provides a percent chance for opponents to face one of your turrets in PvP. Each turret increases the detection chance rate by 5%, up to 30% if you have built six turrets. The constructed Radar increases the detection chance rate by extra 20%. A shield can be activated for 48hrs by paying 6 medals to double detection rate up to 100%.

TODO What is to be done to build the radar: The Radar can be build after researching he subsequent technology under "Tactics and Strategy" section for 500 points.

http://evo-wiki.com/buildings/radar/