The Biometric sensors are a type of sensors that not only detect Life Signs, in addition, are capable of differentiate bewtwen life signs of different races, like Goa'uld and human, etc.
Only two races are seen capable of this feat.
Atlantis Biometric Sensor ArrayEdit
The biometric sensor array is a console found in Atlantis that was moved to Stargate Operations by the Atlantis expedition in their first year. The console activates the internal (and external) sensors and is able to locate and differentiate between life forms. The console was activated after being touched by Chaya Sar (who was an Ancient) which led Dr. Rodney McKay to believe she was not who she claimed to be (SGA: "Sanctuary"). Later that year the device was used to locate a Wraith hiding in the city. (SGA: "The Siege, Part 1")
It is unknown is other Ancient ships possessed that type of sensors, but in known that the Ancient Warships do not possessed them.
Asgard Biometric SensorsEdit
The asgard possesses biometric sensors capable of distinguish human/Goa'uld even from the orbit in all his ships, and in his lab of the Adara System.