Sensor

Overview
The Ancients whilst in the Pegasus galaxy possessed 4 types of sensors.

Long Range
Long range sensors were used on ships to detect other vessels and planets.

City-ship
The sensors on city ships could scan massive distances, at least a quarter of a galaxy, and are the only ones known to be able to detect ships in hyperspace.

Standard
Thease were installed on Aurora class warships and other vessels of similar status. They are virtually identical to the Asgard varients.

Short Range
Short range sensors scanned in much more detail but at a far shorter range.

City-ship
City ships possessed sensors that could scan all life forms on a planets surface (and probably in orbit over the city,) and identify them. They could also create visual images based on the sensor data, which even the Asgard have not accomplished.

Hand Scanner
Thease could identify both walls and life forms, and energy sources. And could also scan for the Ancient Gene