The term sensor, also referred to aboard starships as subspace sensors or sensor probes, is used to refer to any device which is used to scan, record, or otherwise observe any aspect of an environment surrounding a starship, space station, or person. This could be as simple a device as a manual camera or light sensor, or as complicated as the myriad devices designed to scan many aspects of the matter and energies of subspace, space, time and stellar bodies that make up all of existence.
There are two basic types of sensor arrays employed: passive and active. A passive scan is less obtrusive than an active scan, and may not be detected by the subject being sensed. Also, sensors may be divided into short and long range types.
Long-range sensors can pick up information about targets that were on occasion several hours travel time distant from the sensing ship. Short-range sensors seem to be restricted to a range consistent with the immediate environment of the sensing ship (the term "immediate" being relative), and are most often being used to scan the surface of planets from orbit or to target weapons fire.
There are many ways to mask a sensor scan, sensor screens are the most commonly used. One can also mask a sensor scan with certain materials, or radiation. But to truly hide from a sensor scan one would actually have to change one's molecular structure.
Galaxy-class starships were equipped with high-resolution, multi-spectro sensors.
PAS-37Q System Search Sensor (Phased Array)
An active EM search system that uses phased arrays of small sensor transceivers to create shapable swaths across any portion of the sky.
HSS-114D Hyper-Spectral Scanner (EO)
A hyper-spectral scanner that measures target reflections across a continuous spectrum. Suspected camouflaged or obscured targets can be tested with an active EM sensor to improve accuracy in high-threat environments.
AIS-117M Advanced Imaging Sensor (Synthetic Aperture/Moving Target Indicator)
A combined SA and MTI sensor package that can detect fixed and mobile targets, as well as fuse sensor tracks into a complete picture of the area of interest. The SA suite is also capable of interferometric image analysis, which allows the AI node to build a three-dimensional representation of visible surfaces to a one nanometer resolution at 24 light-seconds.
AIS-117I Advanced Imaging Sensor (Inverse Synthetic Aperture)
An ISA system that is capable of long-range detections of relatively stationary targets in high-noise environments.
ES/A-9R Electronic Support and Attack Measure Suite
Detects active sensor and communications emissions from hostile assets, including ships and missiles. The EA component of the package can be used to jam both types of signals, and in some cases to overload the hostile transceiver and destroy it.
Interphasic Scanner (also known as an IP scanner)
A device capable of revealing objects that are not perceptible by normal humanoid senses or standard scans. Using an IP scanner, you can detect things existing slightly out of phase with normal space.
Proximity Sensor
The proximity sensor is a sensor device that determines how close another object is. Proximity sensors are commonly used on mines, where they trigger the mine's detonation when it nears or impacts a target. A malfunction in a proximity sensor could cause the mine either to detonate prematurely or to not detonate at all
Tomographic Imaging Scanner
A tomographic imaging scanner was a device designed to function as a sensor. The scanner was capable of multiphasic resolution and could penetrate significant amounts of subspace interference.