Intrusion Detection Flashcards
What are classifications of intrusion sensors?
Passive or active,
Covert or visible,
Line-of-sight or terrain-following (exterior only),
Volumetric or line detection,
Application.
How do passive sensors work?
Passive sensors detect energy emitted by the object of interest or detect a target-caused changed in a natural field of energy. Both types use a receiver to collect energy emissions. May include those that detect vibration, heat, sound, or capacitance.
How do active sensors work?
Active sensors transmit energy and detect changes (caused by presence or motion) in the received energy. Typically contain both a transmitter and a receiver. Types include microwave, infrared, and other RF devices.
To work well, these sensors require a clear line of sight in the detection space between both the transmitter and receiver and to use such sensors where the terrain is not flat requires extensive site preparation.
Line of sight sensors
This type of sensor detects equally well on flat and irregular terrain. Transducer elements and a radiated field follow the terrain, creating uniform detection through the zone.
Terrain Following
This type of sensor generates an alarm when an intruder enters the detection volume.
Volumetric Sensor
This type of sensor detects motion along a line or when an intruder violates a particular entry point into a detection zone.
Line detection
3 types of Exterior Intrusion Sensor application
Buried line, fence associated, freestanding
Exterior Sensor that is active, covert, terrain-following, buried underground, and respond to the motion of material with a high dielectric constant or high conductivity, such as human bodies and metal vehicles.
Ported Coaxial Cable
Exterior Sensor that is passive, visible, terrain-following, usually installed on chain link fences, that can detect motion or shock.
Fence Disturbance Sensor
Exterior Sensor that is passive, visible, terrain-following, forming the fence out of transducer elements themselves Designed to detect climbing or cutting the fence.
Sensor Fences
Exterior Sensor that is active, visible, terrain-following design to detect a change in capacitive coupling among a set of wires attached to, but electrically isolated from, a fence.
Electric field or Capacitance
Exterior sensor that is active, visible, line of sight, freestanding, designed to transmit an IR beam collected in a lens that, if blocked by an opaque object, detects the reduction in IR energy.
Freestanding Infrared
Exterior sensor that is active, visible, line of sight, and freestanding, using 2 microwave antennas installed at opposite ends of the detection zone and responds to changes within the detection field (called the vector sum).
Bistatic Microwave Sensors
Exterior sensor designed for detection in a large outdoor, unobstructed open area, suitable for night time use and where rain and fog are a concern. It is considered volumetric as a result.
GBR (Ground Based Radar-Radio. Detection. And. Ranging.)
Exterior sensor that is passive, covert, line of sight, and produces video signals from the video surveillance system.
Video Motion Detectors
Examples of Buried Line Application
Ported Coaxial Cables
Examples of Fence Associated Application
Fence Disturbance Sensors, Sensor Fences, Fiber Fences, Electric Field or Capacitance
Examples of Freestanding Application
Freestanding Infrared Sensors, Bistatic Microwave Sensors, Ground Based Radar (GBR), (Light Imaging, Detection, and Ranging) LiDAR, VMDs (Video Motion Detection)
Where does a perimeter intrusion detection system perform the best?
In an isolated clear zone, usually used at high security facilities.
Examples of volumetric sensors?
Ultrasonic, microwave, passive infrared
Examples of interior sensor application?
Boundary-penetration sensors, Interior Motion, & Proximity Sensors
4 basic types of detection for interior motion detection
Trap detection-narrow or wide detection for high traffic areas or expected travel paths of an intruder to get from Point A to Point B.
Spot detection-detection on a particular object or high value area.
Channel detection-narrow detection in an area where an intruder is expected to cross.
Volumetric detection-wide or broad detection in a defined area.
Interior application group most commonly include vibration & electromechanical technologies. Vibration sensors are passive line sensors that can be visible or covert (examples include glassbreaks). EM sensors are passive, visible line sensors (includes simple switches or door/window contacts).
Boundary Penetration Sensors
