UFC 4-021-02NF
27 September 2006
change 1, 23 October 2006
Table 5-3. False Alarm Causes--Exterior IDS Sensors
Sensor Type
False Alarm Cause
Notes
Animals
Fencing mitigates animal false
Active Infrared
alarms
Wind-blown debris
Reflected light
Not recommended
Passive Infrared (PIR)
Radiated heat
Nearby movement outside IDS
Use of dual-technology PIR
Microwave
area
minimizes false alarms
Same as PIR and microwave
Good choice. Uses both
Dual Technology
microwave and PIR
Railroads--trains
Only works well in low
Vibration
background vibration areas
Roadways--vehicles
Runways--airplanes
Rock quarries--explosions
Seismic event
Wind flexing fence
Temperamental
Coaxial Strain-Sensitive
EMI
Improper noise level adjustment
Recommended technology,
Fiber-Optic
provided suitable fence-mount is
Animal activity
provided and animals are
excluded from the area
Ground shifting due to standing
Varying terrain or material
Buried Cable
or puddling water, or erosion.
composition (asphalt pavement
to grass to gravel) requires
adjusting sensitivity to match
each material
EMI
Very susceptible to EMI from
Ported Cable
large electrical equipment or
Movement of nearby vehicles or
substations and should not be
medium to large animals
used near these installations
Congregation of small animals.
Camera vibration.
Good camera mounting mitigates
Video Content Analysis
camera vibration issues.
Normal operational
Motion Path Analysis
personnel/vehicular movement.
Advanced programming can filter
out false alarms from animals,
Lightning flashes.
rain, snow, birds, waves and so
forth.
Video content analysis works
best in a relatively stable video
environment. For example, video
content analysis works better in a
flat desert environment than a
volatile meteorological such as
windy, rainy or foggy location.
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